1
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Li Z, Zheng Y, Ma H, Cui F. Microcystin-LR (MC-LR) inhibits green algae growth by regulating antioxidant and photosynthetic systems. HARMFUL ALGAE 2024; 134:102623. [PMID: 38705613 DOI: 10.1016/j.hal.2024.102623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 03/07/2024] [Accepted: 03/27/2024] [Indexed: 05/07/2024]
Abstract
Microcystins release from bloom-forming cyanobacteria is considered a way to gain competitive advantage in Microcystis populations, which threaten water resources security and aquatic ecological balance. However, the effects of microcystins on microalgae are still largely unclear. Through simulated culture experiments and the use of UHPLC-MS-based metabolomics, the effects of two microcystin-LR (MC-LR) concentrations (400 and 1,600 μg/L) on the growth and antioxidant properties of three algae species, the toxic Microcystis aeruginosa, a non-toxic Microcystis sp., and Chlorella vulgaris, were studied. The MC-LR caused damage to the photosynthetic system and activated the protective mechanism of the photosynthetic system by decreasing the chlorophyll-a and carotenoid concentrations. Microcystins triggered oxidative stress in C. vulgaris, which was the most sensitive algae species studied, and secreted more glycolipids into the extracellular compartment, thereby destroying its cell structure. However, C. vulgaris eliminated reactive oxygen species (ROS) by secreting terpenoids, thereby resisting oxidative stress. In addition, two metabolic pathways, the vitamin B6 and the sphingolipid pathways, of C. vulgaris were significantly disturbed by microcystins, contributing to cell membrane and mitochondrial damage. Thus, both the low (400 μg/L) and the high (1,600 μg/L) MC-LR concentration inhibited algae growth within 3 to 7 days, and the inhibition rates increased with the increase in the MC-LR concentration. The above results indicate that the toxin-producing Microcystis species have a stronger toxin tolerance under longer-term toxin exposure in natural water environments. Thus, microcystins participates in interspecific interaction and phytoplankton population regulation and creates suitable conditions for the toxin-producing M. aeruginosa to become the dominant species in algae blooms.
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Affiliation(s)
- Zhe Li
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Yun Zheng
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; CSCEC SCIMEE Sci. & Tech. Co., Ltd., Chengdu 610045, China
| | - Hua Ma
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
| | - Fuyi Cui
- College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
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2
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Caen A, Mathias JD, Latour D. How do seasonal temperature variations influence interplay between toxic and non-toxic cyanobacterial blooms? Evidence from modeling and experimental data. HARMFUL ALGAE 2024; 134:102606. [PMID: 38705611 DOI: 10.1016/j.hal.2024.102606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/10/2024] [Accepted: 02/22/2024] [Indexed: 05/07/2024]
Abstract
Summer cyanobacterial blooms exhibit a dynamic interplay between toxic and non-toxic genotypes, significantly influencing the cyanotoxin levels within a lake. The challenge lies in accurately predicting these toxin concentrations due to the significant temporal fluctuations in the proportions of toxic and non-toxic genotypes. Typically, the toxic genotypes dominate during the early and late summer periods, while the non-toxic variants prevail in mid-summer. To dissect this phenomenon, we propose a model that accounts for the competitive interaction between toxic and non-toxic genotypes, as well as seasonal temperature variations. Our numerical simulations suggest that the optimal temperature of the toxic genotypes is lower than that of the optimal temperatures of the non-toxic counterparts. This difference of optimal temperature may potentially contribute to explain the dominance of toxic genotypes at the early and late summer periods, situation often observed in the field. Experimental data from the laboratory align qualitatively with our simulation results, enabling a better understanding of complex interplays between toxic and non-toxic cyanobacteria.
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Affiliation(s)
- Auguste Caen
- INRAE, UR MaIAGE, Domaine de Vilvert, JOUY-EN-JOSAS, 78352, France.
| | - Jean-Denis Mathias
- Université Clermont Auvergne, INRAE, UR LISC, 9 avenue Blaise Pascal - CS 20085, Aubiére, 63178, France.
| | - Delphine Latour
- Université Clermont Auvergne, LMGE, 1, Impasse Amélie Murat, Aubiére, 63178, France.
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3
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Piccini C, Martínez de la Escalera G, Segura AM, Croci C, Kruk C. The Microcystis-microbiome interactions: origins of the colonial lifestyle. FEMS Microbiol Ecol 2024; 100:fiae035. [PMID: 38499447 PMCID: PMC10996927 DOI: 10.1093/femsec/fiae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/21/2024] [Accepted: 03/16/2024] [Indexed: 03/20/2024] Open
Abstract
Species of the Microcystis genus are the most common bloom-forming toxic cyanobacteria worldwide. They belong to a clade of unicellular cyanobacteria whose ability to reach high biomasses during blooms is linked to the formation of colonies. Colonial lifestyle provides several advantages under stressing conditions of light intensity, ultraviolet light, toxic substances and grazing. The progression from a single-celled organism to multicellularity in Microcystis has usually been interpreted as individual phenotypic responses of the cyanobacterial cells to the environment. Here, we synthesize current knowledge about Microcystis colonial lifestyle and its role in the organism ecology. We then briefly review the available information on Microcystis microbiome and propose that changes leading from single cells to colonies are the consequence of specific and tightly regulated signals between the cyanobacterium and its microbiome through a biofilm-like mechanism. The resulting colony is a multi-specific community of interdependent microorganisms.
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Affiliation(s)
- Claudia Piccini
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Gabriela Martínez de la Escalera
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Angel M Segura
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
| | - Carolina Croci
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Carla Kruk
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
- Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República. Iguá 4225, Montevideo 11400, Uruguay
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4
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Harris TD, Reinl KL, Azarderakhsh M, Berger SA, Berman MC, Bizic M, Bhattacharya R, Burnet SH, Cianci-Gaskill JA, Domis LNDS, Elfferich I, Ger KA, Grossart HPF, Ibelings BW, Ionescu D, Kouhanestani ZM, Mauch J, McElarney YR, Nava V, North RL, Ogashawara I, Paule-Mercado MCA, Soria-Píriz S, Sun X, Trout-Haney JV, Weyhenmeyer GA, Yokota K, Zhan Q. What makes a cyanobacterial bloom disappear? A review of the abiotic and biotic cyanobacterial bloom loss factors. HARMFUL ALGAE 2024; 133:102599. [PMID: 38485445 DOI: 10.1016/j.hal.2024.102599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 03/19/2024]
Abstract
Cyanobacterial blooms present substantial challenges to managers and threaten ecological and public health. Although the majority of cyanobacterial bloom research and management focuses on factors that control bloom initiation, duration, toxicity, and geographical extent, relatively little research focuses on the role of loss processes in blooms and how these processes are regulated. Here, we define a loss process in terms of population dynamics as any process that removes cells from a population, thereby decelerating or reducing the development and extent of blooms. We review abiotic (e.g., hydraulic flushing and oxidative stress/UV light) and biotic factors (e.g., allelopathic compounds, infections, grazing, and resting cells/programmed cell death) known to govern bloom loss. We found that the dominant loss processes depend on several system specific factors including cyanobacterial genera-specific traits, in situ physicochemical conditions, and the microbial, phytoplankton, and consumer community composition. We also address loss processes in the context of bloom management and discuss perspectives and challenges in predicting how a changing climate may directly and indirectly affect loss processes on blooms. A deeper understanding of bloom loss processes and their underlying mechanisms may help to mitigate the negative consequences of cyanobacterial blooms and improve current management strategies.
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Affiliation(s)
- Ted D Harris
- Kansas Biological Survey and Center for Ecological Research, University of Kansas, 2101 Constant Ave., Lawrence, KS, 66047
| | - Kaitlin L Reinl
- Lake Superior National Estuarine Research Reserve, University of Wisconsin - Madison Division of Extension, 14 Marina Dr, Superior, WI 54880
| | - Marzi Azarderakhsh
- Department of Construction and Civil Engineering, New York City College of Technology, 300 Jay Street, New York, NY 11201
| | - Stella A Berger
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Zur alten Fischerhütte 2, 16775 Stechlin, Germany
| | - Manuel Castro Berman
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180 and Darrin Freshwater Institute, Rensselaer Polytechnic Institute, Bolton Landing, NY, 12814
| | - Mina Bizic
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Zur alten Fischerhütte 2, 16775 Stechlin, Germany
| | - Ruchi Bhattacharya
- Department of Biological, Geological & Environmental Sciences, Cleveland State University, Cleveland, OH 44115
| | - Sarah H Burnet
- University of Idaho, Fish and Wildlife Sciences, Moscow, ID, USA, 83844
| | - Jacob A Cianci-Gaskill
- Old Woman Creek National Estuarine Research Reserve, Ohio Department of Natural Resources, 2514 Cleveland Rd East, Huron, OH 44839
| | - Lisette N de Senerpont Domis
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6708 PB Wageningen, The Netherlands; Department of Water Resources and Pervasive Systems Group, faculty of EEMCS and ITC, University of Twente, The Netherlands
| | - Inge Elfferich
- Cardiff University, Earth and Environmental Sciences, Main Building, Park Place CF10 3AT, Cardiff, UK
| | - K Ali Ger
- Department of Ecology, Center for Biosciences, Universidade Federal do Rio Grande do Norte, R. das Biociencias, Lagoa Nova, Natal, RN, 59078-970, Brazil
| | - Hans-Peter F Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Zur alten Fischerhütte 2, 16775 Stechlin, Germany; Potsdam University, Institute of Biochemistry and Biology, Maulbeeralle 2, 14469 Potsdam, Germany
| | - Bas W Ibelings
- Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, 66 Blvd Carl Vogt, 1205, Geneva, Switzerland
| | - Danny Ionescu
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Zur alten Fischerhütte 2, 16775 Stechlin, Germany
| | - Zohreh Mazaheri Kouhanestani
- School of Natural Resources, University of Missouri-Columbia, Anheuser-Busch Natural Resources Building, Columbia, MO, 65211-7220
| | - Jonas Mauch
- Department of Community and Ecosystem Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany
| | - Yvonne R McElarney
- Fisheries and Aquatic Ecosystems, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - Veronica Nava
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, MI, Italy.
| | - Rebecca L North
- School of Natural Resources, University of Missouri-Columbia, Anheuser-Busch Natural Resources Building, Columbia, MO, 65211-7220
| | - Igor Ogashawara
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Zur alten Fischerhütte 2, 16775 Stechlin, Germany
| | - Ma Cristina A Paule-Mercado
- Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, Na Sádkách 7, České Budějovice 370 05, Czech Republic
| | - Sara Soria-Píriz
- Département des sciences biologiques, Université du Québec à Montréal, 141 Av. du Président-Kennedy, Montréal, QC H2 × 1Y4, Montréal, QC, Canada
| | - Xinyu Sun
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | | | - Gesa A Weyhenmeyer
- Department of Ecology and Genetics/Limnology, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Kiyoko Yokota
- Biology Department, State University of New York at Oneonta, Oneonta, NY 13820, USA
| | - Qing Zhan
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6708 PB Wageningen, The Netherlands
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5
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Jiang J, Zeng J, Wang J, Zuo J, Wei N, Song L, Shan K, Gan N. Changes in CO 2 concentration drive a succession of toxic and non-toxic strains of Microcystis blooms. WATER RESEARCH 2024; 250:121056. [PMID: 38171175 DOI: 10.1016/j.watres.2023.121056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/30/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024]
Abstract
The dynamic changes between toxic and non-toxic strains of Microcystis blooms have always been a hot topic. Previous studies have found that low CO2 favors toxic strains, but how changing dissolved CO2 (CO2 [aq]) in water body influences the succession of toxic and non-toxic strains in Microcystis blooms remains uncertain. Here, we combined laboratory competition experiments, field observations, and a machine learning model to reveal the links between CO2 changes and the succession. Laboratory experiments showed that under low CO2 conditions (100-150 ppm), the toxic strains could make better use of CO2 (aq) and be dominant. The non-toxic strains demonstrated a growth advantage as CO2 concentration increased (400-1000 ppm). Field observations from June to November in Lake Taihu showed that the percentage of toxic strains increased as CO2 (aq) decreased. Machine learning highlighted links between the inorganic carbon concentration and the proportion of advantageous strains. Our findings provide new insights for cyanoHABs prediction and prevention.
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Affiliation(s)
- Jingyu Jiang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,; University of Chinese Academy of Sciences, Beijing, China
| | - Jiaying Zeng
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,; University of Chinese Academy of Sciences, Beijing, China
| | - Jingkai Wang
- University of Chinese Academy of Sciences, Beijing, China,; Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Jun Zuo
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Institute for Eco-Environmental Research of Sanyang Wetland, Wenzhou University, Wenzhou 325035, China
| | - Nian Wei
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Lirong Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,; University of Chinese Academy of Sciences, Beijing, China
| | - Kun Shan
- University of Chinese Academy of Sciences, Beijing, China,; Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China,.
| | - Nanqin Gan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,; University of Chinese Academy of Sciences, Beijing, China,.
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6
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Stark GF, Truchon AR, Dittmann E, Wilhelm SW. Closed circular genome sequence of a Microcystis aeruginosa PCC7806 Δ mcyB (UTK) non-toxic mutant. Microbiol Resour Announc 2023; 12:e0070023. [PMID: 37855595 PMCID: PMC10652910 DOI: 10.1128/mra.00700-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/14/2023] [Indexed: 10/20/2023] Open
Abstract
Here we report the complete, closed genome of the non-toxic Microcystis aeruginosa PCC7806 ΔmcyB mutant strain. This genome is 5,103,923 bp long, with a GC content of 42.07%. Compared to the published wild-type genome (Microcystis aeruginosa PCC7806SL), there is evidence of accumulated mutations beyond the inserted chloramphenicol resistance marker.
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Affiliation(s)
- Gwendolyn F. Stark
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, Tennessee, USA
| | - Alexander R. Truchon
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, Tennessee, USA
| | - Elke Dittmann
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Steven W. Wilhelm
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, Tennessee, USA
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7
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Microcystin aids in cold temperature acclimation: Differences between a toxic Microcystis wildtype and non-toxic mutant. HARMFUL ALGAE 2023; 129:102531. [PMID: 37951605 PMCID: PMC10640677 DOI: 10.1016/j.hal.2023.102531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 11/14/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26 °C to 19 °C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, reactive oxygen species damage, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19 °C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA.
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8
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D'ors A, Sánchez-Fortún A, Cortés-Téllez AA, Fajardo C, Mengs G, Nande M, Martín C, Costa G, Martín M, Bartolomé MC, Sánchez-Fortún S. Adverse effects of iron-based nanoparticles on freshwater phytoplankton Scenedesmus armatus and Microcystis aeruginosa strains. CHEMOSPHERE 2023; 339:139710. [PMID: 37532199 DOI: 10.1016/j.chemosphere.2023.139710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023]
Abstract
Zero-valent nano-iron particles (nZVI) are increasingly present in freshwater aquatic environments due to their numerous applications in environmental remediation. However, despite the broad benefits associated with the use and development of nZVI nanoparticles, the potential risks of introducing them into the aquatic environment need to be considered. Special attention should be focused on primary producer organisms, the basal trophic level, whose impact affects the rest of the food web. Although there are numerous acute studies on the acute effects of these nanoparticles on photosynthetic primary producers, few studies focus on long-term exposures. The present study aimed at assessing the effects of nZVI on growth rate, photosynthesis activity, and reactive oxygen activity (ROS) on the freshwater green algae Scenedesmus armatus and the cyanobacteria Microcystis aeruginosa. Moreover, microcystin production was also evaluated. These parameters were assessed on both organisms singly exposed to 72 h-effective nZVI concentration for 10% maximal response for 28 days. The results showed that the cell growth rate of S. armatus was initially significantly altered and progressively reached control-like values at 28 days post-exposure, while M. aeruginosa did not show any significant difference concerning control values at any time. In both strains dark respiration (R) increased, unlike net photosynthesis (Pn), while gross photosynthesis (Pg) only slightly increased at 7 days of exposure and then became equal to control values at 28 days of exposure. The nZVI nanoparticles generated ROS progressively during the 28 days of exposure in both strains, although their formation was significantly higher on green algae than on cyanobacteria. These data can provide additional information to further investigate the potential risks of nZVI and ultimately help decision-makers make better informed decisions regarding the use of nZVI for environmental remediation.
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Affiliation(s)
- A D'ors
- Dpt. of Pharmacology and Toxicology, Universidad Complutense de Madrid (UCM), w/n Puerta de Hierro Ave, 28040, Madrid, Spain
| | - A Sánchez-Fortún
- Dpt. of Pharmacology and Toxicology, Universidad Complutense de Madrid (UCM), w/n Puerta de Hierro Ave, 28040, Madrid, Spain
| | - A A Cortés-Téllez
- Environmental Toxicology Laboratory, Faculty of Chemistry-Pharmacobiology, Universidad Michoacana de San Nicolás de Hidalgo, 403 Santiago Tapia St, 58000, Morelia, (Michoacán), Mexico
| | - C Fajardo
- Dpt. of Biomedicine and Biotechnology, Universidad de Alcalá (UAH), w/n San Diego Sq, 28801, Alcalá de Henares, Spain
| | - G Mengs
- Technical and R&D Department, Ecotoxilab SL, 10 Juan XXIII, 28550, Tielmes, Spain
| | - M Nande
- Dpt. of Biochemistry and Molecular Biology, Complutense University, w/n Puerta de Hierro Ave, 28040, Madrid, Spain
| | - C Martín
- Dpt. of Biotechnology-Plant Biology, Universidad Politécnica de Madrid (UPM), 3 Complutense Ave, 28040, Madrid, Spain
| | - G Costa
- Department of Animal Physiology, Faculty of Veterinary Sciences, Complutense University, w/n Puerta de Hierro Ave, 28040, Madrid, Spain
| | - M Martín
- Dpt. of Biochemistry and Molecular Biology, Complutense University, w/n Puerta de Hierro Ave, 28040, Madrid, Spain
| | - M C Bartolomé
- Environmental Toxicology Laboratory, Faculty of Chemistry-Pharmacobiology, Universidad Michoacana de San Nicolás de Hidalgo, 403 Santiago Tapia St, 58000, Morelia, (Michoacán), Mexico.
| | - S Sánchez-Fortún
- Dpt. of Pharmacology and Toxicology, Universidad Complutense de Madrid (UCM), w/n Puerta de Hierro Ave, 28040, Madrid, Spain.
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9
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Qin H, Sandrini G, Piel T, Slot PC, Huisman J, Visser PM. The harmful cyanobacterium Microcystis aeruginosa PCC7806 is more resistant to hydrogen peroxide at elevated CO 2. HARMFUL ALGAE 2023; 128:102482. [PMID: 37714576 DOI: 10.1016/j.hal.2023.102482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 09/17/2023]
Abstract
Rising atmospheric CO2 can intensify harmful cyanobacterial blooms in eutrophic lakes. Worldwide, these blooms are an increasing environmental concern. Low concentrations of hydrogen peroxide (H2O2) have been proposed as a short-term but eco-friendly approach to selectively mitigate cyanobacterial blooms. However, sensitivity of cyanobacteria to H2O2 can vary depending on the available resources. To find out how cyanobacteria respond to H2O2 under elevated CO2, Microcystis aeruginosa PCC 7806 was cultured in chemostats with nutrient-replete medium under C-limiting and C-replete conditions (150 ppm and 1500 ppm CO2, respectively). Microcystis chemostats exposed to high CO2 showed higher cell densities, biovolumes, and microcystin contents, but a lower photosynthetic efficiency and pH compared to the cultures grown under low CO2. Subsamples of the chemostats were treated with different concentrations of H2O2 (0-10 mg·L-1 H2O2) in batch cultures under two different light intensities (15 and 100 μmol photons m-2·s-1) and the response in photosynthetic vitality was monitored during 24 h. Results showed that Microcystis was more resistant to H2O2 at elevated CO2 than under carbon-limited conditions. Both low and high CO2-adapted cells were more sensitive to H2O2 at high light than at low light. Microcystins (MCs) leaked out of the cells of cultures exposed to 2-10 mg·L-1 H2O2, while the sum of intra- and extracellular MCs decreased. Although both H2O2 and CO2 concentrations in lakes vary in response to many factors, these results imply that it may become more difficult to suppress cyanobacterial blooms in eutrophic lakes when atmospheric CO2 concentrations continue to rise.
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Affiliation(s)
- Hongjie Qin
- Guangdong Provincial Key Lab of Ornamental Plant Germplasm Innovation and Utilization, Environmental Horticulture Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Department of Technology & Sources, Evides Water Company, Rotterdam, The Netherlands
| | - Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Pieter C Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands.
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10
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Lai C, Ma Z, Liu Z, Sun H, Yu Q, Xia F, He X, Bao Q, Han Y, Liu X, He H. Alleviating eutrophication by reducing the abundance of Cyanophyta due to dissolved inorganic carbon fertilization: Insights from Erhai Lake, China. J Environ Sci (China) 2023; 131:68-83. [PMID: 37225382 DOI: 10.1016/j.jes.2022.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 05/26/2023]
Abstract
The eutrophication of lakes is a global environmental problem. Regulating nitrogen (N) and phosphorus (P) on phytoplankton is considered to be the most important basis of lake eutrophication management. Therefore, the effects of dissolved inorganic carbon (DIC) on phytoplankton and its role in mitigating lake eutrophication have often been overlooked. In this study, the relationships between phytoplankton and DIC concentrations, carbon isotopic composition, nutrients (N and P), and hydrochemistry in the Erhai Lake (a karst lake) were investigated. The results showed that when the dissolved carbon dioxide (CO2(aq)) concentrations in the water were higher than 15 µmol/L, the productivity of phytoplankton was controlled by the concentrations of TP and TN, especially by that of TP. When the N and P were sufficient and the CO2(aq) concentrations were lower than 15 µmol/L, the phytoplankton productivity was controlled by the concentrations of TP and DIC, especially by that of DIC. Additionally, DIC significantly affected the composition of the phytoplankton community in the lake (p<0.05). When the CO2(aq) concentrations were higher than 15 µmol/L, the relative abundance of Bacillariophyta and Chlorophyta was much higher than those of harmful Cyanophyta. Thus, high concentrations of CO2(aq) can inhibit harmful Cyanophyta blooms. During lake eutrophication, when controlling N and P, an appropriate increase in CO2(aq) concentrations by land-use changes or pumping of industrial CO2 into water may reduce the proportion of harmful Cyanophyta and promote the growth of Chlorophyta and Bacillariophyta, which may provide effectively assist in mitigating water quality deterioration in surface waters.
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Affiliation(s)
- Chaowei Lai
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Zhen Ma
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Hefei University, Hefei 230601, China
| | - Zaihua Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China.
| | - Hailong Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China
| | - Qingchun Yu
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Fan Xia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuejun He
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qian Bao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Sichuan Normal University Key Laboratory of Land Resources Evaluation and Monitoring in Southwest China of Ministry of Education, Chengdu 610066, China
| | - Yongqiang Han
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haibo He
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China
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11
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Roy S, Guljamow A, Dittmann E. Impact of temperature on the temporal dynamics of microcystin in Microcystis aeruginosa PCC7806. Front Microbiol 2023; 14:1200816. [PMID: 37720143 PMCID: PMC10500830 DOI: 10.3389/fmicb.2023.1200816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/17/2023] [Indexed: 09/19/2023] Open
Abstract
Cyanobacterial blooms pose a serious threat to water quality and human health due to the production of the potent hepatotoxin microcystin. In microcystin-producing strains of the widespread genus Microcystis, the toxin is largely constitutively produced, but there are fluctuations between the cellular and extracellular pool and between free microcystin and protein-bound microcystin. Here we addressed the question of how different temperatures affect the growth and temporal dynamics of secondary metabolite production in the strain Microcystis aeruginosa PCC7806 and its microcystin-deficient ΔmcyB mutant. While the wild-type strain showed pronounced growth advantages at 20°C, 30°C, and 35°C, respectively, the ΔmcyB mutant was superior at 25°C. We further show that short-term incubations at 25°C-35°C result in lower amounts of freely soluble microcystin than incubations at 20°C and that microcystin congener ratios differ at the different temperatures. Subsequent assessment of the protein-bound microcystin pool by dot blot analysis and subcellular localization of microcystin using immunofluorescence microscopy showed re-localization of microcystin into the protein-bound pool combined with an enhanced condensation at the cytoplasmic membrane at temperatures above 25°C. This temperature threshold also applies to the condensate formation of the carbon-fixing enzyme RubisCO thereby likely contributing to reciprocal growth advantages of wild type and ΔmcyB mutant at 20°C and 25°C. We discuss these findings in the context of the environmental success of Microcystis at higher temperatures.
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Affiliation(s)
| | | | - Elke Dittmann
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
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12
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Cool temperature acclimation in toxigenic Microcystis aeruginosa PCC 7806 and its non-toxigenic mutant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555099. [PMID: 37693631 PMCID: PMC10491114 DOI: 10.1101/2023.08.28.555099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26° C to 19° C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19° C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
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13
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Joosten ED, Hamelin J, Milferstedt K. Initial type and abundance of cyanobacteria determine morphotype development of phototrophic ecosystems. FEMS Microbiol Ecol 2023; 99:fiad099. [PMID: 37653452 DOI: 10.1093/femsec/fiad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/24/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023] Open
Abstract
Phototrophic aggregates containing filamentous cyanobacteria occur naturally, for example, as cryoconite on glaciers and microbialites in fresh or marine waters, but their formation is not fully understood. Laboratory models are now available to reproduce aggregation, that is, the formation of different morphotypes like hemispheroids, microbial mats or sphere-like aggregates we call photogranules. In the model, activated sludge as starting matrix is transformed into aggregates enclosed by a phototrophic layer of growing cyanobacteria. These cyanobacteria were either enriched from the matrix or we added them intentionally. We hypothesize that the resulting morphotype depends on the type and concentration of the added cyanobacteria. When cyanobacteria from mature photogranules were added to activated sludge, photogranulation was not observed, but microbial mats were formed. Photogranulation of sludge could be promoted when adding sufficient quantities of cyanobacterial strains that form clumps when grown as isolates. The cyanobacteria putatively responsible for photogranulation were undetectable or only present in low abundance in the final communities of photogranules, which were always dominated by mat-forming cyanobacteria. We suggest that, in a temporal succession, the ecosystem engineer initiating photogranulation eventually disappears, leaving behind its structural legacy. We conclude that understanding phototrophic aggregate formation requires considering the initial succession stages of the ecosystem development.
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Affiliation(s)
| | - Jérôme Hamelin
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, 11100, Narbonne, France
| | - Kim Milferstedt
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, 11100, Narbonne, France
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14
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Chatterjee S, More M. Cyanobacterial Harmful Algal Bloom Toxin Microcystin and Increased Vibrio Occurrence as Climate-Change-Induced Biological Co-Stressors: Exposure and Disease Outcomes via Their Interaction with Gut-Liver-Brain Axis. Toxins (Basel) 2023; 15:289. [PMID: 37104227 PMCID: PMC10144574 DOI: 10.3390/toxins15040289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/12/2023] [Accepted: 04/12/2023] [Indexed: 04/28/2023] Open
Abstract
The effects of global warming are not limited to rising global temperatures and have set in motion a complex chain of events contributing to climate change. A consequence of global warming and the resultant climate change is the rise in cyanobacterial harmful algal blooms (cyano-HABs) across the world, which pose a threat to public health, aquatic biodiversity, and the livelihood of communities that depend on these water systems, such as farmers and fishers. An increase in cyano-HABs and their intensity is associated with an increase in the leakage of cyanotoxins. Microcystins (MCs) are hepatotoxins produced by some cyanobacterial species, and their organ toxicology has been extensively studied. Recent mouse studies suggest that MCs can induce gut resistome changes. Opportunistic pathogens such as Vibrios are abundantly found in the same habitat as phytoplankton, such as cyanobacteria. Further, MCs can complicate human disorders such as heat stress, cardiovascular diseases, type II diabetes, and non-alcoholic fatty liver disease. Firstly, this review describes how climate change mediates the rise in cyanobacterial harmful algal blooms in freshwater, causing increased levels of MCs. In the later sections, we aim to untangle the ways in which MCs can impact various public health concerns, either solely or in combination with other factors resulting from climate change. In conclusion, this review helps researchers understand the multiple challenges brought forth by a changing climate and the complex relationships between microcystin, Vibrios, and various environmental factors and their effect on human health and disease.
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Affiliation(s)
- Saurabh Chatterjee
- Environmental Health and Disease Laboratory, Department of Environmental and Occupational Health, Program in Public Health, University of California–Irvine, Irvine, CA 92697, USA
- Toxicology Core, NIEHS Center for Oceans and Human Health on Climate Change Interactions, Department of Environmental and Occupational Health, Program in Public Health, University of California–Irvine, Irvine, CA 92697, USA
- Division of Infectious Disease, Department of Medicine, UCI School of Medicine, University of California–Irvine, Irvine, CA 92697, USA
| | - Madhura More
- Environmental Health and Disease Laboratory, Department of Environmental and Occupational Health, Program in Public Health, University of California–Irvine, Irvine, CA 92697, USA
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15
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Zhang Y, Whalen JK, Cai C, Shan K, Zhou H. Harmful cyanobacteria-diatom/dinoflagellate blooms and their cyanotoxins in freshwaters: A nonnegligible chronic health and ecological hazard. WATER RESEARCH 2023; 233:119807. [PMID: 36871382 DOI: 10.1016/j.watres.2023.119807] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/06/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Human and ecological health depends on the vitality of freshwater systems, but these are increasingly threatened by cyanotoxins released from harmful algal blooms (HABs). Periodic cyanotoxin production, although undesirable, may be tolerable when there is enough time for cyanotoxins to degrade and dissipate in the environment, but the year-round presence of these toxins will be a chronic health for humans and ecosystems. The purpose of this critical review is to document the seasonal shifts of algal species and their ecophysiological acclimatation to dynamic environmental conditions. We discuss how these conditions will create successive occurrences of algal blooms and the release of cyanotoxins into freshwater. We first review the most common cyanotoxins, and evaluate the multiple ecological roles and physiological functions of these toxins for algae. Then, the annual recurring patterns HABs are considered in the context of global change, which demonstrates the capacity for algal blooms to shift from seasonal to year-round growth regimes that are driven by abiotic and biotic factors, leading to chronic loading of freshwaters with cyanotoxins. At last, we illustrate the impacts of HABs on the environment by compiling four health issues and four ecology issues emanating from their presence in the that covers atmosphere, aquatic ecosystems and terrestrial ecosystems. Our study highlights the annual patterns of algal blooms, and proposes that a "perfect storm" of events is lurking that will cause the 'seasonal toxicity' to become a full-blown, 'chronic toxicity' in the context of the deterioration of HABs, highlighting a non-negligible chronic health and ecological hazard.
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Affiliation(s)
- Yanyan Zhang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China; Department of Natural Resource Science, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, QC H9×3V9, Canada; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, China.
| | - Joann K Whalen
- Department of Natural Resource Science, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, QC H9×3V9, Canada
| | - Chen Cai
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Kun Shan
- Chongqing Key Laboratory of Big Data and Intelligent Computing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China, CAS Key Lab on Reservoir Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Hongxu Zhou
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
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16
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Gao Y, Yang H, Li L, Gao X, Li M, Dong J, Zhang M, Zhang J, Li X, Lu Z, Burford MA. Higher resistance of a microcystin (MC)-producing cyanobacterium, Microcystis, to the submerged macrophyte Myriophyllum spicatum. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:63941-63952. [PMID: 37055695 DOI: 10.1007/s11356-023-26654-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/22/2023] [Indexed: 04/15/2023]
Abstract
Outbreaks of Microcystis blooms can affect growth of submerged plants, which in turn can inhibit cyanobacterial growth. Microcystin (MC)-producing and non-MC-producing Microcystis strains typically coexist in Microcystis-dominated blooms. However, the interaction between submerged plants and Microcystis at strain level is not clear. This study was aimed at assessing the effects of a submerged macrophyte Myriophyllum spicatum on one MC-producing versus one non-MC-producing strains of the cyanobacterium Microcystis using plant-Microcystis co-culture experiments. The impacts of Microcystis on M. spicatum were also examined. It showed that the MC-producing Microcystis strain had a higher resistance to negative impacts by the cocultured submerged plant M. spicatum than the non-MC-producing strain. By contrast, the plant M. spicatum was impacted more by the MC-producing Microcystis than the non-MC-producer. The associated bacterioplankton community was affected more by the MC-producing Microcystis than the cocultured M. spicatum. The MC cell quotas were significantly higher in the coculture treatment (the PM + treatment, p < 0.05), indicating that the production and release of MCs might be a key factor responsible for the reduced impact of M. spicatum. The higher concentrations of dissolved organic and reducing inorganic compounds might eventually exacerbate the recovering capacity of coexisting submerged plants. Overall, this study indicated that the capacity to produce MCs, as well as the density of Microcystis, should be taken into account when attempting to reestablish submerged vegetation to undertake remediation works.
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Affiliation(s)
- Yunni Gao
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Hui Yang
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Longfei Li
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Xiaofei Gao
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Mei Li
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Jing Dong
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Man Zhang
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Jingxiao Zhang
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China
| | - Xuejun Li
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China.
- Observation and Research Station On Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang, 474450, China.
| | - Zhiying Lu
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Michele A Burford
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, QLD, 4111, Australia
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17
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Litvinchuk LF, Sharov AN, Chernova EN, Smirnov VV, Berezina NA. Mutual links between microcystins-producing cyanobacteria and plankton community in clear and brown northern lakes. FOOD WEBS 2023. [DOI: 10.1016/j.fooweb.2023.e00279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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18
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Kramer BJ, Hem R, Gobler CJ. Elevated CO 2 significantly increases N 2 fixation, growth rates, and alters microcystin, anatoxin, and saxitoxin cell quotas in strains of the bloom-forming cyanobacteria, Dolichospermum. HARMFUL ALGAE 2022; 120:102354. [PMID: 36470609 DOI: 10.1016/j.hal.2022.102354] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/02/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
The effect of rising CO2 levels on cyanobacterial harmful algal blooms (CHABs) is an emerging concern, particularly within eutrophic ecosystems. While elevated pCO2 has been associated with enhanced growth rates of some cyanobacteria, few studies have explored the effect of CO2 and nitrogen availability on diazotrophic (N2-fixing) cyanobacteria that produce cyanotoxins. Here, the effects of elevated CO2 and fixed nitrogen (NO3-) availability on the growth rates, toxin production, and N2 fixation of microcystin, saxitoxin, and anatoxin-a - producing strains of the genus Dolichospermum were quantified. Growth rates of all Dolichospermum spp. were significantly increased by CO2 or both CO2 and NO3- with rates being highest in treatments with the highest levels of CO2 and NO3-for all strains. While NO3- suppressed N2 fixation, diazotrophy significantly increased when NO3--enriched Dolichospermum spp. were supplied with higher CO2 compared to cultures grown under lower CO2 levels. This suggests that diazotrophy will play an increasingly important role in N cycling in CO2-enriched, eutrophic lentic systems. NO3- significantly increased quotas of the N-rich cyanotoxins, microcystin and saxitoxin, at ambient and enriched CO2 levels, respectively. In contrast, elevated CO2 significantly decreased cell quotas of microcystin and saxitoxin, but significantly increased cell quotas of the N-poor cyanotoxin, anatoxin. N2 fixation was significantly negatively and positively correlated with quotas of N-rich and N-poor cyanotoxins, respectively. Findings suggest cellular quotas of N-rich toxins (microcystin and saxitoxin) may be significantly reduced, or cellular quotas of N-poor toxins (anatoxin) may be significantly enhanced, under elevated CO2 conditions during diazotrophic cyanobacterial blooms. Finally, in the future, ecosystems that experience combinations of excessive N loading and CO2 enrichment may become more prone to toxic blooms of Dolichospermum.
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Affiliation(s)
- Benjamin J Kramer
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Highway, Southampton, NY, United States, 11968
| | - Ronojoy Hem
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Highway, Southampton, NY, United States, 11968
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Highway, Southampton, NY, United States, 11968.
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19
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Huisman J, Dittmann E, Fastner J, Schuurmans JM, Scott JT, Van de Waal DB, Visser PM, Welker M, Chorus I. Comment on “Models predict planned phosphorus load reduction will make Lake Erie more toxic”. Science 2022; 378:eadd9959. [DOI: 10.1126/science.add9959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hellweger
et al
. (Reports, 27 May 2022, pp. 1001) predict that phosphorus limitation will increase concentrations of cyanobacterial toxins in lakes. However, several molecular, physiological, and ecological mechanisms assumed in their models are poorly supported or contradicted by other studies. We conclude that their take-home message that phosphorus load reduction will make Lake Erie more toxic is seriously flawed.
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Affiliation(s)
- Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, Netherlands
| | - Elke Dittmann
- Department of Microbiology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Jutta Fastner
- Department of Drinking Water and Swimming Pool Hygiene, German Environment Agency, Berlin, Germany
| | - J. Merijn Schuurmans
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, Netherlands
| | - J. Thad Scott
- Department of Biology, Center for Reservoir and Aquatic Systems Research, Baylor University, One Bear Place #97388, Waco, Texas, USA
| | - Dedmer B. Van de Waal
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, Netherlands
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Petra M. Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, Netherlands
| | | | - Ingrid Chorus
- Department of Drinking Water and Swimming Pool Hygiene, German Environment Agency, Berlin, Germany
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20
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Zhou QS, Gao Y, Hou JM, Wang T, Tang L. Preference of carbon absorption determines the competitive ability of algae along atmospheric CO 2 concentration. Ecol Evol 2022; 12:e9079. [PMID: 35845373 PMCID: PMC9274100 DOI: 10.1002/ece3.9079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/25/2022] [Accepted: 06/14/2022] [Indexed: 11/07/2022] Open
Abstract
Although many studies have focused on the effects of elevated atmospheric CO2 on algal growth, few of them have demonstrated how CO2 interacts with carbon absorption capacity to determine the algal competition at the population level. We conducted a pairwise competition experiment of Phormidium sp., Scenedesmus quadricauda, Chlorella vulgaris and Synedra ulna. The results showed that when the CO2 concentration increased from 400 to 760 ppm, the competitiveness of S. quadricauda increased, the competitiveness of Phormidium sp. and C. vulgaris decreased, and the competitiveness of S. ulna was always the lowest. We constructed a model to explore whether interspecific differences in affinity and flux rate for CO2 and HCO3 - could explain changes in competitiveness between algae species along the gradient of atmospheric CO2 concentration. Affinity and flux rates are the capture capacity and transport capacity of substrate respectively, and are inversely proportional to each other. The simulation results showed that, when the atmospheric CO2 concentration was low, species with high affinity for both CO2 and HCO3 - (HCHH) had the highest competitiveness, followed by the species with high affinity for CO2 and low affinity for HCO3 - (HCLH), the species with low affinity for CO2 and high affinity for HCO3 - (LCHH) and the species with low affinity for both CO2 and HCO3 - (LCLH); when the CO2 concentration was high, the species were ranked according to the competitive ability: LCHH > LCLH > HCHH > HCLH. Thus, low resource concentration is beneficial to the growth and reproduction of algae with high affinity. With the increase in atmospheric CO2 concentration, the competitive advantage changed from HCHH species to LCHH species. These results indicate the important species types contributing to water bloom under the background of increasing global atmospheric CO2, highlighting the importance of carbon absorption characteristics in understanding, predicting and regulating population dynamics and community composition of algae.
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Affiliation(s)
- Qing Shi Zhou
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of Technology Xi'an China
| | - Yang Gao
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Institute of Water Resources and Hydro-electric Engineering Xi'an University of Technology Xi'an China
| | - Jing Ming Hou
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of Technology Xi'an China
| | - Tian Wang
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of Technology Xi'an China
| | - Long Tang
- School of Human Settlements and Civil Engineering Xi'an Jiaotong University Xi'an China
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21
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Perceived Intensification in Harmful Algal Blooms Is a Wave of Cumulative Threat to the Aquatic Ecosystems. BIOLOGY 2022; 11:biology11060852. [PMID: 35741373 PMCID: PMC9220063 DOI: 10.3390/biology11060852] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/20/2022] [Accepted: 05/28/2022] [Indexed: 12/03/2022]
Abstract
Simple Summary Harmful algal blooms (HABs) are a serious threat to aquatic environments. The intensive expansion of HABs across the world is a warning signal of environmental deterioration. Global climatic change enforced variations in environmental factors causing stressed environments in aquatic ecosystems that favor the occurrence, distribution, and persistence of HABs. Perceived intensification in HABs increases toxin production, affecting the ecological quality as well as serious consequences on organisms including humans. This review outlines the causes and impacts of harmful algal blooms, including algal toxicity, grazing defense, management, control measures, emerging technologies, and their limitations for controlling HABs in aquatic ecosystems. Abstract Aquatic pollution is considered a major threat to sustainable development across the world, and deterioration of aquatic ecosystems is caused usually by harmful algal blooms (HABs). In recent times, HABs have gained attention from scientists to better understand these phenomena given that these blooms are increasing in intensity and distribution with considerable impacts on aquatic ecosystems. Many exogenous factors such as variations in climatic patterns, eutrophication, wind blowing, dust storms, and upwelling of water currents form these blooms. Globally, the HAB formation is increasing the toxicity in the natural water sources, ultimately leading the deleterious and hazardous effects on the aquatic fauna and flora. This review summarizes the types of HABs with their potential effects, toxicity, grazing defense, human health impacts, management, and control of these harmful entities. This review offers a systematic approach towards the understanding of HABs, eliciting to rethink the increasing threat caused by HABs in aquatic ecosystems across the world. Therefore, to mitigate this increasing threat to aquatic environments, advanced scientific research in ecology and environmental sciences should be prioritized.
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22
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Hellweger FL, Martin RM, Eigemann F, Smith DJ, Dick GJ, Wilhelm SW. Models predict planned phosphorus load reduction will make Lake Erie more toxic. Science 2022; 376:1001-1005. [PMID: 35617400 DOI: 10.1126/science.abm6791] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. We performed a large-scale meta-analysis including 103 papers and used it to develop a mechanistic, agent-based model of Microcystis growth and microcystin production. Simulations for Lake Erie suggest that the observed toxigenic-to-nontoxigenic strain succession during the 2014 Toledo drinking water crisis was controlled by different cellular oxidative stress mitigation strategies (protection by microcystin versus degradation by enzymes) and the different susceptibility of those mechanisms to nitrogen limitation. This model, as well as a simpler empirical one, predicts that the planned phosphorus load reduction will lower biomass but make nitrogen and light more available, which will increase toxin production, favor toxigenic cells, and increase toxin concentrations.
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Affiliation(s)
- Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Robbie M Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Falk Eigemann
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
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23
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Direct effects of elevated dissolved CO 2 can alter the life history of freshwater zooplankton. Sci Rep 2022; 12:6134. [PMID: 35414683 PMCID: PMC9005601 DOI: 10.1038/s41598-022-10094-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/01/2022] [Indexed: 11/25/2022] Open
Abstract
Dissolved CO2 levels (pCO2) are increasing in lentic freshwaters across the globe. Recent studies have shown that this will impact the nutritional quality of phytoplankton as primary producers. However, the extent to which freshwater zooplankton may also be directly affected remains unclear. We test this in three model species representative of the main functional groups of primary consumers in freshwaters; the water flea Daphnia magna, the seed shrimp Heterocypris incongruens and the rotifer Brachionus calyciflorus. We experimentally exposed individuals to three pCO2 levels (1,500; 25,500 and 83,000 ppm) to monitor changes in life history in response to current, elevated and extreme future pCO2 conditions in ponds and shallow lakes. All species had reduced survival under the extreme pCO2 treatment, but the water flea was most sensitive. Body size and reproduction were reduced at 25,500 ppm in the water flea and the seed shrimp and population growth was delayed in the rotifer. Overall, our results show that direct effects of pCO2 could impact the population dynamics of freshwater zooplankton. By differentially modulating the life history of functional groups of primary consumers, elevated pCO2 has the potential to change the evolutionary trajectories of populations as well as the ecological functioning of freshwater communities.
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24
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Bao Q, Liu Z, Zhao M, Hu Y, Li D, Han C, Zeng C, Chen B, Wei Y, Ma S, Wu Y, Zhang Y. Role of carbon and nutrient exports from different land uses in the aquatic carbon sequestration and eutrophication process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:151917. [PMID: 34826459 DOI: 10.1016/j.scitotenv.2021.151917] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 06/13/2023]
Abstract
The hydrochemical features affected by differing land uses play a key role in regulating both the primary production of aquatic photosynthetic organisms and the formation of autochthonous organic carbon (AOC); this impacts eutrophication and the global carbon cycle. In shallow water environments where phytoplankton and submerged plants coexist, the C-N-P limitations on the primary production of these aquatic organisms, and the mechanisms by which they promote the formation of AOC are poorly understood. In this study, over the hydrological year September 2018 to August 2019, a large-scale field simulation experiment at the Shawan Karst Test Site (SW China) with various types of land use was systematically conducted to investigate the C-N-P limitations on the primary production of phytoplankton and submerged plants. The results indicate that (1) phytoplankton are co-limited by nitrogen (N) and phosphorus (P) but with the N more important, while submerged plants are limited by carbon (C); (2) Chlorophyta and Bacillariophyta display a stronger competitive advantage than Cyanophyta in aqueous environments with high C but low N-P; (3) there is a seasonal difference in the contribution of phytoplankton and submerged plants to the formation of AOC, however, throughout the year, the contributions of phytoplankton (27%) and submerged plants biomass (28%) to AOC concentrations in the water were similar, combinedly accounting for approximately 17% of the formed AOC. It is concluded that natural restoration of vegetation, or injecting CO2 into water, which results in higher C but lower N-P loadings, may simultaneously help to mitigate eutrophication (with changes in biological structure and species) and increase C sequestration in surface waters.
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Affiliation(s)
- Qian Bao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China.
| | - Zaihua Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China; CAS Center for Excellence in Quaternary Science and Global Change, 710061 Xi'an, China.
| | - Min Zhao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China
| | - Yundi Hu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China
| | - Dong Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cuihong Han
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cheng Zeng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China
| | - Bo Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China
| | - Yu Wei
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network, CAS, Puding 562100, Guizhou, China
| | - Song Ma
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Wu
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yi Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China; Resources and Environmental Engineering, Guizhou Institute of Technology, Guiyang 550008, Guizhou, China
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25
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Genotyping and multivariate regression trees reveal ecological diversification within the Microcystis aeruginosa complex along a wide environmental gradient. Appl Environ Microbiol 2021; 88:e0147521. [PMID: 34818109 DOI: 10.1128/aem.01475-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Addressing the ecological and evolutionary processes underlying biodiversity patterns is essential to identify the mechanisms shaping community structure and function. In bacteria, the formation of new ecologically distinct populations (ecotypes) is proposed as one of the main drivers of diversification. New ecotypes arise when mutations in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, permitting their coexistence with the parental population. We previously reported the presence of microcystin-producing organisms of the Microcystis aeruginosa complex (toxic MAC) through an 800 km environmental gradient ranging from freshwater to estuarine-marine waters in South America. We hypothesize that the success of toxic MAC in such a gradient is due to the existence of very closely related populations that are ecologically distinct (ecotypes), each specialized to a specific arrangement of environmental variables. Here, we analyzed toxic MAC genetic diversity through qPCR and high-resolution melting analysis (HRMA) of a functional gene (mcyJ, microcystin synthetase cluster). We explored the variability of the mcyJ gene along the environmental gradient by multivariate classification and regression trees (mCART). Six groups of mcyJ genotypes were distinguished and associated with different combinations of water temperature, conductivity and turbidity. We propose that each mcyJ variant associated to a defined environmental condition is an ecotype (or species) whose relative abundances vary according to their fitness in the local environment. This mechanism would explain the success of toxic MAC in such a wide array of environmental conditions. Importance Organisms of the Microcystis aeruginosa Complex form harmful algal blooms (HABs) in nutrient-rich water bodies worldwide. MAC HABs are difficult to manage owing to the production of potent toxins (microcystins) that resist water treatment. Besides, the role of microcystins in the ecology of MAC organisms is still elusive, meaning that the environmental conditions driving the toxicity of the bloom are not clear. Furthermore, the lack of coherence between morphology-based and genomic-based species classification makes it difficult to draw sound conclusions about when and where each member species of the MAC will dominate the bloom. Here, we propose that the diversification process and success of toxic MAC in a wide range of waterbodies involves the generation of ecotypes, each specialized in a particular niche, whose relative abundance varies according to its fitness in the local environment. This knowledge can improve the generation of accurate prediction models of MAC growth and toxicity, helping to prevent human and animal intoxication.
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26
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Tee HS, Wood SA, Bouma-Gregson K, Lear G, Handley KM. Genome Streamlining, Plasticity, and Metabolic Versatility Distinguish Co-occurring Toxic and Nontoxic Cyanobacterial Strains of Microcoleus. mBio 2021; 12:e0223521. [PMID: 34700377 PMCID: PMC8546630 DOI: 10.1128/mbio.02235-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/20/2021] [Indexed: 01/21/2023] Open
Abstract
Harmful cyanobacterial bloom occurrences have increased worldwide due to climate change and eutrophication, causing nuisance and animal deaths. Species from the benthic cyanobacterial genus Microcoleus are ubiquitous and form thick mats in freshwater systems, such as rivers, that are sometimes toxic due to the production of potent neurotoxins (anatoxins). Anatoxin-producing (toxic) strains typically coexist with non-anatoxin-producing (nontoxic) strains in mats, although the reason for this is unclear. To determine the genetic mechanisms differentiating toxic and nontoxic Microcoleus, we sequenced and assembled genomes from 11 cultures and compared these to another 31 Microcoleus genomes. Average nucleotide identities (ANI) indicate that toxic and nontoxic strains are distinct species (ANI, <95%), and only 6% of genes are shared across all 42 genomes, suggesting a high level of genetic divergence among Microcoleus strains. Comparative genomics showed substantial genome streamlining in toxic strains and a potential dependency on external sources for thiamine and sucrose. Toxic and nontoxic strains are further differentiated by an additional set of putative nitrate transporter (nitrogen uptake) and cyanophycin (carbon and nitrogen storage) genes, respectively. These genes likely confer distinct competitive advantages based on nutrient availability and suggest nontoxic strains are more robust to nutrient fluctuations. Nontoxic strains also possess twice as many transposable elements, potentially facilitating greater genetic adaptation to environmental changes. Our results offer insights into the divergent evolution of Microcoleus strains and the potential for cooperative and competitive interactions that contribute to the co-occurrence of toxic and nontoxic species within mats. IMPORTANCE Microcoleus autumnalis, and closely related Microcoleus species, compose a geographically widespread group of freshwater benthic cyanobacteria. Canine deaths due to anatoxin-a poisoning, following exposure to toxic proliferations, have been reported globally. While Microcoleus proliferations are on the rise, the mechanisms underpinning competition between, or coexistence of, toxic and nontoxic strains are unknown. This study identifies substantial genetic differences between anatoxin-producing and non-anatoxin-producing strains, pointing to reduced metabolic flexibility in toxic strains, and potential dependence on cohabiting nontoxic strains. Results provide insights into the metabolic and evolutionary differences between toxic and nontoxic Microcoleus, which may assist in predicting and managing aquatic proliferations.
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Affiliation(s)
- Hwee Sze Tee
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | | | - Keith Bouma-Gregson
- U.S. Geological Survey, California Water Science Center, Sacramento, California, USA
| | - Gavin Lear
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Kim M. Handley
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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27
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Cyanobacteria and Cyanotoxins in a Changing Environment: Concepts, Controversies, Challenges. WATER 2021. [DOI: 10.3390/w13182463] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Concern is widely being published that the occurrence of toxic cyanobacteria is increasing in consequence of climate change and eutrophication, substantially threatening human health. Here, we review evidence and pertinent publications to explore in which types of waterbodies climate change is likely to exacerbate cyanobacterial blooms; whether controlling blooms and toxin concentrations requires a balanced approach of reducing not only the concentrations of phosphorus (P) but also those of nitrogen (N); how trophic and climatic changes affect health risks caused by toxic cyanobacteria. We propose the following for further discussion: (i) Climate change is likely to promote blooms in some waterbodies—not in those with low concentrations of P or N stringently limiting biomass, and more so in shallow than in stratified waterbodies. Particularly in the latter, it can work both ways—rendering conditions for cyanobacterial proliferation more favourable or less favourable. (ii) While N emissions to the environment need to be reduced for a number of reasons, controlling blooms can definitely be successful by reducing only P, provided concentrations of P can be brought down to levels sufficiently low to stringently limit biomass. Not the N:P ratio, but the absolute concentration of the limiting nutrient determines the maximum possible biomass of phytoplankton and thus of cyanobacteria. The absolute concentrations of N or P show which of the two nutrients is currently limiting biomass. N can be the nutrient of choice to reduce if achieving sufficiently low concentrations has chances of success. (iii) Where trophic and climate change cause longer, stronger and more frequent blooms, they increase risks of exposure, and health risks depend on the amount by which concentrations exceed those of current WHO cyanotoxin guideline values for the respective exposure situation. Where trophic change reduces phytoplankton biomass in the epilimnion, thus increasing transparency, cyanobacterial species composition may shift to those that reside on benthic surfaces or in the metalimnion, changing risks of exposure. We conclude that studying how environmental changes affect the genotype composition of cyanobacterial populations is a relatively new and exciting research field, holding promises for understanding the biological function of the wide range of metabolites found in cyanobacteria, of which only a small fraction is toxic to humans. Overall, management needs case-by-case assessments focusing on the impacts of environmental change on the respective waterbody, rather than generalisations.
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28
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Hu L, Shan K, Huang L, Li Y, Zhao L, Zhou Q, Song L. Environmental factors associated with cyanobacterial assemblages in a mesotrophic subtropical plateau lake: A focus on bloom toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 777:146052. [PMID: 33677307 DOI: 10.1016/j.scitotenv.2021.146052] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Harmful algal blooms caused by cyanobacteria have been increasing in frequency worldwide. However, the main environmental drivers of this change are often difficult to identify because of the effects of the interaction between eutrophication and climate change. Recently, filamentous N2-fixing cyanobacteria and non-diazotrophic Microcystis have been observed to be co-existing and undergoing succession in some eutrophic lakes. However, the succession patterns of dominant cyanobacteria and the factors driving this in mesotrophic lakes are not well understood. We hypothesized that the changes in cyanobacterial assemblages in mesotrophic lakes could result in a relatively high risks of toxic blooms, and that these changes are associated with the global climatic changes. We tested these hypotheses using data from the subtropical mesotrophic Lake Erhai. We found that the high spatiotemporal variability in the cyanobacterial community, and the increase in biomass were driven primarily by the growth of bloom-forming cyanobacterial taxa. Species-specific biomasses were related to a different environmental stressor; increases in dissolved organic carbon (DOC) concentrations were statistically associated with an increase of Microcystis biomass, whereas increases in surface water temperature favored higher biomass of Pseudanabaena at low transparency and high concentration of phosphorus. In addition, low nitrogen- to- phosphorus ratios were identified as potential determinants of the abundance of N2-fixing Dolichospermum. Furthermore, changes in the concentration of DOC, total nitrogen, pH and water transparency levels were found to affect the composition of Microcystis morphotypes and genotypes mostly. This study highlights that the toxic to non-toxic Microcystis ratio might increase with the water darkening and browning (which occurs in many subtropical plateau lakes). Lake management strategies, therefore, need to consider the toxicity of cyanobacterial assemblages in mesotrophic lakes over the intensity of the cyanobacterial blooms.
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Affiliation(s)
- Lili Hu
- Hunan Engineering Research Center of Aquatic Organism Resources and Environmental Ecology, College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde 415000, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Kun Shan
- Chongqing Key Laboratory of Big Data and Intelligent Computing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Licheng Huang
- Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Yunnan Research Academy of Eco-environmental Sciences, Kunming 650034, China
| | - Yuanrui Li
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, China
| | - Lei Zhao
- School of Information Science and Technology, Yunnan Normal University, Kunming 650500, China
| | - Qichao Zhou
- Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Yunnan Research Academy of Eco-environmental Sciences, Kunming 650034, China; Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, China.
| | - Lirong Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
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29
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Zhang J, Shi J, Chang X. A model of algal growth depending on nutrients and inorganic carbon in a poorly mixed water column. J Math Biol 2021; 83:15. [PMID: 34236498 DOI: 10.1007/s00285-021-01640-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 06/24/2021] [Accepted: 06/27/2021] [Indexed: 11/25/2022]
Abstract
A reaction-diffusion-advection model is proposed to describe the growth of algae depending on both nutrients and inorganic carbon in a poorly mixed water column. Nutrients from the water bottom and inorganic carbon from the water surface form an asymmetric resource supply mechanism for the algal growth. The existence and stability of semi-trivial steady state and positive steady state of the model are proved, and a threshold condition for the regime shift from extinction to survival of algae is established. The influence of environmental parameters on the vertical distribution of algae is investigated in the water column. It is shown that the vertical distribution of algae can exhibit many different profiles under the combined limitation of nutrients and inorganic carbon.
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Affiliation(s)
- Jimin Zhang
- School of Mathematical Sciences, Heilongjiang University, Harbin, Heilongjiang, 150080, People's Republic of China
| | - Junping Shi
- Department of Mathematics, William & Mary, Williamsburg, VA, 23187-8795, USA.
| | - Xiaoyuan Chang
- School of Science, Harbin University of Science and Technology, Harbin, Heilongjiang, 150080, People's Republic of China
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30
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Diel Variations of Extracellular Microcystin Influence the Subcellular Dynamics of RubisCO in Microcystis aeruginosa PCC 7806. Microorganisms 2021; 9:microorganisms9061265. [PMID: 34200971 PMCID: PMC8230624 DOI: 10.3390/microorganisms9061265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/03/2021] [Accepted: 06/07/2021] [Indexed: 12/02/2022] Open
Abstract
The ubiquitous freshwater cyanobacterium Microcystis is remarkably successful, showing a high tolerance against fluctuations in environmental conditions. It frequently forms dense blooms which can accumulate significant amounts of the hepatotoxin microcystin, which plays an extracellular role as an infochemical but also acts intracellularly by interacting with proteins of the carbon metabolism, notably with the CO2 fixing enzyme RubisCO. Here we demonstrate a direct link between external microcystin and its intracellular targets. Monitoring liquid cultures of Microcystis in a diel experiment revealed fluctuations in the extracellular microcystin content that correlate with an increase in the binding of microcystin to intracellular proteins. Concomitantly, reversible relocation of RubisCO from the cytoplasm to the cell’s periphery was observed. These variations in RubisCO localization were especially pronounced with cultures grown at higher cell densities. We replicated these effects by adding microcystin externally to cultures grown under continuous light. Thus, we propose that microcystin may be part of a fast response to conditions of high light and low carbon that contribute to the metabolic flexibility and the success of Microcystis in the field.
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31
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Dick GJ, Duhaime MB, Evans JT, Errera RM, Godwin CM, Kharbush JJ, Nitschky HS, Powers MA, Vanderploeg HA, Schmidt KC, Smith DJ, Yancey CE, Zwiers CC, Denef VJ. The genetic and ecophysiological diversity of Microcystis. Environ Microbiol 2021; 23:7278-7313. [PMID: 34056822 DOI: 10.1111/1462-2920.15615] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 01/30/2023]
Abstract
Microcystis is a cyanobacterium that forms toxic blooms in freshwater ecosystems around the world. Biological variation among taxa within the genus is apparent through genetic and phenotypic differences between strains and via the spatial and temporal distribution of strains in the environment, and this fine-scale diversity exerts strong influence over bloom toxicity. Yet we do not know how varying traits of Microcystis strains govern their environmental distribution, the tradeoffs and links between these traits, or how they are encoded at the genomic level. Here we synthesize current knowledge on the importance of diversity within Microcystis and on the genes and traits that likely underpin ecological differentiation of taxa. We briefly review spatial and environmental patterns of Microcystis diversity in the field and genetic evidence for cohesive groups within Microcystis. We then compile data on strain-level diversity regarding growth responses to environmental conditions and explore evidence for variation of community interactions across Microcystis strains. Potential links and tradeoffs between traits are identified and discussed. The resulting picture, while incomplete, highlights key knowledge gaps that need to be filled to enable new models for predicting strain-level dynamics, which influence the development, toxicity and cosmopolitan nature of Microcystis blooms.
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Affiliation(s)
- Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Melissa B Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jacob T Evans
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Reagan M Errera
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Casey M Godwin
- School for Environment and Sustainability, Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Jenan J Kharbush
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Helena S Nitschky
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - McKenzie A Powers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Henry A Vanderploeg
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Colleen E Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Claire C Zwiers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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Ma J, Wang P. Effects of rising atmospheric CO 2 levels on physiological response of cyanobacteria and cyanobacterial bloom development: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:141889. [PMID: 32920383 DOI: 10.1016/j.scitotenv.2020.141889] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/15/2020] [Accepted: 08/20/2020] [Indexed: 05/19/2023]
Abstract
Increasing atmospheric CO2 concentration negatively impacts aquatic ecosystems and may exacerbate the problem of undesirable cyanobacterial bloom development in freshwater ecosystems. Elevated levels of atmospheric CO2 may increase the levels of dissolved CO2 in freshwater systems, via air-water exchanges, enhancing primary production in the water and catchments. Although high CO2 levels improve cyanobacterial growth and increase cyanobacterial biomass, the impacts on their internal physiological processes can be more complex. Here, we have reviewed previous studies to evaluate the physiological responses of cyanobacteria to high concentrations of CO2. In response to high CO2 concentrations, the pressures of inorganic carbon absorption are reduced, and carbon concentration mechanisms are downregulated, affecting the intracellular metabolic processes and competitiveness of the cyanobacteria. Nitrogen and phosphorus metabolism and light utilization are closely related to CO2 assimilation, and these processes are likely to be affected by resource and energy reallocation when CO2 levels are high. Additionally, the responses of diazotrophic and toxic cyanobacteria to elevated CO2 levels were specifically reviewed. The responses of diazotrophic cyanobacteria to elevated CO2 concentrations were found to be inconsistent, probably because of differences in other factors in experimental designs. Toxic cyanobacteria tended to be superior to non-toxic strains at low levels of CO2; however, the specific effects of microcystin on the regulation require further investigation. Furthermore, the effects of increasing CO2 levels on cyanobacterial competitiveness in phytoplankton communities and nutrient cycling in aquatic ecosystems were reviewed. High CO2 concentrations may make cyanobacteria less competitive relative to other algal taxa; however, due to the complexity of natural systems and the specificity of algal species, the dominant positions of the cyanobacteria do not seems to be changed. To better understand cyanobacterial responses to elevated CO2 levels and help control cyanobacterial bloom developments, this review has identified key areas for future research.
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Affiliation(s)
- Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
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Lines T, Orr P, Beardall J. Elevated co 2 has Differential Effects on Five Species of Microalgae from a Subtropical Freshwater Lake: Possible Implications for Phytoplankton Species Composition. JOURNAL OF PHYCOLOGY 2021; 57:324-334. [PMID: 33191502 DOI: 10.1111/jpy.13104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Rising atmospheric CO2 concentrations are predicted to have a significant impact on global phytoplankton populations. Of particular interest in freshwater systems are those species that produce toxins or impact water quality, though evidence for how these species, and many others, will respond is limited. This study investigated the effects of elevated CO2 (1,000 ppm) relative to current atmospheric CO2 partial pressures (400 ppm), on growth, cell size, carbon acquisition, and photophysiology of five freshwater phytoplankton species including a toxic cyanophyte, Raphidiopsis raciborskii, from Lake Wivenhoe, Australia. Effects of elevated CO2 on growth rate varied between species; notably growth rate was considerably higher for Staurastrum sp. and significantly lower for Stichococcus sp. with a trend to lower growth rate for R. raciborskii. Surface area to volume ratio was significantly lower with elevated CO2 , for all species except Cyclotella sp. Timing of maximum cell concentrations of those genera studied in monoculture occurred in the lake in order of CO2 affinity when free CO2 concentrations dropped below air equilibrium. The results presented here suggest that as atmospheric levels of CO2 rise, R. raciborskii may become less of a problem to water quality, while some species of chlorophytes may become more dominant. This has implications for stakeholders of many freshwater systems.
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Affiliation(s)
- Thomas Lines
- The University of Adelaide, Waite Campus, Glen Osmond, South Australia, 5064, Australia
| | - Philip Orr
- Australian Rivers Institute, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
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Schmidt KC, Jackrel SL, Smith DJ, Dick GJ, Denef VJ. Genotype and host microbiome alter competitive interactions between Microcystis aeruginosa and Chlorella sorokiniana. HARMFUL ALGAE 2020; 99:101939. [PMID: 33218432 DOI: 10.1016/j.hal.2020.101939] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 05/24/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) continue to increase in frequency and magnitude, threatening global freshwater ecosystems and services. In north-temperate lakes cyanobacteria appear in early summer, succeeding green algae as the dominant phytoplankton group, a pattern thought to be mediated by changes in temperature and bioavailable nutrients. To understand additional drivers of this successional pattern our study used reciprocal invasion experiments to examine the competitive interaction between Microcystis aeruginosa, a dominant contributor to cyanoHABs, and the green alga Chlorella sorokiniana. We considered two factors that may impact these interactions: (1) strain variation, with a specific emphasis on the presence or absence of the gene for the hepatotoxin microcystin, and (2) host-associated bacteria. We used toxic M. aeruginosa PCC 7806 (microcystin producing strain), a non-toxic mutant of PCC 7806, non-toxic M. aeruginosa PCC 9701 (non-microcystin producing strain), and C. sorokiniana. Each organism was available free of all bacteria (i.e., axenic) and with a re-introduced defined bacterial community to generate their xenic counterparts. Competitive interactions were assessed with reciprocal invasion experiments between paired xenic and paired axenic populations of C. sorokiniana and one of the two Microcystis strains, each assessed separately. Flow cytometry and random forest models were used to rapidly discriminate and quantify phytoplankton population densities with 99% accuracy. We found that M. aeruginosa PCC 7806, but not strain PCC 9701, could proliferate from low abundance in a steady-state population of C. sorokiniana. Further, the presence of bacteria allowed M. aeruginosa PCC 7806 to grow to a higher population density into an established C. sorokiniana population than when grown axenic. Conversely, when M. aeruginosa was dominant, C. sorokiniana was only able to proliferate from low density into the PCC 9701 strain, and only when axenic. The mutant of PCC 7806 lacking the ability to produce microcystin behaved similarly to the toxic wild-type, implying microcystin is not responsible for the difference in competitive abilities observed between the two wild-type strains. Quantification of microcystins (MCs) when PCC 7806 M. aeruginosa was introduced into the C. sorokiniana culture showed two-fold more MCs per cell when host-associated bacteria were absent compared to present in both species cultures. Our results show that the ability of M. aeruginosa to compete with C. sorokiniana is determined by genomic differences beyond genes involved in microcystin toxin generation and indicate an important role of host-associated bacteria in mediating phytoplankton interspecies interactions. These results expand our understanding of the key drivers of phytoplankton succession and the establishment and persistence of freshwater harmful cyanobacterial blooms.
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Affiliation(s)
- Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara L Jackrel
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gregory J Dick
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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Sandrini G, Piel T, Xu T, White E, Qin H, Slot PC, Huisman J, Visser PM. Sensitivity to hydrogen peroxide of the bloom-forming cyanobacterium Microcystis PCC 7806 depends on nutrient availability. HARMFUL ALGAE 2020; 99:101916. [PMID: 33218441 DOI: 10.1016/j.hal.2020.101916] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Application of low concentrations of hydrogen peroxide (H2O2) is a relatively new and promising method to selectively suppress harmful cyanobacterial blooms, while minimizing effects on eukaryotic organisms. However, it is still unknown how nutrient limitation affects the sensitivity of cyanobacteria to H2O2. In this study, we compare effects of H2O2 on the microcystin-producing cyanobacterium Microcystis PCC 7806 under light-limited but nutrient-replete conditions, nitrogen (N) limitation and phosphorus (P) limitation. Microcystis was first grown in chemostats to acclimate to these different experimental conditions, and subsequently transferred to batch cultures where they were treated with a range of H2O2 concentrations (0-10 mg L-1) while exposed to high light (100 µmol photons m-2 s-1) or low light (15 µmol photons m-2 s-1). Our results show that, at low light, N- and P-limited Microcystis were less sensitive to H2O2 than light-limited but nutrient-replete Microcystis. A significantly higher expression of the genes encoding for anti-oxidative stress enzymes (2-cys-peroxiredoxin, thioredoxin A and type II peroxiredoxin) was observed prior to and after the H2O2 treatment for both N- and P-limited Microcystis, which may explain their increased resistance against H2O2. At high light, Microcystis was more sensitive to H2O2 than at low light, and differences in the decline of the photosynthetic yield between nutrient-replete and nutrient-limited Microcystis exposed to H2O2 were less pronounced. Leakage of microcystin was stronger and faster from nutrient-replete than from N- and P-limited Microcystis. Overall, this study provides insight in the sensitivity of harmful cyanobacteria to H2O2 under various environmental conditions.
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Affiliation(s)
- Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Tianshuo Xu
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Emily White
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Hongjie Qin
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Pieter C Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.
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Wang P, Ma J, Wang X, Tan Q. Rising atmospheric CO 2 levels result in an earlier cyanobacterial bloom-maintenance phase with higher algal biomass. WATER RESEARCH 2020; 185:116267. [PMID: 32798892 DOI: 10.1016/j.watres.2020.116267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/28/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The effect of rising atmospheric CO2 on freshwater lakes is a subject of considerable debate. However, it is not clear how rising CO2 concentration affects cyanobacterial bloom development under potential nutrient limitation conditions and if CO2 should be taken into account in making nutrient reduction strategy. To fill the knowledge gaps, this study investigated the spatiotemporal variability in aquatic CO2 concentration (pCO2) from 2006 to 2016 in Lake Taihu, where cyanobacterial blooms often occurred from late spring to the early fall. Lake Taihu is an atmospheric CO2 source in May and November, with only 18% and 11% pCO2-undersaturated areas, respectively. During cyanobacterial bloom in August, 81% of the lake areas are pCO2-undersaturated, absorbing ~ 0.53 t C/h of atmospheric CO2. The results demonstrated that CO2 transfer across air-water interface was important in supporting cyanobacterial bloom development. Besides, Field investigation showed that the chlorophyll a level is significantly positively correlated with supersaturated pCO2 (>13.56 µmol/L) in May, but pCO2 decreases with high chlorophyll a levels in August, suggesting that cyanobacterial growth would be promoted by high pCO2 over a threshold. These observations suggested that the effect of rising atmospheric CO2 on freshwater lakes and cyanobacterial blooms should be paid attention to. Further, when the N- and P-levels are >0.3 mg/L and >0.02 mg/L, respectively, high-pCO2 conditions allow a more rapid growth rate of cyanobacteria via improved nutrient-use efficiency. Moreover, cyanobacteria afford maximum N- or P-use efficiency at lower N- or P-concentrations with high CO2 concentration. This improvement would result in an earlier bloom-maintenance phase and higher cyanobacterial biomass. In this case, nutrient reduction is more imperative under future high CO2 conditions.
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Affiliation(s)
- Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098.
| | - Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
| | - Qingqian Tan
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
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Paramasivan S, Bassiouni A, Shiffer A, Dillon MR, Cope EK, Cooksley C, Ramezanpour M, Moraitis S, Ali MJ, Bleier B, Callejas C, Cornet ME, Douglas RG, Dutra D, Georgalas C, Harvey RJ, Hwang PH, Luong AU, Schlosser RJ, Tantilipikorn P, Tewfik MA, Vreugde S, Wormald P, Caporaso JG, Psaltis AJ. The international sinonasal microbiome study: A multicentre, multinational characterization of sinonasal bacterial ecology. Allergy 2020; 75:2037-2049. [PMID: 32167574 DOI: 10.1111/all.14276] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/20/2019] [Accepted: 12/18/2019] [Indexed: 02/06/2023]
Abstract
The sinonasal microbiome remains poorly defined, with our current knowledge based on a few cohort studies whose findings are inconsistent. Furthermore, the variability of the sinus microbiome across geographical divides remains unexplored. We characterize the sinonasal microbiome and its geographical variations in both health and disease using 16S rRNA gene sequencing of 410 individuals from across the world. Although the sinus microbial ecology is highly variable between individuals, we identify a core microbiome comprised of Corynebacterium, Staphylococcus, Streptococcus, Haemophilus and Moraxella species in both healthy and chronic rhinosinusitis (CRS) cohorts. Corynebacterium (mean relative abundance = 44.02%) and Staphylococcus (mean relative abundance = 27.34%) appear particularly dominant in the majority of patients sampled. Amongst patients suffering from CRS with nasal polyps, a statistically significant reduction in relative abundance of Corynebacterium (40.29% vs 50.43%; P = .02) was identified. Despite some measured differences in microbiome composition and diversity between some of the participating centres in our cohort, these differences would not alter the general pattern of core organisms described. Nevertheless, atypical or unusual organisms reported in short-read amplicon sequencing studies and that are not part of the core microbiome should be interpreted with caution. The delineation of the sinonasal microbiome and standardized methodology described within our study will enable further characterization and translational application of the sinus microbiota.
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Affiliation(s)
- Sathish Paramasivan
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - Ahmed Bassiouni
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - Arron Shiffer
- Pathogen and Microbiome Institute Northern Arizona University Flagstaff AZ USA
| | - Matthew R. Dillon
- Pathogen and Microbiome Institute Northern Arizona University Flagstaff AZ USA
| | - Emily K. Cope
- Pathogen and Microbiome Institute Northern Arizona University Flagstaff AZ USA
| | - Clare Cooksley
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - Mahnaz Ramezanpour
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - Sophia Moraitis
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | | | - Benjamin Bleier
- Department of Otolaryngology Massachusetts Eye and Ear Infirmary Harvard Medical School Boston MA USA
| | - Claudio Callejas
- Department of Otolaryngology Pontificia Universidad Catolica de Chile Santiago Chile
| | | | | | - Daniel Dutra
- Department of Otorhinolaryngology University of Sao Paulo Sao Paulo Brazil
| | - Christos Georgalas
- Department of Otorhinolaryngology Amsterdam UMC Amsterdam The Netherlands
| | - Richard J. Harvey
- Department of Otolaryngology, Rhinology and Skull base University of New South Wales Sydney NSW Australia
- Faculty of Medicine and Health sciences Macquarie University Sydney NSW Australia
| | - Peter H. Hwang
- Department of Otolaryngology ‐Head and Neck Surgery Stanford University Stanford CA USA
| | - Amber U. Luong
- Department of Otolaryngology ‐Head and Neck Surgery University of Texas Austin TX USA
| | - Rodney J. Schlosser
- Department of Otolaryngology Medical University of South Carolina Charleston SC USA
| | - Pongsakorn Tantilipikorn
- Department of Otorhinolaryngology Faculty of Medicine Siriraj Hospital Mahidol University Bangkok Thailand
| | - Marc A. Tewfik
- Department of Otolaryngology ‐ Head and Neck Surgery McGill University Montreal QC Canada
| | - Sarah Vreugde
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - Peter‐John Wormald
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
| | - J. Gregory Caporaso
- Pathogen and Microbiome Institute Northern Arizona University Flagstaff AZ USA
| | - Alkis J. Psaltis
- Department of Otolaryngology, Head and Neck Surgery University of Adelaide Adelaide SA Australia
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Niu X, Zhang D, Zhang R, Song Q, Li Y, Wang M. Physiological and biochemical responses of Microcystis aeruginosa to phosphine (PH 3) under elevated CO 2. J Environ Sci (China) 2020; 94:171-178. [PMID: 32563481 DOI: 10.1016/j.jes.2020.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
Phosphine (PH3) is an important factor driving the outbreak of cyanobacterial blooms that produce toxic microcystin threating human health. To clarify the physiological and biochemical responses of cyanobacteria to PH3 under elevated CO2 concentration, Microcystis aeruginosa was used in the coupling treatment of 1000 ppmv CO2 and PH3 at different concentrations respectively. The chlorophyll a (Chl-a), carotenoid, net photosynthetic rate and total protein of M. aeruginosa exhibited evidently increasing tendency under the coupling treatment of 1000 ppmv CO2 and PH3 at different concentrations (7.51 × 10-3, 2.48 × 10-2, 7.51 × 10-2 mg/L). The coupling treatments resulted in the higher concentrations of Chl-a and carotenoid of M. aeruginosa, compared to those in the control and the treatment with CO2 alone, and their enhancement increased with the increase in PH3 concentrations. The total antioxidant capacity (T-AOC) in the coupling treatment with CO2 and PH3 of 2.48 × 10-2 mg/L and 7.51 × 10-3 mg/L showed increasing tendency, compared to the treatment with PH3 alone. Additionally, the coupling treatment with 1000 ppmv CO2 and PH3 also altered the pH and DO level in the culture medium. In this regard, the coupling treatment with CO2 and PH3 at an appropriate concentration can enhance the resistance of M. aeruginosa to PH3 toxicity and is beneficial to the reproduction of M. aeruginosa, presumably resulting in potential for the outbreak of cyanobacteria bloom. Given the concern about global warming and the increase in atmospheric CO2 level, our research laid a foundation for the scientific understanding of the correlation between PH3 and cyanobacteria blooms.
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Affiliation(s)
- Xiaojun Niu
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210093, China; Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, Guangzhou 510640, China
| | - Dongqing Zhang
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
| | - Runyuan Zhang
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China
| | - Qi Song
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China
| | - Yankun Li
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China
| | - Mo Wang
- College of Architecture and Urban Planning, Guangzhou University, Guangzhou 510006, China.
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Brown NEM, Bernhardt JR, Harley CDG. Energetic context determines species and community responses to ocean acidification. Ecology 2020; 101:e03073. [DOI: 10.1002/ecy.3073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 03/02/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Norah E. M. Brown
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Joey R. Bernhardt
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Christopher D. G. Harley
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
- Institute for the Oceans and Fisheries University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
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Cabiscol R, Shi H, Wünsch I, Magnanimo V, Finke JH, Luding S, Kwade A. Effect of particle size on powder compaction and tablet strength using limestone. ADV POWDER TECHNOL 2020. [DOI: 10.1016/j.apt.2019.12.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gao Y, Lu J, Orr PT, Chuang A, Franklin HM, Burford MA. Enhanced resistance of co-existing toxigenic and non-toxigenic Microcystis aeruginosa to pyrogallol compared with monostrains. Toxicon 2020; 176:47-54. [PMID: 32103795 DOI: 10.1016/j.toxicon.2020.01.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 11/28/2022]
Abstract
Cyanobacteria species are sensitive to many plant allelochemicals, such as pyrogallol. However, little attention has been paid to the relative effects of these xenobiotics on co-occurring toxigenic and non-toxigenic cyanobacterial strains, despite their co-existence in blooms. Hence, the responses of one toxigenic (TS2) and two non-toxigenic (NS1, NS2) Microcystis aeruginosa strains to pyrogallol were tested under three conditions: mono-culture and co-cultured either directly or separately by dialysis membrane. The study showed that the inhibitory effects of pyrogallol on the growth and photosynthetic yield (Fv/Fm) of either toxigenic or non-toxigenic M. aeruginosa strains were lower in direct and dialysis co-culture conditions than those in mono-culture conditions. This result indicated that chemical-mediated reciprocal effects occur between the co-existing toxigenic and non-toxigenic strains. The toxigenic M. aeruginosa strain was more sensitive to pyrogallol than the non-toxigenic strains in both mono- and co-culture systems, though whether this outcome is due to the former's toxigenic status is unclear. Intracellular microcystin-LR (MC-LR) concentrations of the toxigenic strain decreased after pyrogallol addition in both mono- and co-culture systems, whereas extracellular MC-LR concentrations increased. This finding may reflect the cell damage of M. aeruginosa because of the pyrogallol. At the same initial number of cells, the extracellular MC-LR concentration released from the same amount of TS2 cells in mono-culture was slightly higher than that in dialysis co-culture conditions. Overall, this study shows that plant allelochemicals may have the potential to reduce bloom toxicity by reducing the proportion of toxigenic cyanobacterial strains, and the effects of co-existing strains must be considered when assessing the effects of plant allelochemicals on target strains.
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Affiliation(s)
- Yunni Gao
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, PR China.
| | - Jing Lu
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia
| | - Philip T Orr
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia
| | - Ann Chuang
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia
| | - Hannah M Franklin
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia
| | - Michele A Burford
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, 4111, Australia.
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Golshan A, Evans C, Geary P, Morrow A, Maeder M, Tauler R. Patterns of cyanobacterial abundance in a major drinking water reservoir: what 3 years of comprehensive monitoring data reveals? ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:113. [PMID: 31938950 DOI: 10.1007/s10661-020-8090-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
The present study provides a detailed analysis of the factors influencing variation in cyanobacterial communities of a large shallow off-river drinking water reservoir on the east coast of Australia. Receiving multiple inflows from two unprotected mixed land-use catchments, the Grahamstown Reservoir is a model example of a reservoir which is highly vulnerable to adverse water quality issues, including phytoplankton blooms and the resulting filtration, toxin and taste and odour problems produced. The spatial and temporal distributions of cyanobacteria were assessed for a period of 3 years (January 2012-December 2014) based on samples collected from three monitoring stations within the reservoir. Relationships between cyanobacterial abundance and a range of environmental factors were evaluated by application of multivariate curve resolution-alternating least squares (MCR-ALS) analysis.Results of the analysis indicated that among the 22 physico-chemical variables and 14 cyanobacterial taxa measured, the vertical temperature gradient within the water column and nutrient availability were the most powerful explanatory factors for the observed temporal and spatial distribution patterns in the densities of cyanobacterial taxa. The abundance patterns of the dominant cyanobacterial taxa-Aphanocapsa, Aphanothece, Microcystis and Pseudanabaena-were strongly linked with rainfall and run-off patterns into the reservoir, while Coelosphaerium and Microcystis were the taxa most influenced by the apparent occurrence of thermal stratification. The findings demonstrate the capacity of rigorous multivariate data analysis to identify more subtle relationships between water quality variables, catchment factors and cyanobacterial growth in drinking water reservoirs.
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Affiliation(s)
- Azadeh Golshan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Craig Evans
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.
| | - Phillip Geary
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Abigail Morrow
- Hunter Water Corporation, Newcastle, NSW, 2300, Australia
| | - Marcel Maeder
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Romà Tauler
- IDAEA-CSIC, Jordi Girona 18-24, 08034, Barcelona, Spain
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Dyer SW, Needoba JA. Use of High-Resolution Pressure Nephelometry To Measure Gas Vesicle Collapse as a Means of Determining Growth and Turgor Changes in Planktonic Cyanobacteria. Appl Environ Microbiol 2020; 86:e01790-19. [PMID: 31676479 PMCID: PMC6952233 DOI: 10.1128/aem.01790-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/27/2019] [Indexed: 01/10/2023] Open
Abstract
Previous work has demonstrated that the physical properties of intracellular bacterial gas vesicles (GVs) can be analyzed in vivo using pressure nephelometry. In analyzing the buoyant state of GV-containing cyanobacteria, hydrostatic pressure within a sample cell is increased in a stepwise manner, where the concomitant collapse of GVs due to pressure and the resultant decrease in suspended cells are detected by changes in nephelometric scattering. As the relative pressure at which GVs collapse is a function of turgor pressure and cellular osmotic gradients, pressure nephelometry is a powerful tool for assaying changes in metabolism that affect turgor, such as photosynthetic and osmoregulatory processes. We have developed an updated and automated pressure nephelometer that utilizes visible-infrared (Vis-IR) spectra to accurately quantify GV critical collapse pressure, critical collapse pressure distribution, and cell turgor pressure. Here, using the updated pressure nephelometer and axenic cultures of Microcystis aeruginosa PCC7806, we demonstrate that GV critical collapse pressure is stable during mid-exponential growth phase, introduce pressure-sensitive turbidity as a robust metric for the abundance of gas-vacuolate cyanobacteria, and demonstrate that pressure-sensitive turbidity is a more accurate proxy for abundance and growth than photopigment fluorescence. As cyanobacterium-dominated harmful algal bloom (cyanoHAB) formation is dependent on the constituent cells possessing gas vesicles, characterization of environmental cyanobacteria populations via pressure nephelometry is identified as an underutilized monitoring method. Applications of this instrument focus on physiological and ecological studies of cyanobacteria, for example, cyanoHAB dynamics and the drivers associated with cyanotoxin production in aquatic ecosystems.IMPORTANCE The increased prevalence of bloom-forming cyanobacteria and associated risk of exposure to cyanobacterial toxins through drinking water utilities and recreational waterways are growing public health concerns. Cost-effective, early-detection methodologies specific to cyanobacteria are crucial for mitigating these risks, with a gas vesicle-specific signal offering a number of benefits over photopigment fluorescence, including improved detection limits and discrimination against non-gas-vacuolate phototrophs. Here, we present a multiplexed instrument capable of quantifying the relative abundance of cyanobacteria based on the signal generated from the presence of intracellular gas vesicles specific to bloom-forming cyanobacteria. Additionally, as cell turgor can be measured in vivo via pressure nephelometry, the measurement furnishes information about the internal osmotic pressure of gas-vacuolate cyanobacteria, which relates to the metabolic state of the cell. Together these advances may improve routine waterway monitoring and the mitigation of human health threats due to cyanobacterial blooms.
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Affiliation(s)
- Stuart W Dyer
- Oregon Health and Science University, Institute of Environmental Health, Portland, Oregon, USA
- Oregon Health and Science University-Portland State University, School of Public Health, Portland, Oregon, USA
| | - Joseph A Needoba
- Oregon Health and Science University, Institute of Environmental Health, Portland, Oregon, USA
- Oregon Health and Science University-Portland State University, School of Public Health, Portland, Oregon, USA
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Griffith AW, Gobler CJ. Harmful algal blooms: A climate change co-stressor in marine and freshwater ecosystems. HARMFUL ALGAE 2020; 91:101590. [PMID: 32057338 DOI: 10.1016/j.hal.2019.03.008] [Citation(s) in RCA: 152] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 05/21/2023]
Abstract
Marine and freshwater ecosystems are warming, acidifying, and deoxygenating as a consequence of climate change. In parallel, the impacts of harmful algal blooms (HABs) on these ecosystems are intensifying. Many eutrophic habitats that host recurring HABs already experience thermal extremes, low dissolved oxygen, and low pH, making these locations potential sentinel sites for conditions that will become more common in larger-scale systems as climate change accelerates. While studies of the effects of HABs or individual climate change stressors on aquatic organisms have been relatively common, studies assessing their combined impacts have been rare. Those doing so have reported strong species- and strain-specific interactions between HAB species and climate change co-stressors yielding outcomes for aquatic organisms that could not have been predicted based on investigations of these factors individually. This review provides an ecological and physiological framework for considering HABs as a climate change co-stressor and considers the consequences of their combined occurrence for coastal ecosystems. This review also highlights critical gaps in our understanding of HABs as a climate change co-stressor that must be addressed in order to develop management plans that adequately protect fisheries, aquaculture, aquatic ecosystems, and human health. Ultimately, incorporating HAB species into experiments and monitoring programs where the effects of multiple climate change stressors are considered will provide a more ecologically relevant perspective of the structure and function of marine ecosystems in future, climate-altered systems.
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Affiliation(s)
- Andrew W Griffith
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY, 11968, United States; Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, United States
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY, 11968, United States.
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Burford MA, Carey CC, Hamilton DP, Huisman J, Paerl HW, Wood SA, Wulff A. Perspective: Advancing the research agenda for improving understanding of cyanobacteria in a future of global change. HARMFUL ALGAE 2020; 91:101601. [PMID: 32057347 DOI: 10.1016/j.hal.2019.04.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 05/19/2023]
Abstract
Harmful cyanobacterial blooms (=cyanoHABs) are an increasing feature of many waterbodies throughout the world. Many bloom-forming species produce toxins, making them of particular concern for drinking water supplies, recreation and fisheries in waterbodies along the freshwater to marine continuum. Global changes resulting from human impacts, such as climate change, over-enrichment and hydrological alterations of waterways, are major drivers of cyanoHAB proliferation and persistence. This review advocates that to better predict and manage cyanoHABs in a changing world, researchers need to leverage studies undertaken to date, but adopt a more complex and definitive suite of experiments, observations, and models which can effectively capture the temporal scales of processes driven by eutrophication and a changing climate. Better integration of laboratory culture and field experiments, as well as whole system and multiple-system studies are needed to improve confidence in models predicting impacts of climate change and anthropogenic over-enrichment and hydrological modifications. Recent studies examining adaptation of species and strains to long-term perturbations, e.g. temperature and carbon dioxide (CO2) levels, as well as incorporating multi-species and multi-stressor approaches emphasize the limitations of approaches focused on single stressors and individual species. There are also emerging species of concern, such as toxic benthic cyanobacteria, for which the effects of global change are less well understood, and require more detailed study. This review provides approaches and examples of studies tackling the challenging issue of understanding how global changes will affect cyanoHABs, and identifies critical information needs for effective prediction and management.
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Affiliation(s)
- M A Burford
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Queensland, 4111, Australia.
| | - C C Carey
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061, USA
| | - D P Hamilton
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Queensland, 4111, Australia
| | - J Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - H W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, 28557, USA; College of Environment, Hohai University, Nanjing, 210098, China
| | - S A Wood
- Cawthron Institute, Nelson, 7010, New Zealand
| | - A Wulff
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530, Gothenburg, Sweden
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Glibert PM. Harmful algae at the complex nexus of eutrophication and climate change. HARMFUL ALGAE 2020; 91:101583. [PMID: 32057336 DOI: 10.1016/j.hal.2019.03.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 03/07/2019] [Indexed: 05/21/2023]
Abstract
Climate projections suggest-with substantial certainty-that global warming >1.5 °C will occur by mid-century (2050). Population is also projected to increase, amplifying the demands for food, fuel, water and sanitation, which, in turn, escalate nutrient pollution. Global projections of nutrient pollution, however, are less certain than those of climate as there are regionally decreasing trends projected in Europe, and stabilization of nutrient use in North America and Australia. In this review of the effects of eutrophication and climate on harmful algae, some of the complex, subtle, and non-intuitive effects and interactions on the physiology of both harmful and non-harmful taxa are emphasized. In a future ocean, non-harmful diatoms may be disproportionately stressed and mixotrophs advantaged due to changing nutrient stoichiometry and forms of nutrients, temperature, stratification and oceanic pH. Modeling is advancing, but there is much yet to be understood, in terms of physiology, biogeochemistry and trophodynamics and how both harmful and nonharmful taxa may change in an uncertain future driven by anthropogenic activities.
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Affiliation(s)
- Patricia M Glibert
- University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, MD, 21613, United States.
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Raven JA, Gobler CJ, Hansen PJ. Dynamic CO 2 and pH levels in coastal, estuarine, and inland waters: Theoretical and observed effects on harmful algal blooms. HARMFUL ALGAE 2020; 91:101594. [PMID: 32057340 DOI: 10.1016/j.hal.2019.03.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 06/10/2023]
Abstract
Rising concentrations of atmospheric CO2 results in higher equilibrium concentrations of dissolved CO2 in natural waters, with corresponding increases in hydrogen ion and bicarbonate concentrations and decreases in hydroxyl ion and carbonate concentrations. Superimposed on these climate change effects is the dynamic nature of carbon cycling in coastal zones, which can lead to seasonal and diel changes in pH and CO2 concentrations that can exceed changes expected for open ocean ecosystems by the end of the century. Among harmful algae, i.e. some species and/or strains of Cyanobacteria, Dinophyceae, Prymnesiophyceae, Bacillariophyceae, and Ulvophyceae, the occurrence of a CO2 concentrating mechanisms (CCMs) is the most frequent mechanism of inorganic carbon acquisition in natural waters in equilibrium with the present atmosphere (400 μmol CO2 mol-1 total gas), with varying phenotypic modification of the CCM. No data on CCMs are available for Raphidophyceae or the brown tide Pelagophyceae. Several HAB species and/or strains respond to increased CO2 concentrations with increases in growth rate and/or cellular toxin content, however, others are unaffected. Beyond the effects of altered C concentrations and speciation on HABs, changes in pH in natural waters are likely to have profound effects on algal physiology. This review outlines the implications of changes in inorganic cycling for HABs in coastal zones, and reviews the knowns and unknowns with regard to how HABs can be expected to ocean acidification. We further point to the large regions of uncertainty with regard to this evolving field.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK; Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia; School of Biological Science, University of Western Australia, Crawley, WA, 6009, Australia.
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton NY, 11968, USA.
| | - Per Juel Hansen
- University of Copenhagen, Marine Biological Section, Strandpromenaden 5, DK 3000 Helsingør, Denmark
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Piel T, Sandrini G, White E, Xu T, Schuurmans JM, Huisman J, Visser PM. Suppressing Cyanobacteria with Hydrogen Peroxide Is More Effective at High Light Intensities. Toxins (Basel) 2019; 12:toxins12010018. [PMID: 31906135 PMCID: PMC7020451 DOI: 10.3390/toxins12010018] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/01/2022] Open
Abstract
Hydrogen peroxide (H2O2) can be used as an emergency method to selectively suppress cyanobacterial blooms in lakes and drinking water reservoirs. However, it is largely unknown how environmental parameters alter the effectiveness of H2O2 treatments. In this study, the toxic cyanobacterial strain Microcystis aeruginosa PCC 7806 was treated with a range of H2O2 concentrations (0 to 10 mg/L), while being exposed to different light intensities and light colors. H2O2 treatments caused a stronger decline of the photosynthetic yield in high light than in low light or in the dark, and also a stronger decline in orange than in blue light. Our results are consistent with the hypothesis that H2O2 causes major damage at photosystem II (PSII) and interferes with PSII repair, which makes cells more sensitive to photoinhibition. Furthermore, H2O2 treatments caused a decrease in cell size and an increase in extracellular microcystin concentrations, indicative of leakage from disrupted cells. Our findings imply that even low H2O2 concentrations of 1–2 mg/L can be highly effective, if cyanobacteria are exposed to high light intensities. We therefore recommend performing lake treatments during sunny days, when a low H2O2 dosage is sufficient to suppress cyanobacteria, and may help to minimize impacts on non-target organisms.
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Programmed Cell Death-Like and Accompanying Release of Microcystin in Freshwater Bloom-Forming Cyanobacterium Microcystis: From Identification to Ecological Relevance. Toxins (Basel) 2019; 11:toxins11120706. [PMID: 31817272 PMCID: PMC6950475 DOI: 10.3390/toxins11120706] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 11/29/2019] [Accepted: 12/01/2019] [Indexed: 11/16/2022] Open
Abstract
Microcystis is the most common freshwater bloom-forming cyanobacteria. Its massive blooms not only adversely affect the functionality of aquatic ecosystems, but are also associated with the production of microcystins (MCs), a group of potent toxins that become a threat to public health when cell-bound MCs are significantly released from the dying Microcystis into the water column. Managing Microcystis blooms thus requires sufficient knowledge regarding both the cell death modes and the release of toxins. Recently, more and more studies have demonstrated the occurrence of programmed cell death-like (or apoptosis-like) events in laboratory and field samples of Microcystis. Apoptosis is a genetically controlled process that is essential for the development and survival of metazoa; however, it has been gradually realized to be an existing phenomenon playing important ecological roles in unicellular microorganisms. Here, we review the current progress and the existing knowledge gap regarding apoptosis-like death in Microcystis. Specifically, we focus first on the tools utilized to characterize the apoptosis-related biochemical and morphological features in Microcystis. We further outline various stressful stimuli that trigger the occurrence of apoptosis and discuss the potential mechanisms of apoptosis in Microcystis. We then propose a conceptual model to describe the functional coupling of apoptosis and MC in Microcystis. This model could be useful for understanding both roles of MC and apoptosis in this species. Lastly, we conclude the review by highlighting the current knowledge gap and considering the direction of future research. Overall, this review provides a recent update with respect to the knowledge of apoptosis in Microcystis and also offers a guide for future investigations of its ecology and survival strategies.
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