1
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Moffett JW, Boiteau RM. Metal Organic Complexation in Seawater: Historical Background and Future Directions. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:577-599. [PMID: 37722713 DOI: 10.1146/annurev-marine-033023-083652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
The speciation of most biologically active trace metals in seawater is dominated by complexation by organic ligands. This review traces the history of work in this area, from the early observations that showed surprisingly poor recoveries using metal preconcentration protocols to the present day, where advances in mass spectroscopy and stable isotope geochemistry are providing new insights into the structure, origin, fate, and biogeochemical impact of organic ligands. Many long-standing hypotheses about the specific biological origin of ligands such as siderophores in seawater are finally being validated. This work has revealed the complexity of organic complexation, with multiple ligands and, in some cases, timescales of ligand exchange that are much slower than originally thought. The influence of organic complexation on scavenging is now a key parameter in biogeochemical models of biologically essential metals, especially iron. New insights about the sources and sinks of ligands are required to enhance the usefulness of these models.
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Affiliation(s)
- James W Moffett
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA;
| | - Rene M Boiteau
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA;
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2
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Deng QL, Xiao Y, Jia R, Xie X, Wang L, Wang X, Yang JY, Guo QG, Zhang BH. Devosia lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic Microcystis. Antonie Van Leeuwenhoek 2024; 117:12. [PMID: 38170242 DOI: 10.1007/s10482-023-01909-x] [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: 08/16/2023] [Accepted: 10/21/2023] [Indexed: 01/05/2024]
Abstract
A novel alphaproteobacterial strain JXJ CY 41T was isolated from a culture mass of Microcystis, collected from Lake Dianchi, south-west, China. Strain JXJ CY 41T was gram-strain-negative, aerobic, motile, with rod-shaped cells (0.4-1.0 × 1.7-3.5 μm). It was positive for catalase and starch hydrolysis, negative for oxidase and hydrolysis of Tweens (20, 40, and 80). Growth occurred at 10-44 °C, pH 5.0-10.0, and 0-5.0% (w/v) NaCl. Major fatty acids included C16:0 (28.1%), 11-methyl C18:1 ω7c (36.7%) and C18:1 ω7c (20.8%). Q10 was the sole ubiquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipid, and an unidentified lipid. The DNA G + C content was 63.1%. Its 16S rRNA gene sequence showed high similarities with Devosia oryziradicis G19T (99.5%; not validly published), D. yakushimensis Yak96BT (98.3%) and D. ginsengisoli Gsoil 520T (98.1%), and less than 98.1% similarities with other members of the genus Devosia. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain JXJ CY 41T and its 5 closest similar strains were 19.9-24.1% and 75.7-80.5%, respectively. Based on the data above, strain JXJ CY 41T was identified as a novel species of the genus Devosia, for which the epithet Devosia lacusdianchii sp. nov. was proposed. The type strain is JXJ CY 41T (= KCTC 72812T = CGMCC 1.17502T). Strain JXJ CY 41T exhibited different interactions with Microcystis aeruginosa FACHB-905 (Maf) under different conditions, and Maf could control the bacterial cellular density by secreting unknown specific chemical compounds according to its nutritional requirements.
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Affiliation(s)
- Qing-Lin Deng
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Yao Xiao
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Ru Jia
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Xin Xie
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Le Wang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Xin Wang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Jian-Yuan Yang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China.
| | - Qi-Gen Guo
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China
| | - Bing-Huo Zhang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332000, People's Republic of China.
- Jiujiang Key Laboratory for the Development and Utilization of Traditional Chinese Medicine Resources in Northwest Jiangxi, Jiujiang, People's Republic of China.
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3
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Koedooder C, Zhang F, Wang S, Basu S, Haley ST, Tolic N, Nicora CD, Glavina del Rio T, Dyhrman ST, Gledhill M, Boiteau RM, Rubin-Blum M, Shaked Y. Taxonomic distribution of metabolic functions in bacteria associated with Trichodesmium consortia. mSystems 2023; 8:e0074223. [PMID: 37916816 PMCID: PMC10734445 DOI: 10.1128/msystems.00742-23] [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: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Colonies of the cyanobacteria Trichodesmium act as a biological hotspot for the usage and recycling of key resources such as C, N, P, and Fe within an otherwise oligotrophic environment. While Trichodesmium colonies are known to interact and support a unique community of algae and particle-associated microbes, our understanding of the taxa that populate these colonies and the gene functions they encode is still limited. Characterizing the taxa and adaptive strategies that influence consortium physiology and its concomitant biogeochemistry is critical in a future ocean predicted to have increasingly resource-depleted regions.
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Affiliation(s)
- Coco Koedooder
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Futing Zhang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Siyuan Wang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Subhajit Basu
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Microsensor Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sheean T. Haley
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
| | - Nikola Tolic
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Carrie D. Nicora
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Tijana Glavina del Rio
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Sonya T. Dyhrman
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, USA
| | | | - Rene M. Boiteau
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
| | | | - Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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4
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Eichner M, Inomura K, Pierella Karlusich JJ, Shaked Y. Better together? Lessons on sociality from Trichodesmium. Trends Microbiol 2023; 31:1072-1084. [PMID: 37244772 DOI: 10.1016/j.tim.2023.05.001] [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: 12/27/2022] [Revised: 04/30/2023] [Accepted: 05/01/2023] [Indexed: 05/29/2023]
Abstract
The N2-fixing cyanobacterium Trichodesmium is an important player in the oceanic nitrogen and carbon cycles. Trichodesmium occurs both as single trichomes and as colonies containing hundreds of trichomes. In this review, we explore the benefits and disadvantages of colony formation, considering physical, chemical, and biological effects from nanometer to kilometer scale. Showing that all major life challenges are affected by colony formation, we claim that Trichodesmium's ecological success is tightly linked to its colonial lifestyle. Microbial interactions in the microbiome, chemical gradients within the colony, interactions with particles, and elevated mobility in the water column shape a highly dynamic microenvironment. We postulate that these dynamics are key to the resilience of Trichodesmium and other colony formers in our changing environment.
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Affiliation(s)
- Meri Eichner
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | | | - Yeala Shaked
- Freddy and Nadine Herrmann Institute of Earth Sciences, Hebrew University, Jerusalem, Israel; Interuniversity Institute for Marine Sciences, Eilat, Israel
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5
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Pfreundt U, Słomka J, Schneider G, Sengupta A, Carrara F, Fernandez V, Ackermann M, Stocker R. Controlled motility in the cyanobacterium Trichodesmium regulates aggregate architecture. Science 2023; 380:830-835. [PMID: 37228200 DOI: 10.1126/science.adf2753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 04/25/2023] [Indexed: 05/27/2023]
Abstract
The ocean's nitrogen is largely fixed by cyanobacteria, including Trichodesmium, which forms aggregates comprising hundreds of filaments arranged in organized architectures. Aggregates often form upon exposure to stress and have ecological and biophysical characteristics that differ from those of single filaments. Here, we report that Trichodesmium aggregates can rapidly modulate their shape, responding within minutes to changes in environmental conditions. Combining video microscopy and mathematical modeling, we discovered that this reorganization is mediated by "smart reversals" wherein gliding filaments reverse when their overlap with other filaments diminishes. By regulating smart reversals, filaments control aggregate architecture without central coordination. We propose that the modulation of gliding motility at the single-filament level is a determinant of Trichodesmium's aggregation behavior and ultimately of its biogeochemical role in the ocean.
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Affiliation(s)
- Ulrike Pfreundt
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
| | - Jonasz Słomka
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
| | - Giulia Schneider
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
| | - Anupam Sengupta
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, Luxembourg City, Grand Duchy of Luxembourg
| | - Francesco Carrara
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
| | - Vicente Fernandez
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
| | - Martin Ackermann
- Department of Environmental Systems Sciences, Microbial Systems Ecology Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zürich, Switzerland
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Sciences, Dübendorf, Switzerland
| | - Roman Stocker
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zürich, Switzerland
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6
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Rucker HR, Kaçar B. Enigmatic evolution of microbial nitrogen fixation: insights from Earth's past. Trends Microbiol 2023:S0966-842X(23)00091-4. [PMID: 37061455 DOI: 10.1016/j.tim.2023.03.011] [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: 02/10/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 04/17/2023]
Abstract
The evolution of nitrogen fixation undoubtedly altered nearly all corners of the biosphere, given the essential role of nitrogen in the synthesis of biomass. To date, there is no unified view on what planetary conditions gave rise to nitrogen fixation or how these conditions have sustained it evolutionarily. Intriguingly, the concentrations of metals that nitrogenases require to function have changed throughout Earth's history. In this review, we describe the interconnection of the metal and nitrogen cycles with nitrogenase evolution and the importance of ancient ecology in the formation of the modern nitrogen cycle. We argue that exploration of the nitrogen cycle's deep past will provide insights into humanity's immediate environmental challenges centered on nitrogen availability.
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Affiliation(s)
- Holly R Rucker
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
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7
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Webb EA, Held NA, Zhao Y, Graham ED, Conover AE, Semones J, Lee MD, Feng Y, Fu FX, Saito MA, Hutchins DA. Importance of mobile genetic element immunity in numerically abundant Trichodesmium clades. ISME COMMUNICATIONS 2023; 3:15. [PMID: 36823453 PMCID: PMC9950141 DOI: 10.1038/s43705-023-00214-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/13/2022] [Accepted: 01/12/2023] [Indexed: 02/25/2023]
Abstract
The colony-forming cyanobacteria Trichodesmium spp. are considered one of the most important nitrogen-fixing genera in the warm, low nutrient ocean. Despite this central biogeochemical role, many questions about their evolution, physiology, and trophic interactions remain unanswered. To address these questions, we describe Trichodesmium pangenomic potential via significantly improved genomic assemblies from two isolates and 15 new >50% complete Trichodesmium metagenome-assembled genomes from hand-picked, Trichodesmium colonies spanning the Atlantic Ocean. Phylogenomics identified ~four N2 fixing clades of Trichodesmium across the transect, with T. thiebautii dominating the colony-specific reads. Pangenomic analyses showed that all T. thiebautii MAGs are enriched in COG defense mechanisms and encode a vertically inherited Type III-B Clustered Regularly Interspaced Short Palindromic Repeats and associated protein-based immunity system (CRISPR-Cas). Surprisingly, this CRISPR-Cas system was absent in all T. erythraeum genomes, vertically inherited by T. thiebautii, and correlated with increased signatures of horizontal gene transfer. Additionally, the system was expressed in metaproteomic and transcriptomic datasets and CRISPR spacer sequences with 100% identical hits to field-assembled, putative phage genome fragments were identified. While the currently CO2-limited T. erythraeum is expected to be a 'winner' of anthropogenic climate change, their genomic dearth of known phage resistance mechanisms, compared to T. thiebautii, could put this outcome in question. Thus, the clear demarcation of T. thiebautii maintaining CRISPR-Cas systems, while T. erythraeum does not, identifies Trichodesmium as an ecologically important CRISPR-Cas model system, and highlights the need for more research on phage-Trichodesmium interactions.
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Affiliation(s)
- Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Noelle A Held
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Environmental Systems Science, ETH, Zurich, Switzerland
| | - Yiming Zhao
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Elaina D Graham
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Asa E Conover
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Jake Semones
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Michael D Lee
- Blue Marble Space Institute of Science, NASA Ames Research Center, Mountain View, CA, 94035, USA
| | - Yuanyuan Feng
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Fei-Xue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mak A Saito
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
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8
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Quantitative Analysis of the Trade-Offs of Colony Formation for Trichodesmium. Microbiol Spectr 2022; 10:e0202522. [PMID: 36374046 PMCID: PMC9769814 DOI: 10.1128/spectrum.02025-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
There is considerable debate about the benefits and trade-offs for colony formation in a major marine nitrogen fixer, Trichodesmium. To quantitatively analyze the trade-offs, we developed a metabolic model based on carbon fluxes to compare the performance of Trichodesmium colonies and free trichomes under different scenarios. Despite reported reductions in carbon fixation and nitrogen fixation rates for colonies relative to free trichomes, we found that model colonies can outperform individual cells in several cases. The formation of colonies can be advantageous when respiration rates account for a high proportion of the carbon fixation rate. Negative external influence on vital rates, such as mortality due to predation or micronutrient limitations, can also create a net benefit for colony formation relative to individual cells. In contrast, free trichomes also outcompete colonies in many scenarios, such as when respiration rates are equal for both colonies and individual cells or when there is a net positive external influence on rate processes (i.e., optimal environmental conditions regarding light and temperature or high nutrient availability). For both colonies and free trichomes, an increase in carbon fixation relative to nitrogen fixation rates would increase their relative competitiveness. These findings suggest that the formation of colonies in Trichodesmium might be linked to specific environmental and ecological circumstances. Our results provide a road map for empirical studies and models to evaluate the conditions under which colony formation in marine phytoplankton can be sustained in the natural environment. IMPORTANCE Trichodesmium is a marine filamentous cyanobacterium that fixes nitrogen and is an important contributor to the global nitrogen cycle. In the natural environment, Trichodesmium can exist as individual cells (trichomes) or as colonies (puffs and tufts). In this paper, we try to answer a longstanding question in marine microbial ecology: how does colony formation benefit the survival of Trichodesmium? To answer this question, we developed a carbon flux model that utilizes existing published rates to evaluate whether and when colony formation can be sustained. Enhanced respiration rates, influential external factors such as environmental conditions and ecological interactions, and variable carbon and nitrogen fixation rates can all create scenarios for colony formation to be a viable strategy. Our results show that colony formation is an ecologically beneficial strategy under specific conditions, enabling Trichodesmium to be a globally significant organism.
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9
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Vaksmaa A, Egger M, Lüke C, Martins PD, Rosselli R, Asbun AA, Niemann H. Microbial communities on plastic particles in surface waters differ from subsurface waters of the North Pacific Subtropical Gyre. MARINE POLLUTION BULLETIN 2022; 182:113949. [PMID: 35932724 DOI: 10.1016/j.marpolbul.2022.113949] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
The long-term fate of plastics in the ocean and their interactions with marine microorganisms remain poorly understood. In particular, the role of sinking plastic particles as a transport vector for surface microbes towards the deep sea has not been investigated. Here, we present the first data on the composition of microbial communities on floating and suspended plastic particles recovered from the surface to the bathypelagic water column (0-2000 m water depth) of the North Pacific Subtropical Gyre. Microbial community composition of suspended plastic particles differed from that of plastic particles afloat at the sea surface. However, in both compartments, a diversity of hydrocarbon-degrading bacteria was identified. These findings indicate that microbial community members initially present on floating plastics are quickly replaced by microorganisms acquired from deeper water layers, thus suggesting a limited efficiency of sinking plastic particles to vertically transport microorganisms in the North Pacific Subtropical Gyre.
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Affiliation(s)
- Annika Vaksmaa
- Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 't Horntje, the Netherlands.
| | - Matthias Egger
- The Ocean Cleanup, Rotterdam, the Netherlands; Egger Research and Consulting, St. Gallen, Switzerland
| | - Claudia Lüke
- Radboud University, Department of Microbiology, Nijmegen, the Netherlands
| | | | - Riccardo Rosselli
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Spain; LABAQUA S.A.U, C/Dracma 16-18, Pol. Ind. Las Atalayas, 03114 Alicante, Spain
| | - Alejandro Abdala Asbun
- Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 't Horntje, the Netherlands
| | - Helge Niemann
- Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 't Horntje, the Netherlands; Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, the Netherlands
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10
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The Self-Bleaching Process of Microcystis aeruginosa is Delayed by a Symbiotic Bacterium Pseudomonas sp. MAE1-K and Promoted by Methionine Deficiency. Microbiol Spectr 2022; 10:e0181422. [PMID: 35771009 PMCID: PMC9430746 DOI: 10.1128/spectrum.01814-22] [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] [Indexed: 11/24/2022] Open
Abstract
Various interactions between marine cyanobacteria and heterotrophic bacteria have been known, but the symbiotic relationships between Microcystis and heterotrophic bacteria remain unclear. An axenic M. aeruginosa culture (NIES-298) was quickly bleached after exponential growth, whereas a xenic M. aeruginosa culture (KW) showed a normal growth curve, suggesting that some symbiotic bacteria may delay this bleaching. The bleaching process of M. aeruginosa was distinguished from the phenomena of previously proposed chlorosis and programmed cell death in various characteristics. Bleached cultures of NIES-298 quickly bleached actively growing M. aeruginosa cultures, suggesting that M. aeruginosa itself produces bleach-causing compounds. Pseudomonas sp. MAE1-K delaying the bleaching of NIES-298 cultures was isolated from the KW culture. Bleached cultures of NIES-298 treated with strain MAE1-K lost their bleaching ability, suggesting that strain MAE1-K rescues M. aeruginosa from bleaching via inactivation of bleaching compounds. From Tn5 transposon mutant screening, a metZ mutant of strain MAE1-K (F-D3) unable to synthesize methionine, promoting the bleaching of NIES-298 cultures but capable of inactivating bleaching compounds, was obtained. The bleaching process of NIES-298 cultures was promoted with the coculture of mutant F-D3 and delayed by methionine supplementation, suggesting that the bleaching process of M. aeruginosa is promoted by methionine deficiency. IMPORTANCE Cyanobacterial blooms in freshwaters represent serious global concerns for the ecosystem and human health. In this study, we found that one of the major species in cyanobacterial blooms, Microcystis aeruginosa, was quickly collapsed after exponential growth by producing self-bleaching compounds and that a symbiotic bacterium, Pseudomonas sp. MAE1-K delayed the bleaching process via the inactivation of bleaching compounds. In addition, we found that a metZ mutant of strain MAE1-K (F-D3) causing methionine deficiency promoted the bleaching process of M. aeruginosa, suggesting that methionine deficiency may induce the production of bleaching compounds. These results will provide insights into the symbiotic relationships between M. aeruginosa and heterotrophic bacteria that will contribute to developing novel strategies to control cyanobacterial blooms.
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11
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Hogle SL, Hackl T, Bundy RM, Park J, Satinsky B, Hiltunen T, Biller S, Berube PM, Chisholm SW. Siderophores as an iron source for picocyanobacteria in deep chlorophyll maximum layers of the oligotrophic ocean. THE ISME JOURNAL 2022; 16:1636-1646. [PMID: 35241788 PMCID: PMC9122953 DOI: 10.1038/s41396-022-01215-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 11/09/2022]
Abstract
Prochlorococcus and Synechococcus are the most abundant photosynthesizing organisms in the oceans. Gene content variation among picocyanobacterial populations in separate ocean basins often mirrors the selective pressures imposed by the region's distinct biogeochemistry. By pairing genomic datasets with trace metal concentrations from across the global ocean, we show that the genomic capacity for siderophore-mediated iron uptake is widespread in Synechococcus and low-light adapted Prochlorococcus populations from deep chlorophyll maximum layers of iron-depleted regions of the oligotrophic Pacific and S. Atlantic oceans: Prochlorococcus siderophore consumers were absent in the N. Atlantic ocean (higher new iron flux) but constituted up to half of all Prochlorococcus genomes from metagenomes in the N. Pacific (lower new iron flux). Picocyanobacterial siderophore consumers, like many other bacteria with this trait, also lack siderophore biosynthesis genes indicating that they scavenge exogenous siderophores from seawater. Statistical modeling suggests that the capacity for siderophore uptake is endemic to remote ocean regions where atmospheric iron fluxes are the smallest, especially at deep chlorophyll maximum and primary nitrite maximum layers. We argue that abundant siderophore consumers at these two common oceanographic features could be a symptom of wider community iron stress, consistent with prior hypotheses. Our results provide a clear example of iron as a selective force driving the evolution of marine picocyanobacteria.
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Affiliation(s)
- Shane L Hogle
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Biology, University of Turku, Turku, Finland.
| | - Thomas Hackl
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Randelle M Bundy
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Jiwoon Park
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Brandon Satinsky
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Teppo Hiltunen
- Department of Biology, University of Turku, Turku, Finland
| | - Steven Biller
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biological Sciences, Wellesley College, Wellesley, MA, USA
| | - Paul M Berube
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sallie W Chisholm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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12
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Koedooder C, Landou E, Zhang F, Wang S, Basu S, Berman-Frank I, Shaked Y, Rubin-Blum M. Metagenomes of Red Sea Subpopulations Challenge the Use of Marker Genes and Morphology to Assess Trichodesmium Diversity. Front Microbiol 2022; 13:879970. [PMID: 35707175 PMCID: PMC9189399 DOI: 10.3389/fmicb.2022.879970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
Trichodesmium are filamentous cyanobacteria of key interest due to their ability to fix carbon and nitrogen within an oligotrophic marine environment. Their blooms consist of a dynamic assemblage of subpopulations and colony morphologies that are hypothesized to occupy unique niches. Here, we assessed the poorly studied diversity of Trichodesmium in the Red Sea, based on metagenome-assembled genomes (MAGs) and hetR gene-based phylotyping. We assembled four non-redundant MAGs from morphologically distinct Trichodesmium colonies (tufts, dense and thin puffs). Trichodesmium thiebautii (puffs) and Trichodesmium erythraeum (tufts) were the dominant species within these morphotypes. While subspecies diversity is present for both T. thiebautii and T. erythraeum, a single T. thiebautii genotype comprised both thin and dense puff morphotypes, and we hypothesize that this phenotypic variation is likely attributed to gene regulation. Additionally, we found the rare non-diazotrophic clade IV and V genotypes, related to Trichodesmium nobis and Trichodesmium miru, respectively that likely occurred as single filaments. The hetR gene phylogeny further indicated that the genotype in clade IV could represent the species Trichodesmium contortum. Importantly, we show the presence of hetR paralogs in Trichodesmium, where two copies of the hetR gene were present within T. thiebautii genomes. This may lead to the overestimation of Trichodesmium diversity as one of the copies misidentified T. thiebautii as Trichodesmium aureum. Taken together, our results highlight the importance of re-assessing Trichodesmium taxonomy while showing the ability of genomics to capture the complex diversity and distribution of Trichodesmium populations.
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Affiliation(s)
- Coco Koedooder
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Israel Oceanographic and Limnological Research, Haifa, Israel
- *Correspondence: Coco Koedooder,
| | - Etai Landou
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Futing Zhang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Siyuan Wang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Subhajit Basu
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Microsensor Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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13
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Aerosol Nutrients and Their Biological Influence on the Northwest Pacific Ocean (NWPO) and Its Marginal Seas. BIOLOGY 2022; 11:biology11060842. [PMID: 35741363 PMCID: PMC9219953 DOI: 10.3390/biology11060842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/22/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary With intensifying human activities in the past decades, East Asia has recorded increasingly severe air pollution and become the second largest aerosol source on earth. The large quantity of aerosol emissions is not only a major health threat to humans, but can also be transported for a long distance and deposited in downwind seas and oceans. The aerosol contains major ions, heavy metals, and organic matters that are important external nutrients in upper oceans and potentially influence marine microbes and biogeochemical cycles. Therefore, the role of atmospheric deposition to oceans has received growing attention in recent years. In this paper, the current state of knowledge on the atmospheric nutrients and the biological effect of East Asian aerosol deposition on the northwest Pacific Ocean are reviewed, which could help us better understand the comprehensive influence of East Asian aerosols on marine ecosystems, and give insights into future research directions, especially under the future scenarios of changing human activities and climate. Abstract Atmospheric deposition is recognized as a significant source of nutrients in the surface ocean. The East Asia region is among the largest sources of aerosol emissions in the world, due to its large industrial, agricultural, and energy production. Thus, East Asian aerosols contain a large proportion of anthropogenic particles that are characterized by small size, complex composition, and high nutrient dissolution, resulting in important influences on marine microbes and biogeochemical cycles in the downwind areas of the northwest Pacific Ocean (NWPO). By using remote sensing, modeling, and incubation experimental methods, enhanced primary production due to the East Asian aerosol input has been observed in the NWPO, with subsequent promotion and inhibition impacts on different phytoplankton taxa. Changes of bacterial activity and diversity also occur in response to aerosol input. The impact of East Asian aerosol loadings is closely related to the amount and composition of the aerosol deposition as well as the hydrological condition of the receiving seawater. Here, we review the current state of knowledge on the atmospheric nutrients and the effects of the East Asian aerosols on microbes in the NWPO region. Future research perspectives are also proposed.
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14
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Qu PP, Fu FX, Wang XW, Kling JD, Elghazzawy M, Huh M, Zhou QQ, Wang C, Mak EWK, Lee MD, Yang N, Hutchins DA. Two co-dominant nitrogen-fixing cyanobacteria demonstrate distinct acclimation and adaptation responses to cope with ocean warming. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:203-217. [PMID: 35023627 DOI: 10.1111/1758-2229.13041] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 05/28/2023]
Abstract
The globally dominant N2 -fixing cyanobacteria Trichodesmium and Crocosphaera provide vital nitrogen supplies to subtropical and tropical oceans, but little is known about how they will be affected by long-term ocean warming. We tested their thermal responses using experimental evolution methods during 2 years of selection at optimal (28°C), supra-optimal (32°C) and suboptimal (22°C) temperatures. After several hundred generations under thermal selection, changes in growth parameters, as well as N and C fixation rates, suggested that Trichodesmium did not adapt to the three selection temperature regimes during the 2-year evolution experiment, but could instead rapidly and reversibly acclimate to temperature shifts from 20°C to 34°C. In contrast, over the same timeframe apparent thermal adaptation was observed in Crocosphaera, as evidenced by irreversible phenotypic changes as well as whole-genome sequencing and variant analysis. Especially under stressful warming conditions (34°C), 32°C-selected Crocosphaera cells had an advantage in survival and nitrogen fixation over cell lines selected at 22°C and 28°C. The distinct strategies of phenotypic plasticity versus irreversible adaptation in these two sympatric diazotrophs are both viable ways to maintain fitness despite long-term temperature changes, and so could help to stabilize key ocean nitrogen cycle functions under future warming scenarios.
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Affiliation(s)
- Ping-Ping Qu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Fei-Xue Fu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Xin-Wei Wang
- School of Marine Sciences, Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Joshua D Kling
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mariam Elghazzawy
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Megan Huh
- Department of Preventative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Qian-Qian Zhou
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian, 361005, China
| | - Chunguang Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian, 361005, China
| | - Esther Wing Kwan Mak
- Department of Ocean Sciences and Institute of Marine Sciences, University of California, Santa Cruz, CA, 95064, USA
| | - Michael D Lee
- Exobiology Branch, NASA Ames Research Center, Mountain View, CA, 94035, USA
- Blue Marble Space Institute of Science, Seattle, WA, 98154, USA
| | - Nina Yang
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - David A Hutchins
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
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15
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Zoccarato L, Sher D, Miki T, Segrè D, Grossart HP. A comparative whole-genome approach identifies bacterial traits for marine microbial interactions. Commun Biol 2022; 5:276. [PMID: 35347228 PMCID: PMC8960797 DOI: 10.1038/s42003-022-03184-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/30/2021] [Indexed: 12/11/2022] Open
Abstract
Microbial interactions shape the structure and function of microbial communities with profound consequences for biogeochemical cycles and ecosystem health. Yet, most interaction mechanisms are studied only in model systems and their prevalence is unknown. To systematically explore the functional and interaction potential of sequenced marine bacteria, we developed a trait-based approach, and applied it to 473 complete genomes (248 genera), representing a substantial fraction of marine microbial communities. We identified genome functional clusters (GFCs) which group bacterial taxa with common ecology and life history. Most GFCs revealed unique combinations of interaction traits, including the production of siderophores (10% of genomes), phytohormones (3-8%) and different B vitamins (57-70%). Specific GFCs, comprising Alpha- and Gammaproteobacteria, displayed more interaction traits than expected by chance, and are thus predicted to preferentially interact synergistically and/or antagonistically with bacteria and phytoplankton. Linked trait clusters (LTCs) identify traits that may have evolved to act together (e.g., secretion systems, nitrogen metabolism regulation and B vitamin transporters), providing testable hypotheses for complex mechanisms of microbial interactions. Our approach translates multidimensional genomic information into an atlas of marine bacteria and their putative functions, relevant for understanding the fundamental rules that govern community assembly and dynamics.
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Affiliation(s)
- Luca Zoccarato
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany.
| | - Daniel Sher
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 3498838, Haifa, Israel.
| | - Takeshi Miki
- Faculty of Advanced Science and Technology, Ryukoku University, 520-2194, Otsu, Japan
| | - Daniel Segrè
- Departments of Biology, Biomedical Engineering, Physics, Boston University, 02215, Boston, MA, USA
- Bioinformatics Program & Biological Design Center, Boston University, 02215, Boston, MA, USA
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany.
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195, Berlin, Germany.
- Institute of Biochemistry and Biology, Potsdam University, 14476, Potsdam, Germany.
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16
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Manck LE, Park J, Tully BJ, Poire AM, Bundy RM, Dupont CL, Barbeau KA. Petrobactin, a siderophore produced by Alteromonas, mediates community iron acquisition in the global ocean. THE ISME JOURNAL 2022; 16:358-369. [PMID: 34341506 PMCID: PMC8776838 DOI: 10.1038/s41396-021-01065-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 02/07/2023]
Abstract
It is now widely accepted that siderophores play a role in marine iron biogeochemical cycling. However, the mechanisms by which siderophores affect the availability of iron from specific sources and the resulting significance of these processes on iron biogeochemical cycling as a whole have remained largely untested. In this study, we develop a model system for testing the effects of siderophore production on iron bioavailability using the marine copiotroph Alteromonas macleodii ATCC 27126. Through the generation of the knockout cell line ΔasbB::kmr, which lacks siderophore biosynthetic capabilities, we demonstrate that the production of the siderophore petrobactin enables the acquisition of iron from mineral sources and weaker iron-ligand complexes. Notably, the utilization of lithogenic iron, such as that from atmospheric dust, indicates a significant role for siderophores in the incorporation of new iron into marine systems. We have also detected petrobactin, a photoreactive siderophore, directly from seawater in the mid-latitudes of the North Pacific and have identified the biosynthetic pathway for petrobactin in bacterial metagenome-assembled genomes widely distributed across the global ocean. Together, these results improve our mechanistic understanding of the role of siderophore production in iron biogeochemical cycling in the marine environment wherein iron speciation, bioavailability, and residence time can be directly influenced by microbial activities.
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Affiliation(s)
- Lauren E Manck
- Geosciences Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
| | - Jiwoon Park
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Benjamin J Tully
- Center for Dark Energy Biosphere Investigations, University of Southern California, Los Angeles, CA, USA
| | - Alfonso M Poire
- Department of Environment and Sustainability, J. Craig Venter Institute, La Jolla, CA, USA
| | - Randelle M Bundy
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Christopher L Dupont
- Department of Environment and Sustainability, J. Craig Venter Institute, La Jolla, CA, USA
- Department of Human Health, J. Craig Venter Institute, La Jolla, CA, USA
- Department of Synthetic Biology, J. Craig Venter Institute, La Jolla, CA, USA
| | - Katherine A Barbeau
- Geosciences Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
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17
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Wang S, Koedooder C, Zhang F, Kessler N, Eichner M, Shi D, Shaked Y. Colonies of the marine cyanobacterium Trichodesmium optimize dust utilization by selective collection and retention of nutrient-rich particles. iScience 2022; 25:103587. [PMID: 35005537 PMCID: PMC8718973 DOI: 10.1016/j.isci.2021.103587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/01/2021] [Accepted: 12/06/2021] [Indexed: 12/11/2022] Open
Abstract
Trichodesmium, a globally important, N2-fixing, and colony-forming cyanobacterium, employs multiple pathways for acquiring nutrients from air-borne dust, including active dust collection. Once concentrated within the colony core, dust can supply Trichodesmium with nutrients. Recently, we reported a selectivity in particle collection enabling Trichodesmium to center iron-rich minerals and optimize its nutrient utilization. In this follow-up study we examined if colonies select Phosphorus (P) minerals. We incubated 1,200 Trichodesmium colonies from the Red Sea with P-free CaCO3, P-coated CaCO3, and dust, over an entire bloom season. These colonies preferably interacted, centered, and retained P-coated CaCO3 compared with P-free CaCO3. In both studies, Trichodesmium clearly favored dust over all other particles tested, whereas nutrient-free particles were barely collected or retained, indicating that the colonies sense the particle composition and preferably collect nutrient-rich particles. This unique ability contributes to Trichodesmium's current ecological success and may assist it to flourish in future warmer oceans. Natural Trichodesmium colonies collect and maintain dust within their colony core Using synthetic particles we tested if colonies select the particles they collect Colonies selectively collect and retain nutrient-rich over nutrient-free particles Selective collection of particles optimizes their nutrient acquisition from dust
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Affiliation(s)
- Siyuan Wang
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Coco Koedooder
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel.,Israel Limnology and Oceanography Research, Haifa, Israel
| | - Futing Zhang
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel.,State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Nivi Kessler
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Meri Eichner
- Laboratory of Photosynthesis, Center Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Dalin Shi
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Yeala Shaked
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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18
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Dynamic diel proteome and daytime nitrogenase activity supports buoyancy in the cyanobacterium Trichodesmium. Nat Microbiol 2022; 7:300-311. [PMID: 35013592 DOI: 10.1038/s41564-021-01028-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022]
Abstract
Cyanobacteria of the genus Trichodesmium provide about 80 Tg of fixed nitrogen to the surface ocean per year and contribute to marine biogeochemistry, including the sequestration of carbon dioxide. Trichodesmium fixes nitrogen in the daylight, despite the incompatibility of the nitrogenase enzyme with oxygen produced during photosynthesis. While the mechanisms protecting nitrogenase remain unclear, all proposed strategies require considerable resource investment. Here we identify a crucial benefit of daytime nitrogen fixation in Trichodesmium spp. that may counteract these costs. We analysed diel proteomes of cultured and field populations of Trichodesmium in comparison with the marine diazotroph Crocosphaera watsonii WH8501, which fixes nitrogen at night. Trichodesmium's proteome is extraordinarily dynamic and demonstrates simultaneous photosynthesis and nitrogen fixation, resulting in balanced particulate organic carbon and particulate organic nitrogen production. Unlike Crocosphaera, which produces large quantities of glycogen as an energy store for nitrogenase, proteomic evidence is consistent with the idea that Trichodesmium reduces the need to produce glycogen by supplying energy directly to nitrogenase via soluble ferredoxin charged by the photosynthesis protein PsaC. This minimizes ballast associated with glycogen, reducing cell density and decreasing sinking velocity, thus supporting Trichodesmium's niche as a buoyant, high-light-adapted colony forming cyanobacterium. To occupy its niche of simultaneous nitrogen fixation and photosynthesis, Trichodesmium appears to be a conspicuous consumer of iron, and has therefore developed unique iron-acquisition strategies, including the use of iron-rich dust. Particle capture by buoyant Trichodesmium colonies may increase the residence time and degradation of mineral iron in the euphotic zone. These findings describe how cellular biochemistry defines and reinforces the ecological and biogeochemical function of these keystone marine diazotrophs.
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19
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Conover AE, Morando M, Zhao Y, Semones J, Hutchins DA, Webb EA. Alphaproteobacteria facilitate Trichodesmium community trimethylamine utilization. Environ Microbiol 2021; 23:6798-6810. [PMID: 34519133 DOI: 10.1111/1462-2920.15773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/26/2021] [Accepted: 09/09/2021] [Indexed: 11/28/2022]
Abstract
In the surface waters of the warm oligotrophic ocean, filaments and aggregated colonies of the nitrogen (N)-fixing cyanobacterium Trichodesmium create microscale nutrient-rich oases. These hotspots fuel primary productivity and harbour a diverse consortium of heterotrophs. Interactions with associated microbiota can affect the physiology of Trichodesmium, often in ways that have been predicted to support its growth. Recently, it was found that trimethylamine (TMA), a globally abundant organic N compound, inhibits N2 fixation in cultures of Trichodesmium without impairing growth rate, suggesting that Trichodesmium can use TMA as an alternate N source. In this study, 15 N-TMA DNA stable isotope probing (SIP) of a Trichodesmium enrichment was employed to further investigate TMA metabolism and determine whether TMA-N is incorporated directly or secondarily via cross-feeding facilitated by microbial associates. Herein, we identify two members of the marine Roseobacter clade (MRC) of Alphaproteobacteria as the likely metabolizers of TMA and provide genomic evidence that they converted TMA into a more readily available form of N, e.g., ammonium (NH4 + ), which was subsequently used by Trichodesmium and the rest of the community. The results implicate microbiome-mediated carbon (C) and N transformations in modulating N2 fixation and thus highlight the involvement of host-associated heterotrophs in global biogeochemical cycling.
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Affiliation(s)
- Asa E Conover
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
| | - Michael Morando
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
| | - Yiming Zhao
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
| | - Jacob Semones
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
| | - David A Hutchins
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
| | - Eric A Webb
- Department of Marine and Environmental Biology, University of Southern California, CA, USA
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20
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Ansari AA, Ansari AA, Abouhend AS, Gikonyo JG, Park C. Photogranulation in a Hydrostatic Environment Occurs with Limitation of Iron. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10672-10683. [PMID: 34255495 DOI: 10.1021/acs.est.0c07374] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Filamentous cyanobacteria are an essential element of oxygenic photogranules for granule-based wastewater treatment with photosynthetic aeration. Currently, mechanisms for the selection of this microbial group and their development in the granular structure are not well understood. Here, we studied the characteristics and fate of iron in photogranulation that proceeds in a hydrostatic environment with an activated sludge (AS) inoculum. We found that the level of Fe in bulk liquids (FeBL) sharply increased due to the decay of the inoculum but quickly diminished along with the bloom of microalgae and the advent of the oxic environment. Iron linked with extracellular polymeric substances (FeEPS) continued to decline but reached steady low values, which occurred along with the appearance of granular structure. Strong negative correlations were found between FeEPS and the pigments specific for cyanobacteria. Spectroscopies revealed the presence of amorphous ferric oxides in pellet biomass, which seemed to remain unaltered during the photogranulation process. These results suggest that the availability of FeEPS in AS inoculums-after algal bloom-selects cyanobacteria, and the limitation of this Fe pool becomes an important driver for cyanobacteria to granulate in a hydrostatic environment. We therefore propose that the availability of iron has a strong influence on the photogranulation process.
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Affiliation(s)
- Abeera A Ansari
- Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- U.S.-Pakistan Center for Advanced Studies in Energy (USPCAS-E), National University of Sciences and Technology (NUST), H-12 Sector, 44000 Islamabad , Pakistan
| | - Arfa A Ansari
- Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Ahmed S Abouhend
- Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Joseph G Gikonyo
- Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Chul Park
- Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
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21
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Held NA, Sutherland KM, Webb EA, McIlvin MR, Cohen NR, Devaux AJ, Hutchins DA, Waterbury JB, Hansel CM, Saito MA. Mechanisms and heterogeneity of in situ mineral processing by the marine nitrogen fixer Trichodesmium revealed by single-colony metaproteomics. ISME COMMUNICATIONS 2021; 1:35. [PMID: 36739337 PMCID: PMC9723768 DOI: 10.1038/s43705-021-00034-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/10/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023]
Abstract
The keystone marine nitrogen fixer Trichodesmium thrives in high-dust environments. While laboratory investigations have observed that Trichodesmium colonies can access the essential nutrient iron from dust particles, less clear are the biochemical strategies underlying particle-colony interactions in nature. Here we demonstrate that Trichodesmium colonies engage with mineral particles in the wild with distinct molecular responses. We encountered particle-laden Trichodesmium colonies at a sampling location in the Southern Caribbean Sea; microscopy and synchrotron-based imaging then demonstrated heterogeneous associations with iron oxide and iron-silicate minerals. Metaproteomic analysis of individual colonies by a new low-biomass approach revealed responses in biogeochemically relevant proteins including photosynthesis proteins and metalloproteins containing iron, nickel, copper, and zinc. The iron-storage protein ferritin was particularly enriched implying accumulation of mineral-derived iron, and multiple iron acquisition pathways including Fe(II), Fe(III), and Fe-siderophore transporters were engaged. While the particles provided key trace metals such as iron and nickel, there was also evidence that Trichodesmium was altering its strategy to confront increased superoxide production and metal exposure. Chemotaxis regulators also responded to mineral presence suggesting involvement in particle entrainment. These molecular responses are fundamental to Trichodesmium's ecological success and global biogeochemical impact, and may contribute to the leaching of particulate trace metals with implications for global iron and carbon cycling.
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Affiliation(s)
- Noelle A Held
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Kevin M Sutherland
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Matthew R McIlvin
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Natalie R Cohen
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Alexander J Devaux
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - John B Waterbury
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Colleen M Hansel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Mak A Saito
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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22
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Iron transport in cyanobacteria - from molecules to communities. Trends Microbiol 2021; 30:229-240. [PMID: 34175176 DOI: 10.1016/j.tim.2021.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 11/22/2022]
Abstract
Iron is an essential micronutrient for the ecologically important photoautotrophic cyanobacteria which are found across diverse aquatic environments. Low concentrations and poor bioavailability of certain iron species exert a strong control on cyanobacterial growth, affecting ecosystem structure and biogeochemical cycling. Here, we review the iron-acquisition pathways cyanobacteria utilize for overcoming these challenges. As the molecular details of cyanobacterial iron transport are being uncovered, an overall scheme of how cyanobacteria handle and exploit this scarce and redox-active micronutrient is emerging. Importantly, the range of biological solutions used by cyanobacteria to increase iron fluxes goes beyond transport and includes behavioral traits of colonial cyanobacteria and intricate cyanobacteria-bacteria interactions.
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Smith DJ, Tan JY, Powers MA, Lin XN, Davis TW, Dick GJ. Individual Microcystis colonies harbour distinct bacterial communities that differ by Microcystis oligotype and with time. Environ Microbiol 2021; 23:3020-3036. [PMID: 33830633 DOI: 10.1111/1462-2920.15514] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 03/11/2021] [Accepted: 04/06/2021] [Indexed: 12/31/2022]
Abstract
Interactions between bacteria and phytoplankton in the phycosphere have impacts at the scale of whole ecosystems, including the development of harmful algal blooms. The cyanobacterium Microcystis causes toxic blooms that threaten freshwater ecosystems and human health globally. Microcystis grows in colonies that harbour dense assemblages of other bacteria, yet the taxonomic composition of these phycosphere communities and the nature of their interactions with Microcystis are not well characterized. To identify the taxa and compositional variance within Microcystis phycosphere communities, we performed 16S rRNA V4 region amplicon sequencing on individual Microcystis colonies collected biweekly via high-throughput droplet encapsulation during a western Lake Erie cyanobacterial bloom. The Microcystis phycosphere communities were distinct from microbial communities in whole water and bulk phytoplankton seston in western Lake Erie but lacked 'core' taxa found across all colonies. However, dissimilarity in phycosphere community composition correlated with sampling date and the Microcystis 16S rRNA oligotype. Several taxa in the phycosphere were specific to and conserved with Microcystis of a single oligotype or sampling date. Together, this suggests that physiological differences between Microcystis strains, temporal changes in strain phenotypes, and the composition of seeding communities may impact community composition of the Microcystis phycosphere.
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Affiliation(s)
- Derek J Smith
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - James Y Tan
- Department of Chemical Engineering, The University of Michigan, NCRC, 2800 Plymouth Rd., Ann Abor, MI, 48109, USA
| | - McKenzie A Powers
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Xiaoxia N Lin
- Department of Chemical Engineering, The University of Michigan, NCRC, 2800 Plymouth Rd., Ann Abor, MI, 48109, USA
| | - Timothy W Davis
- Department of Biological Sciences, Bowling Green State University, Life Sciences Building, Corner of N. College Dr and E. Merry Avenue, Bowling Green, OH, 43403, USA
| | - Gregory J Dick
- Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA
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24
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Wang S, Tang W, Delage E, Gifford S, Whitby H, González AG, Eveillard D, Planquette H, Cassar N. Investigating the microbial ecology of coastal hotspots of marine nitrogen fixation in the western North Atlantic. Sci Rep 2021; 11:5508. [PMID: 33750865 PMCID: PMC7943828 DOI: 10.1038/s41598-021-84969-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/27/2021] [Indexed: 11/24/2022] Open
Abstract
Variation in the microbial cycling of nutrients and carbon in the ocean is an emergent property of complex planktonic communities. While recent findings have considerably expanded our understanding of the diversity and distribution of nitrogen (N2) fixing marine diazotrophs, knowledge gaps remain regarding ecological interactions between diazotrophs and other community members. Using quantitative 16S and 18S V4 rDNA amplicon sequencing, we surveyed eukaryotic and prokaryotic microbial communities from samples collected in August 2016 and 2017 across the Western North Atlantic. Leveraging and significantly expanding an earlier published 2015 molecular dataset, we examined microbial community structure and ecological co-occurrence relationships associated with intense hotspots of N2 fixation previously reported at sites off the Southern New England Shelf and Mid-Atlantic Bight. Overall, we observed a negative relationship between eukaryotic diversity and both N2 fixation and net community production (NCP). Maximum N2 fixation rates occurred at sites with high abundances of mixotrophic stramenopiles, notably Chrysophyceae. Network analysis revealed such stramenopiles to be keystone taxa alongside the haptophyte diazotroph host Braarudosphaera bigelowii and chlorophytes. Our findings highlight an intriguing relationship between marine stramenopiles and high N2 fixation coastal sites.
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Affiliation(s)
- Seaver Wang
- Division of Earth and Ocean Sciences, Duke University, Grainger Environment Hall, 9 Circuit Drive, Box 90328, Durham, NC, 27708, USA
| | - Weiyi Tang
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Erwan Delage
- LS2N, UMR 6004, CNRS, Université de Nantes, 44000, Nantes, France
| | - Scott Gifford
- Department of Marine Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Hannah Whitby
- Department of Earth, Ocean, and Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Aridane G González
- Instituto de Oceanografía y Cambio Global (IOCAG), Universidad de Las Palmas de Gran Canaria, ULPGC, Las Palmas, Spain.,Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Technopôle Brest-Iroise, 13 Plouzané, 29280, Locmaria-Plouzané, France
| | - Damien Eveillard
- LS2N, UMR 6004, CNRS, Université de Nantes, 44000, Nantes, France
| | - Hélène Planquette
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Technopôle Brest-Iroise, 13 Plouzané, 29280, Locmaria-Plouzané, France
| | - Nicolas Cassar
- Division of Earth and Ocean Sciences, Duke University, Grainger Environment Hall, 9 Circuit Drive, Box 90328, Durham, NC, 27708, USA. .,Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Technopôle Brest-Iroise, 13 Plouzané, 29280, Locmaria-Plouzané, France.
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Inomura K, Deutsch C, Masuda T, Prášil O, Follows MJ. Quantitative models of nitrogen-fixing organisms. Comput Struct Biotechnol J 2020; 18:3905-3924. [PMID: 33335688 PMCID: PMC7733014 DOI: 10.1016/j.csbj.2020.11.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 10/26/2022] Open
Abstract
Nitrogen-fixing organisms are of importance to the environment, providing bioavailable nitrogen to the biosphere. Quantitative models have been used to complement the laboratory experiments and in situ measurements, where such evaluations are difficult or costly. Here, we review the current state of the quantitative modeling of nitrogen-fixing organisms and ways to enhance the bridge between theoretical and empirical studies.
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Affiliation(s)
- Keisuke Inomura
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, Třeboň, Czech Republic
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, Třeboň, Czech Republic
| | - Michael J. Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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26
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Sutak R, Camadro JM, Lesuisse E. Iron Uptake Mechanisms in Marine Phytoplankton. Front Microbiol 2020; 11:566691. [PMID: 33250865 PMCID: PMC7676907 DOI: 10.3389/fmicb.2020.566691] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 12/20/2022] Open
Abstract
Oceanic phytoplankton species have highly efficient mechanisms of iron acquisition, as they can take up iron from environments in which it is present at subnanomolar concentrations. In eukaryotes, three main models were proposed for iron transport into the cells by first studying the kinetics of iron uptake in different algal species and then, more recently, by using modern biological techniques on the model diatom Phaeodactylum tricornutum. In the first model, the rate of uptake is dependent on the concentration of unchelated Fe species, and is thus limited thermodynamically. Iron is transported by endocytosis after carbonate-dependent binding of Fe(III)' (inorganic soluble ferric species) to phytotransferrin at the cell surface. In this strategy the cells are able to take up iron from very low iron concentration. In an alternative model, kinetically limited for iron acquisition, the extracellular reduction of all iron species (including Fe') is a prerequisite for iron acquisition. This strategy allows the cells to take up iron from a great variety of ferric species. In a third model, hydroxamate siderophores can be transported by endocytosis (dependent on ISIP1) after binding to the FBP1 protein, and iron is released from the siderophores by FRE2-dependent reduction. In prokaryotes, one mechanism of iron uptake is based on the use of siderophores excreted by the cells. Iron-loaded siderophores are transported across the cell outer membrane via a TonB-dependent transporter (TBDT), and are then transported into the cells by an ABC transporter. Open ocean cyanobacteria do not excrete siderophores but can probably use siderophores produced by other organisms. In an alternative model, inorganic ferric species are transported through the outer membrane by TBDT or by porins, and are taken up by the ABC transporter system FutABC. Alternatively, ferric iron of the periplasmic space can be reduced by the alternative respiratory terminal oxidase (ARTO) and the ferrous ions can be transported by divalent metal transporters (FeoB or ZIP). After reoxidation, iron can be taken up by the high-affinity permease Ftr1.
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Affiliation(s)
- Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czechia
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Boatman TG, Upton GJG, Lawson T, Geider RJ. Projected expansion of Trichodesmium's geographical distribution and increase in growth potential in response to climate change. GLOBAL CHANGE BIOLOGY 2020; 26:6445-6456. [PMID: 32870567 DOI: 10.1111/gcb.15324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Estimates of marine N2 fixation range from 52 to 73 Tg N/year, of which we calculate up to 84% is from Trichodesmium based on previous measurements of nifH gene abundance and our new model of Trichodesmium growth. Here, we assess the likely effects of four major climate change-related abiotic factors on the spatiotemporal distribution and growth potential of Trichodesmium for the last glacial maximum (LGM), the present (2006-2015) and the end of this century (2100) by mapping our model of Trichodesmium growth onto inferred global surface ocean fields of pCO2 , temperature, light and Fe. We conclude that growth rate was severely limited by low pCO2 at the LGM, that current pCO2 levels do not significantly limit Trichodesmium growth and thus, the potential for enhanced growth from future increases in CO2 is small. We also found that the area of the ocean where sea surface temperatures (SST) are within Trichodesmium's thermal niche increased by 32% from the LGM to present, but further increases in SST due to continued global warming will reduce this area by 9%. However, the range reduction at the equator is likely to be offset by enhanced growth associated with expansion of regions with optimal or near optimal Fe and light availability. Between now and 2100, the ocean area of optimal SST and irradiance is projected to increase by 7%, and the ocean area of optimal SST, irradiance and iron is projected to increase by 173%. Given the major contribution of this keystone species to annual N2 fixation and thus pelagic ecology, biogeochemistry and CO2 sequestration, the projected increase in the geographical range for optimal growth could provide a negative feedback to increasing atmospheric CO2 concentrations.
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Affiliation(s)
| | - Graham J G Upton
- Department of Mathematical Sciences, University of Essex, Colchester, UK
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
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28
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Predetermined clockwork microbial worlds: Current understanding of aquatic microbial diel response from model systems to complex environments. ADVANCES IN APPLIED MICROBIOLOGY 2020; 113:163-191. [PMID: 32948266 DOI: 10.1016/bs.aambs.2020.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In the photic zone of aquatic ecosystems, microorganisms with different metabolisms and their viruses form complex interactions and food webs. Within these interactions, phototrophic microorganisms such as eukaryotic microalgae and cyanobacteria interact directly with sunlight, and thereby generate circadian rhythms. Diel cycling originally generated in microbial phototrophs is directly transmitted toward heterotrophic microorganisms utilizing the photosynthetic products as they are excreted or exuded. Such diel cycling seems to be indirectly propagated toward heterotrophs as a result of complex biotic interactions. For example, cell death of phototrophic microorganisms induced by viral lysis and protistan grazing provides additional resources of dissolved organic matter to the microbial community, and so generates diel cycling in other heterotrophs with different nutrient dependencies. Likewise, differences in the diel transmitting pathway via complex interactions among heterotrophs, and between heterotrophs and their viruses, may also generate higher variation and time lag diel rhythms in different heterotrophic taxa. Thus, sunlight and photosynthesis not only contribute energy and carbon supply, but also directly or indirectly control diel cycling of the microbial community through complex interactions in the photic zone of aquatic ecosystems.
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Patin NV, Brown E, Chebli G, Garfield C, Kubanek J, Stewart FJ. Microbial and chemical dynamics of a toxic dinoflagellate bloom. PeerJ 2020; 8:e9493. [PMID: 33240577 PMCID: PMC7676380 DOI: 10.7717/peerj.9493] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/17/2020] [Indexed: 01/10/2023] Open
Abstract
Harmful Algal Blooms (HABs) exert considerable ecological and economic damage and are becoming increasingly frequent worldwide. However, the biological factors underlying HABs remain uncertain. Relationships between algae and bacteria may contribute to bloom formation, strength, and duration. We investigated the microbial communities and metabolomes associated with a HAB of the toxic dinoflagellate Karenia brevis off the west coast of Florida in June 2018. Microbial communities and intracellular metabolite pools differed based on both bacterial lifestyle and bloom level, suggesting a complex role for blooms in reshaping microbial processes. Network analysis identified K. brevis as an ecological hub in the planktonic ecosystem, with significant connections to diverse microbial taxa. These included four flavobacteria and one sequence variant unidentified past the domain level, suggesting uncharacterized diversity in phytoplankton-associated microbial communities. Additionally, intracellular metabolomic analyses associated high K. brevis levels with higher levels of aromatic compounds and lipids. These findings reveal water column microbial and chemical characteristics with potentially important implications for understanding HAB onset and duration.
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Affiliation(s)
- Nastassia V Patin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States of America.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Emily Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Gabriella Chebli
- Department of Chemistry, Agnes Scott College, Decatur, GA, United States of America
| | - Claire Garfield
- School of Arts and Sciences, State University of New York at Stony Brook, Stony Brook, NY, United States of America
| | - Julia Kubanek
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States of America.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, United States of America.,School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Frank J Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States of America.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, United States of America.,Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States of America
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30
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Selective collection of iron-rich dust particles by natural Trichodesmium colonies. ISME JOURNAL 2019; 14:91-103. [PMID: 31551530 PMCID: PMC6908701 DOI: 10.1038/s41396-019-0505-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 07/31/2019] [Accepted: 08/09/2019] [Indexed: 02/07/2023]
Abstract
Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe). Colonies of the globally important cyanobacterium, Trichodesmium, overcome these constraints by efficient dust capturing and active dust-Fe dissolution. In this study we examined the ability of Trichodesmium colonies to maximize their Fe supply from dust by selectively collecting Fe-rich particles. Testing for selectivity in particle collection, we supplied ~600 individual colonies, collected on multiple days from the Gulf of Aqaba, with natural dust and silica minerals that were either cleaned of or coated with Fe. Using a stereoscope, we counted the number of particles retained by each colony shortly after addition and following 24 h incubation with particles, and documented translocation of particles to the colony core. We observed a strong preference for Fe-rich particles over Fe-free particles in all tested parameters. Moreover, some colonies discarded the Fe-free particles they initially collected. The preferred collection of Fe-rich particles and disposal of Fe-free particles suggest that Trichodesmium can sense Fe and selectively choose Fe-rich dust particles. This ability assists Trichodesmium obtain Fe from dust and facilitate its growth and subsequent contribution to nutrient cycling and productivity in the ocean.
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31
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Gledhill M, Basu S, Shaked Y. Metallophores associated with Trichodesmium erythraeum colonies from the Gulf of Aqaba. Metallomics 2019; 11:1547-1557. [PMID: 31475278 DOI: 10.1039/c9mt00121b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trichodesmium is a globally important marine nitrogen fixing cyanobacteria which forms colonies and utilizes atmospherically derived dust as a source for the limiting micro-nutrient iron. Here we report the identification of metallophores isolated from incubations of natural Trichodesmium colonies collected from the Gulf of Aqaba in the Red Sea. Three of our compounds were identified as the ferrioxamine siderophores B, E, and G. The remaining fifteen metallophores had mass to charge ratios that, to our knowledge, are not common to known siderophores. Putative sum formulas suggest most of these compounds were not structurally related to each other. We also found that the novel metallophores readily formed complexes with aluminium and were less specific for iron than the ferrioxamines. In our incubations of Trichodesmium colonies, the abundance of ten of the novel metallophores positively correlated with Trichodesmium biomass, but not with bacterial biomass, whilst ferrioxamine siderophores were more strongly associated with bacterial biomass. We identified ferrioxamines and our novel metallophores in filtered surface seawater samples from the Gulf of Aqaba. However, our novel metallophores were only observed in the surface seawater sample collected at the time of highest Trichodesmium abundance, while ferrioxamines were observed even when Trichodesmium was not present. We hypothesize that the novel metallophores were specifically associated with Trichodesmium colonies. Together with the bacterially produced ferrioxamines they likely contribute to a distinctive "ligandosphere" surrounding the Trichodesmium colonies, with potential implications for metal homeostasis within the colony environment.
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Affiliation(s)
- Martha Gledhill
- GEOMAR Helmholtz Centre for Ocean Research, 24148 Kiel, Germany.
| | - Subhajit Basu
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel and The Interuniversity Institute for Marine Sciences in Eilat, Eilat 88103, Israel
| | - Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel and The Interuniversity Institute for Marine Sciences in Eilat, Eilat 88103, Israel
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