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Vinuganesh A, Kumar A, Prakash S, Korany SM, Alsherif EA, Selim S, AbdElgawad H. Evaluation of growth, primary productivity, nutritional composition, redox state, and antimicrobial activity of red seaweeds Gracilaria debilis and Gracilaria foliifera under pCO 2-induced seawater acidification. Mar Pollut Bull 2022; 185:114296. [PMID: 36343546 DOI: 10.1016/j.marpolbul.2022.114296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/01/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
The genus Gracilaria is an economically important group of seaweeds as several species are utilized for various products such as agar, used in medicines, human diets, and poultry feed. Hence, it is imperative to understand their response to predicted ocean acidification conditions. In the present work, we have evaluated the response of Gracilaria foliifera and Gracilaria debilis to carbon dioxide (pCO2) induced seawater acidification (pH 7.7) for two weeks in a controlled laboratory conditions. As a response variable, we have measured growth, productivity, redox state, primary and secondary metabolites, and mineral compositions. We found a general increase in the daily growth rate, primary productivity, and tissue chemical composition (such as pigments, soluble and insoluble sugars, amino acids, and fatty acids), but a decrease in the mineral contents under the acidified condition. Under acidification, there was a decrease in malondialdehyde. However, there were no significant changes in the total antioxidant capacity and a majority of enzymatic and non-enzymatic antioxidants, except for an increase in tocopherols, ascorbate and glutathione-s-transferase in G. foliifera. These results indicate that elevated pCO2 will benefit the growth of the studied species. No sign of oxidative stress markers indicating the acclimatory response of these seaweeds towards lowered pH conditions. Besides, we also found increased antimicrobial activities of acidified samples against several of the tested food pathogens. Based on these observations, we suggest that Gracilaria spp. will be benefitted from the predicted future acidified ocean.
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Affiliation(s)
- A Vinuganesh
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India
| | - Amit Kumar
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India; Sathyabama Marine Research Station, Sallimalai Street, Rameswaram, Tamil Nadu, India.
| | - S Prakash
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India; Sathyabama Marine Research Station, Sallimalai Street, Rameswaram, Tamil Nadu, India
| | - Shereen Magdy Korany
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
| | - Emad A Alsherif
- Biology Department, College of Science and Arts at Khulis, University of Jeddah, Jeddah 21959, Saudi Arabia; Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72388, Saudi Arabia
| | - Hamada AbdElgawad
- Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
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Dee S, Cuttler M, Cartwright P, McIlwain J, Browne N. Encrusters maintain stable carbonate production despite temperature anomalies among two inshore island reefs of the Pilbara, Western Australia. Mar Environ Res 2021; 169:105386. [PMID: 34116385 DOI: 10.1016/j.marenvres.2021.105386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/23/2021] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
Encrusting reef organisms such as crustose coralline algae (CCA), serpulid worms, bivalves, bryozoans, and foraminifera (collectively termed encrusters) provide essential ecosystem services and are a critical part of the reef framework. Globally, research into in situ growth and carbonate production of encrusters has focused on clear water fore-reef settings in the Pacific and Caribbean, with limited studies being conducted on marginal reef systems or within the Indian Ocean. Here we examined spatial and temporal variation in CCA coverage (%) and total encruster carbonate production rates (g cm-2 yr-1) across two inshore turbid island reefs of northern Western Australia. We recorded average carbonate production rates of 0.039 ± 0.002 g cm-2 yr-1, which are comparable to healthy reef sites globally. Our results show variation in lateral CCA cover over small spatial scales, with a strong seasonal signature, while constant average carbonate production rates were maintained. Additionally, we recorded in situ water temperatures above predicted coral bleaching threshold of 29 °C for four weeks and found annual patterns of sea surface temperature anomalies (SSTA) of 2 °C or more being a regular occurrence over the hotter months. Encrusters on these reefs are considered to have a vital contribution to the reef carbonate budgets, and if they maintain stable carbonate production through periods of SSTA, they may support net positive reef carbonate budgets.
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Affiliation(s)
- Shannon Dee
- School of Molecular and Life Sciences, Curtin University, Bentley Campus, Perth, WA, Australia.
| | - Michael Cuttler
- Oceans Graduate School and UWA Oceans Institute, University of Western Australia, Perth, WA, Australia; Wave Energy Research Centre, The University of Western Australia, Albany, WA, Australia
| | - Paula Cartwright
- Oceans Graduate School and UWA Oceans Institute, University of Western Australia, Perth, WA, Australia
| | - Jennifer McIlwain
- School of Molecular and Life Sciences, Curtin University, Bentley Campus, Perth, WA, Australia
| | - Nicola Browne
- School of Molecular and Life Sciences, Curtin University, Bentley Campus, Perth, WA, Australia
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Zuñiga-Rios D, Vásquez-Elizondo RM, Caamal E, Robledo D. Photosynthetic responses of Halimeda scabra (Chlorophyta, Bryopsidales) to interactive effects of temperature, pH, and nutrients and its carbon pathways. PeerJ 2021; 9:e10958. [PMID: 33717694 PMCID: PMC7938779 DOI: 10.7717/peerj.10958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/27/2021] [Indexed: 12/04/2022] Open
Abstract
In this study, we evaluated the interactive effects of temperature, pH, and nutrients on photosynthetic performance in the calcareous tropical macroalga Halimeda scabra. A significant interaction among these factors on gross photosynthesis (Pgross) was found. The highest values of Pgross were reached at the highest temperature, pH, and nutrient enrichment tested and similarly in the control treatment (no added nutrients) at 33 °C at the lowest pH. The Q10Pgross values confirmed the effect of temperature only under nutrient enrichment scenarios. Besides the above, bicarbonate (HCO3−) absorption was assessed by the content of carbon stable isotope (δ13C) in algae tissue and by its incorporation into photosynthetic products, as well as by carbonic anhydrase (CA) inhibitors (Acetazolamide, AZ and Ethoxyzolamide, EZ) assays. The labeling of δ13C revealed this species uses both, CO2 and HCO3− forms of Ci relying on a CO2 Concentration Mechanism (CCM). These results were validated by the EZ-AZ inhibition assays in which photosynthesis inhibition was observed, indicating the action of internal CA, whereas AZ inhibitor did not affect maximum photosynthesis (Pmax). The incorporation of 13C isotope into aspartate in light and dark treatments also confirmed photosynthetic and non-photosynthetic the HCO3−uptake.
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Affiliation(s)
| | | | - Edgar Caamal
- Department of Marine Resources, Cinvestav, Merida, Yucatan, Mexico
| | - Daniel Robledo
- Department of Marine Resources, Cinvestav, Merida, Yucatan, Mexico
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Valdespino-Castillo PM, Bautista-García A, Favoretto F, Merino-Ibarra M, Alcántara-Hernández RJ, Pi-Puig T, Castillo FS, Espinosa-Matías S, Holman HY, Blanco-Jarvio A. Interplay of microbial communities with mineral environments in coralline algae. Sci Total Environ 2021; 757:143877. [PMID: 33316514 DOI: 10.1016/j.scitotenv.2020.143877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 06/12/2023]
Abstract
Coralline algae are worldwide carbonate builders, considered to be foundational species and biodiversity hotspots. Coralline habitats face increasing pressure from human activities and effects related to Global Change, yet their ecological properties and adaptive responses remain poorly understood. The relationships of the algal microbiota with the mineral bioconstructions, as well as plasticity and resilience of coralline holobionts in a changing environment, are of particular interest. In the Gulf of California, Neogoniolithon trichotomum (Rhodophyta) is the main carbonate builder in tidal pools. We performed a multi-disciplinary assessment of the N. trichotomum microstructure using XRD, SEM microscopy and SR-FTIR spectromicroscopy. In the algal perithallus, magnesium-calcite and aragonite were spatially segregated and embedded in a polysaccharide matrix (rich in sulfated polysaccharides). Mg-calcites (18-19 mol% Mg) were the main mineral components of the thallus overall, followed by iron carbonates related to dolomite (ankerite) and siderite. Minerals of late evaporitic sequences (sylvite and bischofite) were also present, suggesting potential halophilic microenvironments within the algal thalli. The diverse set of abundant halophilic, halotolerant and oligotrophic taxa, whose abundance increase in the summer, further suggests this condition. We created an integrated model, based on environmental parameters and the microbiota distribution, that identified temperature and nutrient availability (particularly nitrate and silicate) as the main parameters related to specific taxa patterns. Among these, Hahella, Granulossicoccus, Ferrimonas, Spongiibacteraceae and cyanobacterial Xenococcaceae and Nostocaceae change significantly between seasons. These bacterial components might play relevant roles in algal plasticity and adaptive responses to a changing environment. This study contributes to the understanding of the interplay of the prokaryotic microbiota with the mineral microenvironments of coralline algae. Because of their carbonates with potential resistance to dissolution in a higher pCO2 world and their seasonally dynamic bacteria, coralline algae are relevant targets to study coastal resilience and carbonated systems responses to changing environments.
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Affiliation(s)
- Patricia M Valdespino-Castillo
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Andrea Bautista-García
- Laboratorio de Bioingeniería y Ciencias Ambientales (BICA), Departamento Académico de Ingeniería en Pesquerías, Universidad Autónoma de Baja California Sur, La Paz, BCS, Mexico
| | - Fabio Favoretto
- Laboratorio de Bioingeniería y Ciencias Ambientales (BICA), Departamento Académico de Ingeniería en Pesquerías, Universidad Autónoma de Baja California Sur, La Paz, BCS, Mexico; Gulf of California Marine Program, Scripps Institution of Oceanography, University of California San Diego, CA, United States
| | - Martín Merino-Ibarra
- Unidad Académica de Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Teresa Pi-Puig
- Instituto de Geología, Universidad Nacional Autónoma de México, Mexico City, Mexico; Laboratorio Nacional de Geoquímica y Mineralogía (LANGEM), Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - F Sergio Castillo
- Unidad Académica de Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Silvia Espinosa-Matías
- Laboratorio de Microscopía Electrónica de Barrido, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hoi-Ying Holman
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Anidia Blanco-Jarvio
- Laboratorio de Bioingeniería y Ciencias Ambientales (BICA), Departamento Académico de Ingeniería en Pesquerías, Universidad Autónoma de Baja California Sur, La Paz, BCS, Mexico.
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5
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Marques JA, Flores F, Patel F, Bianchini A, Uthicke S, Negri AP. Acclimation history modulates effect size of calcareous algae (Halimeda opuntia) to herbicide exposure under future climate scenarios. Sci Total Environ 2020; 739:140308. [PMID: 32846507 DOI: 10.1016/j.scitotenv.2020.140308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Tropical marine habitat-builders such as calcifying green algae can be susceptible to climate change (warming and acidification). This study evaluated the cumulative effects of ocean warming (OW), ocean acidification (OA) and the herbicide diuron on the calcifying green algae Halimeda opuntia. We also assessed the influence of acclimation history to experimental climate change conditions on physiological responses. H. opuntia were exposed for 15 days to orthogonal combinations of three climate scenarios [ambient (28 °C, pCO2 = 378 ppm), 2050 (29 °C, pCO2 = 567 ppm) and 2100 (30 °C, pCO2 = 721 ppm)] and to six diuron concentrations (up to 29 μg L-1). Half of the H. opuntia had been acclimated for eight months to the climate scenarios in a mesocosm approach, while the remaining half were not pre-acclimated, as is current practice in most experiments. Climate effects on quantum yield (ΔF/Fm'), photosynthesis and calcification in future climate scenarios were significantly stronger (by -24, -46 and +26%, respectively) in non-acclimated algae, suggesting experimental bias may exaggerate effects in organisms not appropriately acclimated to future-climate conditions. Thus, full analysis was done on acclimated plants only. Interactive effects of future climate scenarios and diuron were observed for ΔF/Fm', while the detrimental effects of climate and diuron on net photosynthesis and total antioxidant capacity (TAC) were additive. Calcification-related enzymes were negatively affected only by diuron, with inhibition of Ca-ATPase and upregulation of carbonic anhydrase. The combined and consistent physiological and biochemical evidence of negative impacts (across six indicators) of both herbicide and future-climate conditions on the health of H. opuntia highlights the need to address both climate change and water quality. Guideline values for contaminants may also need to be lowered considering 'climate adjusted thresholds'. Importantly, this study highlights the value of applying substantial future climate acclimation periods in experimental studies to avoid exaggerated organism responses to OW and OA.
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Affiliation(s)
- Joseane A Marques
- Programa de Pós-Graduação em Oceanografia Biológica, Universidade Federal do Rio Grande, RS, Brazil.
| | - Florita Flores
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
| | - Frances Patel
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
| | - Adalto Bianchini
- Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, RS, Brazil.
| | - Sven Uthicke
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
| | - Andrew P Negri
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
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Wei Z, Long C, Yang F, Long L, Huo Y, Ding D, Mo J. Increased irradiance availability mitigates the physiological performance of species of the calcifying green macroalga Halimeda in response to ocean acidification. ALGAL RES 2020; 48:101906. [DOI: 10.1016/j.algal.2020.101906] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Qui-Minet ZN, Coudret J, Davoult D, Grall J, Mendez‐Sandin M, Cariou T, Martin S. Combined effects of global climate change and nutrient enrichment on the physiology of three temperate maerl species. Ecol Evol 2019; 9:13787-13807. [PMID: 31938482 PMCID: PMC6953553 DOI: 10.1002/ece3.5802] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 01/20/2023] Open
Abstract
Made up of calcareous coralline algae, maerl beds play a major role as ecosystem engineers in coastal areas throughout the world. They undergo strong anthropogenic pressures, which may threaten their survival. The aim of this study was to gain insight into the future of maerl beds in the context of global and local changes. We examined the effects of rising temperatures (+3°C) and ocean acidification (-0.3 pH units) according to temperature and pH projections (i.e., the RCP 8.5 scenario), and nutrient (N and P) availability on three temperate maerl species (Lithothamnion corallioides, Phymatolithon calcareum, and Lithophyllum incrustans) in the laboratory in winter and summer conditions. Physiological rates of primary production, respiration, and calcification were measured on all three species in each treatment and season. The physiological response of maerl to global climate change was species-specific and influenced by seawater nutrient concentrations. Future temperature-pH scenario enhanced maximal gross primary production rates in P. calcareum in winter and in L. corallioides in both seasons. Nevertheless, both species suffered an impairment of light harvesting and photoprotective mechanisms in winter. Calcification rates at ambient light intensity were negatively affected by the future temperature-pH scenario in winter, with net dissolution observed in the dark in L. corallioides and P. calcareum under low nutrient concentrations. Nutrient enrichment avoided dissolution under future scenarios in winter and had a positive effect on L. incrustans calcification rate in the dark in summer. In winter conditions, maximal calcification rates were enhanced by the future temperature-pH scenario on the three species, but P. calcareum suffered inhibition at high irradiances. In summer conditions, the maximal calcification rate dropped in L. corallioides under the future global climate change scenario, with a potential negative impact on CaCO3 budget for maerl beds in the Bay of Brest where this species is dominant. Our results highlight how local changes in nutrient availability or irradiance levels impact the response of maerl species to global climate change and thus point out how it is important to consider other abiotic parameters in order to develop management policies capable to increase the resilience of maerl beds under the future global climate change scenario.
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Affiliation(s)
- Zujaila Nohemy Qui-Minet
- Sorbonne UniversitésCNRSUMR 7144 Adaptation et Diversité en Milieu MarinStation Biologique de RoscoffRoscoffFrance
| | - Jérôme Coudret
- Sorbonne UniversitésCNRSUMR 7144 Adaptation et Diversité en Milieu MarinStation Biologique de RoscoffRoscoffFrance
| | - Dominique Davoult
- Sorbonne UniversitésCNRSUMR 7144 Adaptation et Diversité en Milieu MarinStation Biologique de RoscoffRoscoffFrance
| | - Jacques Grall
- Université de Bretagne OccidentaleIUEMPlouzanéFrance
| | - Miguel Mendez‐Sandin
- Sorbonne UniversitésCNRSUMR 7144 Adaptation et Diversité en Milieu MarinStation Biologique de RoscoffRoscoffFrance
| | - Thierry Cariou
- Sorbonne UniversitésCNRS, FR2424Station Biologique de RoscoffRoscoffFrance
| | - Sophie Martin
- Sorbonne UniversitésCNRSUMR 7144 Adaptation et Diversité en Milieu MarinStation Biologique de RoscoffRoscoffFrance
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Zweng RC, Koch MS, Bowes G. The role of irradiance and C-use strategies in tropical macroalgae photosynthetic response to ocean acidification. Sci Rep 2018; 8:9479. [PMID: 29930306 PMCID: PMC6013460 DOI: 10.1038/s41598-018-27333-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/27/2018] [Indexed: 12/02/2022] Open
Abstract
Fleshy macroalgae may increase photosynthesis with greater CO2 availability under ocean acidification (OA) and outcompete calcifying macroalgae important for tropical reef accretion. Macroalgae use energy-dependent carbon concentrating mechanisms (CCMs) to take up HCO3-, the dominant inorganic carbon for marine photosynthesis, but carbon-use strategies may depend on the pCO2, pH and irradiance. We examined photosynthesis in eight tropical macroalgae across a range of irradiances (0-1200 μmol photon m-2 s-1), pH levels (7.5-8.5) and CO2 concentrations (3-43 μmol kg-1). Species-specific CCM strategies were assessed using inhibitors and δ13C isotope signatures. Our results indicate that the log of irradiance is a predictor of the photosynthetic response to elevated pCO2 (R2 > 0.95). All species utilized HCO3-, exhibited diverse C-use pathways and demonstrated facultative HCO3- use. All fleshy species had positive photosynthetic responses to OA, in contrast to a split amongst calcifiers. We suggest that shifts in photosynthetically-driven tropical macroalgal changes due to OA will most likely occur in moderate to high-irradiance environments when CCMs are ineffective at meeting the C-demands of photosynthesis. Further, facultative use of HCO3- allows greater access to CO2 for photosynthesis under OA conditions, particularly amongst fleshy macroalgae, which could contribute to enhance fleshy species dominance over calcifiers.
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Affiliation(s)
- Regina C Zweng
- Biological Sciences Department, Aquatic Plant Ecology Lab, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA
- Department of Ecology and Evolutionary Biology, University of California, 618 Charles E Young Dr S, Los Angeles, CA, 90095, USA
| | - Marguerite S Koch
- Biological Sciences Department, Aquatic Plant Ecology Lab, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA.
| | - George Bowes
- Department of Biology University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
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Reidenbach LB, Fernandez PA, Leal PP, Noisette F, McGraw CM, Revill AT, Hurd CL, Kübler JE. Growth, ammonium metabolism, and photosynthetic properties of Ulva australis (Chlorophyta) under decreasing pH and ammonium enrichment. PLoS One 2017; 12:e0188389. [PMID: 29176815 DOI: 10.1371/journal.pone.0188389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 11/06/2017] [Indexed: 11/21/2022] Open
Abstract
The responses of macroalgae to ocean acidification could be altered by availability of macronutrients, such as ammonium (NH4+). This study determined how the opportunistic macroalga, Ulva australis responded to simultaneous changes in decreasing pH and NH4+ enrichment. This was investigated in a week-long growth experiment across a range of predicted future pHs with ambient and enriched NH4+ treatments followed by measurements of relative growth rates (RGR), NH4+ uptake rates and pools, total chlorophyll, and tissue carbon and nitrogen content. Rapid light curves (RLCs) were used to measure the maximum relative electron transport rate (rETRmax) and maximum quantum yield of photosystem II (PSII) photochemistry (Fv/Fm). Photosynthetic capacity was derived from the RLCs and included the efficiency of light harvesting (α), slope of photoinhibition (β), and the light saturation point (Ek). The results showed that NH4+ enrichment did not modify the effects of pH on RGRs, NH4+ uptake rates and pools, total chlorophyll, rETRmax, α, β, Fv/Fm, tissue C and N, and the C:N ratio. However, Ek was differentially affected by pH under different NH4+ treatments. Ek increased with decreasing pH in the ambient NH4+ treatment, but not in the enriched NH4+ treatment. NH4+ enrichment increased RGRs, NH4+ pools, total chlorophyll, rETRmax, α, β, Fv/Fm, and tissue N, and decreased NH4+ uptake rates and the C:N ratio. Decreased pH increased total chlorophyll content, rETRmax, Fv/Fm, and tissue N content, and decreased the C:N ratio. Therefore, the results indicate that U. australis growth is increased with NH4+ enrichment and not with decreasing pH. While decreasing pH influenced the carbon and nitrogen metabolisms of U. australis, it did not result in changes in growth.
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Meyer FW, Schubert N, Diele K, Teichberg M, Wild C, Enríquez S. Effect of Inorganic and Organic Carbon Enrichments (DIC and DOC) on the Photosynthesis and Calcification Rates of Two Calcifying Green Algae from a Caribbean Reef Lagoon. PLoS One 2016; 11:e0160268. [PMID: 27487195 PMCID: PMC4972524 DOI: 10.1371/journal.pone.0160268] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 07/15/2016] [Indexed: 11/18/2022] Open
Abstract
Coral reefs worldwide are affected by increasing dissolved inorganic carbon (DIC) and organic carbon (DOC) concentrations due to ocean acidification (OA) and coastal eutrophication. These two stressors can occur simultaneously, particularly in near-shore reef environments with increasing anthropogenic pressure. However, experimental studies on how elevated DIC and DOC interact are scarce and fundamental to understanding potential synergistic effects and foreseeing future changes in coral reef function. Using an open mesocosm experiment, the present study investigated the impact of elevated DIC (pHNBS: 8.2 and 7.8; pCO2: 377 and 1076 μatm) and DOC (added as 833 μmol L-1 of glucose) on calcification and photosynthesis rates of two common calcifying green algae, Halimeda incrassata and Udotea flabellum, in a shallow reef environment. Our results revealed that under elevated DIC, algal photosynthesis decreased similarly for both species, but calcification was more affected in H. incrassata, which also showed carbonate dissolution rates. Elevated DOC reduced photosynthesis and calcification rates in H. incrassata, while in U. flabellum photosynthesis was unaffected and thalus calcification was severely impaired. The combined treatment showed an antagonistic effect of elevated DIC and DOC on the photosynthesis and calcification rates of H. incrassata, and an additive effect in U. flabellum. We conclude that the dominant sand dweller H. incrassata is more negatively affected by both DIC and DOC enrichments, but that their impact could be mitigated when they occur simultaneously. In contrast, U. flabellum can be less affected in coastal eutrophic waters by elevated DIC, but its contribution to reef carbonate sediment production could be further reduced. Accordingly, while the capacity of environmental eutrophication to exacerbate the impact of OA on algal-derived carbonate sand production seems to be species-specific, significant reductions can be expected under future OA scenarios, with important consequences for beach erosion and coastal sediment dynamics.
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Affiliation(s)
| | - Nadine Schubert
- Laboratory of Photobiology, Unidad Académica de Sistemas Arrecifales Puerto Morelos (ICMyL), Universidad Nacional Autónoma de México (UNAM), Cancún, Mexico
| | - Karen Diele
- Edinburgh Napier University, School of Life, Sport and Social Sciences, EH11 4BN Edinburgh, United Kingdom
- St Abbs Marine Station, St Abbs, Berwickshire, TD14 5QF, United Kingdom
| | - Mirta Teichberg
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
| | - Christian Wild
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- Faculty of Biology & Chemistry, University of Bremen, Bibliothekstraße 1, Bremen, Germany
| | - Susana Enríquez
- Laboratory of Photobiology, Unidad Académica de Sistemas Arrecifales Puerto Morelos (ICMyL), Universidad Nacional Autónoma de México (UNAM), Cancún, Mexico
- * E-mail: ;
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11
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Ow YX, Vogel N, Collier CJ, Holtum JAM, Flores F, Uthicke S. Nitrate fertilisation does not enhance CO2 responses in two tropical seagrass species. Sci Rep 2016; 6:23093. [PMID: 26976685 PMCID: PMC4792133 DOI: 10.1038/srep23093] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/26/2016] [Indexed: 12/05/2022] Open
Abstract
Seagrasses are often considered "winners" of ocean acidification (OA); however, seagrass productivity responses to OA could be limited by nitrogen availability, since nitrogen-derived metabolites are required for carbon assimilation. We tested nitrogen uptake and assimilation, photosynthesis, growth, and carbon allocation responses of the tropical seagrasses Halodule uninervis and Thalassia hemprichii to OA scenarios (428, 734 and 1213 μatm pCO2) under two nutrients levels (0.3 and 1.9 μM NO3(-)). Net primary production (measured as oxygen production) and growth in H. uninervis increased with pCO2 enrichment, but were not affected by nitrate enrichment. However, nitrate enrichment reduced whole plant respiration in H. uninervis. Net primary production and growth did not show significant changes with pCO2 or nitrate by the end of the experiment (24 d) in T. hemprichii. However, nitrate incorporation in T. hemprichii was higher with nitrate enrichment. There was no evidence that nitrogen demand increased with pCO2 enrichment in either species. Contrary to our initial hypothesis, nutrient increases to levels approximating present day flood plumes only had small effects on metabolism. This study highlights that the paradigm of increased productivity of seagrasses under ocean acidification may not be valid for all species under all environmental conditions.
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Affiliation(s)
- Y. X. Ow
- College of Marine and Environmental Science, James Cook University, Townsville Queensland 4811, Australia
- Australian Institute of Marine Science, Townville MC Queensland 4810, Australia
- Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Blk S3, #02-05, 117543, Singapore
| | - N. Vogel
- Australian Institute of Marine Science, Townville MC Queensland 4810, Australia
| | - C. J. Collier
- College of Marine and Environmental Science, James Cook University, Townsville Queensland 4811, Australia
- Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns, Queensland 4870, Australia
| | - J. A. M. Holtum
- College of Marine and Environmental Science, James Cook University, Townsville Queensland 4811, Australia
| | - F. Flores
- Australian Institute of Marine Science, Townville MC Queensland 4810, Australia
| | - S. Uthicke
- Australian Institute of Marine Science, Townville MC Queensland 4810, Australia
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Meyer FW, Vogel N, Teichberg M, Uthicke S, Wild C. The physiological response of two green calcifying algae from the Great Barrier Reef towards high dissolved inorganic and organic carbon (DIC and DOC) availability. PLoS One 2015; 10:e0133596. [PMID: 26267650 PMCID: PMC4534297 DOI: 10.1371/journal.pone.0133596] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 06/29/2015] [Indexed: 11/18/2022] Open
Abstract
Increasing dissolved inorganic carbon (DIC) concentrations associated with ocean acidification can affect marine calcifiers, but local factors, such as high dissolved organic carbon (DOC) concentrations through sewage and algal blooms, may interact with this global factor. For calcifying green algae of the genus Halimeda, a key tropical carbonate producer that often occurs in coral reefs, no studies on these interactions have been reported. These data are however urgently needed to understand future carbonate production. Thus, we investigated the independent and combined effects of DIC (pCO2 402 μatm/ pHtot 8.0 and 996 μatm/ pHtot 7.7) and DOC (added as glucose in 0 and 294 μmol L-1) on growth, calcification and photosynthesis of H. macroloba and H. opuntia from the Great Barrier Reef in an incubation experiment over 16 days. High DIC concentrations significantly reduced dark calcification of H. opuntia by 130 % and led to net dissolution, but did not affect H. macroloba. High DOC concentrations significantly reduced daily oxygen production of H. opuntia and H. macroloba by 78 % and 43 %, respectively, and significantly reduced dark calcification of H. opuntia by 70%. Combined high DIC and DOC did not show any interactive effects for both algae, but revealed additive effects for H. opuntia where the combination of both factors reduced dark calcification by 162 % compared to controls. Such species-specific differences in treatment responses indicate H. opuntia is more susceptible to a combination of high DIC and DOC than H. macroloba. From an ecological perspective, results further suggest a reduction of primary production for Halimeda-dominated benthic reef communities under high DOC concentrations and additional decreases of carbonate accretion under elevated DIC concentrations, where H. opuntia dominates the benthic community. This may reduce biogenic carbonate sedimentation rates and hence the buffering capacity against further ocean acidification.
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Affiliation(s)
- Friedrich Wilhelm Meyer
- Department of Ecology, Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- * E-mail:
| | - Nikolas Vogel
- Department of Ecology, Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Mirta Teichberg
- Department of Ecology, Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
| | - Sven Uthicke
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Christian Wild
- Department of Ecology, Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- Faculty of Biology and Chemistry, University of Bremen, Germany
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