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Servetto N, de Aranzamendi MC, Bettencourt R, Held C, Abele D, Movilla J, González G, Bustos DM, Sahade R. Molecular mechanisms underlying responses of the Antarctic coral Malacobelemnon daytoni to ocean acidification. MARINE ENVIRONMENTAL RESEARCH 2021; 170:105430. [PMID: 34340030 DOI: 10.1016/j.marenvres.2021.105430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 07/15/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Benthic organisms of the Southern Ocean are particularly vulnerable to ocean acidification (OA), as they inhabit cold waters where calcite-aragonite saturation states are naturally low. OA most strongly affects animals with calcium carbonate skeletons or shells, such as corals and mollusks. We exposed the abundant cold-water coral Malacobelemnon daytoni from an Antarctic fjord to low pH seawater (LpH) (7.68 ± 0.17) to test its physiological responses to OA, at the level of gene expression (RT-PCR) and enzyme activity. Corals were exposed in short- (3 days) and long-term (54 days) experiments to two pCO2 conditions (ambient and elevated pCO2 equaling RCP 8.5, IPCC 2019, approximately 372.53 and 956.78 μatm, respectively). Of the eleven genes studied through RT-PCR, six were significantly upregulated compared with control in the short-term in the LpH condition, including the antioxidant enzyme superoxide dismutase (SOD), Heat Shock Protein 70 (HSP70), Toll-like receptor (TLR), galaxin and ferritin. After long-term exposure to low pH conditions, RT-PCR analysis showed seven genes were upregulated. These include the mannose-binding C-Lectin and HSP90. Also, the expression of TLR and galaxin, among others, continued to be upregulated after long-term exposure to LpH. Expression of carbonic anhydrase (CA), a key enzyme involved in calcification, was also significantly upregulated after long-term exposure. Our results indicated that, after two months, M. daytoni is not acclimatized to this experimental LpH condition. Gene expression profiles revealed molecular impacts that were not evident at the enzyme activity level. Consequently, understanding the molecular mechanisms behind the physiological processes in the response of a coral to LpH is critical to understanding the ability of polar species to cope with future environmental changes. Approaches integrating molecular tools into Antarctic ecological and/or conservation research make an essential contribution given the current ongoing OA processes.
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Affiliation(s)
- N Servetto
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales.,Cátedra de Ecología Marina, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Ecosistemas Marinos Polares, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina.
| | - M C de Aranzamendi
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales.,Cátedra de Ecología Marina, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Ecosistemas Marinos Polares, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina
| | - R Bettencourt
- OKEANOS Marine Research Center/Department of Oceanography and Fisheries, Faculty of Science and Technology, University of the Azores, 9900-862, Horta, Portugal
| | - C Held
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - D Abele
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - J Movilla
- Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Estación de Investigación Jaume Ferrer, La Mola s/n 07720, Menorca, Spain
| | - G González
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales.,Cátedra de Ecología Marina, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Ecosistemas Marinos Polares, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina
| | - D M Bustos
- Laboratorio de Integración de Señales Celulares, Instituto de Histología y Embriología de Mendoza (IHEM CONICET-UNCUYO), and Facultad de Ciencias Exactas y Naturales (UNCUYO), Mendoza, Argentina
| | - R Sahade
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales.,Cátedra de Ecología Marina, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Ecosistemas Marinos Polares, Av. Vélez Sarsfield 299, X5000JJC, Córdoba, Argentina.
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Dell'Acqua O, Trębala M, Chiantore M, Hannula SP. Robustness of Adamussium colbecki shell to ocean acidification in a short-term exposure. MARINE ENVIRONMENTAL RESEARCH 2019; 149:90-99. [PMID: 31254931 DOI: 10.1016/j.marenvres.2019.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/12/2019] [Accepted: 06/16/2019] [Indexed: 06/09/2023]
Abstract
Atmospheric pCO2 has increased since the industrial revolution leading to a lowering of the ocean surface water pH, a phenomenon called ocean acidification (OA). OA is claimed to be a major threat for marine organisms and ecosystems and, particularly, for Polar regions. We explored the impact of OA on the shell mechanical properties of the Antarctic scallop Adamussium colbecki exposed for one month to acidified (pH 7.6) and natural conditions (unmanipulated littoral water), by performing Scanning Electron Microscopy, nanoindentation and Vickers indentation on the scallop shell. No effect of pH could be detected either in crystal deposition or in the mechanical properties. A. colbecki shell was found to be resistant to OA, which suggests this species to be able to face a climate change scenario that may threat the persistence of the endemic Antarctic species. Further investigation should be carried out in order to elucidate the destiny of this key species in light of global change.
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Affiliation(s)
- Ombretta Dell'Acqua
- Department for the Earth, Environment and Life Sciences (DiSTAV), University of Genoa, Italy.
| | - Michal Trębala
- Department of Chemistry and Materials Science, Aalto University, Espoo, Finland.
| | - Mariachiara Chiantore
- Department for the Earth, Environment and Life Sciences (DiSTAV), University of Genoa, Italy.
| | - Simo-Pekka Hannula
- Department of Chemistry and Materials Science, Aalto University, Espoo, Finland.
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Cummings VJ, Barr NG, Budd RG, Marriott PM, Safi KA, Lohrer AM. In situ response of Antarctic under-ice primary producers to experimentally altered pH. Sci Rep 2019; 9:6069. [PMID: 30988340 PMCID: PMC6465331 DOI: 10.1038/s41598-019-42329-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/29/2019] [Indexed: 11/17/2022] Open
Abstract
Elevated atmospheric CO2 concentrations are contributing to ocean acidification (reduced seawater pH and carbonate concentrations), with potentially major ramifications for marine ecosystems and their functioning. Using a novel in situ experiment we examined impacts of reduced seawater pH on Antarctic sea ice-associated microalgal communities, key primary producers and contributors to food webs. pH levels projected for the following decades-to-end of century (7.86, 7.75, 7.61), and ambient levels (7.99), were maintained for 15 d in under-ice incubation chambers. Light, temperature and dissolved oxygen within the chambers were logged to track diurnal variation, with pH, O2, salinity and nutrients assessed daily. Uptake of CO2 occurred in all treatments, with pH levels significantly elevated in the two extreme treatments. At the lowest pH, despite the utilisation of CO2 by the productive microalgae, pH did not return to ambient levels and carbonate saturation states remained low; a potential concern for organisms utilising this under-ice habitat. However, microalgal community biomass and composition were not significantly affected and only modest productivity increases were noted, suggesting subtle or slightly positive effects on under-ice algae. This in situ information enables assessment of the influence of future ocean acidification on under-ice community characteristics in a key coastal Antarctic habitat.
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Affiliation(s)
- Vonda J Cummings
- National institute of Water and Atmospheric Research, Wellington, New Zealand.
| | - Neill G Barr
- National institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Rod G Budd
- National institute of Water and Atmospheric Research, Hamilton, New Zealand
| | - Peter M Marriott
- National institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Karl A Safi
- National institute of Water and Atmospheric Research, Hamilton, New Zealand
| | - Andrew M Lohrer
- National institute of Water and Atmospheric Research, Hamilton, New Zealand
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Santagata S, Ade V, Mahon AR, Wisocki PA, Halanych KM. Compositional Differences in the Habitat-Forming Bryozoan Communities of the Antarctic Shelf. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Carbonate chemistry of an in-situ free-ocean CO 2 enrichment experiment (antFOCE) in comparison to short term variation in Antarctic coastal waters. Sci Rep 2018; 8:2816. [PMID: 29434330 PMCID: PMC5809532 DOI: 10.1038/s41598-018-21029-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 01/29/2018] [Indexed: 11/08/2022] Open
Abstract
Free-ocean CO2 enrichment (FOCE) experiments have been deployed in marine ecosystems to manipulate carbonate system conditions to those predicted in future oceans. We investigated whether the pH/carbonate chemistry of extremely cold polar waters can be manipulated in an ecologically relevant way, to represent conditions under future atmospheric CO2 levels, in an in-situ FOCE experiment in Antarctica. We examined spatial and temporal variation in local ambient carbonate chemistry at hourly intervals at two sites between December and February and compared these with experimental conditions. We successfully maintained a mean pH offset in acidified benthic chambers of -0.38 (±0.07) from ambient for approximately 8 weeks. Local diel and seasonal fluctuations in ambient pH were duplicated in the FOCE system. Large temporal variability in acidified chambers resulted from system stoppages. The mean pH, Ωarag and fCO2 values in the acidified chambers were 7.688 ± 0.079, 0.62 ± 0.13 and 912 ± 150 µatm, respectively. Variation in ambient pH appeared to be mainly driven by salinity and biological production and ranged from 8.019 to 8.192 with significant spatio-temporal variation. This experiment demonstrates the utility of FOCE systems to create conditions expected in future oceans that represent ecologically relevant variation, even under polar conditions.
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Evans TG, Pespeni MH, Hofmann GE, Palumbi SR, Sanford E. Transcriptomic responses to seawater acidification among sea urchin populations inhabiting a natural pH mosaic. Mol Ecol 2017; 26:2257-2275. [PMID: 28141889 DOI: 10.1111/mec.14038] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 01/07/2023]
Abstract
Increasing awareness of spatial and temporal variation in ocean pH suggests some marine populations may be adapted to local pH regimes and will therefore respond differently to present-day pH variation and to long-term ocean acidification. In the Northeast Pacific Ocean, differences in the strength of coastal upwelling cause latitudinal variation in prevailing pH regimes that are hypothesized to promote local adaptation and unequal pH tolerance among resident populations. In this study, responses to experimental seawater acidification were compared among embryos and larvae from six populations of purple sea urchins (Strongylocentrotus purpuratus) inhabiting areas that differ in their frequency of low pH exposure and that prior research suggests are locally adapted to seawater pH. Transcriptomic analyses demonstrate urchin populations most frequently exposed to low pH seawater responded to experimental acidification by expressing genes within major ATP-producing pathways at greater levels than populations encountering low pH less often. Multiple genes within the tricarboxylic acid cycle, electron transport chain and fatty acid beta oxidation pathways were upregulated in urchin populations experiencing low pH conditions most frequently. These same metabolic pathways were significantly over-represented among genes both expressed in a population-specific manner and putatively under selection to enhance low pH tolerance. Collectively, these data suggest natural selection is acting on metabolic gene networks to redirect ATP toward maintaining acid-base homeostasis and enhance tolerance of seawater acidification. As a trade-off, marine populations more tolerant of low pH may have less energy to put towards other aspects of fitness and to respond to additional ocean change.
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Affiliation(s)
- Tyler G Evans
- Department of Biological Sciences, California State University East Bay, Hayward, CA, 94542, USA
| | - Melissa H Pespeni
- Department of Biology, University of Vermont, Burlington, VT, 05405, USA
| | - Gretchen E Hofmann
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Stephen R Palumbi
- Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA, 93950, USA
| | - Eric Sanford
- Department of Evolution and Ecology and Bodega Marine Laboratory, University of California Davis, Bodega Bay, CA, 94923, USA
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Davis BE, Miller NA, Flynn EE, Todgham AE. Juvenile Antarctic rockcod (Trematomus bernacchii) are physiologically robust to CO2-acidified seawater. ACTA ACUST UNITED AC 2016; 219:1203-13. [PMID: 26944503 DOI: 10.1242/jeb.133173] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/15/2016] [Indexed: 01/04/2023]
Abstract
To date, numerous studies have shown negative impacts of CO2-acidified seawater (i.e. ocean acidification, OA) on marine organisms, including calcifying invertebrates and fishes; however, limited research has been conducted on the physiological effects of OA on polar fishes and even less on the impact of OA on early developmental stages of polar fishes. We evaluated aspects of aerobic metabolism and cardiorespiratory physiology of juvenile emerald rockcod, ITALIC! Trematomus bernacchii, an abundant fish in the Ross Sea, Antarctica, to elevated partial pressure of carbon dioxide ( ITALIC! PCO2 ) [420 (ambient), 650 (moderate) and 1050 (high) μatm ITALIC! PCO2 ] over a 1 month period. We examined cardiorespiratory physiology, including heart rate, stroke volume, cardiac output and ventilation rate, whole organism metabolism via oxygen consumption rate and sub-organismal aerobic capacity by citrate synthase enzyme activity. Juvenile fish showed an increase in ventilation rate under high ITALIC! PCO2 compared with ambient ITALIC! PCO2 , whereas cardiac performance, oxygen consumption and citrate synthase activity were not significantly affected by elevated ITALIC! PCO2 Acclimation time had a significant effect on ventilation rate, stroke volume, cardiac output and citrate synthase activity, such that all metrics increased over the 4 week exposure period. These results suggest that juvenile emerald rockcod are robust to near-future increases in OA and may have the capacity to adjust for future increases in ITALIC! PCO2 by increasing acid-base compensation through increased ventilation.
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Affiliation(s)
- Brittany E Davis
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA 95616, USA
| | - Nathan A Miller
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, CA 94920, USA
| | - Erin E Flynn
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA
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Abstract
Understanding how declining seawater pH caused by anthropogenic carbon emissions, or ocean acidification, impacts Southern Ocean biota is limited by a paucity of pH time-series. Here, we present the first high-frequency in-situ pH time-series in near-shore Antarctica from spring to winter under annual sea ice. Observations from autonomous pH sensors revealed a seasonal increase of 0.3 pH units. The summer season was marked by an increase in temporal pH variability relative to spring and early winter, matching coastal pH variability observed at lower latitudes. Using our data, simulations of ocean acidification show a future period of deleterious wintertime pH levels potentially expanding to 7–11 months annually by 2100. Given the presence of (sub)seasonal pH variability, Antarctica marine species have an existing physiological tolerance of temporal pH change that may influence adaptation to future acidification. Yet, pH-induced ecosystem changes remain difficult to characterize in the absence of sufficient physiological data on present-day tolerances. It is therefore essential to incorporate natural and projected temporal pH variability in the design of experiments intended to study ocean acidification biology.
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