pH variability at volcanic CO2 seeps regulates coral calcifying fluid chemistry

Comeau, Steeve, Cornwall, Christopher E., Shlesinger, Tom, Hoogenboom, Mia, Mana, Ralph, McCulloch, Malcolm T., and Rodolfo-metalpa, Riccardo (2022) pH variability at volcanic CO2 seeps regulates coral calcifying fluid chemistry. Global Change Biology, 28 (8). pp. 2751-2763.

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Coral reefs are iconic ecosystems with immense ecological, economic and cultural value, but globally their carbonate-based skeletal construction is threatened by ocean acidification (OA). Identifying coral species that have specialised mechanisms to maintain high rates of calcification in the face of declining seawater pH is of paramount importance in predicting future species composition, and growth of coral reefs. Here, we studied multiple coral species from two distinct volcanic CO2 seeps in Papua New Guinea to assess their capacity to control their calcifying fluid (CF) chemistry. Several coral species living under conditions of low mean seawater pH, but with either low or high variability in seawater pH, were examined and compared with those living in 'normal' (non-seep) ambient seawater pH. We show that when mean seawater pH is low but highly variable, corals have a greater ability to maintain constant pH(cf) in their CF, but this characteristic was not linked with changes in abundance. Within less variable low pH seawater, corals with limited reductions in pH(cf) at the seep sites compared with controls tended to be more abundant at the seep site than at the control site. However, this finding was strongly influenced by a single species (Montipora foliosa), which was able to maintain complete pH(cf) homeostasis. Overall, although our findings indicate that there might be an association between ecological success and greater pH(cf) homeostasis, further research with additional species and at more sites with differing seawater pH regimes is required to solidify inferences regarding coral ecological success under future OA.

Item ID: 72479
Item Type: Article (Research - C1)
ISSN: 1354-1013
Keywords: abundance,calcification,calcifying fluid,coral,coral reefs,dissolved inorganic carbon,ocean acidification,Papua New Guinea
Copyright Information: © 2022 John Wiley & Sons Ltd
Funders: Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies (CECRS)
Projects and Grants: CECRS (CE140100020), ARC Laureate Fellowship (LF120100049), ARC DECRA (DE160100668)
Date Deposited: 16 Feb 2022 07:37
FoR Codes: 41 ENVIRONMENTAL SCIENCES > 4101 Climate change impacts and adaptation > 410102 Ecological impacts of climate change and ecological adaptation @ 60%
31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 20%
31 BIOLOGICAL SCIENCES > 3103 Ecology > 310303 Ecological physiology @ 20%
SEO Codes: 19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1905 Understanding climate change > 190506 Effects of climate change on the South Pacific (excl. Australia and New Zealand) (excl. social impacts) @ 50%
18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180504 Marine biodiversity @ 20%
18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180501 Assessment and management of benthic marine ecosystems @ 30%
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