Cold-water coral ecosystems under future ocean change: Live coral performance vs. framework dissolution and bioerosion

Janina V. Büscher, Armin Uwe Form, Max Wisshak, Rainer Kiko, Ulf Riebesell

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3 Citations (Scopus)
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Abstract

Physiological sensitivity of cold-water corals to ocean change is far less understood than of tropical corals and very little is known about the impacts of ocean acidification and warming on degradative processes of dead coral framework. In a 13-month laboratory experiment, we examined the interactive effects of gradually increasing temperature and pCO2 levels on survival, growth, and respiration of two prominent color morphotypes (colormorphs) of the framework-forming cold-water coral Lophelia pertusa, as well as bioerosion and dissolution of dead framework. Calcification rates tended to increase with warming, showing temperature optima at ~ 14°C (white colormorph) and 10–12°C (orange colormorph) and decreased with increasing pCO2. Net dissolution occurred at aragonite undersaturation (ΩAr < 1) at ~ 1000 μatm pCO2. Under combined warming and acidification, the negative effects of acidification on growth were initially mitigated, but at ~ 1600 μatm dissolution prevailed. Respiration rates increased with warming, more strongly in orange corals, while acidification slightly suppressed respiration. Calcification and respiration rates as well as polyp mortality were consistently higher in orange corals. Mortality increased considerably at 14–15°C in both colormorphs. Bioerosion/dissolution of dead framework was not affected by warming alone but was significantly enhanced by acidification. While live corals may cope with intermediate levels of elevated pCO2 and temperature, long-term impacts beyond levels projected for the end of this century will likely lead to skeletal dissolution and increased mortality. Our findings further suggest that acidification causes accelerated degradation of dead framework even at aragonite saturated conditions, which will eventually compromise the structural integrity of cold-water coral reefs.

Original languageEnglish
Pages (from-to)2497-2515
Number of pages19
JournalLimnology and Oceanography
Volume67
Issue number11
DOIs
Publication statusPublished (in print/issue) - 1 Nov 2022

Bibliographical note

Funding Information:
This study was carried out as part of the BMBF (Federal Ministry of Education and Research) funded project BIOACID II (Grant number: FKZ 03F0655A). Coral sampling took place at the outer Norwegian Trondheimsfjord and was conducted with kind permission of the Norwegian Directorate of Fisheries (Fiskeridirektoratet). Rainer Kiko would furthermore like to acknowledge funding via the SFB 754 “Climate-Biogeochemistry Interactions in the Tropical Ocean” (grant number: 27542298 of the German Science Foundation DFG) and via a “Make Our Planet Great Again” grant of the French National Research Agency within the “Programme d'Investissements d'Avenir” (reference: ANR-19-MPGA-0012). The captain and crew of RV POSEIDON are greatly thanked for support during the research cruise POS455. Export and import permits for the cold-water coral L. pertusa were obtained through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) by the Norwegian Environment Agency (Miljø Direktoratet) and the Federal Agency for Nature Conversation (BfN). The authors would like to thank the student assistants Nils Kreuter and Marie Küter for support throughout the experiment, Dr. Lydia Beuck for assistance with coral framework preparations, and Kerstin Nachtigall, Andrea Ludwig, and Jana Meyer for assistance with chemical analyses. Dr. Sandra Brooke and Dr. Rachel Cave greatly thanked for constructive feedback on the manuscript. Dr. Mark Lenz is further greatly thanked for statistical advice. This paper was completed at NUI Galway, Ireland where the lead author has been working on the Ocean Acidification and Biogeochemistry: Variability, trends and Vulnerability (VOCAB) project since April 2020, funded by the Marine Institute of Ireland. The authors would like to extend our gratitude to two anonymous reviewers for their constructive and careful comments. Open Access funding enabled and organized by Projekt DEAL.

Funding Information:
This study was carried out as part of the BMBF (Federal Ministry of Education and Research) funded project BIOACID II (Grant number: FKZ 03F0655A). Coral sampling took place at the outer Norwegian Trondheimsfjord and was conducted with kind permission of the Norwegian Directorate of Fisheries (Fiskeridirektoratet). Rainer Kiko would furthermore like to acknowledge funding via the SFB 754 “Climate‐Biogeochemistry Interactions in the Tropical Ocean” (grant number: 27542298 of the German Science Foundation DFG) and via a “Make Our Planet Great Again” grant of the French National Research Agency within the “Programme d'Investissements d'Avenir” (reference: ANR‐19‐MPGA‐0012). The captain and crew of RV POSEIDON are greatly thanked for support during the research cruise POS455. Export and import permits for the cold‐water coral were obtained through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) by the Norwegian Environment Agency (Miljø Direktoratet) and the Federal Agency for Nature Conversation (BfN). The authors would like to thank the student assistants Nils Kreuter and Marie Küter for support throughout the experiment, Dr. Lydia Beuck for assistance with coral framework preparations, and Kerstin Nachtigall, Andrea Ludwig, and Jana Meyer for assistance with chemical analyses. Dr. Sandra Brooke and Dr. Rachel Cave greatly thanked for constructive feedback on the manuscript. Dr. Mark Lenz is further greatly thanked for statistical advice. This paper was completed at NUI Galway, Ireland where the lead author has been working on the Ocean Acidification and Biogeochemistry: Variability, trends and Vulnerability (VOCAB) project since April 2020, funded by the Marine Institute of Ireland. The authors would like to extend our gratitude to two anonymous reviewers for their constructive and careful comments. Open Access funding enabled and organized by Projekt DEAL. L. pertusa

Publisher Copyright:
© 2022 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography.

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