Effects of High Dissolved Inorganic and Organic Carbon Availability on the Physiology of the Hard Coral Acropora millepora from the Great Barrier Reef

Meyer, Friedrich W; Vogel, Nikolas; Diele, Karen; Kunzmann, Andreas; Uthicke, Sven; Wild, Christian

Abstract

Coral reefs are facing major global and local threats due to climate change-induced
increases in dissolved inorganic carbon (DIC) and because of land-derived increases in
organic and inorganic nutrients. Recent research revealed that high availability of labile dissolved
organic carbon (DOC) negatively affects scleractinian corals. Studies on the interplay
of these factors, however, are lacking, but urgently needed to understand coral reef
functioning under present and near future conditions. This experimental study investigated
the individual and combined effects of ambient and high DIC (pCO2 403 ?atm/ pHTotal 8.2
and 996 ?atm/pHTotal 7.8) and DOC (added as Glucose 0 and 294 ?mol L-1, background
DOC concentration of 83 ?mol L-1) availability on the physiology (net and gross photosynthesis,
respiration, dark and light calcification, and growth) of the scleractinian coral Acropora
millepora (Ehrenberg, 1834) from the Great Barrier Reef over a 16 day interval. High
DIC availability did not affect photosynthesis, respiration and light calcification, but significantly
reduced dark calcification and growth by 50 and 23%, respectively. High DOC availability
reduced net and gross photosynthesis by 51% and 39%, respectively, but did not
affect respiration. DOC addition did not influence calcification, but significantly increased
growth by 42%. Combination of high DIC and high DOC availability did not affect photosynthesis,
light calcification, respiration or growth, but significantly decreased dark calcification
when compared to both controls and DIC treatments. On the ecosystem level, high DIC concentrations
may lead to reduced accretion and growth of reefs dominated by Acropora that
under elevated DOC concentrations will likely exhibit reduced primary production rates, ultimately
leading to loss of hard substrate and reef erosion. It is therefore important to consider
the potential impacts of elevated DOC and DIC simultaneously to assess real world scenarios,
as multiple rather than single factors influence key physiological processes in coral
reefs.

Citation

Meyer, F. W., Vogel, N., Diele, K., Kunzmann, A., Uthicke, S., & Wild, C. (2016). Effects of High Dissolved Inorganic and Organic Carbon Availability on the Physiology of the Hard Coral Acropora millepora from the Great Barrier Reef. PLOS ONE, 11, https://doi.org/10.1371/journal.pone.0149598

• Journal Article Type: Article
• Acceptance Date: Feb 3, 2016
• Online Publication Date: Mar 9, 2016
• Publication Date: Mar 9, 2016
• Deposit Date: Mar 11, 2016
• Publicly Available Date: Mar 11, 2016
• Print ISSN: 1932-6203
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Article Number: e0149598
• DOI: https://doi.org/10.1371/journal.pone.0149598
• Keywords: Coral reefs; dissolved organic carbon; DIC; ecosystems; Great Barrier Reef; Acropora millepora; reef erosion
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/9657
• Publisher URL: http://dx.doi.org/10.1371/journal.pone.0149598
• Related Public URLs: https://dx.doi.org/10.6084/m9.figshare.2075254.v1