Ocean acidification alters early successional coral reef communities and their rates of community metabolism

Noonan, Sam, Kluibenschedl, Anna, and Fabricius, Katharina (2018) Ocean acidification alters early successional coral reef communities and their rates of community metabolism. PLoS ONE, 13 (5). e0197130.

[img]
Preview
PDF (Published Version) - Published Version
Available under License Creative Commons Attribution.

Download (10MB) | Preview
View at Publisher Website: https://doi.org/10.1371/journal.pone.019...
 
55


Abstract

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover). Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined) significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and will significantly change rates of community metabolism.

Item ID: 75727
Item Type: Article (Research - C1)
ISSN: 1932-6203
Related URLs:
Copyright Information: © 2018 Noonan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Date Deposited: 24 Aug 2022 03:54
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 33%
31 BIOLOGICAL SCIENCES > 3199 Other biological sciences > 319902 Global change biology @ 34%
31 BIOLOGICAL SCIENCES > 3103 Ecology > 310303 Ecological physiology @ 33%
SEO Codes: 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280102 Expanding knowledge in the biological sciences @ 100%
Downloads: Total: 55
Last 12 Months: 8
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page