Benthic buffers and boosters of ocean acidification on coral reefs

Anthony, K. R. N., Diaz-Pulido, G., Verlinden, N., Tilbrook, B. and Andersson, A. J. (2013) Benthic buffers and boosters of ocean acidification on coral reefs. Biogeosciences, 10 7: 4897-4909. doi:10.5194/bg-10-4897-2013

Author Anthony, K. R. N.
Diaz-Pulido, G.
Verlinden, N.
Tilbrook, B.
Andersson, A. J.
Title Benthic buffers and boosters of ocean acidification on coral reefs
Journal name Biogeosciences   Check publisher's open access policy
ISSN 1726-4170
Publication date 2013-01
Sub-type Article (original research)
DOI 10.5194/bg-10-4897-2013
Open Access Status DOI
Volume 10
Issue 7
Start page 4897
End page 4909
Total pages 13
Place of publication Goettingen, Germany
Publisher Copernicus
Collection year 2014
Language eng
Formatted abstract
Ocean acidification is a threat to marine ecosystems globally. In shallow-water systems, however, ocean acidification can be masked by benthic carbon fluxes, depending on community composition, seawater residence time, and the magnitude and balance of net community production (NCP) and calcification (NCC). Here, we examine how six benthic groups from a coral reef environment on Heron Reef (Great Barrier Reef, Australia) contribute to changes in the seawater aragonite saturation state (Ωa). Results of flume studies using intact reef habitats (1.2 m by 0.4 m), showed a hierarchy of responses across groups, depending on CO2 level, time of day and water flow. At low CO 2 (350-450 μatm), macroalgae (Chnoospora implexa), turfs and sand elevated Ωa of the flume water by around 0.10 to 1.20 h-1 - normalised to contributions from 1 m2 of benthos to a 1 m deep water column. The rate of Ωa increase in these groups was doubled under acidification (560-700 μatm) and high flow (35 compared to 8 cm s -1). In contrast, branching corals (Acropora aspera) increased Ωa by 0.25 h-1 at ambient CO2 (350-450 μatm) during the day, but reduced Ωa under acidification and high flow. Nighttime changes in Ωa by corals were highly negative (0.6-0.8 h -1) and exacerbated by acidification. Calcifying macroalgae (Halimeda spp.) raised Ωa by day (by around 0.13 h-1), but lowered Ωa by a similar or higher amount at night. Analyses of carbon flux contributions from benthic communities with four different compositions to the reef water carbon chemistry across Heron Reef flat and lagoon indicated that the net lowering of Ωa by coral-dominated areas can to some extent be countered by long water-residence times in neighbouring areas dominated by turfs, macroalgae and carbonate sand.
Keyword Primary Productivity
Marine Organisms
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Biological Sciences Publications
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