The effect of ocean acidification on tropical coral calcification: Insights from calcification fluid DIC chemistry

Last modified: 
September 20, 2018 - 9:11am
Type: Journal Article
Year of publication: 2018
Date published: 09/2018
Authors: Nicola Allison, Catherine Cole, Chris Hintz, Ken Hintz, James Rae, Adrian Finch
Journal title: Chemical Geology
ISSN: 00092541

Ocean acidification typically reduces calcification in tropical marine corals but the mechanism for this process is not understood. We use skeletal boron geochemistry (B/Ca and δ11B) to reconstruct the calcification fluid DIC of corals cultured over both high and low seawater pCO2 (180, 400 and 750 μatm). We observe strong positive correlations between calcification fluid pH and concentrations of the DIC species potentially implicated in aragonite precipitation (be they CO32−, HCO3 or HCO3 + CO32−). Similarly, with the exception of one outlier, the fluid concentrations of precipitating DIC species are strongly positively correlated with coral calcification rate. Corals cultured at high seawater pCO2usually have low calcification fluid pH and low concentrations of precipitating DIC, suggesting that a reduction in DIC substrate at the calcification site is responsible for decreased calcification. The outlier coral maintained high pHCF and DICCF at high seawater pCO2 but exhibited a reduced calcification rate indicating that the coral has a limited energy budget to support proton extrusion from the calcification fluid and meet other calcification demands. We find no evidence that increasing seawater pCO2 enhances diffusion of CO2into the calcification site. Instead the overlying [CO2] available to diffuse into the calcification site appears broadly comparable between seawater pCO2 treatments, implying that metabolic activity (respiration and photosynthesis) generates a similar [CO2] in the vicinity of the calcification site regardless of seawater pCO2.

Freely available?: 
Yes
Approximate cost to purchase or rent this item from the publisher: US $39.95

(Links to preprints and postprints are checked for validity at the time of publication. If this link does not work, please let us know in the comments below. Additionally, you may use the Google Scholar link below to search for alternative freely-available versions of this resource.)

Summary available?: 
No

Report an error or inaccuracy

Notice an error in the Literature item above? Please let us know in the comments section below. Thank you for helping us keep the Literature Library up-to-date!

Add new comment