Dolomite-rich coralline algae in reefs resist dissolution in acidified conditions, supplement to: Nash, Merinda C; Opdyke, Bradley N; Troitzsch, U; Russell, Bayden D; Adey, W H; Kato, A; Diaz-Pulido, Guillermo; Brent, C; Gardner, M; Prichard, J; Kline, David I (2012): Dolomite-rich coralline algae in reefs resist dissolution in acidified conditions. Nature Climate Change, 3(3), 268-272

• Main Authors: Nash, Merinda C, Opdyke, Bradley N, Troitzsch, U, Russell, Bayden D, Adey, W H, Kato, A, Diaz-Pulido, Guillermo, Brent, C, Gardner, M, Prichard, J, Kline, David I
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2013
• Subjects: Benthos; Bottles or small containers/Aquaria <20 L; Calcification/Dissolution; Coast and continental shelf; Laboratory experiment; Macroalgae; Plantae; Porolithon onkodes; Rhodophyta; Single species; South Pacific; Temperate; Treatment; Species; Group; Replicate; Sample code/label; Magnesium carbonate, magnesite; Aragonite; Weight loss; Salinity; Temperature, water; Carbon, inorganic, dissolved; Alkalinity, total; pH; Bicarbonate ion; Carbonate ion; Partial pressure of carbon dioxide water at sea surface temperature wet air; Calcite saturation state; Aragonite saturation state; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Potentiometric titration; Potentiometric; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Gardner; Nash; Diaz; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.825092; https://doi.pangaea.de/10.1594/PANGAEA.825092

Coral reef ecosystems develop best in high-flow environments but their fragile frameworks are also vulnerable to high wave energy. Wave-resistant algal rims, predominantly made up of the crustose coralline algae (CCA) Porolithon onkodes and P. pachydermum, are therefore critical structural elements for the survival of many shallow coral reefs. Concerns are growing about the susceptibility of CCA to ocean acidification because CCA Mg-calcite skeletons are more susceptible to dissolution under low pH conditions than coral aragonite skeletons. However, the recent discovery of dolomite (Mg0.5Ca0.5(CO3)), a stable carbonate, in P. onkodes cells necessitates a reappraisal of the impacts of ocean acidification on these CCA. Here we show, using a dissolution experiment, that dried dolomite-rich CCA have 6-10 times lower rates of dissolution than predominantly Mg-calcite CCA in both high-CO2 (~ 700 ppm) and control (~ 380 ppm) environments, respectively. We reveal this stabilizing mechanism to be a combination of reduced porosity due to dolomite infilling and selective dissolution of other carbonate minerals. Physical break-up proceeds by dissolution of Mg-calcite walls until the dolomitized cell eventually drops out intact. Dolomite-rich CCA frameworks are common in shallow coral reefs globally and our results suggest that it is likely that they will continue to provide protection and stability for coral reef frameworks as CO2 rises. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2013-12-25.