Seawater carbonate chemistry and net dissolution rate for experiment of Shiraho reef, supplement to: Yamamoto, Shoji; Kayanne, Hajime; Terai, Makoto; Watanabe, Atsushi; Kato, Ken; Negishi, Akira; Nozaki, Ken (2012): Threshold of carbonate saturation state determined by CO2 control experiment. Biogeosciences, 9(4), 1441-1450

• Main Authors: Yamamoto, Shoji, Kayanne, Hajime, Terai, Makoto, Watanabe, Atsushi, Kato, Ken, Negishi, Akira, Nozaki, Ken
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2012
• Subjects: Benthos; Bottles or small containers/Aquaria <20 L; Calcification/Dissolution; Coast and continental shelf; Entire community; Laboratory experiment; North Pacific; Rocky-shore community; Temperate; Treatment; Carbon dioxide, partial pressure; Sample mass; Duration; Temperature, water; Salinity; Alkalinity, total; Carbon, inorganic, dissolved; Fugacity of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Water volume; Dissolution rate; Carbonate system computation flag; pH; Carbon dioxide; Partial pressure of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Calcite saturation state; Experiment; Infrared gas analyzer NDIR; Potentiometric titration; Standardized to a constant salinity; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.820200; https://doi.pangaea.de/10.1594/PANGAEA.820200

Acidification of the oceans by increasing anthropogenic CO2 emissions will cause a decrease in biogenic calcification and an increase in carbonate dissolution. Previous studies have suggested that carbonate dissolution will occur in polar regions and in the deep sea where saturation state with respect to carbonate minerals (Omega) will be <1 by 2100. Recent reports demonstrate nocturnal carbonate dissolution of reefs, despite a Omega a (aragonite saturation state) value of >1. This is probably related to the dissolution of reef carbonate (Mg-calcite), which is more soluble than aragonite. However, the threshold of Omega for the dissolution of natural sediments has not been clearly determined. We designed an experimental dissolution system with conditions mimicking those of a natural coral reef, and measured the dissolution rates of aragonite in corals, and of Mg-calcite excreted by other marine organisms, under conditions of Omega a > 1, with controlled seawater pCO2. The experimental data show that dissolution of bulk carbonate sediments sampled from a coral reef occurs at Omega a values of 3.7 to 3.8. Mg-calcite derived from foraminifera and coralline algae dissolves at Omega a values between 3.0 and 3.2, and coralline aragonite starts to dissolve when Omega a = 1.0. We show that nocturnal carbonate dissolution of coral reefs occurs mainly by the dissolution of foraminiferans and coralline algae in reef sediments. : 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 2013-10-13.