Seawater carbonate chemistry and calcification rate in flume experiment

• Main Authors: Comeau, Steeve, Edmunds, Peter J, Lantz, Coulson A, Carpenter, Robert C
• Format: Dataset
• Language: English
• Published: PANGAEA 2015
• Subjects: Alkalinity; total; Aragonite saturation state; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification rate; Calcite saturation state; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Date; Entire community; EXP; Experiment; French Polynesia; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Laboratory experiment; Moorea; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Potentiometric titration; Rocky-shore community; Salinity; Sample code/label; Sample comment; South Pacific; Spectrophotometric; Temperature; water; Treatment; Tropical; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.847986; https://doi.org/10.1594/PANGAEA.847986

Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (400 matm) and high pCO2 (1300 matm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was reduced by 59% under high pCO2, with sediment dissolution explaining ~ 50% of this decrease; net calcification of corals and calcified algae remained positive but was reduced by 29% under elevated pCO2. These results show that, despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might transition to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.