Seawater carbonate chemistry and calcification at Anse des Cuivres, NW Mediterranean, 2004

• Main Authors: Bensoussan, Nathaniel, Gattuso, Jean-Pierre
• Format: Dataset
• Language: English
• Published: PANGAEA 2007
• Subjects: Alkalinity; total; Alkalinity anomaly technique (Smith and Key; 1975); Aragonite saturation state; Automatic module for alkalinity measurement (AMAM); Benthos; BG_07; Bicarbonate ion; BIO; Biology; Calcification/Dissolution; Calcification rate of calcium carbonate; Calcite saturation state; Calculated; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; DATE/TIME; DEPTH; water; Entire community; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Field observation; Fugacity of carbon dioxide in seawater; Mediterranean Sea; Multi meter; WTW; LF 197; NW Mediterranean; OA-ICC; Ocean Acidification International Coordination Centre; PAR sensor LI-190SA; LI-COR Inc.; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Radiation; photosynthetically active; Rocky-shore community; Salinity; South Pacific; Temperate; Pacific; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.717852; https://doi.org/10.1594/PANGAEA.717852

The community metabolism of a shallow infralittoral ecosystem dominated by the calcareous macroalgae Corallina elongata was investigated in Marseilles (NW Mediterranean), by monitoring hourly changes of seawater pH and total alkalinity over 6 d in February 2000. Fair weather conditions prevailed over the study period as indicated by oceanographic (temperature, salinity, and current velocity and direction) and meteorological variables, which validated the standing water hypothesis. This temperate ecosystem exhibited high community gross primary production (GPP = 519 ± 106 mmol C m-2 d-1, n = 6) and also supported high rates of community respiration (R). As a result, the system was slightly autotrophic (net community production, NCP = 20 mmol C m-2 d-1), with a GPP/R ratio of 1.06. NCP exhibited circadian variations with 2- to 3-fold changes in community respiration, both in the light and in the dark. Rates of net community calcification also exhibited circadian variations, with positive rates (up to 24 mmol CaCO3 m-2 h-1) for irradiance values >300 W m-2 (about 1380 µmol photon m-2 s-1). Below this irradiance threshold, net community dissolution prevailed. Daily net calcification (G) was on average 8 mmol CaCO3 m-2 d-1. CO2 fluxes generated by primary production, respiration, and calcification suggest that the study site was a potential atmospheric CO2 sink of 15 mmol CO2 m-2 d-1 at the time of measurement.