Seawater carbonate chemistry and calcification during experiments with maerl beds, 2007

• Main Authors: Martin, Sophie, Clavier, Jacques, Chauvaud, Laurent, Thouzeau, Gérard, Richard, M, Jean, Frédéric
• Format: Dataset
• Language: English
• Published: PANGAEA 2007
• Subjects: Alkalinity; Gran titration (Gran; 1950); total; Alkalinity anomaly technique (Smith and Key; 1975); Aragonite saturation state; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification rate of calcium carbonate; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Date; DEPTH; water; Entire community; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; EXP; Experiment; Field observation; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); LICOR quantameter (LI-COR LI-192SA); Martin_etal_07; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH meter (Radiometer; PHM; 240); Radiation; photosynthetically active; Salinity; Sample ID; Soft-bottom community; Temperate; Temperature; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.721761; https://doi.org/10.1594/PANGAEA.721761

Maerl community respiration, photosynthesis and calcification were measured seasonally in the Bay of Brest (France). The dynamics of oxygen, carbon and carbonate fluxes at the water-sediment interface were assessed using benthic chambers. Community respiration (CR) fluctuated in accordance with the seasonal changes in water temperature, from 1.5 mmol C m**-2 h**-1 in winter to 8.7 mmol C m**-2 h**-1 in summer. Mean gross community production (GCP) varied significantly among seasons, according to incident irradiance and temperature, from 3.4 mmol C m**-2 h**-1 in winter to 12.7 mmol C m-2 h-1 in summer. Mean annual Pmax for the P-E curve was estimated to 13.3 mmol C m-2 h-1. Carbonate precipitation only occurred during light incubations and varied seasonally from 0.7 mmol CaCO3 m-2 h-1 in winter to 4.2 mmol CaCO3 m-2 h-1 in summer. Mean annual Pmax was 3.2 mmol CaCO3 m-2 h-1. Annual CR was estimated to 407.4 g C m**-2 yr**-1, and GCP, to 240.9 g C m**-2 yr**-1. Maerl communities are, therefore, heterotrophic systems (GCP:CR = 0.6), and are a source of CO2 for surrounding environments. In addition, CO2 released by calcification averaged 39.2 g C m**-2 yr**-1. Maerl community annual carbonate production was estimated to 486.7 g CaCO3 m**-2 yr**-1; they are therefore one of the most important carbonate producers in shallow coastal waters.