| Although the organic and inorganic carbon cycles contribute about equally to the global coastal carbon cycle, almost all studies of temperate coastal systems have been restricted to the production and use of organic carbon and the importance of calcification in these areas is not known. In temperate regions many benthic organisms exist that are important calcium carbonate producers. We will investigate and quantify the production of calcium carbonate by benthic organisms in the North Sea and adjacent systems (Waddenzee, Westerschelde, Oosterschelde). Carbonate production will be estimated by combining macrobenthos biomass (available from extensive monitoring studies) with estimates of biomass turnover and CaCO3 production. The fate of this carbonate production will be assessed studying natural processes such as build-up of shell banks, and removal by human exploitation (using cockle and mussel fisheries as examples) and by dissolution. Carbonate dissolution, which is poorly known, will be studied in detail in contrasting coastal sediments (intertidal vs. subtidal and muddy vs. sandy). Carbonate diagenesis will be studied through the state of the art modeling of in situ profiles, obtained by micro-profiling, conventional pore-water and solid phase sampling techniques. The thus obtained regional estimates of carbonate production and removal will then be compared with available estimates for the total carbon cycle in these regions to estimate the contribution of inorganic carbon to the coastal carbon cycle. |
