Origin and fate of dissolved inorganic carbon in interstitial waters of two freshwater intertidal areas: A case study of the Scheldt Estuary, Belgium
Hellings, L.; Van Den Driessche, K.; Baeyens, W.; Keppens, E.; Dehairs, F. (2000). Origin and fate of dissolved inorganic carbon in interstitial waters of two freshwater intertidal areas: A case study of the Scheldt Estuary, Belgium. Biogeochemistry 51(2): 141-160. hdl.handle.net/10.1023/A:1006472213070
Processes affecting the concentration and isotopic composition of dissolved inorganic carbon (DIC) were investigated in pore waters of two freshwater intertidal areas of the Scheldt Estuary, Belgium. Porewater d13CDIC values from marshes and mudflats varied from -27 to +13.4‰, these very largevariations reflect the contribution of different carbon sources to the DIC pool.
In pore waters of the upper mudflat, river water DICand dissolution of calcite contribute to a lesser extent (10% and 16% respectively) to the total DICpool. Results indicate that inorganic carbon added tothe pore water of the mudflats has a d13Cvalue of +20.3‰ in May 1998. These strongly enrichedd13CDIC values suggest that the major contribution (up to three-quarters) to total DIC isCO2 derived from methanogenesis.
In pore waters of the marshes, CO2 derived from organic matter degradation (-27.5‰) and river DIC(-11.5 to -16.1‰) are the major sources of inorganic carbon contribution to the total DIC pool. In porewaters from a marsh site colonised by willow trees,the contribution from CO2 derived from organic matter degradation is larger than in pore waters from an area with only reed vegetation. In the latter case river water DIC is the major source of pore water DIC.