Gillikin D.P., Lorrain Anne, Bouillon S., Dehairs F., Willenz P. (2006). Delta13C in Mytilus edulis shells : relation to salinity, DIC, phytoplankton and metabolism. Organic Geochemistry, 37 (10), p. 1371-1382.
Titre du document
Delta13C in Mytilus edulis shells : relation to salinity, DIC, phytoplankton and metabolism
Année de publication
2006
Type de document
Article
Auteurs
Gillikin D.P., Lorrain Anne, Bouillon S., Dehairs F., Willenz P.
Source
Organic Geochemistry, 2006,
37 (10), p. 1371-1382
Bivalve shells can potentially record the carbon isotopic signature of the dissolved inorganic carbon (?13CDIC) in estuarine waters, thereby providing information about past estuarine biogeochemical cycles. However, the fluid from which these animals calcify is a ?pool' of metabolic CO2 and external dissolved inorganic carbon (DIC). The incorporation of respired 13C depleted carbon into the skeletons of aquatic invertebrates is well documented, and may affect the ?13CDIC record of the skeleton. Typically, less than 10 % of the carbon in the skeleton is metabolic in origin, although higher amounts have been reported. If this small offset is more or less constant, large biogeochemical gradients in estuaries may be recorded in the ?13C value of bivalve shells. In this study, it is assessed if the ?13C values of Mytilus edulis shells can be used as a proxy of ?13CDIC as well as provide an indication of salinity. First, the ?13C values of respired CO2 (?13CR) was considered using the ?13C values of soft tissues as a proxy for ?13CR. Along the strong biogeochemical gradient of the Scheldt estuary (The Netherlands ? Belgium), ?13CR was linearly related to ?13CDIC (r2 = 0.87), which in turn was linearly related to salinity (r2 = 0.94). The mussels were highly selective, assimilating most of their carbon from phytoplankton out of the total particulate organic carbon (POC) pool. However, on a seasonal basis, tissue ?13C varied differently than ?13CDIC and ?13CPOC, most likely due to lipid content of the tissue. All shells contained less than 10 % metabolic C, but ranged from near zero to 10 %, thus excluding the use of ?13C in these shells as a robust ?13CDIC or salinity proxy. As an example, an error in salinity of about five would have been made at one site. Nevertheless, large changes in ?13CDIC (>2 ?) can be determined using M. edulis shell ?13C.
