Barium uptake into the shells of the common mussel (Mytilus edulis) and the potential for estuarine paleo-chemistry reconstruction

David Paul Gillikin (1) , F. Dehairs (2) , Anne Lorrain (3) , Dirk Steenmans (1) , Willy Baeyens (1) , Luc André (4)

1 VUB - Vrije Universiteit Brussel
2 Department of Analytical and Environmental Chemistry [Bruxelles]
3 LEMAR - Laboratoire des Sciences de l'Environnement Marin (LEMAR)
4 RMCA - Royal Museum for Central Africa [Tervuren]

In this study we test if calcite shells of the common mussel, Mytilus edulis, contain barium in proportion to the water in which they grew. Similar to all bivalves analyzed to date, the [Ba/Ca]shell profiles are characterized by a relatively flat background [Ba/Ca]shell, interrupted by sharp [Ba/Ca]shell peaks. Previous studies have focused on these [Ba/Ca]shell peaks, but not on the background [Ba/Ca]shell. We show that in both laboratory and field experiments, there is a direct relationship between the background [Ba/Ca]shell and [Ba/Ca]water in M. edulis shells. The laboratory and field data provided background Ba/Ca partition coefficients (DBa) of 0.10 ± 0.02 and 0.071 ± 0.001, respectively. This range is slightly higher than the DBa previously determined for inorganic calcite, and slightly lower than foraminiferal calcite. These data suggest that M. edulis shells can be used as an indicator of [Ba/Ca]water, and therefore, fossil or archaeological M. edulis shells could be used to extend knowledge of estuarine dissolved Ba throughputs back in time. Moreover, considering the inverse relationship between [Ba/Ca]water and salinity, background [Ba/Ca]shell data could be used as an estuary specific indicator of salinity. The cause of the [Ba/Ca]shell peaks are more confusing, both the laboratory and field experiments indicate that they cannot be used as a direct proxy of [Ba/Ca]water or phytoplankton production, but may possibly be caused by barite ingestion.

Domains: Environmental Sciences

David Paul Gillikin, F. Dehairs, Anne Lorrain, Dirk Steenmans, Willy Baeyens, et al.. Barium uptake into the shells of the common mussel (Mytilus edulis) and the potential for estuarine paleo-chemistry reconstruction. Geochimica et Cosmochimica Acta, 2006, 70 (2), pp.395-407. ⟨hal-00452801⟩