The Combined Effect of Dissolved Organic Carbon and Salinity on the Bioaccumulation of Copper in Marine Mussel Larvae

The Combined Effect of Dissolved Organic Carbon and Salinity on the Bioaccumulation of Copper in Marine Mussel Larvae 

ESnTDue to natural and anthropogenic influences, copper concentrations can be elevated in the aquatic environment. However, the total dissolved Cu concentration is, by itself, an inefficient predictor of copper toxicity. Considerable efforts have been made to improve the prediction of toxic effects by taking into account the aquatic concentration of other elements and dissolved organic carbon (DOC). These models are based on Cu accumulation at a so-called biotic ligand somewhere in the exposed organism. Mussels, and especially the larvae, are very sensitive to copper. Because of their ecological and economical importance, more specific knowledge about the influence of salinity and DOC on Cu accumulation and distribution in mussel larvae was needed. By collaborating with the X-ray microscopy and imaging group of the UGent (XMI), we could use synchrotron X-ray fluorescence spectroscopy and measure the Cu body burden of individual larvae with a spatial resolution up to 100*100nm. The results indicate that accumulated Cu is homogenously distributed in mussel larvae and decreases with increasing DOC concentrations. Salinity also altered Cu accumulation in a nonlinear way which indicates that alterations in salinity change the physiology of the larvae. The latter is important because this means that Cu accumulation in mussel larvae cannot be predicted solely based on water chemistry.

 

Scientific abstract

Larvae of Mytilus spp. are among the most Cu sensitive marine species. In this study we assessed the combined effect of salinity and dissolved organic carbon (DOC) on Cu accumulation on mussel larvae. Larvae were exposed for 48 h to three Cu concentrations in each of nine salinity/DOC treatments. Synchrotron radiation X-ray fluorescence was used to determine the Cu concentration in 36 individual larvae with a spatial resolution of 10 × 10 μm. Cu body burden concentrations varied between 1.1 and 27.6 μg/g DW larvae across all treatments and Cu was homogeneously distributed at this spatial resolution level. Our results indicate decreasing Cu accumulation with increasing DOC concentrations which can be explained by an increase in Cu complexation. In contrast, salinity had a nonlinear effect on Cu. This cannot be explained by copper speciation or competition processes and suggests a salinity-induced alteration in physiology.

 

Full reference

Deruytter D, Garrevoet J, Vandegehuchte M, Vergucht E, De Samber B, Vekemans B, Appel K, Falkenberg G, Delbeke K, Blust R,De Schamphelaere K, Vincze L, Janssen C. 2014. The Combined Effect of Dissolved Organic Carbon and Salinity on the Bioaccumulation of Copper in Marine Mussel Larvae. Environmental Science & Technology 48(1), 698–705. DOI: 10.1021/es4024699

 

Category: