We measured short-term uptake rates of copper using the gamma-emitting radioisotope 67Cu in seven algal species in natural and artificial seawater. Cellular net uptake of Cu was typically rapid over periods of 2-20 min. Net uptake ceased after about 60 min. The most copper-sensitive species examined, Synechococcus sp., exhibited 2-3 orders of magnitude higher carbon and surface-area-normalized Cu-accumulation rates (46 μmol Cu mol C-1 min-1 and 1,100 zmol Cu μm-2 min-1) (zmol = 10-21 moles) than those measured in diatoms, chlorophytes, a dinoflagellate, and a coccolithophore. Cu-accumulation rates for Thalassiosira weissflogii were three times faster in natural seawater than in EDTA-buffered artificial seawater containing an inorganic Cu concentration of 28 pmol L -1. Calculations showing that the diffusive flux of inorganic Cu was insufficient to account for observed short-term uptake rates suggest that some of the Cu bound to naturally occurring organic ligands is released through the rapid dissociation of those complexes in the cell's boundary layer.
All Science Journal Classification (ASJC) codes
- Aquatic Science