PARENT SESSION

PH08 Metals in the Environment: Aquatic Biological Perspectives
Exhibit Hall
8:00 AM - Thursday

(PH076) Bioavailability of copper probed with the marine alga Thalassiosira weissflogii.

Karner, D¹, Hemming, J¹, Shafer, M², Overdier, J², Armstrong, D², ¹ Wisconsin State Laboratory of Hygiene, Madison, WI, USA² University of Wisconsin, Madison, WI, USA

ABSTRACT- Natural colloids and dissolved complexes present in natural water can sequester metals and thus regulate bioavailability to algae. Laboratory-based assays using the marine diatom Thalassiosira weissflogii were used to assess the bioavailability of copper in two estuaries along the U.S. east coast; the James and Elizabeth Rivers in Norfolk, Virginia and the Cape Fear River in Wilmington, North Carolina. Trace-metal clean separation techniques were employed to fractionate field samples into < 0.45 m and < 1kD sizes in order to determine the influence of colloids and dissolved complexes on Cu availability. T. weissflogii was exposed to the fractionated samples in 30 hour metal uptake bioassay experiments using 65Cu stable isotope. Our studies document large gradients in metal speciation and metal-binding ligand both between and within study systems. Colloidal phases are shown to play a major role in regulating uptake and toxicity of Cu to T. weissflogii.

Key words: bioavailability, Thalassiosira weissflogii, copper, colloids