Tellurium-speciation in seawater and accumulation by marine phytoplankton and crustaceans

Experiments were performed to determine the speciation of tellurium (using 129mTe as a radiotracer) in seawater and the extent of its accumulation by cultures of marine phytoplankton and crustaceans. Tellurite Te(IV) added to distilled water and to sterile filtered seawater was gradually transformed to the tellurate Te(VI) form, whereas Te(IV) tracer added to phytoplankton cultures was almost instantaneously transformed to a neutral form. Accumulation of radiotracer by phytoplankton (Dunaliella tertiolecta and Thallassiosira pseudonana) was moderate and for Dunaliella was greater in static cultures than in those which were actively dividing. Equilibrium concentration factors of 20 and 8 were established respectively after up to seven days' exposure of the herbivorous brine shrimp (Artemia salina) to labelled seawater with and without added phytoplankton. The loss of radionuclide upon transfer to uncontaminated running seawater was extensive and complete after one day, indicating that no true assimilation occurred. Transfer of radioactivity from Artemia salina to a predator, the Monaco shrimp (Lysmata seticaudata), was not observed. (author)