Aquatic Sciences Meeting, Albuquerque 2001

PC13 Phytoplankton: Trace Metals and Biochemistry

Date: Thursday, February 15, 2001

Location: Southwest Hall

Wei, L, , Cornell University, Ithaca, USA, LW68@cornell.edu

Ahner, B, A, Cornell University, Ithaca, USA, baa7@cornell.edu

DEGRADATION OF PHYTOCHELATIN IN NATURAL SEAWATER

Phytochelatin is a small sulfhydryl-containing peptide produced by eucaryotic marine phytoplankton when exposed to heavy metals. They play a role in heavy metal detoxification by chelating metals intracellularly. They may also influence heavy metal cycling in natural ecosystems as an extracellular chelator. Phytochelatins are released to the surrounding seawater by exudation and cell breakage, however little work has been done to determine their turnover rates in seawater. Both biological and chemical degradation are possible. As peptides, they are probably degraded readily by bacteria, serving as a source of necessary carbon, nitrogen and sulfur. Using a synthesized phytochelatin standard, chemical degradation rates were measured in artificial seawater in the presence of sodium azide, a bacterial inhibitor. We compared the degradation rates of phytochelatin and phytochelatin-metal complexes. First order kinetics were used to estimate rates and half-lives. Biological degradation experiments were performed in fresh seawater. By comparing degradation rates, it is apparent that bacteria play an important role in degrading phytochelatin in natural waters.

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Aquatic Sciences Meeting, Albuquerque 2001

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