The Time-Concentration Relationship of Trace Metals in the Growth of Algae

Abstract

<p> The time relationship of metabolically important trace metals (Fe, Cu, Zn, Co, Cd, Cr) in Lake Erie plankton were analyzed from samples collected during an algal (Aphanizomenon) bloom. Iron and cobalt showed a rapid increase in concentretion during the initial period of the bloom, followed by a decrease and levelling off to an equilibrium value. Copper and zinc were found to behave similarily undergoing a slight decrease at the beginning and then steadily increasing in concentration with time. Different depths of sampling were correlated to the life-death cycle of the organism and specific metal concentration trends. Algae from the lowest level of sampling (9.7 m; dead organism level) exhibited an increasing nutrient concentration (Fe, Zn, Co, and PO4) with time.</p> <p> Factor analysis suggested a Fe, Co, depth, 1/Biomass relationship; a Cu, Zn relationship; and a PO4, time relationship. The first two were verified from the experimental results; the last was not.</p>