EFFECTS OF HYPHOMONAS PM-1 BIOFILMS ON THE TOXICITY OF COPPER AND ZINC TO CRASSOSTREA-GIGAS AND CRASSOSTREA-VIRGINICA LARVAL SET

We tested the hypothesis that microbial biofilms bioconcentrate copper (Cu) and zinc (Zn) from ambient water to levels that inhibit oyster s et. Cu or Zn concentrations of 0.1 ppm in MBL artificial seawater did not affect oyster larval viability, swimming behavior, DOPA-induced se arch behavior, or epinephrine-induced metamorphosis; however, they did significantly inhibit larval set in the presence of biofilms as compa red with control films which had not been exposed to additions of Cu o r Zn. The mechanism is attributed to the bioconcentration of metals by the films. Therefore, complex interactions between toxic metals, bact erial films, and oyster larvae can affect oyster larval set and recrui tment in Chesapeake Bay and other aquatic habitats.