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EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS
Citation:
Lores, E M., J. R. Pennock, AND G. McManus. EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS. Presented at Estuaries: Bridges from Watersheds to Coastal Seas: Abstracts: Estuarine Research Foundation 13th Biennial International Conference, Corpus Christi, TX, November 12 - 16, 1995.
Impact/Purpose:
Presentation
Description:
This research is part of an ongoing project designed to determine the effect of humic acid on the uptake and transfer of metals by marine organisms at the lower end of the food chain. Binding affinities for Cu, Cd, Zn, and Cr to Suwannee River humic acid were determined at various salinities. Copper was the only metal with more than 50% bound to the humic acid at 15%. Subsequent experiments were then initiated to determine the effect of humic acid on uptake and transfer of copper through a microbial > ciliate> copepod food chain. Mixed cultures of microbes were allowed to grow to stationary phase in cultures with and without humic acid and copper. Ciliates (Pleuronema sp. in one experiment and Euronema sp. in another) were introduced to feed on the microbes. The resulting ciliates were then fed to copepods (Acartia tonsa). Early results suggest that the presence of humic acid significantly reduced the uptake of copper by copepods but had no effect on copper uptake by ciliates. Survival and reproduction of copepods exposed to copper were enhanced in the presence of humic acid. Ongoing experiments are being conducted to more closely examine the effects on uptake of copper in ciliates.