Effects of the water-soluble fraction of microbiologically or physically altered crude petroleum on the heterotrophic activity of marine bacteria

Crude petroleum was emulsified or degraded by marine microorganisms and physically altered by an artificial weathering process. Only the water-soluble fraction from emulsified crude petroleum inhibited glutamate uptake by marine microorganisms from South Carolina and Georgia coastal waters. Chloroform extraction recovered almost equal amounts of total hydrocarbon from each water-soluble fraction. Chromatographic data indicated that the composition of microbially emulsified petroleum was similar to that of microbially degraded petroleum. Emulsification of crude petroleum was only observed in summer water samples and did not consistently occur at a given location. Results of this study indicate that the process by which crude petroleum is altered will influence its toxicity to microbial heterotrophic activity.