An inquiry was made into the suitability of protozoa bioindicators of oil pollution. Oil uptake rates and oil toxicity were measured for the marine ciliate protozoan Euplotes diadaleos. Euplotes ingest oil at a rate of approximately 1 ng/min over the first three hours of exposure to an emulsion of oil in water. The 90hr LC50 of the solubilized fraction of crude oil is 1.7 ppm. Toxicity is directly correlated with the log of the concentration of oil with one interesting exception: the population of Euplotes increases dramatically at 8 ppm. Field experiments using artificial substrates in oiled ponds indicated that (1) oil descends through the water column as droplets associated with detritus, (2) the rate of descent is directly correlated with the salinity of the water, and (3) the interaction of oil with microfaunal communities is complex. The biological parameters of population, species number, and community diversity index generally exceeded pre-spill levels after three weeks. In one substrate, however, the values of these parameters were reduced to zero. The data suggest an interaction between a stimulating effect of oil as seen with Euplotes at 8 ppm, and a toxicity of oil that, in time, can overcome microfaunal defense mechanisms.

  • Corporate Authors:

    Coast Guard

    Office of Research and Development
    Washington, DC  United States 
  • Authors:
    • Lanier, J J
    • Light, M
  • Publication Date: 1978-6

Media Info

  • Pagination: 53 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00191392
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: CGR/DC-10/78, USCG-D-83-78
  • Files: NTIS
  • Created Date: May 26 2003 12:00AM