EFFECTS OF A CONTINUOUS LOW-LEVEL NO. 2 FUEL DISPERSION ON LABORATORY-HELD INTERTIDAL COLONIES

ABSTRACT Marine intertidal colonies on concrete substrates were exposed for six months to 0.1 and 0.6 mg/l No. 2 fuel oil (API Ref. Oil III, 38% aromatics). A continuous supply of the fuel oil dispersion was prepared by a mixing-separation apparatus, and nonfloating material was used as the contaminant. Monitoring of No. 2 fuel was by IR analysis of CCl4 extracts. Supplementary analyses were performed by gas chromatography, helium partitioning gas chromatography, and mass spectrometry. Colonies were obtained by stratified random sampling from an initial 500 field-colonized bricks. Field colonization time was nine months. Replicates of treatment concentrations and controls were studied under constant continuous photoperiod. Initial colonies consisted of approximately 83 species of intertidal plants and animals. Effects were measured by comparison of species diversity, relative abundance, numbers of species, and individual frequency of occurrence patterns. Species diversity was significantly lower in treate...