Document Type



Virginia Institute of Marine Science

Publication Date



Primary productivity, heterotrophic potential, chlorophyll i! and phaeophytin, ATP, and direct bacterial counts were measured in the sea surface layer under controlled spills of La Rosa and Murban crude oils following immediate dispersal with the EXXON dispersant, Corexit 9527. Tests were conducted off New York on November 9, 1978.

The response of productivity to dispersed oil appeared as an initial increase in rates, a reduction to minimal rates 1-2 hours after dispersion, and a return to pre-spill rates after 3 hours. Comparison of productivity measurements from the two tests suggested a more efficient and rapid dispersion of the somewhat lighter La Rosa crude. Heterotrophic uptake at one meter below the La Rosa spill mirrored productivity results; missing samples at the Murban spill prohibited interpretation.

While oil and dispersant appeared to have little effect on chlorophyll-~ and direct bacterial counts, ATP concentrations decreased· to below detectable limits shortly after the application of the dispersant. Phaeophytin, expressed as a percentage of chlorophyll, varied inversely with ATP in both tests.


Oil pollution of the sea, Oil spills -- Environmental aspects