Mysid shrimp, Neomysis integer, were acclimated to 4 temperatures (6, 10, 15 or 20 "C) and exposed to water-soluble fractions (WSF) of light fuel oil under 2 different regimes. The first, a chronic exposure scheme, employed ng 1-' hydrocarbon levels and lasted 2 wk. The second, acute exposure, employed yg 1-' levels and exposure occurred during determination of physiological parameters. We determined oxygen consumption, ammonium excretion rates, and computed oxygen nitrogen ( 0 : N ) ratios.

more »

... gen consumption was more strongly influenced by temperature than was ammonia excretion. Chronic exposure for 2 wk to aromatic petroleum hydrocarbons at the ng 1-' level did not significantly affect the parameters measured. Exposure to WSF at concentrations between ca. 200 and 1000 pg 1-l produced increases in oxygen consumption and decreases in ammonia excretion; these were strongly influenced by temperature with the greatest effect of oil exposure occurring at 21.5 "C, the highest temperature tested. Laboratory rearing conditions were shown to increase oxygen consumption and ammonia excretion rates compared to those of f~eld-collected mysids; however, the relative response to oil was not affected.