Annual changes of microalgae biomass in Antarctic sea ice contaminated by crude oil and diesel fuel

The influence of diesel fuel and “Arabian light” crude oil contamination were investigated on the land fast ice located in the continental shelf of Terre Adélie, Antarctica, during the austral winter 1993. Autotrophic biomass exhibited a clear seasonal pattern. In uncontaminated sea ice, chlorophyll a concentration showed two maxima, one in April (50 mg m−3) during sea-ice formation, and the second one in spring just before the ice thaw (20 mg m−3). The crude oil and diesel fuel contamination induced a negative effect on ice-microalgae biomass, which remained at a weak level throughout the ice-covered period. However, the inhibitory effect of diesel contamination was immediate while the crude oil effect occurred after the autumn phytoplankton bloom. Addition of fertilizer (Inipol EAP-22) to diesel and crude oil had a clear favourable effect on ice-microalgae. Chlorophyll a biomass exhibited the same seasonal pattern in fertilized and uncontaminated areas.