RESUMO
Although considered pristine, Antarctica has not been impervious to hydrocarbon pollution. Antarctica's history is peppered with oil spills and numerous abandoned waste disposal sites. Both spill events and constant leakages contribute to previous and current sources of pollution into marine sediments. Here we compare the response of the benthic diatom communities over 5 years to exposure to a commonly used standard synthetic lubricant oil, an alternative lubricant marketed as more biodegradable, in comparison to a control treatment. Community composition varied significantly over time and between treatments with some high variability within contaminated treatments suggesting community stress. Both lubricants showed evidence of significant effects on community composition after 5 years even though total petroleum hydrocarbon reduction reached approximately 80% over this time period. It appears that even after 5 years toxicity remains high for both the standard and biodegradable lubricants revealing the temporal scale at which pollutants persist in Antarctica.