Contamination effects by a ‘conventional’ and a ‘biodegradable’ lubricant oil on infaunal recruitment to Antarctic sediments: A field experiment

To investigate the impacts of synthetic lubricants on Antarctic infaunal communities, a field experiment was setup near Australia's Casey Station, East Antarctica. Two types of synthetic lubricants were tested: an ‘Unused’ and ‘Used’ conventional synthetic lubricant, and an alternative marketed as ‘biodegradable’. Clean defaunated sediment was contaminated with the lubricants, decanted into trays, and deployed by divers onto the seabed in a randomised block design. Sediments were sampled 5 and 56 weeks after deployment. After 5 weeks, benthic assemblages that had recruited to the lubricant contaminated sediments were significantly different to those in ‘Control’ sediments, and differences were more pronounced after 56 weeks. Total number of individuals did not significantly differ between treatments after 5 weeks. However, after 56 weeks total individuals in the ‘Control’ sediments were significantly greater than in the contaminated sediments. Nototanais antarcticus (tanaid) and to a lesser extent Monoculodes sp. (gammarid), Tanaid sp. IV and Eudorella sp. (cumacean) had significantly higher abundances in the control sediments after 56 weeks compared to the contaminated sediments. Copepods numerically dominated the benthic assemblages at both sampling times; however, their abundance did not significantly differ across treatments. The community recruiting to the contaminated sediments remained different from that in the ‘Control’ sediments for the duration of the experiment (1 year). The ‘biodegradable’ lubricant was just as environmentally harmful to the Antarctic infauna as the ‘conventional’ lubricant currently used at Australia's Antarctic stations. Our results demonstrate that changes to recruitment are one of the potential environmental consequences of a lubricant spill to Antarctic benthic communities, and reinforce the importance of preventative oil spill management and effective clean-up procedures. Further monitoring of this field experiment will provide much needed information about the long-term impacts by synthetic lubricants in the Antarctic marine environment.