Ice free areas in Antarctica make up <1% of the surface of the continent, including exposed rock and soils. This exposed, solid ground make ice-free good places to establish research stations and historically, military and fishing operations. These terrestrial environments are home to microfauna including rotifers and tardigrades which can be impacted by human activities. Some soil-dwelling microinvertebrates (like rotifers and tardigrades) are not as well studied as their water-dwelling counterparts and we have little knowledge of their response to contaminants. To protect these fauna, their sensitivity to toxicants needs to be determined to properly inform site assessment and -if necessary- remediation of soils at potentially impacted sites.
We conducted ecotoxicological assays on an Antarctic rotifer (Bdelloidea sp) isolated from terrestrial environments in proximity to Casey station, East Antarctica. Twenty one day exposures to Cu and Ni were done in a soil elutriate to reflect conditions in their natural environment with mortality, sublethal behavioural (activity) and reproductive (egg production, hatching success) endpoints recorded for both taxa. Dose-response relationships were found for both taxa to both metals. An EC50 for rotifer activity was determined to be 3286 µg/L for Ni, and 564 µg/L for Cu after 21 days of exposure. Reproductive success was also affected by elevated metals, with total egg production lower in Cu treatments of 1800 µg/L (p<0.05), and Ni treatments of 9957 µg/L (p<0.0001), and egg hatching success lower at Ni concentrations ≥4488 µg/L (p<0.01). No statistical significance was found between Cu concentration and egg hatching success. The sensitivity data presented here for endemic Antarctic species will contribute to informing risk assessment and management of soil contamination in impacted Antarctic environments.