Over more than 80 years, scientists from Antarctic Treaty-participating countries have been conducting research in Antarctica, establishing research stations across the continent. These stations are essential for conducting scientific research and providing living conditions for extended stays, enabling in-depth studies that would be otherwise impossible.
Presently, there are 112 research stations in Antarctica, with 62 located in coastal regions for ease of access. However, while these stations have greatly benefited scientific endeavours, they have also introduced environmental challenges that were previously non-existent. This article focuses on the environmental effects of the Australian research base “Casey” on the surrounding marine environment.
The original Casey station was constructed 1960’s on the Bailey Peninsula, replacing a previous Australian station. Due to poor building quality, the station was dismantled in the 1980s, and a new Casey station was built 1 km away (Fig 1). Today, this new station comprises 18 permanent buildings that can house up to 120 people, with an average population of 25 in winter and 90 in summer.
Up until 1986, solid waste from Casey Station was disposed of in a site at Thala Valley (Fig 2), causing environmental contamination in Brown Bay by erosion and melt streams carrying contaminated material into the waters. After the Protocol on Environmental Protection to the Antarctic Treaty (Madrid Protocol), signed in 1991, Australia had to remove most waste from Antarctica, leading to improvements in waste management and environmental protection. Efforts were made to remediate the Thala Valley waste disposal site, including waste removal, construction of meltwater trenches, and the installation of a water treatment plant to prevent further contamination of the nearby waters. The concentrations of metal contaminants in the soil and seabed floor were also assessed, and a monitoring program was initiated to evaluate the effectiveness of these measures.
By analyzing sediment samples from 1997 to 2015, focusing on variations in sediment properties and contaminants, the study revealed a clear signal of anthropogenic contamination in the marine environment around Casey Station. Multiple pollutants were found in marine sediment in levels several orders of magnitude greater than control locations.
Brown Bay (adjacent to the former waste disposal site) was contaminated with pollutants at levels higher than observed anywhere else, Shannon Bay (site of wastewater outfall) and the Casey Wharf also had consistently higher concentrations of contaminants than controls, while Wilkes (adjacent to an older waste disposal site) had lower levels and most contaminants were close to background values. Notably, Brown Bay Outer displayed an increase in contaminant concentrations from pre-2000 to 2014, suggesting the movement of sediment-bound contaminants from Inner to Outer sites, possibly due to resuspension and lateral transport. These patrons of contamination coincide with the distance to the current location of the station, the closer the site higher the contamination.
Contamination levels of sites around Casey were found to be much higher than those at other Australian stations but similar to those at impacted areas near the USA’s McMurdo Station. Brown Bay levels of contamination are also similar to some heavily modified estuaries worldwide such as the Sydney Harbour and Rio de Janeiro and may have significant effects on the health of benthic fish species, as observed in other stations. Nevertheless, the article highlights that the spatial extent of contamination around Antarctic stations is likely limited to a few kilometres from the station due to the calm nature of Antarctic coastal sub-marine environments.
In summary, the article underscores the environmental impacts associated with research bases like Casey in Antarctica. While these bases are essential for scientific research, they must be managed carefully to mitigate their ecological effects on this sensitive and pristine environment.
Author: Lucas Bastos
Source: Stark JS, Johnstone GJ, King C, Raymond T, Rutter A, Stark SC, et al. (2023) Contamination of the marine environment by Antarctic research stations: Monitoring marine pollution at Casey station from 1997 to 2015. PLoS ONE 18(8): e0288485. DOI: 10.1371/JOURNAL.PONE.0288485
