Australian Antarctic Program scientists are undertaking the first comprehensive biodiversity surveys, and environmental risk assessment for contamination and human impacts, within the Mawson research station operational area.
The three-person team is using drones, remotely operated vehicles (ROVs), and physical collection methods, to map and sample ice-free areas, looking at vegetation across the landscape, and microbial, algal and microinvertebrate communities in soils, lakes, marine sediments and summer melt streams.
Environmental toxicologist Dr Catherine King said the study area spans some 90 km east to west along the coast, into the Framnes Mountains in the south, and across islands to the north of Mawson station.
"We're aiming to characterise the biological communities and the natural values of terrestrial and local nearshore marine environments at Mawson," Dr King said.
"From there we can do a risk assessment on the impacts of human activities, particularly contamination and physical disturbance in our operational areas, on these communities and values.
"We can then determine the best way of protecting the ecosystem."
Sampling from above and below
As part of the Australian Antarctic Program's 'A Cleaner Antarctica' project, the team is spending three months in the field, making day trips from the station to study sites, or staying in field huts.
Drone pilot Dr Gwilym Price is conducting aerial surveys across ice free areas to map the physical environment and to support terrestrial biodiversity mapping.
This drone work is being validated through on-ground sampling and surveys of mosses, terrestrial algae, and microinvertebrates in soil and terrestrial water sources.
The team is also using ROVs, deployed through holes drilled in the sea ice, to assess nearshore marine communities.
Once back in Australia, the team will analyse the soil, sediment and water samples collected around the station, field huts and other disturbed sites, for contaminants, including fuels, metals, PFAS (per- and polyfluoroalkyl substances) and other persistent organic pollutants.
Learning from the past
To guide the field sampling design, the ACA team did a preliminary desktop analysis of potential contamination hotspots.
"We looked at historical records at Mawson to see where there may have been a fuel spill, fire, a contamination event or some other disturbance," Dr King said.
"We also investigated locations where waste was disposed of in the past, and the current station wastewater discharge site."
Samples from potential hotspots and within the main operational limits of the station will be used to map contamination across the station and any other areas that humans may have impacted.
"We'll then look at biodiversity at contaminated sites and compare that to biodiversity in comparable areas away from the station, to see if there's a difference in community structure and/or function," Dr King said.
"From there we can ask the question, does that contamination matter in terms of ecosystem health? Is it of risk to biological communities, and is it having, or is it likely to have an impact on biodiversity?"
Clean, contain or restrict
Under the Environmental Protocol to the Antarctic Treaty, Australia is committed to the clean-up of past and present waste and contamination, so long as this does not result in greater adverse environmental impact than leaving the waste material in its existing location.
Dr King said that sometimes trying to reduce contamination makes no improvement to the biological communities, or it can make things worse by changing the nature of the contamination. In these instances, making sure the contamination is contained rather than disturbing it or cleaning it up, may be the best option.
"If active remediation is not going to provide a net environmental benefit, we need to focus on containing contamination at the site, preventing offsite migration and not expanding our footprint any further," she said.
In future years the team will apply the same methodology across other impacted sites at Australia's Antarctic and sub-Antarctic stations and field camp sites.
For now though, Dr King and her team are excited to begin piecing together the first picture of Mawson's biodiversity.
"The communities really could be quite unique. It's going to be exciting to get the results and see what actually is living there, and compare that to other regions where we have a reasonable understanding of the biodiversity, such as the Vestfold Hills near Davis station," she said.
