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Microbial communities as sedimentary indicators of anthropogenic impact in Fildes Peninsula, South Shetland Islands, Antarctica

Since the discovery of Antarctica in the early 19th Century, the number of humans arriving to the continent has progressively increased. This increased human footprint has generated concern about the threats posed to the region’s fragile ecosystems. The Fildes Peninsula (King George Island, South Shetland Islands) has been the site of year-round human presence since the construction of Bellingshausen Station in 1968. However, the degree of environmental impact due to the infrastructure installed to support bases is still poorly understood. Lakes are a pervasive feature of Fildes Peninsula landscapes, with a large number of them in close proximity to the permanent stations and several used as sources of water. Although it seems logical that these water bodies have been affected in some way by the presence of bases, very little research has been done to investigate their chemical processes and biological communities.

This project will study seven lakes (including two control lakes) of the Fildes Peninsula using a combined paleolimnological-molecular approach in order to assess the degree to which they have been impacted by anthropogenic activities during the last century.

The seven lakes are situated on Fildes Peninsula, South Shetland Islands, Antarctica. Five of them are near bases and used as water supplies. Two remote lakes (control lakes) on Fildes Peninsula are distant from human installations and therefore have no or greatly reduced impact from human activities.

Key limnological characteristics will be determined in water samples, including basic physicochemical parameters, nutrients and metals, both below the ice and during the end-summer open water period. Sediment cores will be taken to examine biological indicators from the past, including fossil pigments and analysis of microbial community DNA, which will provide information about how aquatic communities have changed over time and whether they have been affected by local human activities. Fossil pigments will be analyzed by high performance liquid chromatography (HPLC) and will help to evaluate possible trophic state changes during the past century, how phytoplankton dynamics may have changed and how these changes may be related to human activities in the region. Ancient DNA (aDNA) will be extracted and a community fingerprinting-based method will be applied (amplification of the bacterial intergenic-transcribed spacers from the ribosomal operon) to determine changes in microbial community composition over time.

We expect changes over the time in the microbial diversity and community composition. By comparing the changes observed in affected and control lakes, this study will provide important results about the impact of Fildes Peninsula bases on water quality, will help to better understand how the changing intensity of human activities may affect the local landscape, and therefore help predict how the region’s ecosystems may respond to future changes.