Cold-loving microorganisms in Antarctic glaciers: a review of South Shetland archipelago glaciers

Abstract

Antarctic glaciers have been considered classically uninhabited. However, they constitute an authentic biome and are populated by microorganisms that not only survive in them but also maintain an active metabolism. The South Shetland archipelago is a good study model to observe the diversity and evolution of the microbial populations that inhabit its glaciers. From a geological point of view, this archipelago is of considerable interest due to the intense and relatively recent volcanic eruptions on Deception Island. Additionally, it has been a place of transit for human and animal populations over time. All of these factors have influenced the composition and diversity of the microbial communities inhabiting the glacial ice. Among these microorganisms, a great diversity of bacteria, archaea, viruses and microeukaryotes such as algae and unicellular fungi have been identified thanks to high-throughput technologies. These cold-adapted microorganisms develop molecular mechanisms of adaptation to the extreme environment they inhabit and contribute to global energy cycles through the processing of organic and inorganic compounds. This review summarizes current knowledge on the biodiversity, ecology and molecular mechanisms of adaptation of cold-adapted microorganisms, and it details the specific characteristics of the microbial populations housed in the Antarctic glaciers in the South Shetland archipelago.