Evidence of plant and animal communities at exposed and subglacial (cave) geothermal sites in Antarctica

Abstract

Geothermal areas, such as volcanoes, might have acted as glacial microrefugia for a wide 2 range of species. The heavily-glaciated but volcanically-active Antarctic continent presents 3 an ideal system for assessing this hypothesis. Ice-free terrain around volcanoes in Antarctica is, however, often restricted to small patches, whereas subglacial cave systems, formed by vented volcanic steam, can be extensive and interconnected. No observations of macrobiota have yet been made for subglacial geothermal environments in Antarctica, but these organisms are often patchily distributed and can be difficult to find. We carried out metabarcoding (eDNA) analyses of soil samples taken from exposed areas on three volcanoes in Victoria Land, and subglacial caves on Mount Erebus. We found evidence of numerous eukaryotic groups, including mosses, algae, arthropods, oligochaetes and nematodes, at both exposed and subglacial sites. Our findings support the notion that geothermal areasincluding subglacial environments-can nurture biodiversity in glaciated regions.

Differential Colonization and Succession of Microbial Communities in Rock and Soil Substrates on a Maritime Antarctic Glacier Forefield

“…Several green algal lichen photobiont genera were found in our dataset, such as Trebouxia, Prasiola, Diplosphaera, and Chloroidium (Darienko et al, 2010;Thüs et al, 2011;Garrido-Benavent et al, 2017). Some of these genera have also been found free-living in lithic niches (Yung et al, 2014) and at subglacial and exposed geothermal sites (Fraser et al, 2018) in Continental Antarctica. Other free-living algae detected may constitute cysts or propagules of ice-and snow-dominating groups such as the Chlamydomonadales and Chlorellales (Brown et al, 2016;Anesio et al, 2017).…”

Multiple colonization and dispersal events hide the early origin and induce a lack of genetic structure of the moss Bryum argenteum in Antarctica

“…Indeed, assuming niche conservatism (the tendency of species to retain their niches and related ecological traits over time; Wiens et al., 2010), the contemporary distribution of B. argenteum in Antarctica shows no close relationship to geothermal sites. In Victoria Land, the species is absent from Mount Melbourne fumaroles (also Mount Rittmann) (Bargagli, Broady, & Walton, 1996) and there is one specimen record from 1965 (Ochyra et al., 2008) and one more recent sequence record (98% similarity) in an eDNA study (Fraser, Connell, Lee, & Cary, 2018) for the Mt. Erebus area.…”

Chapter 7.2 Mount Erebus

“…The isolated nature of EV, in particular the geothermally impacted caves and soils, makes these latter useful environments for the study of this potential phenomenon. A recent study of ice caves and fumarolic soils near the crater and Tramway Ridge, respectively, focused on the detection and identification of plant and animal DNA using molecular approaches (Fraser et al, 2018). This included an examination of recovered 28S rRNA and intragenic spacer region gene sequences from sediments from Warren Cave and Harry's Dream, in addition to a cave termed "22 Blue".…”