The microbiome of glaciers and ice sheets

Abstract

Glaciers and ice sheets, like other biomes, occupy a significant area of the planet and harbour biological communities with distinct interactions and feedbacks with their physical and chemical environment. In the case of the glacial biome, the biological processes are dominated almost exclusively by microbial communities. Habitats on glaciers and ice sheets with enough liquid water to sustain microbial activity include snow, surface ice, cryoconite holes, englacial systems and the interface between ice and overridden rock/soil. There is a remarkable similarity between the different specific glacial habitats across glaciers and ice sheets worldwide, particularly regarding their main primary producers and ecosystem engineers. At the surface, cyanobacteria dominate the carbon production in aquatic/sediment systems such as cryoconite holes, while eukaryotic Zygnematales and Chlamydomonadales dominate ice surfaces and snow dynamics, respectively. Microbially driven chemolithotrophic processes associated with sulphur and iron cycle and C transformations in subglacial ecosystems provide the basis for chemical transformations at the rock interface under the ice that underpin an important mechanism for the delivery of nutrients to downstream ecosystems. In this review, we focus on the main ecosystem engineers of glaciers and ice sheets and how they interact with their chemical and physical environment. We then discuss the implications of this microbial activity on the icy microbiome to the biogeochemistry of downstream ecosystems.

Snow algae communities in Antarctica: metabolic and taxonomic composition

“…Conversely, cooler periods with a shift in the general wind direction could see the current habitat for snow algae preserved. With habitat regression, or if areas of snow melt completely early in the summer, the ecosystem may be lost entirely for that season (Convey, 2011;Anesio et al, 2017). Whichever outcome prevails which is likely to vary with locationthere is an urgent need to study these polar communities to provide a balanced view of polar terrestrial biodiversity and to avoid the loss of these extremophilic primary producers and their community structure at both local and continental scales (Williams et al, 2003;Rogers et al, 2007;Hamilton & Havig, 2017;Rintoul et al, 2018).…”

Microbial assemblages reflect environmental heterogeneity in alpine streams

“…The diverse microbial communities of glacier ice (Anesio & Laybourn-Parry, 2012;Anesio, Lutz, Chrismas, & Benning, 2017), snow (Lutz et al, 2016), and stream habitats (Zeglin, 2015) carry out important functional roles in terms of energy flow and nutrient transformation (Anesio et al, 2010;Hotaling, Hood, & Hamilton, 2017). As high-elevation headwaters, alpine streams are a key hydrological link between cryospheric processes and downstream habitats, both freshwater and marine (Hood, Battin, Fellman, O'Neel, & Spencer, 2015;Hotaling, Hood, et al, 2017;O'Neel et al, 2015).…”

Melting of clean and debris‐rich ice differentially affect nutrients, dissolved organic matter and bacteria respiration in the early ontogeny of the newly formed proglacial Ventisquero Negro Lake (Patagonia Argentina)

“…According to Coble (), C1 is associated with a labile protein‐like component. In glacier surface meltwater, microbial communities are the primary driver for labile dissolved organic carbon production (Anesio et al., ; Musilova et al., ). In the clean ice, this microbial activity may have generated the presence of labile protein‐like component (C1).…”

“…(Anesio et al, 2010). However, the final nutrient availability is likely influenced by bacterial activity that enriches supraglacial debris (Anesio, Lutz, Chrismas, & Benning, 2017). Nevertheless, knowledge of the bacterial community and activity related to these debris-covered glaciers is very scarce (Darcy & Schmidt, 2016;Franzetti et al, 2013;Mertes, Thompson, Booth, Gulley, & Benn, 2017).…”