Surface of the Antarctic Ice Sheet is one of the harshest habitats on the planet. Surprisingly, it is also Earth’s largest freshwater ecosystem. It contains bacteria, algae, viruses and other microbes that are transported there by wind and redistributed by ice flow. In order for life to flourish in Antarctica, microbial communities moved below the surface of the ice. Translucent blue-ice offers them protection from the surface conditions and enough solar radiation for photosynthesis to take place. In addition, generated heat has the capacity to melt the ice and where debris is present, generate a greenhouse-type environment called a cryoconite hole (CH, see below). These greenhouse power plants of microbial activity within the Antarctic Ice Sheet usually contain both oxygen producing phototrophic communities that are adapted to low-light conditions, and heterotrophic organisms that produce CO2 . In addition to gasses, CH ecosystems take part in production of organic carbon (DOC), nitrogen (NO3, NH4), phosphorus (PO4) and other life supporting nutrients (e.g., Fe, Si)

Blue Ice Oases of Microbial Life on the Antarctic Ice Sheet (BIOICE)

Cryoconite Holes

Blue Ice Areas (BIA) around the periphery of the Antarctic Ice Sheet

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     The interest in the Blue Ice Areas (BIA) begun in the early 1960’s, when field observations attributed their formation to horizontal katabatic winds removing accumulated snow (Carry & Wilson 1961). A few years later, these curious snow free areas of the Antarctic continent were also found to be meteorite collectors (Yoshida et al 1971). The importance of this discovery was highlighted earlier this year when Trollenaar et al (2022) named Antarctic continent as the most productive region for recovering meteorites, majority of them are located in the BIA.

BIA are also used for research of the paleoclimate record that, thanks to ice flow regime, is stored on their surface. Thus, recovered from BIA climate records can provide information on the evolution of the ice sheet and processes in the Southern Ocean (e.g., Sinisalo and Moore 2010).

BIA cover approx. 1% of the continent (or c. 120 000km2, Winther et al 2017), their net ablation is attributed mainly to sublimation. Thanks to the properties of the ice, albedo over BIA is much lower to that of snow (0.56 vs 0.8), and thanks to katabatic winds blue ice surface is also much smoother (Bintanja 1999), making it a good location for infrastructures like an airfield. Recently, it was suggested that 2 types of blue ice are present in Antarctica. Those formed by wind-induced processes (as it was known for the last 60years) and those formed by melt (in melt-freeze cycles) occurring at lower elevations. Dronning Maud Land was shown to have both, Jutulsessen being the former while Jutulstraumen the latter (Winther et al 2017). Interestingly, it was also suggested that BIA in Antarctica were formed roughly in 50% by each process.   

     Ice properties of the BIA, and their proximity to geological formations allow for the sediment and rock debris to gather on the ice surface and melt into the ice to form a cryoconite hole.

 

Cryoconite holes are ice-bound ecosystems that thrive underneath the surface. It is possible because blue ice is translucent and allows penetration of solar radiation up to 1m into the ice, while debris can trap heat, melt the ice and produce nutrients able to support life. As a result a hidden ecosystem is created in one of the harshest environments on the planet. An environment invisible to remote sensing research.

 

A study in Vestfold Hills discovered rate of low-light-adapted photosynthesis (c.10% of surface irradiance) to be on average 2060ng of carbon per day, with communities of cyanobacteria and chloroplastida. A heterotrophic communities were also present there, although not as active as photo-autotrophic ones (Hodson et al 2017).

Antarctica is just one of our target sites. To compare microorganisms survival in different types of ice, we will also perform fieldwork in the Norwegian High Arctic. 

In so doing we will give close attention to the fate of certain microorganisms that are found to be important in both polar regions and we will be able to explain how microbes cope with the different burial and snow to ice metamorphism conditions.

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Blue Ice Area in the vicinity of Troll Research Station

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