Exploring extreme subglacial ecosystems
Deep, cold, remote, buried by kilometres of moving ice - what life can survive?
Life beneath ice sheets
Liquid water exists over most of the bed of the Greenland Ice Sheet and about half of of the bed of the Antarctic Ice Sheet, and where there is water - there is usually life. This life must endure the cold, high pressures from the weight of the ice, limited access to nutrients and organic carbon to sustain it and complete darkness. The types of microbes that are adapted to such conditions are often called “extremophiles” - they are suited to survive within challenging conditions. We know that many of them, in the absence of sunlight, can make their own energy (and carbon) via chemical reactions involving rocks. Others live off the carbon produced by these rock-feeding microbes plus any fossil carbon preserved in sediments. Understanding deep, subglacial ecosystems requires novel technologies that enable us to “go there” and recover data and samples. While challenging, their exploration can help reveal the limits to life on Earth, and potentially other icy planets and moons.
Funded projects
Funded by the following grants/funders:
DELVE: DEveLopment and Validation of first generation chemical sensors for icy Ecosystems
NERC-funded ATLANTIS: “AnTarctic subglacial LAke CECs biogeochemistry: CoNtrols on ecosysTem sustainability and nutrIent transformationS”- as part of the UK/Chilean plans to drill into and recover samples from Subglacial Lake CECS, W. Antarctica
NERC-funded BEAMISH “Basal conditions on Rutford Ice Stream” (in collaboration with British Antarctic Survey)
Antarctic Subglacial Lakes
Over 400 lakes exist beneath the Antarctic Ice Sheet bed. While two shallow, actively draining lakes have recently been cleanly penetrated and sampled at the margins of the West Antarctic Ice Sheet (Mercer and Whillans), the direct and clean access of deeper and more hydraulically stable lakes within the continental interior has yet to be achieved. These inland lakes embody one of the most extreme life habitats on Earth since they are very isolated, have slow rates of ice/water flow and with infrequent re-supply of organic matter by marine flooding during deglaciation. This means their energy, carbon and nutrient inputs will be extremely limited, shaped by the reactivity of ancient organic matter and the availability of redox pairs via rock flour to support chemolithoautotrophy. ATLANTIS aims to determine microbial life support mechanisms and biogeochemical cycling in an inland lake (Subglacial Lake CECS) in West Antarctica, and will inform plans to detect microbial life on Europa via the ESA JUICE mission to Jupiter’s icy moons. Image credit: Subglacial Lake CECS (SLC) location (Makinson et al, 2021)
Glacier and ice stream beds
The beds of large glaciers and ice streams are often highly erosive, hosting variable thicknesses of rock ground-up by the ice and linked to active hydrological systems. Thus, meltwaters here have prolonged contact with reactive rock material from anything from months (Greenland) to many years (Antarctica). The combination of glacial grinding and water flow favour microbes which rely on rock as a source of energy and carbon. The cycling of elements such as silicon and iron are likely to be important here, where long flow paths for meltwater create the potential for high export of rock-sourced nutrients. Very little data exists on microbial communities and solute/nutrient cycling from the interior of Greenland and Antarctica. The BAS/NERC-funded BEAMISH drilling project has recovered sediments from the bed of the Rutford Ice Stream, which should provide some first clues.
Extreme engineering to delve deep into ice sheets
Ice sheets are vibrant habitats for life but are frustratingly challenging to study - cold, remote and with some kilometres of moving ice, they require innovative technologies to gather data and to go where we cannot. The NERC-funded DELVE project, in collaboration with the National Oceanography Centre Southampton, aimed to develop and adapt novel marine technologies for use in understanding how life and biogeochemical processes operate within and beneath ice sheets, and what impact they may have on other parts of the Earth system.
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Antarctic Subglacial Lakes
Hawkings, J.R. M.L. Skidmore, J.L. Wadham, J.C. Priscu, P.L. Morton, J.E. Hatton, C.B. Gardner, T.J. Kohler, M. Stibal, E.A. Bagshaw, A. Steigmeyer, J. Barker, J.E. Dore, W.B. Lyons, M. Tranter, R.G.M. Spencer and the SALSA Science Team. 2020. Enhanced trace element mobilization from Earth’s ice sheets, Proceedings of the National Academy of Sciences, 117(50) 31648-31659.
Siegert, M.J., J. Priscu, I. Alekhina and J.L. Wadham. 2016. Antarctic subglacial lake exploration: first results and future plans, Philosophical Transactions of the Royal Society, 374 (2059).
Ross, N. and The Lake Ellsworth Consortium (including J.L. Wadham). 2011. Ellsworth Subglacial Lake, West Antarctica: a review of its history and recent field campaigns, AGU Geophysical Monograph Series, 192, 221-233.
Cockell, C., E. Bagshaw, M. Balme, P. Doran, C.P. McKay, K. Miljkovic, D. Pearce, M.J. Siegert, M. Tranter, M. Voytek, Wadham, J.L. 2011. Subglacial Environments and the Search for Life Beyond the Earth, In Antarctic Subglacial Aquatic Environments, AGU Geophysical Monograph Series, 192, 111-127.
Mowlem, M. and the Lake Ellsworth consortium (including J.L. Wadham). 2011. Probe Technology for the Direct Measurement and Sampling of Ellsworth Subglacial Lake, In Antarctic Subglacial Aquatic Environments, AGU Geophysical Monograph Series, 192, 149-157.
Siegert, M.J. and 19 others, inc. J.L. Wadham. 2007. Exploration of Ellsworth Subglacial Lake: a concept paper on the development, organisation and execution of an experiment to explore, measure and sample the environment of a West Antarctic subglacial lake, Reviews in Environmental Science and Biotechnology, 6(1-3), 161-179.
Laybourn-Parry, J. and J.L. Wadham. 2014. Antarctic Lakes, Oxford University Press, 215pp.
Wadham, J.L. and Doran, P. 2014. Advancing Clean Technologies for the Exploration of Glacial Aquatic Ecosystems, Annals of Glaciology Special Issue
Antarctic Ice Streams
Wadham, J.L., M. Tranter, M. Skidmore, A.J. Hodson, J. Priscu, W. B. Lyons, M. Sharp, P. Wynn, M. Jackson.. 2010. Biogeochemical weathering under ice: size matters, Global Biogeochemical Cycles, Doi:10.1029/2009GB003642.
Greenland Ice Sheet
Hawkings, J., L. Benning, R. Raiswell, B. Kaulich, T. Araki, M. Abyaneh, A. Stockdale, M. Kock-Müller, J.L. Wadham, M. Tranter. 2018. Biolabile ferrous iron bearing nanoparticles in glacial sediments, Earth and Planetary Science Letters, 493, 92-101.
Dubnick, A. S. Kazemi, M. Sharp, J.L. Wadham, B. Lanoil, J. Hawkings. 2017. Hydrological controls upon microbially exported microbial assemblages, Journal of Geophysical Research, 122, 1049-1061.
Cameron, K., M. Stibal, J. Hawkings, A. Mikkelsen, J. Telling, T. Kohler, J. Zarsky, J.L. Wadham, C. Jacobsen. 2017. Meltwater export of prokaryotic cells from the Greenland Ice Sheet, Environmental Microbiology Reports, 19(2), 524-534.
Telling, J., E.S. Boyd, N. Bone, E.J. Jones, M. Tranter, J.W. Macfarlane, P.G. Martin, J.L. Wadham, G. Lamarche-Gagnon, M.L. Skidmore, T.L. Hamilton, E. Hill, M. Jackson and D.A. Hodgson. 2015. Rock Comminution as a source of hydrogen for subglacial ecosystems, Nature Geoscience, 8, 851-855.
Extreme Engineering
Bagshaw, E.A., A. Beaton, J.L. Wadham, M. Mowlem, J. Hawkings and M. Tranter. 2016. Chemical sensors for in situ data collection in the cryosphere, Trends in Analytical Chemistry, 8, 348-357.
Beaton, A., J.L. Wadham, J. Hawkings, E.A. Bagshaw, G. Lamarche-Gagnon, M.C. Mowlem and M. Tranter. 2017. High-resolution in situ measurement of nitrate in runoff from the Greenland Ice Sheet, Environmental Science and Technology, 51(21), 12518-12527.
Bagshaw, E.A., J.L. Wadham, M. Tranter, R. Perkins, A. Morgan, C.J. Williamson, A.G. Fountain, S. Fitzsimons, A. Dubnick. 2016. Response of Antarctic Cryoconite Microbial Communities to Light, FEMs Microbiology, 92(6), Doi:10.1093/femsec/fiw076.
Bagshaw, E.A. M. Tranter, J.L. Wadham, A.G. Fountain and S. Fitzsimons. 2015. Processes controlling carbon cycling in Antarctic Glacier surface ecosystems, Geochemical Perspectives Letters, 2(1), Doi: 10.7185/geochemlet.1605.
