ICICLES · Iron and Carbon Interactions and Biogeochemical CycLing in Subglacial EcosystemS

Iron and Carbon Interactions and Biogeochemical CycLing in Subglacial EcosystemS

Glaciers have been conventionally viewed as lifeless bodies that have little impact on biogeochemical cycles. It is now known that liquid water is present under all large ice masses. In Antarctica, subglacial lakes and rivers have been discovered, while in Greenland subglacial water channels and interconnected isolated hydrological systems exist. Two subglacial lakes, Whillans Subglacial Lake and Mercer Subglacial Lake, were accessed in 2013 and 2018, and support diverse and metabolically active microbial ecosystems, while microbial communities are also known to be exist under the Greenland Ice Sheet. This raises questions about biogeochemical cycling within these ecosystems. Specifically, the sources, concentrations, flows, modifications and interactions between life essential nutrients. The nutrients sourced from these environments might have an impact on downstream ecosystem productivity. This is of particular importance as the Southern Ocean, which surrounds Antarctica, where iron is the primary limiting element for life. Organic matter is thought to play a major role in regulating the flux and bioavailability of iron, and may also be an important source of bioavailable carbon. The main objective of ICICLES was to investigate the cycling and interactions between iron and carbon (as organic matter) in glacial environments. Iron, organic matter and associated trace elements in waters and sediment samples from three sites beneath the Antarctic Ice Sheet and from large rivers emerging from the Greenland Ice Sheet and the Patagonian Ice Fields have been characterised using state-of-the-art spectroscopic and microscopic techniques. The fate of these glacier-derived elements in downstream near-coastal systems has been ascertained by sampling coastal marine environments fed by glacial meltwaters. A new budget of trace element and organic matter export from these ice sheet and ice field environments has been constructed and is available for use in regional and global ocean models to help assess the impact of subglacial meltwaters on marine productivity. This data provides unprecedented insight into elemental cycling in subglacial ecosystems and helps evaluate the role of ice sheets in global biogeochemical cycles. The results of this fellowship emphasise the complex societal implications of climate warming induced melting of the cryosphere, via alteration of both essential and toxic elemental fluxes from ice-to-ocean and raises more questions about the associated impacts of ice melt on ecosystem services.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз