Institute of Applied Geoscience (IAG)
Upcoming Earth and Environment seminars

Research Seminars

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Ironing out glacier nutrient cycling

Date: Friday 20th April

Time: 15:00 to 16:00

Presenter: Jon Hawkings, University of Bristol

Location: 10.125, School of Earth & Environment

Iron (Fe) is the major limiting nutrient in around one third of the oceanic euphotic zone, most significantly in the Southern Ocean proximal to Antarctica. In these areas, the availability of bioavailable iron can influence the amount of primary production, and thus the strength of the biological pump and associated carbon drawdown from the atmosphere. Due to the extreme cold, remoteness and their perceived “stasis”, ice sheets have previously been thought of as insignificant in global biogeochemical cycles, including in the cycling and export of Fe. However, large marine algal blooms have been observed in Fe-limited areas where glacial influence is large, and recent evidence suggests it is possible that at least some of these regions are stimulated by bioavailable iron input from nearby glaciers. Here the potential importance of glaciers in the global Fe cycle will be evaluated using data from the Greenland Ice Sheet, the Antarctic Ice Sheet, Svalbard and the Patagonian Ice Fields. Trace element data, bulk meltwater chemistry, isotopic and mineralogical analysis, including high resolution microscopy and synchrotron based spectroscopy, will be used to produce a conceptual model of the glacial Fe cycle from source to sink. Additionally, evidence of Fe controls on glacier based phosphorus cycling, and a potential role for amorphous silica in stabilisation of potentially biolabile Fe(II)-rich species will be discussed. This data provides new insights into the importance of glaciers and ice sheets in regional biogeochemical cycling.

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