Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597913
Title: Solubility and bioavailability of iron from dust in Antarctic ice cores
Author: Conway, T. M.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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Abstract:
The Iron Hypothesis suggests that an increased flux of aerosol iron to the Southern Ocean (and other Fe limited regions of the ocean) during glacial intervals may have stimulated primary productivity. This could have resulted in more storage of carbon in the deep ocean and less in the atmosphere. This study was designed to increase our understanding of the iron hypothesis, by increasing constraints on several aspects of the theory. The results show that the mean aerosol Fe solubility at Dome C during the Last Glacial Maximum was relatively high (10%), compared to the solubility of typical crustal materials and assumptions used in previous models of ocean biogeochemistry, but also very variable (1-42%). Measurements of other major elemental concentrations in ice were made to assess their suitability for use as proxies of Fe concentrations in dust and to discriminate changes in dust composition and mineralogy. This study shows that ice core Ca concentration is a good proxy for total, but not seawater-soluble, aerosol Fe concentration. These results suggest that atmospheric dust which was deposited at Dome C was enriched in K-rich clay minerals over the Patagonian source regions. New methods were developed to sublimate ice-core material to extract dry dust for use in biological incubation experiments. This study has been the first to incubate siliceous Antarctic phytoplankton (diatoms) with dust of last glacial maximum age, extracted from the EDC ice core, under realistic conditions. The results show that dissolved Fe released from dust had a direct fertilising effect.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.597913  DOI: Not available
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