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Author Topic: Ice Sheets as a source of Iron to Oceans - Possible negative feedback  (Read 1465 times)


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Prof. Marco Tedesco's site has been quiet for a couple of years, but there have been a couple of postings recently on several papers which have already been discussed here.  one that hasn't as far as I know is below, and the full paper is freely available at Nature.

It identifies a possible negative feedback as a result of increased run off from Greenland/Antarctic, which is as a source of iron.  Iron being dumped into the ocean as a form of geoengineering has been thought of as a possible sink as it increases algal blooms.  I've copied the link and abstract below, which links to the full paper.

Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans
Jon R. Hawkings, Jemma L. Wadham, Martyn Tranter, Rob Raiswell, Liane G. Benning, Peter J. Statham, Andrew Tedstone, Peter Nienow, Katherine Lee & Jon Telling

The Greenland and Antarctic Ice Sheets cover ~\n10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40–2.54 Tg per year in Greenland and 0.06–0.17 Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting.