Enhanced trace element mobilization by Earth’s ice sheets
Jon Hawkings, Mark Skidmore, Jemma L. Wadham, John C. Priscu, Peter L. Morton, Jade Hatton, Christopher B. Gardner, Tyler J. Kohler, Marek Stibal, Elizabeth Bagshaw, August Steigmeyer, Joel Barker, John E. Dore, W. Berry Lyons, Martyn Tranter, Robert G. M. Spencer, the SALSA Science Team
Abstract
Significance Trace elements are integral to biogeochemical processes at the Earth’s surface and play an important role in the carbon cycle as micronutrients to support biological productivity. We present data from the Greenland and Antarctic ice sheets to demonstrate the importance of subglacial biogeochemical processes in mobilizing substantial quantities of these elements. Usually immobile elements are found in subglacial meltwaters at elevated concentrations compared with typical rivers, with most exhibiting distinctive size fractionation due to adsorption onto nanoparticles. Our findings suggest that ice sheets need to be included in models of global biogeochemical cycles of trace elements and studies of the fertilization of adjacent marine systems, especially the Southern Ocean, due to large export fluxes of micronutrients, most notably iron.