This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The investigators will measure mercury (Hg) concentrations, mercury isotopes, and a suite of trace metals in previously-collected Arctic sediment cores in order to increase understanding of paleoceanographic conditions in the Arctic Ocean as well as overall understanding of mercury cycling, particularly prior to the interference of humans with the mercury cycle. The abundance and isotopic composition of mercury in Arctic sediments may be sensitive to (and thus record changes in) such processes as sea ice cover, biological productivity, and changing sources of mercury. Questions that can be addressed over the course of this research include:
1)What is the Hg isotopic composition of the Pleistocene-Holocene Arctic Ocean? 2)Can Hg isotopes be used to infer different Hg sources to the Arctic Ocean? 3)Can Hg isotopes be used to quantify extent of sea ice growth and retreat in the Pleistocene-Holocene Arctic? That is, can Hg isotopes by used as a proxy for sea ice? 4)Is the Hg isotopic system sensitive to changes in organic productivity during shifts in Arctic climate and ice volume? 5)Can Hg isotopic investigations of the ancient record help predict changes in the Hg cycle during an ice-free (summer) Arctic environment of the future? 6)Can knowledge gained by studying Hg isotopes in the unique environment of the Arctic be applied globally to ocean productivity and circulation studies?
This work has potential impacts in understanding the geochemical cycling of mercury, an important neurotoxin. It also promises to improve our ability to decipher Arctic paleoclimate. One graduate student and three undergraduate research interns would be supported by the proposed research.
