Cobalt Biogeochemistry in the Arctic Ocean in Relation to Riverine Flux and Phytoplankton Productivity


Arctic Research Initiative
2009 Funded Project


The Arctic Ocean is in the midst of perhaps the largest oceanic transformation in recorded history.  Increased seasonal sea ice melting, believed caused by global warming, is exposing vast new regions of the sea surface to direct sunlight.  This exposure caused a >3 fold increase in phytoplankton productivity in 2007 relative to the 1998-2002 mean.  Yet little is known about what nutrients are controlling the primary productivity of these newly exposed waters.  Comparable high latitude environments such as the Southern Ocean are known to be strongly iron limited due to ice cover of the Antarctic continent and lack of other nearby continental dust sources.  I propose to analyze the dissolved cobalt abundances on the Canadian GEOTRACES cruise in the Arctic Ocean in August of 2009.  This cruise will sample the coastal waters of the Chukchi and Mackenzie River outflow, as well as the open ocean waters of the Canada Basin.  The few iron measurements available for the Arctic Ocean suggest that this metal is relatively abundant due to atmospheric deposition.  If iron is relatively abundant, other scarce bioactive metals such as cobalt and zinc could be quite important to phytoplankton nutrition in this region.  In addition sampling of the Mackenzie river outflow will provide insight into riverine fluxes of metals into the Arctic Ocean.