Ocean Circulation,

Oxygen and Nutrient Cycles

During the Last Glacial








The correlation between glacial Indian and Pacific Ocean sediments that document oxygen minimum zones and abrupt changes in the glacial North Atlantic climate on millennial time scales is among the most spectacular manifestations of global climate teleconnections. Nitrogen isotope ratios in organic matter provide a window into changes in the ocean's oxygen minimum zones, because they respond to denitrification. We will address the dynamics of oxygen minimum zones in global climate change by embedding a model of nitrogen isotope δ15N cycling in an existing coupled ocean-atmosphere-sea ice model of intermediate complexity that includes biogeochemistry, and is capable of multi-millennial runs. Simulations with this model and comparison with the marine geological record will provide new and important insights on mechanisms controlling past changes in ocean circulation, productivity, oxygen and nutrient cycling.




Funded by the Marine Geology and Geophysics Program of the National Science Foundation