Elise Olson, 2010 Joint Program Student


I will study the quantity and controls on nitrogen fixation by Trichodesmium in the tropical North Atlantic through a combination of analysis of cruise data, satellite observation, and coupled physical and biological modeling. I will assist with data collection on cruises scheduled for October 2010 and May 2011 between Bermuda and Puerto Rico. I plan to use results of the observational effort to improve satellite-based estimates of Trichodesmium biomass and nitrogen fixation in the region. Including additional fields such as sea surface height, temperature, and wind fields as part of the algorithm itself, rather than merely as criteria for elimination of false-positives, may lead to increased accuracy. Satellite estimates of surface Trichodesmium biomass will be coupled to an eddy-resolving physical-biogeochemical model to estimate nitrogen fixation by Trichodesmium throughout the water column. The model will be used to assess the relative importance of mesoscale and submesoscale physical processes and nitrogen fixation by Trichodesmium as nitrogen sources in the Southern Sargasso and tropical Atlantic. The ultimate result of this project will be an estimate of Trichodesmium abundance and nitrogen fixation in the Southern Sargasso Sea and tropical Atlantic.