Amy Gobel ’12
Source analysis and quantification of nitrogen deposition to the Sargasso Sea
The goal of this internship was to understand how anthropogenic nitrogen fixation affects nitrogen deposition in the North Atlantic Ocean. To this end, the internship consisted of three elements. First, rainwater and aerosol samples were collected at meteorological data stations at various locations in Bermuda. Second, the samples were analyzed using an ion chromatograph, an instrument that determines the concentration of specified ions within a sample. Third, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) atmospheric modeling program of the National Oceanic and Atmospheric Administration (NOAA) was used to determine the origin of the air masses that brought the rainwater and aerosols. The air masses were divided into two categories: those from the North American continent (containing anthropogenic nitrogen) and those from the surrounding ocean (containing biological nitrogen). Combining the data about air mass sources with the concentration data, the concentrations of anthropogenic nitrogen were compared with the concentrations of biological nitrogen. The results show that the nitrogenic ion averages weighted by volume were not different between anthropogenic and biological sources, whereas all other ions analyzed showed a significant difference between the two sources.
Climate and Energy
Bermuda Institute for Ocean Sciences, Bermuda
Danny Sigman, Dusenbury Professor of Geological and Geophysical Sciences. Professor of Geosciences