This project consists of the development of a scanning fiber optic spectrometer for use aboard a U.S. Navy submarine, and the analysis of water samples obtained in various parts of the Arctic Ocean in order to determine dispersion processes of river-borne trace elements and pollutants. Prior results, using conservative tracers, have provided some integrated measures of riverine influence, but the spatial coverage has not been sufficient to delineate the pathways of freshwater inputs. Furthermore the tracers that have been used, such as alkalinity, calcium, and oxygen isotopes, cannot be used to distinguish among different river sources. This project will extend the suite of available tracers to include humic acid and minor constituents such as manganese, barium, rubidium, strontium, bromine, and iodine. Manganese is a particularly useful tracer since its concentration in river water is typically two orders of magnitude greater than its open ocean value, and this concentration is sensitive to river chemistry and environmental conditions. Dissolved manganese can therefore be expected to help provide a particular river signature, and provide information on the dispersion characteristics of a given river plume. ***
