Grant: Research Tools and Instruments - Category 1 (<$150,000)

Funds are requested to purchase six Baker-style sequential sediment traps for the study of cycling of organic matter and associated contaminants in the Canadian Arctic Ocean. As the Arctic is undergoing dramatic change, so are the quantity and composition of land-derived organic matter entering the Arctic Ocean. Alterations in organic matter in the sea not only directly affect marine productivity and exchange of greenhouse gases, but also the behavior of contaminants such as mercury, which cycle in association with organic matter. The latter is of particular importance as mercury, especially its organic form methylmercury, is one of the primary contaminants of concern in the Arctic marine ecosystem. Evidence is emerging that the production of methylmercury in seawater is associated with organic matter, yet the mechanism remains poorly known. Sediment traps are the only means by which we can gather hard data about the amounts and kinds of organic matter and mercury transported from surface to deep waters in the ocean. The sequential sediment traps requested in this proposal will be used for seasonal to annual deployments on oceanographic moorings in continental margin areas of the Arctic Ocean. This will allow for the collection of particulate organic matter for set time intervals over a full year, making it possible to study organic matter and mercury interactions year-round in remote, inaccessible parts of the Arctic Ocean. Year-round measurements are critical because the Arctic is highly seasonal in terms of its ice cover, river runoff, and biological activity. The new data obtained from the sediment traps will let us understand the changes in the sources, transport and fate of organic matter in a changing Arctic Ocean, and where, when and how organic matter is involved in converting mercury into its toxic form methylmercury. Such understanding is critically needed for predicting how mercury levels in Arctic marine mammals will change under a changing climate. The requested sediment traps will also be made available to support other collaborative research and education in the fields of Arctic oceanography, biogeochemistry, and environmental science.