An Empirical Test of the Arctic Ocean Sedimentation Hypothesis


OCCI Funded Project: 2006

Proposed Research

According to the current hypothesis to explain Arctic Ocean sediment processes, a major portion of sediment including organic carbon may be supplied to the deep basin from the surrounding large continental shelves that constitute 52% of the Arctic Ocean area. If a major fraction of the carbon is indeed margin derived, a key follow-up question is; what proportion of carbon is derived from primary production in the marginal seas (e.g., Chukchi, Beaufort) and from terrigenous inputs via the numerous large rivers that drain into the Arctic? Retreat of sea ice and destabilization of permafrost soils are likely to lead to increases in carbon fluxes from these sources, respectively, as a result of warming of Artic climate. Potential impacts on Arctic biogeochemical cycles thus require detailed assessments of inputs of biogenic and detrital materials as well as the construction of time-series data sets.

In this proposal we seek funding to analyze a suite of sinking particle samples from the deep Canadian Basin (75°N, 150°W, 3,824m water depth). The 21 samples were collected by a time-series sediment trap that was deployed at 3000m (824 meters above bottom) on a mooring in the ice covered area of Beaufort Gyre for one year, and represent the first collection of its kind.  With the information obtained from the elemental (total mass, OC, inorganic carbon, N, P, biogenic Si, lithogenic Si, Al ), C-isotopic (d13C, D14C), and biomarker analyses of these samples, we will be able to test the Arctic sedimentation hypothesis and distinguish between material delivered from the overlying waters and material transported from the shelf areas, as well as to establish the origin of any shelf-derived material.  In addition, we plan to integrate concurrent time-series hydrographic data related to surface conditions including ice coverage and halocline hydrography collected from another OCCI project entitled “The Beaufort Freshwater Observing System”. The resulting data will provide foundation for a future research project for NSF OPP Arctic Sciences program.