An In situ investigation of the relationship between sediment trap collection efficiency and trap hydrodynamics will be conducted for sediment trap designs, cone shaped and cylindrical, which are integral to the Global Ocean Flux initiative in the Atlantic Ocean. The studies will include a careful assessment of moored versus drifting sediment trap collection systems at the Bermuda site where long term observations are in progress. The independent variable in this investigation is sediment trap geometry, while the dependent variables are trap hydrodynamics and collection efficiency. In situ hydrodynamic observations will be obtained using laboratory-calibrated self-contained instrument packages (HDS) which record both flow and well shearing stress in a non-obstrusive way at critical locations inside and outside the traps. One of the principal products of the work will be a simple, easy-to-use, flow-field sensor package which can be applied to Global Ocean Flux investigations. By linking particle accumulation rates with In situ hydrodynamic observations in and around sediment traps, it is expected that fluid-dynamic bias can be removed and flux rates inferred which are functionally equivalent to those provided by an ideal, non- obtrusive collection device.
