There has been recent concern over the historically low dissolved oxygen concentrations in Hood Canal, a fjord-like side basin of Puget Sound in Washington State, USA.

Understanding oxygen depletion in Hood Canal requires knowledge of not only the levels of oxygen and nutrients, but also their supply rates of "fluxes." Both the physical flow and turbulent diffusion affect supply rates; hence, it is vital to measure both of these.

The density records from McClane Moored Profiler observations in South Hood Canal can be used to infer the turbulent diffusivity, which governs the vertical supply of nutrients to the euphotic zone, and the downward supply of oxygen to the deeper layer. The velocity and oxygen records allow us to measure the lateral supply of oxygen and nutrients to Hood Canal. We use these records, together with model output, to piece together the three-dimensional flow fields in the Canal, which in turn are key in setting the oxygen distribution.

Figure 1
Hood Canal. Sund Rock, the 2005 mooring site, is shown as a blue dot.