Studies will be continued of benthic flux and benthic metabolism in continental shelf and slope sediments. These sediments frequently underlie areas of high primary production and this coupled with a short transit distance to the bottom results in high organic rain rates to the sediments. Consequently, continental margin sediments play an important role in controlling water column distributions and global balances of several elements. Benthic fluxes and processes related to the major bioactive elements will be measured to evaluate the importance of these processes in global elemental budgets. Specifically, three questions will be addressed: 1) what are carbon oxidation rates and associated benthic fluxes in continental shelf and slope sediments, 2) how important is denitrification in continental shelf and slope sediments in the marine combined nitrogen budget and, 3) how important are bioturbation and irrigation in enhancing and modifying benthic fluxes. The proposed work consists of modification of the existing benthic flux chamber Tripod for use as a free-vehicle. Field work will focus on the Washington State and Mexican continental margins. Due to the lack of oxygen in the overlying waters of the latter, comparison of the two areas will describe the importance of benthic macrofauna in flux enhancement and modification.
