Frederick L. Sayles and William Martin; Woods Hole Oceanographic Institution

"Benthic Cycling and Accumulation of Organic Matter, Biogenic Opal, and CaCO₃ in the JGOFS Southern Ocean Study Areas"

We will characterize benthic remineralization, burial, and the role of benthic processes in the cycling of organic matter, CaCO₃, and biogenic SiO₂ through pore water and sediment studies. Specifically we will 1) Determine the magnitude of fluxes of species central to the recycling of organic matter, CaCO₃, and Opal; 2) Define benthic reactions, rates, and the relative importance of various benthic processes in determining variations in them; 3) Identify the factors which influence preservation efficiency and hence control the relation between surface water production and accumulation rate; and 4) Evaluate the relative roles of preservation and sediment focusing in determining the high opal accumulation rates in the PFZ.

MEASUREMENTS: Pore Water: Nutrients, TCO₂, Alk, Ca, O₂, DOC, *¹³C, Sediment: uranium series isotopes; SiO₂, CaCO₃, O, C.; sediment physical properties

INSTRUMENTATION: Wire lowered in situ pore water sampler: collects both pore waters and ~50 cm cores.