Biogeochemical controls of surface ocean phosphate.

Surface ocean phosphate is commonly below the standard analytical detection limits, leading to an incomplete picture of the global variation and biogeochemical role of phosphate. A global compilation of phosphate measured using high-sensitivity methods revealed several previously unrecognized low-phosphate areas and clear regional differences. Both observational climatologies and Earth system models (ESMs) systematically overestimated surface phosphate.

Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES.

Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes.

Aeolian contamination of Se and Ag in the North Pacific from Asian fossil fuel combustion.

Energy production from fossil fuels, and in particular the burning of coal in China, creates atmospheric contamination that is transported across the remote North Pacific with prevailing westerly winds. In recent years this pollution from within Asia has increased dramatically, as a consequence of vigorous economic growth and corresponding energy consumption. During the fourth Intergovernmental Oceanographic Commission baseline contaminant survey in the western Pacific Ocean from May to June, 2002, surface waters and aerosol samples were measured to investigate whether atmospheric deposition of trace elements to the surface North Pacific was altering trace element biogeochemical cycling.

Increased selenium threat as a result of invasion of the exotic bivalve Potamocorbula amurensis into the San Francisco Bay-Delta.

Following the aggressive invasion of the bivalve, Potamocorbula amurensis, in the San Francisco Bay-Delta in 1986, selenium contamination in the benthic food web increased. Concentrations in this dominant (exotic) bivalve in North Bay were three times higher in 1995-1997 than in earlier studies, and 1990 concentrations in benthic predators (sturgeon and diving ducks) were also higher than in 1986. The contamination was widespread, varied seasonally and was greater in P.