Real-time ocean chemistry for improved biogeochemical observation in dynamic coastal environments

We describe a new ocean observation system that integrates mass spectroscopy, hydrographic instrumentation, and satellite imagery (SeaWIFS). We used a quadrupole ICP mass spectrometer at sea to acquire continuous trace element data during separate surveys of the Baja California coastal margin, and the San Diego Bay and coastal environment. There is evidence for extreme Ba depletion in surface waters off the Baja coast, which is the result of biological productivity and marine barite precipitation. The synoptic data are used to elucidate the biochemical mechanism of barium removal; to constrain the spatial and temporal boundaries over which the phenomenon occurs; and to quantify surface flux to sediments. Further systems application led to mapping of the distribution of a suite of biologically active trace metals (Mn, Ni, Zn, Cu, and Cd) in San Diego Bay, and the Bay signature was tracked in tidal plumes into the coastal ocean. The continuous data provided chemical gradients within the Bay, with which we estimate the contaminant metal flux that is discharged from the Bay into the coastal ocean during tidal pumping.