SS9.01 Ecosystem Science Practiced in an Urbanized Estuary: South San Francisco Bay Buck, K, N, University of California Santa Cruz, Santa Cruz, USA, kbuck@ucsc.edu Bruland, K, W, University of California Santa Cruz, Santa Cruz, USA, bruland@ucsc.edu   COPPER SPECIATION IN SAN FRANCISCO BAY Total dissolved copper concentrations and the associated chemical speciation were determined at six sites throughout San Francisco Bay in January and March 2003 to compliment the data sets from previous summertime samplings. For speciation analyses, multiple analytical windows were incorporated into an established competitive ligand exchange- adsorptive cathodic stripping voltammetry (CLE-ACSV) method, which employs salicylaldoxime (SA) as the added competitive ligand (Bruland et al. 2000). High analytical windows strongly compete against the natural CuL1 complexes, accurately portraying the ambient Cu2+ concentrations. Lower windows compete less, but define the ligand pool carrying capacity and enable predictions of [Cu2+] as total dissolved copper concentrations change. All results indicate that strong copper-binding L1 ligand concentrations exceed dissolved copper concentrations at each site, with dissolved copper greater than 99.9% complexed by these ligands. Additionally, the [Cu2+] never exceeded 10exp-13 M, a concentration sufficiently below the toxicity threshold for phytoplankton (Brand et al. 1986). Thus, the excess of strong Cu-binding ligands appears to effectively buffer the free Cu2+ at low concentrations and San Francisco Bay is not impaired by the existing levels of copper.   Return to This Session's Schedule     Abstract Search