Accession Number : ADA318399

Title :   Metal-Complexing Ligands and Metal Speciation in Sediment Pore Waters: Implications for Sediment/Water Exchange and Water Column Speciation.

Descriptive Note : Annual rept. 1 Oct 95-30 Sep 96,

Corporate Author : OLD DOMINION UNIV NORFOLK VA

Personal Author(s) : Donat, John R. ; Burdige, David J.

PDF Url : ADA318399

Report Date : 09 NOV 1996

Pagination or Media Count : 7

Abstract : Fluxes of TDCu and Cu ligands have been determined at two sites in the Chesapeake Bay for June and October 95, and in March 96. TDCu appears to flux out of the sediments at both sites in both spring and summer. In March 95, the TDCu flux out of site M (mid-Bay) sediments (41 + or - 10 nmol/sq m/d) exceeded that at site S (southern Bay: 7 + or - 3 nmol/sq m/d). However, in June 95, the TDCu flux out at site S (52 + or - 25 nmol/sq m/d) exceeded that at site M (13 + or - 15 nmol/sq m/d). There is a significant out-flux (200 to 800 nmol/sq m/d) of total Cu-binding ligands (TLcu) from the sediments at both sites in both spring and summer, but the TLcu flux at site M exceeded that at site S. The TLcu is 3-60x greater than the TDCu flux, and the ligands fluxing out are comparable in strength (log K'=15) to that of the very strong L1 class that controls the speciation of TDCu in most marine surface waters, and previously only observed in these surface waters. Sediment fluxes of this very strong ligand in June 95 ranged from 200 to 600 nmol/sq m/d, representing up to 50% of the sediment TLcu flux, and exceeded the TDCu by up to 20x. Thus, sediments may be a significant, but previously-unrecognized, source of Cu-complexing ligands to overlying waters.

Descriptors :   *WATER, *LIGANDS, *SEA WATER, *SEDIMENTS, *METAL COMPLEXES, COMPLEX COMPOUNDS, FLUX(RATE), SITES, COPPER, SURFACE WATERS, EXCHANGE, SUMMER, OCEANOGRAPHY, BAYS, CHESAPEAKE BAY.

Subject Categories : Physical Chemistry
      Inorganic Chemistry
      Physical and Dynamic Oceanography
      Hydrology, Limnology and Potamology

Distribution Statement : APPROVED FOR PUBLIC RELEASE