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Name:
John R. Donat
Address:
143 Ocean/Physics Building, Old Dominion University,  Norfolk, VA -23529 USA
John R. Donat

E-Mail:  jdonat@odu.edu
Interests:
Determination of the chemical forms and concentrations of trace metals (e.g., copper, cadmium, zinc, nickel, cobalt, iron, platinum) in the waters and sediment pore waters of Chesapeake Bay, the coastal western North Atlantic, the western South Atlantic, and local Virginia lakes.
These metals exist at extremely low concentrations (10-9 to 10-14 M) in natural waters, but many of them are important nutrients or toxicants to the aquatic phytoplankton at the base of the food chain. In addition, the different forms of these metals have different biochemical and geochemical behaviors. Dr. Donat's research group has produced/is producing the first data reported on the complexation and speciation of these metals in the Chesapeake Bay water column and sediment porewaters, in the South Atlantic, and in Virginia lakes. Knowledge of their chemical forms and concentrations is critically important to identifying and quantifying the bioavailability of these metals as nutrients and toxicants, and in understanding their fate and transport and biogeochemical cycling. Investigation of the flux and persistence of copper- and zinc-complexing organic ligands originating from Chesapeake Bay pore waters. Copper and zinc speciation in surface seawater is dominated by organic complexes. Much of the current knowledge about copper and zinc speciation has focused on copper- and zinc-complexing ligand distributions in the water column and their autochthonous (in situ) production by water column phytoplankton. However, recent work performed by collaborative efforts involving Dr. Donat's research group and that of Dr. David Burdige (ODU Oceanography) has demonstrated that copper-complexing ligands fluxing out of Chesapeake Bay sediment pore waters may supply 10 to 50% of the standing stock of copper-complexing ligands in the Chesapeake Bay water column. In addition, this research collaboration has shown that these copper ligands persist in the water column for at least 30 days. These results represent the first direct evidence that porewater-derived copper-complexing ligands may have a significant influence on copper speciation and biogeochemistry in the water column of Chesapeake Bay.




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SETAC Europe 34th Annual Meeting
05.05.2024
Seville, Spain
Junganalytiker:innen Forum der Österreichischen Gesellschaft für Analytische Chemie (ASAC)
16.05.2024
Graz, Austria
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