Mitra, S. Tulane University, smitra@mailhost.tcs.tulane.edu
Bianchi, T. Tulane University, tbianch@mailhost.tcs.tulane.edu
Guo, L. Texas A&M University, guo@tamug.tamu.edu
Santschi, P. Texas A&M University, satnschi@tamug.tamu.edu

 
SOURCES, AGE, AND TRANSPORT OF TERRESTRIALLY-DERIVED COLLOIDAL ORGANIC MATTER IN THE CHESAPEAKE BAY AND MID-ATLANTIC BIGHT, USA
 
Concentrations of lignin-phenols were analyzed in colloidal organic matter (COM) isolated from surface waters of the Chesapeake Bay (C. Bay) and surface and deep waters of the Mid-Atlantic Bight (MAB-SW and MAB-DW, respectively). The abundance of lignin in COM decreased with distance outward from the head of C. Bay into the MAB-SW, indicating that the sources of this terrestrial biomarker to MAB-SW colloids originate near the head of C. Bay. COM in surface waters of C. Bay, MAB-SW and MAB-DW fall into three distinct radiocarbon age groups. COM in MAB-DW is comprised of relatively young carbon in comparison to COM in MAB-SW at the same stations. Lignin-phenol abundances in MAB-DW COM were significantly higher than in sediments and were also higher than in surface water COM at the same stations. When considering depth profiles of suspended particulate matter in these areas with lignin-phenol concentrations, C:N ratios, and radiocarbon age of the COM, it appears that terrestrially-derived COM in the MAB originates from the seabed in near-shore areas and is laterally transported offshore to adjacent sites in deeper waters of the MAB via the benthic nephloid layer.
 
Day: Tuesday, Feb. 2
Time: 02:15 - 02:30pm
Location: Eldorado Hotel
 
Code: SS34TU0215E