HR: 16:45h
AN: OS44A-04    [Abstracts]
TI: Characterization of Particulate Organic Matter in the Water Column and Sediments of the Fly River Delta and Clinoform, Gulf of Papua (Papua New Guinea)
AU: * Goni, M A
EM: goni@geol.sc.edu
AF: University of South Carolina, Dept. of Geological Sciences, Columbia, SC 29208 United States
AU: Monacci, N
AF: University of South Carolina, Dept. of Geological Sciences, Columbia, SC 29208 United States
AU: Gisewhite, R
AF: University of South Carolina, Dept. of Geological Sciences, Columbia, SC 29208 United States
AU: Clinton, R
AF: University of South Carolina, Dept. of Geological Sciences, Columbia, SC 29208 United States
AU: Crockett, J
AF: University of Washington, School of Oceanography, Seattle, WA 98195 United States
AU: Ogston, A
AF: University of Washington, School of Oceanography, Seattle, WA 98195 United States
AB: Suspended particles and surface sediments were collected from the delta and inner topset region of the Fly River clinoform in order to investigate the sources, transport and fate of particular organic matter (POM) in this region. Total suspended sediment concentrations ranged from 1 to 500 mg/L, with the highest values observed near the sea bed and in the shallow region adjacent to the north channel of the Fly Delta. Suspended particles in surface waters displayed organic carbon contents (OC) of 6.1 +/- 1.3 wt. percent, atomic carbon:nitrogen ratios (C/N) of 23 +/- 6.2 and stable carbon compositions (d13C) of -28.0 +/- 0.4 per mil. The suspended particles collected from bottom waters had similar compositions, although the average POC and PN concentrations were almost two orders of magnitude higher within the benthic boundary layer than in the surface plume. Surface seabed sediments from the northeast region of the delta and inner shelf displayed OC contents of 1.0 to 1.4 wt. percent, C/N ratios of 14 to 24 and d13C signatures of -26 to -27 per mil. In contrast, sediments from the southwest region of the delta and inner shelf displayed OC values of 0.4 to 0.8 wt. percent, C/N ratios of 12 to 24 and d13C values of -24 to -25 per mil. Significant contrasts in average lignin phenol yields were also observed between the sediments from the northeast region of the Fly River delta/inner topset (4.8 +/- 0.3 mg/100 mg OC) and those from the southwest region (3.0 +/- 0.4 mg/100 mg OC). Overall these data indicate that the majority of POM in the water column and sediments of this region of the Gulf of Papua originates from terrigenous C3 plant sources, including vascular plant fragments from the delta and soil organic matter from the Fly River drainage basin. The observed spatial contrasts suggest an efficient export of terrigenous POM to the northeast region of the study area and much inputs to the southwest. These results will be discussed in the context of physical forcings and factors, including particle transport dynamics, sediment deposition and river discharge.
DE: 4850 Organic marine chemistry
DE: 4863 Sedimentation
DE: 4558 Sediment transport
DE: 4564 Tsunamis and storm surges
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting