HR: 13:45h
AN: H23C-02    [Abstracts]
TI: Modeling Spatial and Temporal Dynamics of Riverine Sediment and Carbon Delivery to the South China Sea
AU: * Higgitt, D L
EM: geodlh@nus.edu.sg
AF: National University of Singapore, Department of Geography, National University of Singapore, 1 Arts Link, Singapore, 117570 Singapore
AU: Lu, X
EM: geoluxx@nus.edu.sg
AF: National University of Singapore, Department of Geography, National University of Singapore, 1 Arts Link, Singapore, 117570 Singapore
AU: Zhang, S
EM: geoluxx@nus.edu.sg
AF: National University of Singapore, Department of Geography, National University of Singapore, 1 Arts Link, Singapore, 117570 Singapore
AB: The export of carbon from land to sea by the process of erosion and fluvial transport represents a major link in the global cycle and one which remains poorly understood and inadequately quantified. Large continental rivers are particularly significant in this respect but river basin development has a profound impact on inputs of freshwater, sediment and carbon to the oceans. The South China Sea is one of the most significant interchanges between terrestrial and ocean stores on the planet. High fluvial suspended sediment loads are driven by the active tectonic setting, rapid weathering rates, high rainfall and human activities which promote erosion. It follows that the controls on the delivery of carbon from terrestrial sources to the SCS region and the extent to which river basin development activities enhance supply and/or inhibit delivery is of fundamental importance for modeling carbon dynamics. In addition to the direct input of terrestrial carbon from fluvial supply, the buoyancy affect of freshwater plumes drives the upwelling of nutrients. Developing a capability for modeling water, sediment and carbon fluxes within large river basins is therefore an important task. Hydrological data archives provide a source of information for evaluating the impact of recent land use change and basin development on water and sediment fluxes, though the compilation of databases is a time consuming task. Adapting a methodology developed by the authors to investigate sediment yield variability within the Yangtze River, the paper is concerned with the delivery dynamics of two large fluvial systems (Pearl/Xi Jiang and the Mekong) which drain into the South China Sea. The approach employs a GIS framework to investigate temporal and spatial dynamics of sediment delivery, its influence on carbon pathways and the statistical significance of controlling catchment variables. While the Xi Jiang system exhibits heterogeneity in sediment yield trends, a notable decline in water and sediment flux throughout the Mekong system is apparent following the closure of the Manwan Dam in the Chinese section of the basin.
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 1806 Chemistry of fresh water
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2005 Joint Assembly