GCRC Program Summary |
Findings
Georgia Rivers Land Margin Ecosystem Research Program:
A comparative study of the transport and transformation of materials from rivers through the land-sea margin.
Estuarine exchange:
Marsh-estuarine exchange in the Georgia estuaries occurs by irregular tidal dynamics that are extremely important for moving water and sorting materials. Two distinct types of tidal current distributions characterize the Georgia estuaries and coastal marshes: tidal currents with maximum ebb and flood currents near the time of high water (typical of mouths of large tidal creeks) and currents with maximum ebb and flood currents near the time of low water (typical of shallow tidal drainage systems and flood tide deltas) (Blanton and Andrade, 2001). One of the important consequences of this tidal current distribution is that it alters the transport of suspended materials. There are classes of suspended sediments within the Georgia estuaries that settle too slowly to reach the bed, yet others that settle within a tidal cycle and have distributions that clearly correlate with current speed. Differential transport of these particle types affects their residence time in the estuarine system and consequently their involvement in biogeochemical transformations (Blanton et al. 1999, Alber, 2000). Cross-system exchange in the other direction, between the estuary and the ocean, occurs within a complex spatial structure surrounding individual plumes that evolve during a tidal cycle (Kapolnai et al. 1996, Blanton et al. 1997).
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