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.
CO2 and O2 Flux:
The low-salinity regions of the Georgia estuaries are characterized by unusually high pCO2 values that are frequently coupled to undersaturation of oxygen (Cai et al. 1999). The observed gas concentrations cannot be explained by within-estuary processes (i.e., respiration in the estuarine water column and sediments); instead, they are driven by high biological activity in the aerobic and anaerobic subsystems of the adjacent intertidal marshes (Cai et al. 1999, Pomeroy et al, in press). Inorganic products of respiratory activity are funneled into the estuarine water from the marshes by tidal action in proportion to the ratio of marsh area:estuary area, which varies predictably within each estuary (Cai et al. 1999). The high productivity of the intertidal marshes thus affect the estuaries by exporting endproducts from within-marsh decomposition (CO2, HCO3), with outwelling of organic matter to the estuaries a minor process by comparison (Cai et al. 1999, Cai et al., 2000). These end products are predicted to have little influence on the adjacent coastal ocean.
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