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.
Modeling:
Modeling has been
an essential tool to link physical movements of materials with biological processes
in the GARLMER estuaries. Water circulation is being described through an extensive
estuary-wide study of a GARLMER estuary (the Satilla River), based on moored
instruments (providing data on currents, temperature, salinity, and pressure)
complemented by spatial surveys emphasizing lateral as well as longitudinal
variability. Calculations of salt content variability from a 3-D finite element
numerical model that simulates wetting and drying of tidal marshes and channels
are being compared with these empirical results. More simple models allowing
a date-specific method for determining estuarine flushing times have also been
developed (Alber & Sheldon, 1999b), and are being used to interpret distributions
of particulate and dissolved materials in the estuaries. Mass balance models
of O2 and CO2 concentrations and flux have addressed the export of gases to
the coastal ocean, and predict a seasonal phase lag in CO2 uptake and release
which, extrapolated to coastal marshes worldwide, could be an important factor
in global CO2 models (Cai et al. 1999). A water transport/land use model of
one GARLMER estuary that simulates river flow and material output on a daily
basis predicts that nutrient output from the estuaries is the parameter likely
to show the greatest impacts from anthropogenic disturbances within the watershed
(Dai et al., in prep). Funds from the Georgia Coastal Zone Management (CZM)
program and the State of Georgia provided essential supplemental funding for
these modeling projects.