Ecosystem Services in a Regulated River: Variability in Nutrient Uptake and Net Ecosystem Metabolism in the Chattahoochee River
Gibson, Cathy A.
Meyer, Judy L.
MetadataShow full item record
Rivers provide vital ecosystem services that are often difficult to quantify economically and overlooked by management agencies. Two of these services, nutrient uptake and net ecosystem metabolism, are especially important in urban rivers receiving large quantities of point source discharge. However, little is known about the mechanisms that facilitate these ecosystem processes in large, regulated rivers such as the Chattahoochee. We examined how nutrient uptake and net ecosystem metabolism varied under different baseflows on the Chattahoochee River downstream of Atlanta. Nutrient uptake was measured as uptake length, the average distance traveled downstream by a nutrient molecule before it is removed from the water column. Our results showed that nutrient uptake length was variable, but often exceeded the length of the river between the major Atlanta dischargers and West Point Lake. This means that phosphorous entering in effluent was not removed from the river before it entered West Point Lake. Net ecosystem metabolism data indicated that the Chattahoochee below Atlanta is a highly heterotrophic system, but respiration appears to decrease under lower discharge.