GCRC Project Summary |
Assessment of the St Marys River Biological Quality and Primary Productivity
PI: Keith W. Gates and Katy A. Smith (University of Georgia Marine Extension Service, Athens, GA, USA)
Support: GA DNR Coastal Zone Management (through a Coastal Incentive Grant), also OCRM, NOAA
Timeframe: 2006 - 2008
Project Overview:
The University of Georgia Marine Extension Service (MAREX) has conducted ongoing water quality research in Georgia’s major coastal rivers over the past eight years. The St. Mary’s River was the fourth among the five major rivers to be monitored for one year. The initial monitoring began with scouting of the river in October 2006 and continued with monthly monitoring through September 2007. A suite of information was collected to assess the water quality of the St. Mary’s River.
Findings:
The lower tidal portion of the St. Mary’s River, the area from the Highway 17 bridge to Cumberland Sound, was investigated during this one-year study.
-Bacterial levels observed from November 2006 to September 2007 were occasionally higher than the standards for recreational waters (MPN 104 per 100mL for Enterococci and MPN 200 per 100mL for fecal coliforms) and generally higher up river. The exact source(s) for the bacteria are unknown, but most likely occur from a combination of human and animal sources.
-Average carbon and nitrogen concentrations and average silicate levels showed up-river increases as well. However, average chlorophyll levels were lower up river.
- Physical parameters measured during the study indicate a generally healthy river system. Dissolved oxygen levels fall to around 3 mg/L in late summer, but return to normal levels once the water temperatures cool down in the fall. Reduced oxygen levels in the summer are common in Georgia’s estuaries. Biological oxygen demand and pH levels measured indicated a healthy estuarine system as well. Total suspended solids concentrations were generally low in the St. Mary’s River.
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