Date of Award





Earth and Space Science - Environmental Science Track


Earth & Space Science

First Advisor

James A. Gore


Nutrients are considered the second largest nonpoint source pollutant in Georgia's running water ecosystems. Nutrients can naturally occur in low amounts and are typically increased in streams as a result of industry, agriculture, silviculture, and urbanization. In large amounts, nutrients can cause many problems to occur in the stream ecosystem. Macroinvertebrates have been established as good indicators for determining the level of impairment of a stream; however, not much research has been done on how nutrients affect macroinvertebrates in a stream. Approximately 225 reference and impaired streams were sampled over a 3 - year field season, (index period from September to February), using the EPA's rapid bioassessment protocol (RBP). The concentrations of nutrients were measured in mg/L and ranged as follows: nitrite and nitrite/nitrate <0.01 to >1.0, ammonia <0.03 to 3.0, and phosphorous <0.01 to 1.2. Analysis determined (1) the RBP has the potential to indicate nutrient loading; (2) nutrient parameters that were significantly different varied across the state, varied at ecoregion level and varied at subecoregion within an ecoregion; (3) the data indicated some correlations between nutrients and macroinvertebrate distribution, however the RBP was not a good indicator of nutrient loading in all ecoregions and subecoregions across the state; and (4) nutrient analysis should continue to be part of the rapid bioassessment protocol.