Nutrient pollution in streams

Researchers study how influxes of nutrients into freshwater systems impact stream processes

Nutrient pollution (particularly from nitrogen and phosphorus) is introduced into freshwater systems through human activity like agriculture and lawn care. This research investigates the ways that nutrients impact forested stream ecosystems. In particular, we investigated the relative importance of nitrogen and phosphorus, and how changing ratios altered ecosystem responses. 

This research is conducted at Coweeta Hydrological Laboratory with a paired watershed design, and stemmed from prior studies, which enriched a stream for five years with nitrogen and phosphorus. Previous results showed significant effects on heterotrophic microorganisms, steam macroinvertebrates and energy flow pathways (Gulis et al. 2003, Cross et al. 2006, Rosemond et al. 2008, Davis et al. 2010, Suberkropp et al. 2010). 

These studies and more recent research have allowed us to identify the mechanisms by which nutrients change streams, and have determined the concentrations and ratios of nitrogen and phosphorus that cause undesirable ecosystem shifts. In order to protect aquatic ecosystems, and maintain water quality for wildlife and human use, it is important to understand these concentrations.

To read more about this research, visit P.I. Dr. Amy Rosemond’s website, here.