Quantification of Organic Matter Retention and Transport in Streams

Urbanization and land use changes affect the physical, hydrological, and biological characteristics of freshwater streams. Loss of riparian vegetation and increased impervious surface area can cause reductions in the quantity of leaf litter inputs from the watershed and more rapid transport downstream. As a result, urbanization and land-use changes may impact the availability of carbon for aquatic food webs. This study compared the quantity and retention of coarse particulate organic matter (CPOM; particles \u3e1mm in size) in more urban and rural settings to evaluate the potential impacts of urbanization on stream food webs. Four locations, Noonday Creek at Kurtz Road, Noonday Creek at Shallowford Road, Peachtree Creek, and Raccoon Creek, were chosen to be a part of this experiment. Each stream contained some woody and nonwoody debris, allochthonous materials such as leaves and insects, and autochthonous organic matter sources like algae and dead aquatic animals. Within each stream, coarse particulate organic matter on the stream bed was measured, and leaf litter export was estimated by tracking releases of Ginkgo biloba leaves. These leaves were specifically chosen because their unique shape distinguishes them from other leaves that reside within these environments. Stream aspects such as sinuosity, woody debris, riparian vegetation, and water velocity of the stream can affect CPOM accumulation and transport. Results will be compared across urban and rural locations to evaluate the potential impacts of watershed modifications on organic matter cycling