Poster Presentation Freshwater Sciences 2023

Biodegradable dissolved organic carbon and seasonal trends in stream outflow of urban stormwater and beaver pondsĀ  (#693)

Jordan A Landis 1 , Sandra M Clinton 1
  1. University of North Carolina at Charlotte, Charlotte, NORTH CAROLINA, United States

Urbanization increases water runoff from impervious surfaces which contributes to the degradation of local streams. In response, urban areas have relied on stormwater infrastructure to reduce runoff into streams by retaining water in ponds. However, stormwater ponds receive elevated concentrations of dissolved organic carbon (DOC) from urban runoff, and combined with high algal production, may have higher quality DOC than naturally occurring ponds. Elevated concentrations of higher quality DOC could accelerate microbial processing rates and affect sequential carbon and nutrient cycling in-pond and downstream. Beaver ponds are a natural alternative to stormwater ponds and have the potential to abate microbial processing rates. This study quantifies biodegradable dissolved organic carbon (BDOC) and evaluates seasonal DOC trends at downstream progressions of urban stormwater and beaver ponds. BDOC samples were collected from in-flow, in-pond, and out-flow sites of one urban stormwater and beaver pond. Each sample was filtered to remove microbes, incubated containing an inoculum curated of microorganism colonies native to each pond, and were measured intervally for DOC concentration and quality. The experimental data were summarized as percent DOC loss (BDOC) to investigate the relationship between DOC concentration and quality. Preliminary data, representative of the growing season (June 2022), showed the in-flow site of the stormwater pond had the highest BDOC percentage, while in-pond and out-flow beaver pond sites measured next highest. BDOC data are currently being collected for the non-growing season (February 2023). Seasonal trends of DOC quantity and quality are being evaluated from approximately weekly data from 2021 to 2023. These findings will generate a better understanding of how DOC concentration and quality in urban stormwater and beaver ponds can impact DOC processing, which can provide insight to the sequential carbon and nutrient cycling that occur in these freshwater ecosystems and downstream.