Investigating Source and Quantity of Dissolved Organic Matter in Waller Creek

Rebekah Garza, Nathan Vu, Ariel Wang, Austin Lu, and Dr. Mary Poteet, Freshman Research Initiative, The University of Texas at Austin, 103 W. 24th Street, G2550 Austin, TX 78712

        Dissolved organic matter (DOM) acts as a major essential energy source for heterotrophic organisms in all aquatic ecosystems. In urban streams, DOM is typically found in abnormally high concentrations and is usually microbially-derived. A study will be done in Waller Creek, an urbanized stream in Austin, Texas. In the lower regions of that stream, a flood diversion tunnel has recently been implemented, significantly altering the source water. The tunnel is designed to divert flood waters underground and directly into a local lake. This study will attempt to determine the source and quantity of DOM in Waller Creek in both the upper and lower regions. We will use a combination of discrete and continuous measurements of dissolved organic carbons and nitrates, pH, turbidity, and temperature across seven different sites. Samples will be analyzed using fluorescence spectroscopy, a combustion TOC analyzer, and UV-VIS methods. The data will then be used to determine DOM quantity and source within the stream at different locations.

        We have two primary hypotheses. First, alterations of source water will cause a decrease in DOM concentrations in lower Waller Creek relative to the upstream concentrations. Second, the source of DOM in lower Waller Creek will shift toward more microbially derived content. The results of this study have several major impacts. It will evaluate the effects of restoration efforts on DOM quantity and source in urban streams. The results will also add to communal knowledge of the effects of restoration projects on stream function. In addition, the findings will contribute to our understanding of the drivers of energy production in urban streams. Finally, the results will be communicated with the City of Austin planners to allow them to make informed restoration decisions specifically regarding the flood diversion tunnel. 

Additional Abstract Information

Presenter: Rebekah Garza

Institution: University of Texas at Austin

Type: Poster

Subject: Environmental Science & Sustainability

Status: Approved

Time and Location

Session: Poster 7
Date/Time: Tue 3:30pm-4:30pm
Session Number: 5000