The Stream Metabolism branch of the FRI Urban Ecosystems research stream has been conducting research on the metabolic processes that drive energy exchange in Waller Creek. In addition, our team also has the goal of understanding the impact of a water restoration facility in the middle of Waller Creek. Dataloggers that record Dissolved Oxygen (DO), light penetration, pressure, and temperature have been placed at 4 sites along Waller Creek. Two of the loggers in Waller Creek have been placed upstream of the Waller Creek Flood Control Tunnel and the other two are downstream of it. Furthermore, there are two other sets of data loggers that we placed in Bear Creek, a non-urbanized creek, to record data as a control group. We would like to understand whether Waller Creek and Bear Creek are ecosystems that are driven by primary production or ecosystems driven by respiration (Wenger et al. 2009).
After collecting some data from our loggers and plotting the relationship between dissolved oxygen and temperature, we displayed data from three different sites. The first site, San Jacinto, is upstream of the flood control tunnel facility in Waller Creek. The second site, Palm Park, is downstream of the same water flood control tunnel. Finally, the third site is located in Bear Creek.
After studying the relationships between DO and temperature, our team noticed an interesting trend. At San Jacinto, there are many large spikes and shifts in dissolved oxygen that seemingly indicate that the non-restored portion of Waller Creek is mostly driven by cellular respiration caused by the decomposition of excess amounts of algae. This indicates that this section of the creek has large inputs of organic matter from terrestrial or sewage sources. Meanwhile, at Palm Park, the shifts and spikes in DO are still present, but of far less magnitude. This is likely due to the lower variability in temperature and reduced algal growth in this section of the creek. This shows that although the stream ecosystem at Palm Park is still likely being respiration driven, it appears to be more balanced with primary production than the creek ecosystem at San Jacinto. Meanwhile, the graph of Bear Creek shows minimal shifts, indicating that the Bear Creek environment is likely mostly driven by primary production (Wenger et al. 2009).
The implications of our research team’s data are large. With further data collection and processing, more concrete representations of the primary productivity and ecosystem respiration of the different sections of the creeks can be drawn, allowing for a better understanding of the stream ecosystems that can be used by the city of Austin to help improve the quality of its waterways.
Rahul Anand
Team Energy
FRI Urban Ecosystems Research Stream
Works Cited
- Wenger, S.J., A.H. Roy, C.R. Jackson, E.S. Bernhardt, T.L. Carter, S. Filoso, et al. 2009. Twenty-six research questions in urban stream ecology: an assessment of the state of the science. Journal of the North American Benthological Society 28:1080-1098.