Poster Presentation Symposium on Urbanization and Stream Ecology 2025

Urban Creeks Don’t Follow the Seasons: Metabolic Decoupling in a Changing Landscape (#47)

Mary Poteet 1 , Carol Tran 1 , Isabella Serrao 1 , Ria Bhatia 1
  1. The University of Texas at Austin, TX, United States

Metabolic regimes provide a framework for evaluating how creek ecosystems respond to disturbance by tracking shifts in gross primary production (GPP) and ecosystem respiration (ER). Metabolic fingerprinting can be used to visualize these shifts, enabling comparisons across systems with varying degrees of urbanization. To assess patterns of metabolic regimes across urban, rural, and hydrologically managed creeks, we measured daily GPP and ER in Austin, TX, across multiple years. Rural creeks exhibited strong seasonal synchrony in both GPP and ER, with higher metabolic activity in spring and summer and lower rates in fall and winter, following a near 1:1 relationship. This suggests that metabolism in rural streams is closely linked to seasonal fluctuations in temperature, light availability, and natural hydrology. Urban creeks exhibited a range of metabolic patterns, with some showing high variability and others highly constrained fingerprints, but most displayed weak or inconsistent coupling between GPP and ER. These differences likely result from site-specific combinations of flood dynamics, hydrologic modifications, and external organic inputs. For example, the diversion-regulated segment of Waller Creek displayed fluctuating but aseasonal and constrained metabolism, suggesting that altered flow suppresses seasonal signals and weakens the coupling between GPP and ER. These findings indicate that urbanization alters the balance between GPP and ER, leads to aseasonal metabolic regimes, and increases reliance on urban organic matter sources. This research highlights the value of metabolic fingerprints in assessing how urbanization reshapes stream metabolism, with implications for urban water management, stream restoration, and climate resilience in rapidly developing areas.