Metabolic Response to Storm Events in Urban Streams
Abstract
Stream metabolism, the coupling of gross primary production (GPP) and ecosystem respiration (ER), is a fundamental ecological process that captures the predominant bioenergetics of stream ecosystems. Frequent and intense flow events in urban streams can scour stream beds and increase turbidity, which can constrain development of stream communities and reduce metabolic rates. Alternatively, these events can transport energetic subsidies, including nutrients and allochthonous carbon, from the surrounding terrestrial landscape to the stream, thereby amplifying stream processes. In this study, we had two objectives: 1) investigate the response of stream metabolism to flow disturbances in urbanized streams, and 2) assess the dominant landscape, riparian, and geomorphic controls on the metabolic response. Using ten years of high frequency dissolved oxygen, temperature, and discharge data, we estimated daily GPP and ER and analyzed the metabolic response to 400 flow events across 11 urban streams (watershed size: 18-168 km2) in Charlotte, North Carolina, USA. We calculated the magnitude of change in metabolic rates from pre-disturbance to post-disturbance and the recovery time of metabolic rates post-disturbance (we define disturbance as the flood pulse). We then determined whether the response and recovery of metabolic rates are controlled by landscape, riparian, and/or stream geomorphic characteristics. Preliminary results show that ER was typically resistant to flow disturbances and showed more resistance to disturbance than GPP. Additionally, GPP and ER exhibited similar recovery times (1-11 days). A better understanding of flow-induced metabolism dynamics in urban streams may lead to improved indicators of stream ecosystem health and help identify effectiveness of watershed-scale restoration, conservation, and stormwater management activities.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B22A..01S