Baltimore Ecosystem Study Institute of Ecosystem Studies

2017 BES Annual Meeting Presentation and Poster Abstracts

Initial results from a long-term stream metabolism monitoring network across Baltimore
Reisinger, AJ
Co-Authors: Emma J. Rosi Peter M. Groffman

Abstract: Stream metabolism represents the overall energy budget of a stream, and balances the process of gross primary production (GPP) and ecosystem respiration (ER). Stream metabolism integrates a range of biological processes and provides an integrative metric to assess the overall functioning of a stream, with implications for other processes such as nutrient cycling and food web dynamics. Beginning in February, 2016, we deployed dissolved oxygen, temperature, and photosynthetically active radiation sensors at the eight long-term stream monitoring sites of the Baltimore Ecosystem Study (BES). These sensors, coupled with standard modeling approaches, allow us to estimate daily GPP and ER, and will remain deployed to provide an additional long-term datastream for BES. Currently, we have successfully modeled metabolism at all eight monitoring sites for 6 - 8 months from February to November 2016. Preliminary results suggest that urbanization increases GPP but does not have as large of an effect on ER. This result leads to urban streams being less heterotrophic, or even autotrophic, representing more of a carbon sink and reiterating other studies which have shown that urban streams have high rates of biogeochemical functioning. Additionally, GPP is highly seasonal due to changes in riparian canopy cover altering light availability for photosynthesis. This seasonality is particularly evident in reference and exurban/suburban sites, whereas more urbanized streams exhibit reduced seasonality, likely caused by a reduction in riparian vegetation. These preliminary results highlight the potential insights to be gained from the continued monitoring of urban stream metabolism across the Baltimore area.