2022 Early Hearing Detection & Intervention Virtual Conference

March 13 - 15, 2022

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5/22/2018 | 2:45 PM - 3:00 PM | CARBON CYCLING IN A BOREAL TEMPORARY STREAM: INSIGHT FROM AN EXPERIMENTAL HYDROLOGICAL MANIPULATION | 310 B

CARBON CYCLING IN A BOREAL TEMPORARY STREAM: INSIGHT FROM AN EXPERIMENTAL HYDROLOGICAL MANIPULATION

Climate and land use changes are expected to increase the occurrence of intermittency and alter flood regimes worldwide. Such changes have widespread implications for stream ecosystems, including their capacity to transform organic carbon (C). We manipulated discharge from a boreal lake to test the effects of drying and flooding on C cycling along the 1.4 km outlet stream. Flow manipulation created a longitudinal gradient in drought severity over a 18-day period, which we terminated with an experimental flood. In response, we estimated stream metabolism and quantified C gases in the stream surface and subsurface water. Drying and flooding modified the hydrological mechanisms that regulate C delivery to the stream and the residence time by which these C resources are processed under different redox conditions. Where most severe, drying induced a transition from oxic to anoxic conditions in hyporheic sediments that increased methane concentrations in the stream surface water (from 10.1 to 53.7 µg/L). Drying also interacted with groundwater inputs to create heterogeneity in metabolic rates and C gas concentrations along the experimental reach. Our results emphasize the sensitivity of stream C cycling to extreme flow events in the boreal region.

Carbon
Intermittent
Hydrology

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Presenters/Authors

Lluís Gómez-Gener (), Department of Ecology and Environmental Science, Umeå University, gomez.gener87@gmail.com;