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Integrating Ecosystem Patch Contributions to Stream Corridor Carbon Dioxide and Methane Fluxes
Author(s) -
Bretz Kristen A.,
Jackson Alexis R.,
Rahman Sumaiya,
Monroe Jonathon M.,
Hotchkiss Erin R.
Publication year - 2021
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2021jg006313
Subject(s) - streams , environmental science , riparian zone , hydrology (agriculture) , greenhouse gas , carbon dioxide , ecosystem , methane , carbon cycle , watershed , carbon fibers , atmospheric sciences , ecology , habitat , geology , computer network , geotechnical engineering , machine learning , computer science , biology , materials science , composite number , composite material
The heterogeneity of carbon dioxide (CO 2 ) and methane (CH 4 ) sources within and across watersheds presents a challenge to understanding the contributions of different ecosystem patch types to stream corridor and watershed carbon cycling. Changing hydrologic connections between corridor patches (e.g., streams, vernal pools, hillslopes) can influence stream corridor greenhouse gas emissions, but the spatiotemporal dynamics of emissions within and among corridor patches are not well‐quantified. To identify patterns and sources of carbon emissions across stream corridors, we measured gas concentrations and fluxes over two summers at Coweeta Hydrologic Laboratory, NC. We sampled CO 2 and CH 4 along four stream channels (including flowing and dry reaches), adjacent vernal pools, and riparian hillslopes. Stream CO 2 and CH 4 emissions were spatially heterogeneous. All streams were sources of CO 2 to the atmosphere (median = 97.2 mmol m −2 d −1 ) but were sources or sinks of CH 4 depending on location (−0.19 to 4.57 mmol m −2 d −1 ). CO 2 emissions were lower during the drier of two sampling years but were stable from month to month in the drier summer. CO 2 and CH 4 emissions also varied by both corridor and patch type; the presence of a vernal pool in the corridor had the strongest impact on emissions. Vernal pool patches emitted more CO 2 and CH 4 (246 and 1.95 mmol m −2 d −1 , respectively) than their adjacent streams. High resolution sampling of carbon fluxes from patches within and among stream corridors improves our understanding of the connections between terrestrial, riparian, and aquatic zones in a watershed and their contributions to overall catchment carbon emissions.