2022 Early Hearing Detection & Intervention Virtual Conference

March 13 - 15, 2022

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5/23/2019  |   11:15 AM - 11:30 AM   |  THE PREVALENCE OF HYPOXIA IN RIVER NETWORKS AND THE ROLE OF NOT SO DEAD ZONES IN ELEMENT CYCLING   |  251 AB

THE PREVALENCE OF HYPOXIA IN RIVER NETWORKS AND THE ROLE OF NOT SO DEAD ZONES IN ELEMENT CYCLING

Though well understood to be a widespread challenge for water quality managers, hypoxia (defined as [DO] < 5mgL-1) in fluvial systems is understudied by stream ecologists who tend to work in well-aerated stream segments. A high resolution synoptic sampling of 20km of the New Hope Creek river network in the Piedmont of North Carolina found that more than 40% of the network was hypoxic. Time series data from nine locations along this network show that some hypoxic segments oscillate on a diel cycle while others remain hypoxic for weeks between storm flows. Hypoxia was more prevalent in incised channel reaches where slopes have declined as a result of flow impoundments. In addition to being stressful for many aquatic organisms, hypoxia has implications for microbial metabolism. In many locations along this continuum, we measured high co-occurring concentrations of methane, nitrous oxide, hydrogen sulfide and reduced iron. Predictions of metabolic pathway rates based on these concentrations and on thermodynamic constraints (using the GANGSTA model) indicate that anaerobic metabolism is significant for energy cycling. Incorporating hypoxia into the conceptual model of river networks provides a more complete understanding of metabolism in rivers.

  • Metabolism
  • Biogeochemistry
  • Geomorphology

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Presenters/Authors

Alice Carter (), Duke University, alicecarter05@gmail.com;


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Joanna Blaszczak (), Global Water Center and Department of Natural Resources and Environmental Science, University of Nevada, Reno, jblaszczak@unr.edu;


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Martin Doyle (), Duke University, martin.doyle@duke.edu;


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Ashley Helton (), University of Connecticut, ashley.helton@uconn.edu;


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Jim Heffernan (), Duke University, james.heffernan@duke.edu;


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Emily Bernhardt (), Duke University, emily.bernhardt@duke.edu;


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