Impacts of water level on metabolism and transient storage in vegetated lowland rivers - insights from a mesocosm study

Autor: Kurz, MJ, Drummond, JD, Marti, E, Zarnetske, JP, Lee-Cullin, J, Klaar, MJ, Folegot, S, Keller, T, Ward, AS, Fleckenstein, JH, Datry, T, Hannah, DM, Krause, S
Přispěvatelé: Helmholtz Centre for Environmental Research (UFZ), Centre d'Estudis Avançats de Blanes (CEAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Department of Earth and Environmental Sciences [East Lansing], Michigan State University [East Lansing], Michigan State University System-Michigan State University System, University of Birmingham [Birmingham], Indiana University [Bloomington], Indiana University System, Milieux aquatiques, écologie et pollutions (UR MALY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Journal of Geophysical Research: Biogeosciences
Journal of Geophysical Research: Biogeosciences, American Geophysical Union, 2017, 122 (3), pp.628-644. ⟨10.1002/2016JG003695⟩
Digital.CSIC. Repositorio Institucional del CSIC
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ISSN: 2169-8953
Popis: Este artículo contiene 5 páginas, 5 figuras.
Transient storage zones for water represent potential hot spots for metabolic activity in streams. In lowland rivers, the high abundance of submerged vegetation can increase water transient storage, bioreactive surface areas and, ultimately, in-stream metabolic activity. Changes in flow resulting from climatic and anthropogenic factors that influence the presence of aquatic vegetation can also, thereby, impact in-stream metabolism and nutrient cycling. We investigated the effects of water column depth on aquatic vegetation cover and its implications on water transient storage and associated metabolic activity in stream mesocosms (n=8) that represent typical conditions of lowland streams. Continuous injections of metabolically reactive (resazurin-resorufin) tracers were conducted and used to quantify hydraulic transport and whole-mesocosm aerobic respiration. Acetate, a labile carbon source, was added during a second stage of the tracer injection to investigate metabolic responses. We observed both higher vegetation coverage and resazurin uptake velocity, used as a proxy of mesocosm respiration, with increasing water column depth. The acetate injection had a slight, positive effect on metabolic activity. A hydrodynamic model estimated the water transport and retention characteristics and first-order reactivity for three mesocosms. These results suggest that both the vegetated surface water and sediments contribute to metabolically active transient storage within the mesocosms, with vegetation having a greater influence on ecosystem respiration. Our findings suggest that climate and external factors that affect flow and submerged vegetation of lowland rivers will result in changes in stream respiration dynamics and that submerged vegetation are a particularly important and sensitive location for stream respiration.
Financial support for the experiment was provided by The Leverhulme Trust through the project "Where rivers, groundwater and disciplines meet: A hyporheic research network‟ and from the authors' institutions.
Databáze: OpenAIRE
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