title: Global change impacts on river ecosystems: A high-resolution watershed study of Ebro river metabolism.
abstract: Global change is transforming freshwater ecosystems, mainly through changes in basin flow dynamics. This study assessed how the combination of climate change and human management of river flow impacts metabolism of the Ebro River (the largest river basin in Spain, 86,100km(2)), assessed as gross primary production-GPP-and ecosystem respiration-ER. In order to investigate the influence of global change on freshwater ecosystems, an analysis of trends and frequencies from 25 sampling sites of the Ebro river basin was conducted. For this purpose, we examined the effect of anthropogenic flow control on river metabolism with a Granger causality study; simultaneously, took into account the effects of climate change, a period of extraordinary drought (largest in past 140years). We identified periods of sudden flow changes resulting from both human management and global climate effects. From 1998 to 2012, the Ebro River basin was trending toward a more autotrophic condition indicated by P/R ratio. Particularly, the results show that floods that occurred after long periods of low flows had a dramatic impact on the respiration (i.e., mineralization) capacity of the river. This approach allowed for a detailed characterization of the relationships between river metabolism and drought impacts at the watershed level. These findings may allow for a better understanding of the ecological impacts provoked by flow management, thus contributing to maintain the health of freshwater communities and ecosystem services that rely on their integrity.
authors.affiliation: FACOPS Foundation, Calle Pineta 17, 50410 Cuarte de Huerva, Zaragoza, Spain; Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain; Pyrenean Institute of Ecology (CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain. Electronic address: jval@biodiversa.es.
authors.forename: Jonatan
authors.initials: J
authors.lastname: Val
authors.affiliation: Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain. Electronic address: dchinarro@usj.es.
authors.forename: David
authors.initials: D
authors.lastname: Chinarro
authors.affiliation: Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain. Electronic address: rpino@usj.es.
authors.forename: María Rosa
authors.initials: MR
authors.lastname: Pino
authors.affiliation: Pyrenean Institute of Ecology (CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain. Electronic address: enrique.navarro@ipe.csic.es.
authors.forename: Enrique
authors.initials: E
authors.lastname: Navarro
mesh_terms: D057231:Climate Change; D055864:Droughts; D017753:Ecosystem; D004784:Environmental Monitoring; D045483:Rivers / Q000737:chemistry*; D013030:Spain
keywords: Extreme drought; Flow control; Freshwater ecosystems; Global change; Water quality; ecosystem metabolism