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Does the severity of non‐flow periods influence ecosystem structure and function of temporary streams? A mesocosm study
Author(s) -
Muñoz Isabel,
Abril Meritxell,
CasasRuiz Joan Pere,
Casellas Maria,
GómezGener Lluís,
Marcé Rafael,
Menéndez Margarita,
Obrador Biel,
Sabater Sergi,
Schiller Daniel,
Acuña Vicenç
Publication year - 2018
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.13098
Subject(s) - streams , mesocosm , environmental science , biogeochemical cycle , arid , ecosystem , hydrology (agriculture) , flow conditions , sediment , intermittency , ecology , carbon cycle , total organic carbon , dissolved organic carbon , organic matter , flow (mathematics) , biology , geography , geology , meteorology , paleontology , geometry , geotechnical engineering , mathematics , computer science , turbulence , computer network
Global change is dramatically altering flow regimes worldwide. Among the most important consequences are the transition of many permanent waterways to temporary waterways, the increase in duration and frequency of non‐flow periods of temporary streams, and the increase in the severity (i.e. irradiance, temperature and humidity) of the non‐flow period. Nowadays, there is a lack of knowledge on how changes in duration, frequency and severity of the non‐flow period will reflect on biodiversity and biogeochemical changes in temporary streams. We designed a manipulative experiment using artificial streams to evaluate the effects of severity of the non‐flow period on stream biofilms. Sixteen artificial streams were assigned to four treatments: continuous flow, continuous intermittency and intermittency with and without rain events. Effects were assessed on selected features of stream biofilm structure (i.e. bacterial density and basal fluorescence) and function (photosynthetic efficiency and enzymatic activities), as well as CO 2 emissions and dissolved organic matter quantity and quality from water column and sediments. The occurrence of rain events during the non‐flow period enhanced organic carbon processing and CO 2 emissions to the atmosphere, reducing the sediment reservoir of exportable organic carbon and therefore reducing the dissolved organic carbon exports from streambeds at flow resumption. Given the ongoing reducing trends in the frequency of rain events in semi‐arid and arid regions, we expect temporary streams to process and emit less and to export more carbon to downstream systems.