engleski

Sediment Respiration Pulses in Intermittent Rivers and Ephemeral Streams

Intermittent rivers and ephemeral streams (IRES) may represent over half the global stream network, but their contribution to respiration and carbon dioxide (CO2) emissions is largely undetermined. In particular, little is knownabout the variabilityand drivers ofrespiration in IRES sediments upon rewetting, which could result in largepulses of CO2.We present a global study examining sediments from 200 dry IRES reaches spanning multiple biomes. Results from standardized assays show that mean respiration increased 32–66-fold upon sediment rewetting. Structural equation modelling indicates that this response was driven by sediment texture and organic matter quantity and quality, which, in turn, were influenced by climate, land use and riparian plantcover. Our estimates suggest that respiration pulses resulting from rewetting of IRES sediments could contribute significantly to annual CO2emissions from the global stream network, with a single respiration pulse potentially increasing emission by 0.2–0.7%. As the spatial and temporal extent of IRES increasesglobally, our results highlight the importance of recognizing the influence of wetting-dryingcycles on respiration and CO2emissions instream networks.

River ; Stream ; Intermittent ; Temporary ; Respiration ; CO2

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