engleski

Sediment respiration pulses in intermittent rivers and ephemeral streams

Intermittent rivers and ephemeral streams (IRES) may represent over half the global streamnetwork, but their contribution to respiration and carbon dioxide (CO2) emissions is largelyundetermined. In particular, little is known about the variability and drivers of respiration in IRESsediments upon rewetting, which could result in large pulses of CO2. We present a global studyexamining sediments from 200 dry IRES reaches spanning multiple biomes. Results from standardizedassays show that mean respiration increased 32‐fold to 66‐fold upon sediment rewetting. Structuralequation modeling indicates that this response was driven by sediment texture and organic matterquantity and quality, which, in turn, were influenced by climate, land use, and riparian plant cover. Ourestimates suggest that respiration pulses resulting from rewetting of IRES sediments could contributesignificantly to annual CO2emissions from the global stream network, with a single respiration pulsepotentially 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‐drying cycles onrespiration and CO2emissions in stream networks.

CO2 emissions ; C cycling ; stream respiration

nije evidentirano