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- Title
Implications of flow intermittency on sediment nitrogen availability and processing rates in a Mediterranean headwater stream.
- Authors
Arce, María; Sánchez-Montoya, María del; Vidal-Abarca, María; Suárez, María; Gómez, Rosa
- Abstract
Most streams draining to the Mediterranean basin are temporary. As a result of their hydrological regime, temporary streams are affected by drying and rewetting periods. Drying can alter in-stream nitrogen (N) availability and reduce N processing rates and subsequent retention after re-wetting. We sought to determine if hydrologic drying modifies reach-scale sediment chemical properties and constrains the response of N processing to rewetting. We compared different abiotic characteristics of sediments and nitrification and denitrification rates between a perennial and intermittent reach in the same stream over a wet period, when surface water flowed in both reaches, and a dry period, when the intermittent reach dried up. We analyzed N processing rates by incubating sediments with stream water, thereby simulating a rewetting when sediments from the intermittent reach were dry. We found that drying increased the sediment nitrate (NO) content. Conversely, drying did not reduce the recovery of N processing rates to pre-dry levels after simulated flooding conditions. Our results suggest that dry reaches may act as a potential NO source by releasing downstream NO pulses after stream flow recovery. Given the European Water Framework Directive requirements to assess stream ecological status, these N pulses following rewetting should be considered when designing management plans in temporary streams. Our study highlights the rapid response of in-stream N processing to rewetting period following a drought. This high resilience to process N should be seen as a vital ecosystem service provided by temporary streams despite annual dry periods.
- Subjects
MEDITERRANEAN Region; SEDIMENTS; NITRIFICATION; GEOLOGICAL basins; ECOSYSTEM services; PERENNIALS
- Publication
Aquatic Sciences, 2014, Vol 76, Issue 2, p173
- ISSN
1015-1621
- Publication type
Article
- DOI
10.1007/s00027-013-0327-2