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Flow intermittence alters carbon processing in rivers through chemical diversification of leaf litter
  • Rubén del Campo,
  • Roland Corti,
  • Gabriel Singer
Rubén del Campo
Leibniz Institute of Freshwater Ecology and Inland Fisheries
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Roland Corti
Irstea Centre de Lyon-Villeurbanne
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Gabriel Singer
University of Innsbruck
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Abstract

The dry phase of intermittent rivers promotes the emergence of diverse terrestrial and aquatic habitats where large amounts of leaf litter can accumulate. This environmental heterogeneity can cause diverse chemical alterations in leaf litter by the co-occurrence of multiple physical and biological degradation processes across these different habitats. After flow resumption, these chemically diversified leaves are mixed and continue decomposition downstream in fully aquatic conditions. Here, we (i) test experimentally the hypothesis that environmental heterogeneity during the dry phase can translate into a chemical diversification of leaf litter, and (ii) investigate how chemical diversity may affect leaf litter decomposition in re-established lotic conditions. Our laboratory treatments mimicking dry-phase habitats caused a strong chemical diversification of leaf litter, which accelerated its decomposition in a perennial river reach. These results suggest that intermittent river reaches may act as hotspots of organic matter diversification with potential implications on C processing at river-network scale.