Header

UZH-Logo

Maintenance Infos

Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter


Abstract

Climate change and human pressures are changing the global distribution and the extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached sub‐ stances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events

Abstract

Climate change and human pressures are changing the global distribution and the extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached sub‐ stances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events

Statistics

Citations

Dimensions.ai Metrics
4 citations in Web of Science®
6 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

32 downloads since deposited on 31 Jul 2019
32 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Evolutionary Biology and Environmental Studies
Dewey Decimal Classification:570 Life sciences; biology
590 Animals (Zoology)
Uncontrolled Keywords:biofilms, leaching, leaf litter, rewetting, sediments, temporary rivers
Language:English
Date:1 May 2019
Deposited On:31 Jul 2019 09:47
Last Modified:31 Oct 2019 08:18
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:1354-1013
OA Status:Green
Publisher DOI:https://doi.org/10.1111/gcb.14537
Official URL:https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.14537
Project Information:
  • : FunderH2020
  • : Grant ID748625
  • : Project TitleSABER CULTURAL - SAfeguarding Biodiversity and Ecosystem seRvices by integrating CULTURAL values in freshwater management: learning from MÄ�ori
  • : FunderSNSF
  • : Grant IDPP00P3_179089
  • : Project TitleBridging biodiversity and ecosystem functioning: a meta-ecosystem perspective
  • : FunderSNSF
  • : Grant IDPP00P3_150698
  • : Project TitleBridging biodiversity and ecosystem functioning in dendritic networks: a meta-ecosystem perspective
  • : FunderURPP Global Change and Biodiversity, University of Zurich
  • : Grant IDU-704-04-15
  • : Project TitleToward a better integration of evolution and community ecology
  • : Project Websitehttps://www.gcb.uzh.ch/en/Research/Phase-II-Projects/Landscapes/Project-2-Florian-Altermatt.html

Download

Green Open Access

Download PDF  'Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter'.
Preview
Content: Accepted Version
Filetype: PDF
Size: 495kB
View at publisher