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

Title
Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter
Publication Date
2019-05
Author(s)
Shumilova, Oleksandra
Zak, Dominik
Datry, Thibault
Schiller, Daniel von
Corti, Roland
Foulquier, Arnaud
Obrador, Biel
Tockner, Klement
Allan, Daniel C
Altermatt, Florian
Arce, María Isabel
Arnon, Shai
Banas, Damien
Banegas‐Medina, Andy
Beller, Erin
Blanchette, Melanie L
Blanco‐Libreros, Juan F
Blessing, Joanna
Boëchat, Iola Gonçalves
Boersma, Kate
Bogan, Michael T
Bonada, Núria
Bond, Nick R
Brintrup, Kate
Bruder, Andreas
Burrows, Ryan
Cancellario, Tommaso
Carlson, Stephanie M
Cauvy‐Fraunié, Sophie
Cid, Núria
Danger, Michael
Terra, Bianca de Freitas
De Girolamo, Anna Maria
Campo, Ruben del
Dyer, Fiona
Elosegi, Arturo
Faye, Emile
Febria, Catherine
Figueroa, Ricardo
Four, Brian
Gessner, Mark O
Gnohossou, Pierre
Cerezo, Rosa Gómez
Gomez‐Gener, Lluís
Graça, Manuel A S
Guareschi, Simone
Gücker, Björn
Hwan, Jason L
Kubheka, Skhumbuzo
Langhans, Simone Daniela
Leigh, Catherine
Little, Chelsea J
Lorenz, Stefan
Marshall, Jonathan
McIntosh, Angus
Mendoza‐Lera, Clara
Meyer, Elisabeth Irmgard
Miliša, Marko
Mlambo, Musa C
Moleón, Marcos
Negus, Peter
Niyogi, Dev
Papatheodoulou, Athina
Pardo, Isabel
Paril, Petr
Pešić, Vladimir
Rodriguez‐Lozano, Pablo
Rolls, Robert J
( author )
OrcID: https://orcid.org/0000-0002-0402-411X
Email: rrolls2@une.edu.au
UNE Id une-id:rrolls2
Sanchez‐Montoya, Maria Mar
Savić, Ana
Steward, Alisha
Stubbington, Rachel
Taleb, Amina
Vorste, Ross Vander
Waltham, Nathan
Zoppini, Annamaria
Zarfl, Christiane
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Wiley-Blackwell Publishing Ltd
Place of publication
United Kingdom
DOI
10.1111/gcb.14537
UNE publication id
une:1959.11/59524
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 substances, 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.

Link
Citation
Global Change Biology, 25(5), p. 1591-1611
ISSN
1354-1013
Start page
1591
End page
1611
Rights
Attribution 4.0 International

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