Ecosystem engineering by periphyton in Alpine proglacial streams

Details

Ressource 1Download: Roncoroni_et_al_ESPL.pdf (10004.84 [Ko])
State: Public
Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_0AE5E930A55C
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Ecosystem engineering by periphyton in Alpine proglacial streams
Journal
Earth Surface Processes and Landforms
Author(s)
Roncoroni Matteo, Ballu Aurélien, Selitaj Adrijan, Mancini Davide, Miesen Floreana, Aguet Marc, Battin Tom I., Lane Stuart N.
ISSN
0197-9337
1096-9837
Publication state
Published
Issued date
03/10/2023
Peer-reviewed
Oui
Volume
49
Number
1
Pages
417-431
Language
english
Abstract
Stream periphytons are candidate ecosystem engineers in proglacial margins. Here, we quantify the extent to which they are engineers for the case of hillslope-fed tributaries in the terrace zones of proglacial margin alluvial plains. Candidate ecosystem engineering effects relate to periphyton-driven changes in (1) vertical infiltration of water, which in turn could aid plant colonization and hence local surface stabilization, and (2) near-bed hydraulics, notably near-bed turbulence properties. We ran two flume experiments in parallel in the proglacial margin of the Otemma glacier (Switzerland), reproducing the environmental conditions found in terrace streams. In both experiments, we followed periphyton development on initially bare sediments for 28 days. Then, whilst the experiment continued undisturbed in one flume, in the second and over a further 26 days, we introduced disturbances in the form of desiccation events. Throughout the entire experiment length, we collected imagery for close-range SfM-MVS photogrammetry, data on vertical infiltration, and near-bed hydraulics. The experiments showed that periphyton development significantly changed the streambed properties. First, periphyton development over the timescale of a few days reduced bed roughness and clogged the benthic interstitial space, reducing water infiltration. These effects were insensitive to the disturbance regime. Second, the changes in streambed roughness modified the near-bed turbulent structures, and this resulted in a reduction of bursting events and in the modification of the turbulent kinetic energy at the near-bed layer. The latter, however, appeared to be less important in these environments as compared with the impacts on infiltration. Given the low water retaining capacity of glacial sediments, the observation that periphyton can reduce vertical infiltration explains wider observations of their importance in glacial floodplains where vegetation succession is critically constrained by water availability. The relatively reduced impacts on near-bed turbulence also contribute to explaining why disturbance in proglacial margin streams remains a key limit on ecological succession.
Keywords
ecosystem engineering, glacial floodplains, infiltration, near-bed turbulence, periphyton, proglacial streams
Open Access
Yes
Funding(s)
Swiss National Science Foundation / CRSII5_180241
Create date
04/10/2023 9:33
Last modification date
05/04/2024 8:14
Usage data