FN Archimer Export Format
PT J
TI Effects of large dams on the aquatic food web along a coastal stream with high sediment loads
BT 
AF Roussel, Jean-Marc
   Fraisse, Stéphane
   Dézerald, Olivier
   Fovet, Ophélie
   Pannard, Alexandrine
   Rodriguez-Perez, Hector
   Crave, Alain
   Gorzerino, Caroline
   Poupelin, Maxime
   Forget, Guillaume
   Huteau, Dominique
   Thomas, Alban
   Chevé, Manuel
   Soissons, Laura
   Piscart, Christophe
AS 1:1;2:1;3:1;4:2;5:2,3;6:3,4;7:5;8:1;9:1;10:1;11:6;12:1;13:1;14:1;15:3;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:;13:;14:;15:;
C1 DECOD, INRAE, IFREMER, L’Institut Agro, Rennes, France
   SAS, INRAE, L’Institut Agro, Rennes, France
   COBIO, CNRS, University of Rennes, UMR 6553, Rennes, France
   OFB, ECOAQUA, DRAS, Aix-en-Provence, France
   GEOSCIENCES Rennes, University of Rennes, CNRS, Rennes, France
   INRAE, Unite Experimentale d′Ecologie et Ecotoxicologie Aquatique, Rennes, France
C2 INST AGRO RENNES-ANGERS, FRANCE
   INST AGRO RENNES-ANGERS, FRANCE
   CNRS, FRANCE
   OFB, FRANCE
   UNIV RENNES, FRANCE
   INRAE, FRANCE
UM DECOD
IN WOS Cotutelle UMR
   DOAJ
   copubli-france
   copubli-univ-france
IF 3
TC 1
UR https://archimer.ifremer.fr/doc/00869/98116/107390.pdf
   https://archimer.ifremer.fr/doc/00869/98116/107391.pdf
LA English
DT Article
DE ;nutrient concentrations;sediment fluxes;photosynthetic biofilm;benthic invertebrates;fish;stable isotope analysis;mixing models;carbon flow
AB The contribution of two basal energy sources – detrital organic matter and primary producers – as part of aquatic food webs varies typically along river continua. A host of barriers to river flow increase the water residence time and sediment and nutrient retention in reservoirs worldwide, and potentially alter the balance between detritus-based and algae-based energy pathways in the downstream food webs. We explored this issue on the Sélune River (Normandy, France), a small coastal stream that drains an agricultural catchment with high sediment runoff. Seasonal measurements of the following parameters were compared upstream and downstream of the reservoirs of two large dams (16 m and 36 m high): sediment fluxes, nutrient and chlorophyll a concentrations, algal communities in the epilithic biofilm (taxonomic composition, biomass and growth), and benthic invertebrate communities (abundance and trophic guild structure). As anticipated, annual sediment fluxes were much lower downstream of the reservoirs, where significant decreases in water turbidity, phosphate and silicate concentrations were recorded. A higher chlorophyll a concentration in water and a higher contribution of pelagic algae taxa to the photosynthetic biofilm suggested drifting and deposition of reservoir-borne phytoplankton downriver. Photosynthetic biofilm growth was higher downstream of the reservoirs in spring and fall, and so was the abundance of herbivores in the invertebrate community, notably scrapers and algae eaters. Energy pathways within riverine food webs were traced using stable isotope analyses of carbon (C) and nitrogen in the tissues of aquatic consumers (invertebrates and fish). Mixing models revealed a discontinuity in the origin of the C entering the food webs along the river continuum, confirming a greater contribution of algal C to aquatic consumers downstream of the reservoirs. These results illustrate mechanisms whereby large reservoirs can modulate C flow in food webs along a small coastal river with high sediment loads, and make it possible to anticipate the effects of dam removal on the future river ecosystem. 
PY 2024
PD JAN
SO Frontiers In Ecology And Evolution
SN 2296-701X
PU Frontiers Media SA
VL 11
UT 001142720300001
DI 10.3389/fevo.2023.1250892
ID 98116
ER

EF