Trophic connectivity between offshore upwelling and the inshore food web of Banc d’Arguin (Mauritania): New insights from isotopic analysis

Type Article
Date 2015-11
Language English
Author(s) Carlier AntoineORCID1, Chauvaud Laurent1, Van Der Geest Matthijs2, 3, Le Loc'h Francois1, 4, Le Duff Michel1, Vernet Marc5, Raffray Jean1, Diakhate Djibril6, Labrosse Pierre6, Wague Abdoulaye6, Le Goff Clement7, Gohin Francis7, Chapron Bertrand8, Clavier Jacques1
Affiliation(s) 1 : Inst Univ Europeen Mer, CNRS UBO IRD IFREMER, LEMAR, UMR 6539, F-29280 Plouzane, France.
2 : NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, NL-1790 AB Den Burg, Texel, Netherlands.
3 : Univ Groningen, Ctr Ecol & Evolutionary Studies, Anim Ecol Grp, NL-9700 CC Groningen, Netherlands.
4 : Ctr Rech Halieut, Inst Dev Res, IRD IFREMER UMII, Ecosyst Marins Exploites,UMR EME 212, F-34203 Sete, France.
5 : Univ Paris 06, CNRS, Stn Biol Roscoff,UMR 7144, Adaptat & Diversite Milieu Marin,Equipe Chim Mari, F-29680 Roscoff, France.
6 : Inst Mauritanien Rech Oceanog & Peches, Nouadhibou, Mauritania.
7 : IFREMER, Ctr Bretagne, DYNECO Lab Ecol Pelag, F-29280 Plouzane, France.
8 : IFREMER, Ctr Bretagne, Lab Oceanog Spatiale, F-29280 Plouzane, France.
Source Estuarine Coastal And Shelf Science (0272-7714) (Academic Press Ltd- Elsevier Science Ltd), 2015-11 , Vol. 165 , P. 149-158
DOI 10.1016/j.ecss.2015.05.001
WOS© Times Cited 2
Keyword(s) Banc d'Arguin, West Africa, food web structure, remote sensing, stable isotope, upwelling
Abstract Banc d’Arguin (BA), Mauritania, is a nationally protected shallow gulf > 10,000 km2 between the Sahara desert and the upwelling system off the Mauritanian coast. In the southeast, BA consists of a 500 km2 tidal flat, the most important wintering site for shorebirds using the East Atlantic Flyway. The Mauritanian upwelling-driven phytoplankton production supports the most productive fisheries worldwide, but little is known about its trophic role in the functioning of the inshore BA food web. Using stable isotopes as trophic tracers to distinguish between upwelling-driven phytoplankton, open ocean phytoplankton, and benthic primary producers, we assessed the spatial extent to which the inshore BA food web is fuelled by upwelling-driven phytoplankton production. The δ13C and δ15N signals were characterized in dominant primary producers, benthic invertebrate taxa, and various fish species along an offshore–inshore (northwest–southeast) gradient. We also monitored the spatial and temporal extent of upwelling entering BA during 2008 with remote sensing of sea surface temperature and chlorophyll a data. The results suggest that benthic invertebrates and fishes living in the northwestern part of BA depend on the nearby upwelling phytoplankton production, but this food source does not support the intertidal benthic community in southeast BA. Furthermore, the isotopic signatures of fishes suggest weak trophic connectivity between the northern subtidal and southeastern intertidal BA. Our results support the hypothesis that the southeastern tidal flat region functions as a distinct ecosystem with a food web supported mainly by local benthic primary production, which is crucial knowledge for effective management of the pristine BA national park.
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Carlier Antoine, Chauvaud Laurent, Van Der Geest Matthijs, Le Loc'h Francois, Le Duff Michel, Vernet Marc, Raffray Jean, Diakhate Djibril, Labrosse Pierre, Wague Abdoulaye, Le Goff Clement, Gohin Francis, Chapron Bertrand, Clavier Jacques (2015). Trophic connectivity between offshore upwelling and the inshore food web of Banc d’Arguin (Mauritania): New insights from isotopic analysis. Estuarine Coastal And Shelf Science, 165, 149-158. Publisher's official version : https://doi.org/10.1016/j.ecss.2015.05.001 , Open Access version : https://archimer.ifremer.fr/doc/00269/37999/