Spatiotemporal changes in surface sediment characteristics and benthic macrofauna composition off the Rhône River in relation to its hydrological regimeReportar como inadecuado




Spatiotemporal changes in surface sediment characteristics and benthic macrofauna composition off the Rhône River in relation to its hydrological regime - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

* Corresponding author 1 LECOB - Laboratoire d-Ecogéochimie des environnements benthiques 2 EPOC - UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux 3 OOB - Observatoire océanologique de Banyuls 4 CEFREM - Centre de formation et de recherche sur l-environnement marin 5 CRIOBE - Centre de recherches insulaires et observatoire de l-environnement

Abstract : The consequences of changes in the water flow of the Rhône River on surface sediment characteristics and benthic macrofauna composition were assessed within 3 distinct areas: 1 the delta front, 2 the prodelta, and 3 the distal zone. Five stations were sampled during or closely after: 1 an oceanic flood April 2007, 2 a generalized flood May 2008, 3 a Cevenol flood December 2008, and 4 a dry period July 2011. Measurements of sediment characteristics included granulometry D0.5, bulk descriptors of sedimentary organics OC, TN and THAA, descriptors of labile components of sedimentary organics chloropigments, EHAA, and both descriptors of origin Chl-b-Chl-a, C-N and lability Chl-a-Chl-a+Phaeo-a, EHAA-THAA of sedimentary organics. Sediment Profile Images were collected during April 2007, May 2008 and July 2011. Temporal changes in both sedimentary organics and benthic macrofauna were more important in the delta front and the prodelta than in the distal zone. Bulk characteristics of sedimentary organics presented decreasing inshore-offshore gradients during both April 2007 and July 2011 but not during May and December 2008. There were significant temporal changes in EHAA-THAA at all stations. Changes in benthic macrofauna composition differed between: 1 the delta front and the prodelta, and 2 the distal zone. In the former area, the dry period was associated with establishing a mature community characterized by high abundances and species richness. The best description of spatiotemporal changes in benthic macrofauna composition by surface sediment characteristics was obtained using D0.5, Chl-b-Chl-a, Chl-a-Chl-a+Phaeo-a and EHAA, which supports the role of the quality of sedimentary organics in controlling benthic macrofauna composition.

Keywords : Mediterranean Sea Rhône River floods temporal variations particulate organic matter zoobenthos





Autor: Paulo Bonifácio - Solveig Bourgeois - Céline Labrune - Jean-Michel Amouroux - Karine Escoubeyrou - Roselyne Buscail - Alicia Ro

Fuente: https://hal.archives-ouvertes.fr/



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