Interacting effects of Hydrobia ulvae bioturbation and microphytobenthos on the erodibility of mudflat sediments

Autor: Pierre-Guy Sauriau, Lucette Joassard, Pierre Le Hir, Francis Orvain, Angélique Sygut
Přispěvatelé: Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Centre de Recherche sur les Ecosystèmes Marins et Aquacoles (CREMA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Région Poitou-Charente, CNRS, IFREMER, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Dynamiques de l'Environnement Côtier (DYNECO)
Jazyk: angličtina
Rok vydání: 2004
Předmět:
Zdroj: Marine Ecology Progress Series
Marine Ecology Progress Series, 2004, 278, pp.205-223. ⟨10.3354/meps278205⟩
Marine Ecology Progress Series, Inter Research, 2004, 278, pp.205-223. ⟨10.3354/meps278205⟩
Marine Ecology Progress Series (0171-8630) (Inter-Research), 2004-09, Vol. 278, P. 205-223
ISSN: 0171-8630
1616-1599
Popis: International audience; Microphytobenthos-macrofauna sediment interactions and their effects on sediment erodability were examined in laboratory experiments. Sediment beds were manipulated in a tidal mesocosm to produce diatom mats in exponential or in stationary phases of development after 6, 8 or 11 d of culture. These sediment beds were used in flume experiments to investigate the influence of bioturbation by the gastropod Hydrobia ulvae on both sediment and pigment resuspension as a function of the physiological state of the microphytobenthic mats. In most experiments, only a surface layer was resuspended. A model was used to analyse in detail the contribution of each variable to this surface-layer erosion. Bioturbation was the major factor controlling resuspension, and its extent was influenced by sediment density and the growth stage of the microphytobenthos. The amount and extent of bioturbation is assumed to be influenced by sediment density and chlorophyll a content. Snail bioturbation can, in turn, influence the amount of microalgal resuspension. The quantity of pigment resuspended due to bioturbation increased by a factor of 15 when the diatom mats were in exponential growth stages. However, as the age of the mat increased, the influence of bioturbation on pigment resuspension declined. When the mats became senescent, Type I erosion occurred with erosion rates high enough to obscure any effects of bioturbation. To summarise, we assume that there are 2 causes of microphytobenthos resuspention, depending on the physiological state of the mat: (1) in the exponential phase, bioturbation substantially affects the resuspension of pigments which are present in the surface layer (the biogenic fluff layer) and (2) in the senescent phase, the increase in bed roughness and water content renders the mat fragile, leading to bed erosion.
Databáze: OpenAIRE
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