Publication

2009-08

English

http://archimer.ifremer.fr/doc/2009/publication-6589.pdf (0.20 Mo)

2009 Elsevier B.V. All rights reserved.

Lebreton Benoit¹, Richard Pierre¹, Radenac Gilles¹, Bordes Monique², Breret Martine¹, Arnaud Christophe³, Mornet Francoise³, Blanchard Gerard F.¹

1 : Univ La Rochelle, UMR Littoral Environm & Soc LIENSs, UMR 6250, CNRS,Inst Littoral & Environm, F-17042 La Rochelle, France.
2 : Univ La Rochelle, Ctr Commun Anal, FR EDD 3097, CNRS, F-17071 La Rochelle 9, France.
3 : IFREMER, CNRS, UMS ELA, UMS 3109, F-17137 Lhoumeau, France.

Aquatic Botany (0304-3770) (Elsevier), 2009-08 , Vol. 91 , N. 2 , P. 82-90

5

Biology, Ecology

SEM, Cocconeis spp., Epiphyte diatom, Microphytobenthos, Zostera noltii, Intertidal seagrass bed, Primary producer

The role of epiphytes in an intertidal Zostera noltii seagrass bed in Marennes-Oleron Bay was assessed in comparison with the other main benthic primary producers (Z. noltii, microphytobenthos) at two bathymetric levels and on a seasonal basis. Assemblage and biomass of epiphytes were studied using scanning electron microscopy (SEM). Z noltii and its detrital matter followed a typical seasonal pattern: microphytobenthos was present in large quantities throughout the year representing 21% of the total biomass while detrital matter, above-ground parts and below-ground parts accounted for 65, 9 and 5%, respectively. Only two species of epiphytic diatoms, Cocconeis scutellum and Cocconeis placentula, were observed on seagrass leaves. Epiphyte biomass was very low, representing on average less than 0.001% of that of microphytobenthos or leaves. This low epiphyte biomass is linked with the absence of macroalgae and also with the low biovolume of Cocconeis, which formed a monolayer of cells on leaves. This can be explained by the severe conditions of the intertidal and the high leaf turn-over of Z. noltii leaves. (C) 2009 Elsevier B.V. All rights reserved.