Reference : Impact of grazing by amphipods on the epiphytic cover of the Posidonia oceanica leaves: ...
Scientific congresses and symposiums : Poster
Life sciences : Aquatic sciences & oceanology
Life sciences : Environmental sciences & ecology
Life sciences : Zoology
http://hdl.handle.net/2268/77174
Impact of grazing by amphipods on the epiphytic cover of the Posidonia oceanica leaves: an in situ experiment.
English
Michel, Loïc mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Systématique et diversité animale >]
Dupont, Alessandra mailto [ > > ]
Gobert, Sylvie mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
Dauby, Patrick mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Systématique et diversité animale >]
Lepoint, Gilles mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
22-Oct-2010
A0
No
No
International
17th Benelux Congress of Zoology
22-23/10/2010
Universiteit Gent
Gent
Belgique
[en] amphipod ; grazing ; posidonia ; functional ecology ; ecosystem functioning ; epiphytes
[en] It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled in vitro conditions, three amphipod taxa (Apherusa chiereghinii,Dexamine spiniventris and Gammarus spp.) are able to drastically deplete the biomass of erected algae, thus influencing the epiphytic cover in both a quantitative and a qualitative way. Here, we tried to assess whether this strong and complex trophic interaction was realized in the field. We designed an in situ experiment that used microcosms placed directly in the meadow, at a depth of 10m, to estimate the impact of grazing by the aforementioned amphipod taxa on the dynamics of the epiphytic cover. Both Gammarus spp. and Dexamine spiniventris caused a significant decrease of the biomass of erected algae and erected animals (bryozoans and hydrozoans). Impact of grazing by Apherusa chiereghinii on these two epiphytic groups was less important, although strong but marginally non-significant (0,1>p>0,05) trends to lower biomasses were present. None of the considered taxa seemed to consume encrusting macro-epiphytes. In addition, assimilation of epiphyte-derived carbon and nitrogen by grazers was monitored using stable isotopes (13C and 15N), and epiphyte elemental content (C & N) was measured. Our results shed light on trophic interactions between the amphipods from Posidonia oceanica meadows and the seagrass epiphytic cover, and thus enhance our understanding of the role of these grazers in the functioning of the meadow as an ecosystem.
Centre Interfacultaire de Recherches en Océanologie - MARE
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/77174

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