In vitro experimental assessment of the grazing pressure of two gastropods on Zostera marina L. ephiphytic algae
Hily, C.; Connan, S.; Raffin, C.; Wyllie-Echeverria, S. (2004). In vitro experimental assessment of the grazing pressure of two gastropods on Zostera marina L. ephiphytic algae. Aquat. Bot. 78(2): 183-195. http://dx.doi.org/10.1016/j.aquabot.2003.10.001
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770; e-ISSN 1879-1522, more
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| Keywords |
ANE, France, Brittany, Brest Bay
Aquatic organisms > Heterotrophic organisms > Herbivores
Behaviour > Feeding behaviour > Grazing
Epibionts > Epiphytes
Flora > Weeds > Marine organisms > Seaweeds > Sea grass
Periodicity > Seasonality
Research > Experimental research
Gibbula umbilicalis (da Costa, 1778) [WoRMS]; Jujubinus striatus (Linnaeus, 1758) [WoRMS]; Zostera marina Linnaeus, 1753 [WoRMS]
Bay of Brest [Marine Regions]
Marine/Coastal |
| Author keywords |
seagrass; snails; microherbivores; epiphytic algae; seasonality |
| Authors | | Top |
- Hily, C.
- Connan, S.
- Raffin, C.
- Wyllie-Echeverria, S.
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| Abstract |
This study experimentally assessed the impact of gastropod grazing on epiphyton biomass and taxonomic composition on leaves of the seagrass Zostera marina L. along the coasts of Brittany, France. Image analysis was used to measure the same section of a leaf before and after grazing and assess grazing pressure. It was found that: (1) both grazers, Gibbula umbilicalis and Jujubinus striatus, were highly efficient in reducing epiphytic cover; (2) J. striatus showed a higher specific grazing rate than G. umbilicalis at an equivalent animal biomass; (3) J. striatus increased its activity when epiphytic biomass increased. Analysis of the variability of epiphytic cover along the leaves showed considerable heterogeneity from the basal part of the external leaves of a shoot to the apex. The development of long filamentous algae (mainly ectocarpales) in spring and summer and their concentration at the apex intensified shading impact on the seagrass bed. The grazing of both gastropod species was also concentrated at the apex, thereby enhancing their role in moderating the shading effect. |
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