Marine Biology

, Volume 158, Issue 1, pp 193–203 | Cite as

How do nutrient conditions and species identity influence the impact of mesograzers in eelgrass-epiphyte systems?

  • Sybill JaschinskiEmail author
  • Ulrich Sommer
Original Paper


Coastal eutrophication is thought to cause excessive growth of epiphytes in eelgrass beds, threatening the health and survival of these ecologically and economically valuable ecosystems worldwide. Mesograzers, small crustacean and gastropod grazers, have the potential to prevent seagrass loss by grazing preferentially and efficiently on epiphytes. We tested the impact of three mesograzers on epiphyte biomass and eelgrass productivity under threefold enriched nutrient concentrations in experimental indoor mesocosm systems under summer conditions. We compared the results with earlier identical experiments that were performed under ambient nutrient supply. The isopod Idotea baltica, the periwinkle Littorina littorea, and the small gastropod Rissoa membranacea significantly reduced epiphyte load under high nutrient supply with Rissoa being the most efficient grazer, but only high densities of Littorina and Rissoa had a significant positive effect on eelgrass productivity. Although all mesograzers increased epiphyte ingestion with higher nutrient load, most likely as a functional response to the quantitatively and qualitatively better food supply, the promotion of eelgrass growth by Idotea and Rissoa was diminished compared to the study performed under ambient nutrient supply. Littorina maintained the level of its positive impact on eelgrass productivity regardless of nutrient concentrations.


Filamentous Alga Ambient Nutrient High Nutrient Supply Kiel Fjord Diatom Chain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We are grateful to S. Flöder for critical reading of the MS and helpful comments. Financial support was provided by the German Research Foundation (So 145/20).


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.IFM-GEOMAR Leibniz Institute of Marine SciencesKielGermany

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