de Beer, D.

Reise, Karsten

Volkenborn, Nils

English

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´Ecosystem engineering` in marine sediments:large scale permanent exclusion of the lugworm Arenicola marinaNils Volkenborn, Karsten Reise, Dirk de BeerAlfred Wegener Institutefor Polar- und Marine ResearchWadden Sea Station Syltcontact: nvolkenborn@awi-bremerhaven.deThe lugworm is a dominant bioturbating and bioirrigating polychaete in the Wadden Sea. A large scale, permanent lugworm exclusion experiment(6 times 400 m²) is designed to investigate direct and indirect effects of the lugworm on ecosytem functioning. Effects of lugworms on sediment properties:decreasing fraction of fine materiallowering organic contentincreasing permeabilitylowering Chlorophyll contentEffects of lugworms on biodiversity and benthiccommunity struture:fascilitation of bacterivor polychaetes and oligochaetestemporary inhibition of tube building polychaetesinhibition of bivalve recruitmentEffects of lugworms on biogeochemistry:washing out nutrients in the porewaterincreasing oxygen penetration depthlowering sulfide concentrationsPerspectives:This large scale lugworm exclusion experiment will be run for 8 more years. First results indicate the role of one single key species for ecosystem funtioning.On a total experimental area of 7200 m² the experiment offers opportunities for experts to contribute to this interesting field of interdisciplinary research on key species function, food web efficiency and ecosystem stability.First results indicate huge impacts of the lugworm on several components of the entire ecosystem. As an ecosystem engineer this polychaete alters sediment properties, sediment biogeochemistry and the benthic community structure. 20 meters Effects of lugworms on bird foragingpositive and negative response by different          bird specieslower foraging efficiencyExlusion plots, December 2002Chlorophyll 2003 (0-1cm)101520253035April May June August SeptemberChl µg/g dry sedimentExclusionControlReferenceexperimental setup: complete randomized block designNereis diversicolor02505007501000Exclosure Control AmbientInd. / m²Scoloplos intertidalis0100200300Exclosure Control AmbientInd. / m²200 300 400 500 600 700 800 900Time (minutes)Sulfide on lugworm exclusion plots-100-50depth(mm)sulfideconcentration

´Ecosystem engineering` in marine sediments: large scale permanent exclusion of the lugworm Arenicola marina

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