´Ecosystem engineering` in marine sediments:
large scale permanent exclusion of the lugworm Arenicola marina
Nils Volkenborn, Karsten Reise, Dirk de Beer
Alfred Wegener Institute for Polar- und Marine Research Wadden Sea Station Sylt contact:
nvolkenborn@awi-bremerhaven.de
The 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 material lowering organic content
increasing permeability lowering Chlorophyll content
Effects of lugworms on biodiversity and benthic community struture:
fascilitation of bacterivor polychaetes and oligochaetes temporary inhibition of tube building polychaetes
inhibition of bivalve recruitment
Effects of lugworms on biogeochemistry:
washing out nutrients in the porewater increasing oxygen penetration depth
lowering sulfide concentrations
Perspectives:
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 foraging positive and negative response by different bird species
lower foraging efficiency
Exlusion plots, December 2002
Chlorophyll 2003 (0-1cm)
10 15 20 25 30 35
April May June August September
Chl µg/g dry sediment
Exclusion Control Ref erence
experimental setup: complete randomized block design
Nereis diversicolor
0 250 500 750 1000
Exclosure Control Ambient
Ind. / m²
Scoloplos intertidalis
0 100 200 300
ExclosureControl Ambient
Ind. / m²
200 300 400 500 600 700 800 900
Time (minutes) Sulfide on lugworm exclusion plots
-100 -50
depth(mm) sulfideconcentration
