The development of a test bed and the investigation of the influence of marine vegetation on supporting structures of offshore wind turbines; Project: Experimental investigations of marine growth on test bodies.

The goals of the “EnviSim4Mare”-project include the development of growth monitoring of marine invertebrates on test bodies, including the taxonomic determination of the species communities and the documentation of their succession and dominance in order to achieve the final goal to determine their surface roughness.

As part of this project, test bodies will be mounted on a buoy in the Außenweser (Outer Weser) (north of the wind farm “Nordergründe”, near “Alte Weser”) and at the material test station in Helgoland in order to document the surveys described above. The test bodies are metallic pipes and plates, which are intended to reflect the surfaces of wind farm elements (pile).

In this approach, the growth and the seasonal succession of biofouling-communities on the test bodies shall be documented from the uppermost water layers (including the splash water zone) to the depths of 2-3 m above the seabed (test bodies will be mounted in two or three different depth layers). This depth profile must be considered, as previous studies indicated that depth-related light conditions and other abiotic parameters (e.g. waves, currents) can affect the growth and composition of the vegetation. While an already installed test station can be used for the investigations in Helgoland, an anchorage for the buoy and the racks for the test bodies must be developed for the studies in open water at Nordergründe. While some of the test bodies remain on the racks for one or two years, the remaining bodies are sampled monthly (April - October). The removed test bodies are analysed in the laboratory according to the criteria mentioned above.

A closed circulation system (Recirculating Aquaculture System (RAS)) is developed and installed in order to hold the vegetation communities on the test bodies under natural flow conditions in the laboratory. This also applies to the test bodies taken once a year and used later in a newly built seawater flow channel (Leichtweiß-Institute for Hydraulic Engineering and Water Resources (LIW), Braunschweig) to determine force coefficients. This approach intends to provide information on the wave and load flows changed by the vegetation on the artificial structures introduced.

This project is funded by the Federal Ministry for Economic Affairs and Energy (BMWi) (Funding code: 03SX495B). The administration of the grant is carried out by the project management agency (Research Center Jülich GmbH, Department of Maritime Technologies).



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36 months

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Research, Industry, ministries, regulators