Coates, D.

Vanaverbeke, J.

Vincx, M.

Open Marine Archive

A historical view of the macrobenthic communities on the 
Thorntonbank and Goote Bank 
Coates Delphine, Jan Vanaverbeke and Magda Vincx  
Research Group Marine Biology, Biology Department, Ghent University, Krijgslaan 281, S8,  
B-9000 Ghent, Belgium 
E-mail: Delphine.coates@ugent.be   
The first offshore wind farm in the Belgian part of the North Sea became functional in May 2009 on 
the Thorntonbank. This sandbank is situated 27km offshore and contains coarse, sandy sediments 
with a relatively poor macrobenthic community, dominated by a few species (Reubens et al., 2009).  
In 2005, a monitoring programme was initiated to determine the baseline situation of the soft-
sediment macrobenthos in this area (De Maersschalck et al., 2006). Since 2008, samples have been 
taken yearly to determine any primary impacts on the community that could have arisen during and 
after construction. However, before any impacts can be detected it is crucial to understand the long-
term natural fluctuations of the macrobenthic communities as a result of sediment movements, 
plankton blooms, eutrophication, industrial and fishing activities or even climate change. Any 
impacts caused by the construction of offshore wind farms can subsequently be separated from 
natural fluctuations in the macrobenthic community (Hiscock et al., 2002).  
 
The historical and recent monitoring data were integrated into the Marine Biology Macrobenthos 
database (Macrodat) which contains information on macrobenthic densities together with relevant 
abiotic factors such as median grain size, total organic matter content and temperature. A temporal 
analysis was carried out over a period of approximately 30 years starting from 1979 until 2005 for 
the Thorntonbank and 1980 until 2011 for the Goote Bank (reference stations). Only samples taken 
during autumn were analysed as macrobenthic densities can differ greatly between seasons. The 
data was analysed at different levels to study the reaction at station and sandbank level and 
integrate the habitat suitability communities. These communities were characterised by means of 
sedimentological characteristics (median grain size and mud content) and can be divided into four 
groups: the Nephtys cirrosa, Abra alba, Ophelia limacina and Macoma balthica community 
(Van Hoey et al., 2004; Degraer et al., 2009).  
 
 
References 
De Maersschalck V., K. Hostens, J. Wittoeck, K. Cooreman, M. Vincx, and S. Degraer. 2006. 
Monitoring van de effecten van het Thornton windmolenpark op de benthische macro-
invertebraten en de visfauna van het zachte substraat. p.136. 
Degraer S., U. Braeckman, J. Haelters, K. Hostens, T. Jacques, F. Kerckhof, B. Merckx, M. Rabaut, 
E. Stienen, G. Van Hoey, V. Van Lancker and M. Vincx. 2009. Studie betreffende het opstellen 
van een lijst met potentiële Habitatrichtlijn gebieden in het Belgische deel van de Noordzee. . 
Eindrapport in opdracht van de Federale Overheidsdienst Volksgezondheid, Veiligheid van de 
Voedselketen en Leefmilieu, Directoraat-generaal Leefmilieu. Brussel, België. p.93. 
Hiscock K., H. Tyler-Walters and H. Jones. 2002. High level environment screening study for 
offshore wind farm developments - marine habitats and species project. Report from the Marine 
Biological Association to the Department of Trade and Industry New & Renewable Energy 
Programme. (AEA Technology, Environment Contract: W/35/00632/00/00). p.156. 
Reubens J., S. Vanden Eede and M. Vincx. 2009. Monitoring of the effects of offshore wind farms on 
the endobenthos of soft substrates: Year-0 Bligh Bank and Year-1 Thorntonbank. In: Offshore 
wind farms in the Belgian part of the North Sea: State of the art after two years of 
environmental monitoring. Degraer S and R. Brabant (Eds). Chapter 6, p.61-91. Royal Belgian 
Institute for Natural Sciences, Management Unit of the North Sea Mathematical models.  
Van Hoey G., S. Degraer and M. Vincx. 2004. Macrobenthic community structure of soft-bottom 
sediments at the Belgian Continental Shelf. Estuarine, Coastal and Shelf science 59:599-613. 
 
 
 
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A historical view of the macrobenthic communities on the Thorntonbank and Goote Bank

Management Unit of the North Sea  
Mathematical Models, Belgium 
 

Primer v6 MDS plot averaged Thorntonbank data
Transform: Square root
Resemblance: S17 Bray Curtis similarity
Year
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2010
1979
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19982005
2008
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2010
2D Stress: 0,13
1979
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Year
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 Thorntonbank  Goote Bank


A historical view of the macrobenthic communities on the Thorntonbank and Goote Bank

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