Soetaert, K.

Van Colen, C.

Vanaverbeke, J.

Vlaminck, E.

Open Marine Archive

 126 
Macrobenthos-mediated nutrient cycling in offshore wind farm 
environments under future ocean climate settings 
Vlaminck Ellen
1
, Vanaverbeke Jan
2
, Soetaert Karline
3
 and Van Colen Carl
3 
1
  Marine Biology Research Group, Biology Department, Ghent University, Krijgslaan 281 S8, 9000 
Ghent, Belgium 
 E-mail: evlaminc.Vlaminck@UGent.be 
2
  Royal Belgian Institute of Natural Sciences, Operational Directorate Natural Environment, 
Gulledelle 100, 1200 Brussels, Belgium 
3
  Royal Netherlands Institute for Sea Research (NIOZ), Korringaweg 7, 4401 NT Yerseke, The 
Netherlands 
 
The installation of offshore wind farms (OWFs) in the Belgian part of the North Sea (BPNS) introduces 
large surfaces of artificial hard substrates (AHSs). These AHSs are expected to modify the physico-
chemistry and ecology of the adjacent seabed due to, among others, altered hydrodynamics and 
organic enrichment originating from the OWF fouling fauna and proposed aquaculture activities in 
the OWF concession areas. In addition to local habitat changes associated with the AHSs, global 
climate change stressors such as ocean warming and acidification also challenge coastal ecosystems. 
They can, for example, influence the benthic communities and the way in which the (affected) 
biodiversity contributes to ecosystem services such as biogeochemical cycling. Through bioturbation 
and bio-irrigation, macrofauna reworks the sediment and alters both the physical structure and 
chemical composition, often facilitating microbial activity and removal of nitrogen via coupled 
nitrification-denitrification processes. A consequence of this process is, however, the production of 
the potent greenhouse gas nitrous oxide (N2O), produced during nitrification and denitrification. 
Hence there is a need for knowledge on the cumulative effect of local anthropogenic impacts 
associated with OWFs and global climate change on the coastal ecosystem and the effect on the 
production of the greenhouse gas N2O. 
 
The project PERSUADE (ExPERimental approaches towards Future Sustainable Use of North Sea 
Artificial HarD SubstratEs) aims to investigate ecosystem-wide responses to combined global and local 
stressors and the effect on the production of N2O in a future climate setting. This will be investigated 
by quantifying the interactions between the biotic and abiotic compartments in an OWF environment. 
We therefore consider both the fouling and soft substrate fauna and their effect on nitrogen cycling. 
A four-step approach is envisaged to provide an empirically based, mechanistic understanding of the 
biogeochemical response of the benthic environment to the installation of OWFs. First, the 
behavioural activities that are relevant for mediation of biogeochemical cycling (i.e. particle mixing, 
burrow ventilation, feeding) will be investigated by recording hydraulic porewater signatures in the 
polychaete Lanice conchilega and the bivalves Ensis directus and Abra alba. These species are 
expected to represent dominant members of the benthic community in the OWF environment in the 
BPNS. Secondly, the effect of density and allometry of these species on the N2O production will be 
studied. The developed techniques and insights gained in the first two parts of the project will then 
be used to study the benthos-mediated biogeochemical cycling under future ocean conditions. 
Organisms will be incubated under different climatic conditions (higher temperatures and lower pH) 
and their behavioural responses will be observed. To determine the effect on nutrient cycling, oxygen 
consumption rates will be determined and the solutes exchange across the sediment-water interface 
will be measured. Finally, the acquired results will be incorporated in the development of a model to 
investigate and predict the long-term production of the greenhouse gas N2O in OWF environments 
under future climate scenarios. 
 
Keywords: macrobenthos; ocean acidification; ocean warming; offshore-windfarms; aquaculture; 
biogeochemical cycling  


Macrobenthos-mediated nutrient cycling in offshore wind farm environments under future ocean climate settings

http://www.vliz.be/imisdocs/publications/311620.pdf

Macrobenthos-mediated nutrient cycling in offshore wind farm environments under future ocean climate settings

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