Open Marine Archive

Vanaverbeke, J.

Braeckman, U.

De Borger, E.

Mavraki, N.

Toussaint, E.

Voet, H.

Van Colen, C.

Degraer, S.

-  62  -  
Oral presentation Science in the North Sea 
Interactions between biological and physical effects modify 
local biogeochemical cycling processes in offshore wind farms 
Vanaverbeke Jan
1,2
, Braeckman Ulrike
2
, De Borger Emil
3
, Mavraki Ninon
4
, Toussaint Elise
1,2
, Voet Helena
1,2
, 
Van Colen Carl
2
 and Degraer Steven
1
 
1
  Royal Belgian Institute of Natural Sciences, Operational Directorate Natural Environment, MARECO, 
Gulledelle 100,1200 Brussels, Belgium 
E-mail: jvanaverbeke@naturalsciences.be  
2
  Marine Biology Research Group, Ghent University, Krijgslaan 281/S8, 9000 Gent, Belgium 
3
  Royal Netherlands Institute for Sea Research (NIOZ), Korringaweg 7, 4401 NT Yerseke, Netherlands 
4 
Royal Belgian Institute of Natural Sciences, Operational Directorate Natural Environment, MARECO, 
3de en 23ste Linie Regimentsplein, 8400 Oostende, Belgium  
 
In order to meet the increasing demand for renewable energy production, many European countries have 
installed offshore wind farms (OWFs), thereby introducing large surfaces of artificial hard substrates in 
marine areas often exclusively consisting of sandy sediments. Near the sea surface, these artificial 
communities are dominated by the blue mussel (Mytilus edulis : 18-38 kg m
-2
). Below this mussel belt, 
the amphipod Jassa herdmanni is the dominant organism (minimum 10 000 ind. m
-2
). In order to 
investigate the functional importance of these new communities, we performed clearance rates 
experiments and found that both M. edulis (0.27 l gDWT
-1
 h
-1
) and female J. herdmanni (0.12 l gDWT
-1
 h
-
1
) act as important filter feeders. Given their high densities on the turbines, this result in the filtering of 
more than 500 000 l of seawater by the OWF fouling fauna of 1 gravity-based foundation each day. The 
subsequent production of detritus and (pseudo)faeces by the fouling fauna creates a continuous 
additional source of organic matter to the often permeable sediments. Our detailed study in the vicinity 
of a wind turbine in the North Sea revealed an increase in organic matter, a fining of the sediments and 
a change from a species-poor to a species-rich benthic community dominated by the ecosystem engineer 
Lanice conchilega. Our experiments on the effects of the physical fining of the sediments revealed a 
decreased penetration depth of advective water currents, a reduced trapping of diatoms and a decreased 
mineralization efficiency. Large densities of L. conchilega further result in an increased trapping of fines, 
accelerating the physical changes in the sediment matrix caused by increased deposition rates. As such, 
benthic degradation of organic matter will then no longer be governed by physical processes, but 
mediated by biological processes (bioturbation, bio-irrigation). As a consequence, the introduction of 
fouling communities on artificial hard substrates in the water column will be reflected in the sea-floor 
functioning through a shift from permeable sediments with very efficient mineralization processes 
towards sediments where organic matter can be accumulated for longer periods. 
 
Keywords: North Sea; offshore wind farms, ecosystem functioning 
  


Interactions between biological and physical effects modify local biogeochemical cycling processes in offshore wind farms

-  51  -  
Oral presentation Science in the North Sea 
Functional characteristics of the food web of artificial hard substrates of 
offshore wind farms along a depth gradient 
Mavraki Ninon
1
, Degraer Steven
2-3
 and Vanaverbeke Jan
2-3
 
1 
Marine Ecology and Management, Operational Directorate Natural Environment, Royal Belgian 
Institute of Natural Sciences, 3de en 23ste Linie Regimentsplein, 8400 Oostende, Belgium  
  E-mail: nmavraki@naturalsciences.be  
2 
Marine Ecology and Management, Operational Directorate Natural Environment, Royal Belgian 
Institute of Natural Sciences, Gulledelle 100, 1200 Brussels, Belgium  
3 
Marine Biology Research Group, Department of Biology, Ghent University, Krijgslaan 281/S8, 9000 
Ghent, Belgium  
 
The establishment of man-made structures, such as offshore wind farms, provides hard substrates to 
naturally soft-bottom areas. Hard substrate fauna rapidly colonizes this new habitat, altering the natural 
biodiversity and thus affecting both ecosystem structure and functioning, e.g. food web interactions. 
The aim of the present study is to investigate the structural and functional food web characteristics along 
a depth gradient on a wind turbine in the Belgian part of the North Sea. For this purpose, macrofaunal 
organisms were collected at six different ecological zones along a depth gradient on a gravity-based 
wind turbine: (a) the intertidal zone, (b) the Mytilus edulis zone (~ 5 m water depth), (c) the Jassa 
herdmani zone (8-9 m water depth), (d) the Metridium dianthus zone (15-25 m water depth), (e) the 
erosion protection layer (EPL) and (f) the nearby soft substrate. All organisms were identified at the lowest 
possible taxonomic level and processed for stable isotope analysis (δ15N and δ13C). Based on stable 
isotope signals, the organisms form the seven zones were classified into eight functional groups. δ15N 
values showed that the variation in trophic position ranges was high between different ecological depth 
zones, with the EPL community showing the highest range (2.36 – 6.59), whereas the narrowest range 
was observed by the intertidal community (1.89 – 3.33). The high range for the EPL community suggests 
a possible relation between trophic position and mobility of the organisms. Overall, the structural 
difference in the fouling communities was partly reflected in other food-web characteristics (Layman 
indices) of the fouling communities: the intertidal food web is clearly different from the more 
homogeneous deeper parts which changed gradually with depth. This can be partly explained by the 
trophic plasticity of particular species, such as the anemone Metridium dianthus and the brittle star 
Ophiothrix fragilis which shift food sources and trophic positions depending on the zone they inhabit. 
This study corroborates the hypothesis that there is structural and isotopic variation of the food web 
along the depth gradient at a wind turbine; however, this is not reflected in the functional characteristics 
of the communities, indicating a more complex utilization of food sources and trophic level occupation. 
 
Keywords: stable isotope analysis; artificial hard substrates; trophic interactions  
 
  


Functional characteristics of the food web of artificial hard substrates of offshore wind farms along a depth gradient

Vlaminck, E.

Soetaert, K.

Moens, T.

-  65  -  
Poster Science in the North Sea 
Macrobenthos-mediated nutrient cycling in offshore windmill farm 
environments under future ocean climate settings 
Vlaminck Ellen
1
, Vanaverbeke Jan
2
, Soetaert Karline
3
, Moens Tom
1
 and Van Colen Carl
1
 
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 fouling OWF fauna and proposed aquaculture activities in the OWF 
concession area. 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 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 need for knowledge on the 
cumulative effect of local anthropogenic impacts associated with OWFs and global climate change on the 
coastal ecosystem and its 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, 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 OWF. 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 exchanges 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 windmill farm environments under future ocean climate settings

Benedetti Cecchi, L.

Crowe, T.

Boehme, L.

Boero, F.

Christensen, A.

Grémare, A.

Hernandez, F.

Kromkamp, J.C.

Nogueira García, E.

Petihakis, G.

Sousa Pinto, I.

Zingone, A.

 -  116  -  
Poster General session 
European Marine Board expert working group’s recommendations to 
strengthen Europe's capability in biological ocean observations 
Benedetti Cecchi Lisandro
1
, Crowe Tasman
2
, Boehme Lars
3
, Boero Ferdinando
4
, Christensen Asbjørn
5
, 
Grémare Antoine
6
, Hernandez Francisco
7
, Kromkamp Jacco C.
8
, Nogueira García Enrique
9
, Petihakis 
George
10
, Sousa Pinto Isabel
11
 and Zingone Adriana
12 
1
  University of Pisa, Lungarno Pacinotti 43, 56126 Pisa, Italy 
E-mail: lbenedetti@biologia.unipi.it  
2
  University College Dublin, Belfield, Dublin 4, Ireland  
3
  University of Saint Andrews, College Gate, Saint Andrews KY16 9AJ, Fife, Scotland, United Kingdom  
4
  University of Salento, Piazza Tancredi 7, 73100 Lecce, Italy  
5
  Technical University of Denmark, National Institute of Aquatic Resources, DTU Aqua, Kemitorvet, 
Building 202, 2800 Kgs. Lyngby, Denmark  
6
  Station Marine d’Arcachon, University of Bordeaux, 2 Rue du Professeur Jolyet, 33120 Arcachon 
CEDEX, France  
7
  Flanders Marine Institute (VLIZ), Wandelaarkaai 7, 8400 Oostende, Belgium  
8
  Royal Netherlands Institute for Sea Research, NIOZ, PO Box 140, 4400 AC Yerseke, The Netherlands  
9
  Instituto Español de Oceanografía, IEO, Calle del Corazón de María 8, 28002 Madrid, Spain  
10
  Hellenic Centre for Marine Research, P.O. Box 712, P.C. 19013 Anavyssos, Attiki, Greece  
11
  University of Porto, Reitoria da U. Porto, Praça Gomes Teixeira, 4099-002 Porto, Portugal  
12
  Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy  
 
Biological ocean observations, in addition to current physical and chemical observations, are necessary 
to help understand the structure and functioning of marine ecosystems, to determine patterns and trends 
of biodiversity and to be able to inform the sustainable use of the ocean’s living resources. Only by 
integrating sustained biological observations within monitoring programs, it will be possible to 
understand our changing oceans and to implement flexible management strategies that will adapt to 
evolving scenarios of societal and environmental change. The biological Essential Ocean Variables (EOVs) 
of the Global Ocean Observing System (GOOS), and the marine Essential Biodiversity Variables (EBVs) of 
the Group on Earth Observations Biodiversity Observation Network (GEO BON), are welcomed initiatives 
towards this integration. 
 
Enhanced biological ocean observing capacity is needed to strengthen the European vision of marine 
biodiversity conservation and to fulfil the European Union goal of “Good Environmental Status” for all its 
marine waters, as stated in the Marine Strategy Framework Directive and other legislative initiatives 
seeking a healthy and sustainable managed marine environment. As most of the observing requirements 
in Europe have regional scale characteristics, observing networks must be sustained and adjustable to 
the observing requirements. Technological progress will allow for flexible approaches, improving 
existing observing methodologies and broadening the scope and range of variables that can be 
measured. 
 
A long-term, large-scale integrative biological observing system spanning over both oceanic and coastal 
systems is of fundamental value in expanding knowledge of the world in which we live and in the context 
of current shorter term fluctuations. Observation networks will also fulfil a critical strategic need for 
predictions and a more informed basis for environmental policy to safeguard our natural heritage and to 
guarantee the sustainable use of ocean living resources by multiple users and stakeholders, bringing 
benefits now and for future generations. 
 
Keywords: biology, observations, monitoring, EOOS, EOVs, EBVs 
  


European Marine Board expert Working Group's recommendations to Strengthen Europe's Capability in Biological Ocean Observations-

Baert, J.

Stienen, E.

Heylen, B.

Kavelaars, M.

Buijs, R.-J.

Shamoun-Baranes, J.

Lens, L.

Müller, W.

-  73  -  
Oral presentation Science in a modern era 
Migratory routes and stopover sites of the Lesser Black-backed Gull: 
Where to go if your options are endless? 
Baert Jan
1,2
, Stienen Eric
3
, Heylen Brigitte
1-2
, Kavelaars Marwa
1-2
, Buijs Roland-Jan
4
, Shamoun-Baranes Judy
5
, 
Lens Luc
2
 and Müller Wendt
1 
1
  Behavioral Ecology and Ecophysiology Research group, Antwerp University, Universiteitsplein 1, 2610 
Wilrijk, Belgium 
E-mail: jan.baert@ugent.be 
2
  Terrestrial Ecology Unit, Ghent University, Lendegackstraat 35, 9000 Ghent, Belgium 
3
  Research Institute for Nature and Forest (INBO), Havenlaan 88 box 73, 1000 Brussels, Belgium 
4
  Buijs Eco Consult B.V., Philips van Dorpstraat 49, 4698 RV Oud-Vossemeer, The Netherlands 
5
  Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, P.O. Box 94248, 
1090GE Amsterdam, The Netherlands 
 
Long-distance migration has evolved in many genera of birds to cope with spatio-temporal fluctuations 
in the environment (1). This allows them to complete their annual cycle under favourable conditions, for 
example by taking advantage of seasonal peaks in food availability (2). Within species, populations have 
typically well-defined migration routes, stopover sites and wintering areas (3). However, in individuals 
may still differ in their choice of wintering areas in relation to age, size or sex, which is referred to as 
differential migration (4). 
 
Lesser Black-backed Gulls (Larus fuscus) show pronounced individual variation in migration strategies 
with some birds wintering as close as Northern France or Southern England, while others migrate as far 
south as Senegal (5–7). In addition, Lesser Black-backed Gulls have in the past century progressively 
adapted to anthropogenic food sources, taking advantage of new feeding opportunities in agricultural 
and urban habitats, next to their historic marine habitat (8). Hence, their options to select winter and 
stopover sites are nowadays almost endless. 
 
In this study we used 5 years of GPS tracking data of adult Lesser Black-backed Gulls breeding in the 
southern bight of the North Sea to investigate the movements and temporal dynamics in habitat selection 
outside the breeding season. We did not find differences in migration routes and wintering areas between 
sexes. However, males and females differed significantly in their timing and use of stopover sites 
Differential migration hence occurred during autumn migration. It took females on average 15 days 
longer to reach their wintering sites than males. During autumn migration, females made more extensive 
use of stopover sites, in particular in North France and the UK where they almost exclusively foraged in 
agricultural areas. Males, in contrast, did not significantly alter their diet during autumn migration. This 
shift in habitat use and protracted autumn migration coincided with the timing of moult, which overlaps 
with chick rearing and migration in the Lesser Black-backed Gull. Our results suggest that this overlap 
between energy-demanding activities may cause females to perform a more prolonged autumn migration 
and select different foraging habitats during autumn migration.   
 
References 
1 Berthold, Bird migration: a general survey (Oxford University Press, Oxford, 2001). 
2 Alerstam et al. Long-distance migration: evolution and determinants. Oikos. 103, 247–260 (2003). 
3 Newton, The migration ecology of birds (Elsevier, London, 2007). 
4 Ketterson and Nolan, in Current Ornithology, R. F. Johnston, Ed. (Plenum Press, New York, 1983), pp. 
357–402. 
5 Bosman et al., Effects of body size on sex-related migration vary between two closely related gull 
species with similar size dimorphism. Ibis 154, 52–60 (2012). 
6 Shamoun-Baranes et al., Short distance migrants travel as far as long distance migrants in lesser 
black-backed gulls Larus fuscus. J. Avian Biol. 48, 49–57 (2017). 
7 Klaassen et al., Migration strategy of a flight generalist, the Lesser Black-backed Gull Larus fuscus. 
Behav. Ecol. 23, 58–68 (2012). 
8 Camphuysen et al., Sexually distinct foraging strategies in an omnivorous seabird. Mar. Biol. 162, 
1417–1428 (2015). 
 
Keywords: gulls; migration; gps; tracking; timing; habitat 
  


Migratory routes and stopover sites of the Lesser Black-backed Gull: where to go if your options are endless?

Boicenco, L.

Abaza, V.

Bailly, N.

Bisinicu, E.

Culcea, O.

Dumitrache, C.

Harcota, G.

Filimon, A.

Oset Garcia, P.

Pantea, E.

Tabarcea, C.

Timofte, F.

-  17  -  
Poster Science from a historical perspective 
A database of benthos and plankton in Romanian Black Sea waters  
Boicenco Laura
1
, Abaza Valeria
1
, Bailly Nicolas
2
, Bisinicu Elena
1
, Culcea Oana
1
, Dumitrache Camelia
1
, 
Harcota George
1
, Filimon Adrian
1
, Oset Garcia Paula
3
, Pantea Elena
1
, Tabarcea Cristina
1
 and Timofte Florin
1 
1
  National Institute for Marine Research and Development “Grigore Antipa” (NIMRD), 300 Mamaia Bdv., 
Constanta 900581, Romania 
E-mail: lboicenco@alpha.rmri.ro  
2
  Hellenic Centre for Marine Research (HCMR), Athinon-Souniou Av, P.O. Box 712, Greece 
3
  Flanders Marine Institute (VLIZ), Wandelaarkaai 7, 8400 Oostende, Belgium  
 
Since 1956 several large benthos and plankton datasets had been collected in Romanian Black Sea waters, 
but they remained mostly unavailable to the wider research community. The aim of gathering and 
electronically archiving these historical data sets on marine biodiversity was to save and quality check 
them and render accessible for future spatial and temporal analyses in Black Sea countries and Europe. 
We have searched paper archives and scanned the primary protocols and grey literature on marine 
phytoplankton, zooplankton and macrozoobenthos species from Romanian Black Sea waters for the 
period 1956 -1999. The datasets were collected covering soft bottoms and the pelagic habitats. 
 
The phytoplankton datasets contain 509 stations located in shallow to shelf waters and over 2129 
samples collected from March to November, between 1956 and 1980, with no similar frequency of 
sampling each year, representing 28054 records of abundance data (cells∙L-1) and biomass (mg∙m-3) 
for individual phytoplankton taxa. 
 
The zooplankton datasets for the period 1956 – 1980 contain 1227 samples collected at 675 stations 
from different layers, using the Baskakova net. They represent 39518 records of quantitative (density as 
ind∙L-1 and biomass as mg∙m-3) and qualitative data (zooplankton species diversity). 
 
The macrozoobenthos datasets for the period 1977 – 1999 include 679 samples collected at different 
transects of the Romanian Black Sea littoral, between Sulina and Mangalia, from 5m to 55m depths. Van 
Veen grab with a sampling area of 1/20 m2 was employed as a macrozoobenthos sampler. The datasets 
contain 5102 records of abundance data (ind∙m-2) and biomass (g∙m-2) of macroinvertebrates identified 
at species level where possible. 
 
All datasets have been formatted and converted to Darwin Core and submitted to EMODnet Biology. Units 
and taxonomy have been standardized and checked in WORMS to update the scientific names, with 
erroneous data being removed and all metadata included. Each delivered dataset was subjected to 
standard quality control procedures, especially on the level of taxonomy. 
 
Keywords: historical datasets; phytoplankton; zooplankton; macrozoobenthos; Black Sea 
  


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Interactions between biological and physical effects modify local biogeochemical cycling processes in offshore wind farms

Functional characteristics of the food web of artificial hard substrates of offshore wind farms along a depth gradient

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

European Marine Board expert Working Group's recommendations to Strengthen Europe's Capability in Biological Ocean Observations-

Migratory routes and stopover sites of the Lesser Black-backed Gull: where to go if your options are endless?

A database of benthos and plankton in Romanian Black Sea waters

Europese schol (pladijs) - <i>Pleuronectes platessa</i>

Gewone zeekat - <i>Sepia officinalis</i>

Kathaai - <i>Scyliorhinus stellaris</i>

Noordzeegarnaal - <i>Crangon crangon</i>

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