52nd Liège Colloquium on Ocean Dynamics – Towards understanding and assessing human impacts on coastal marine environments

Liège, Belgium – 17th to 21st May 2021


Considering the situation with the COVID-19 outbreak, the Scientific Committee has decided to leave at this stage the possibility to have the colloquium in a hybrid format: physical meeting + streaming and talks at distance.

If the sanitary situation does not allow a physical meeting, we will move to full virtual. The final decision will be taken in March.

Safety is of course our first priority.

Marilaure Grégoire for the Scientific Committee

The University of Liège

Terms of reference

The coastal ocean (i.e. regions that are directly influenced by their watershed, including estuaries) is under increasing pressures that affect its functioning and health, and compromise the provision of services to the society. Since the middle of the last century, the massive increase in the use of fertilizers has resulted in worldwide eutrophication of the coastal zone resulting in the proliferation hypoxic regions. Overfishing, dredging activities and pollution with notably the increasing amounts of marine litter are further affecting coastal systems with impacts on the physics, biogeochemistry and biodiversity. More recently, the implementation of the Blue Growth strategy led to an increase of marine and maritime activities. In particular, offshore wind farms and dredging have modified the sedimentary environment with consequences for biodiversity and biogeochemistry that are still poorly known at large scales. All these activities are developing in a context of global change with warming, acidification, deoxygenation and global sea level rise adding complexity to the challenge of unraveling the intricate interplay between multiple stressors that may act synergistically or antagonistically. Only after having achieved a proper understanding of human impacts on the coastal ocean, we will be able to set-up a scientifically underpinned ecosystem-based management scheme for the marine ecosystem. Such management should hence be firmly embedded in the science-management-policy interface, taking account of selecting useful and communicable indicators for ecosystem health, targeting ecosystem services and making use of novel analytical tools acknowledging the complexity of Drivers-Pressures-Stressors-Impacts-Responses (DPSIR) interactions.

The complexity of the coastal ocean combined with the conjunction of multiple stressors pose significant challenges to scientists that have to develop the adequate innovative and robust science-based tools in support of a sound management. The colloquium would like to gather an interdisciplinary community of scientists in order to obtain an overview of the progress in our capabilities to understand, monitor and forecast the impact of human activities on coastal marine environments to guarantee a productive and healthy system as requested by the EU Marine Strategy Framework Directive and the UN Sustainable Development Goal 14. A special event gathering scientists, stakeholders and industries is foreseen for reviewing current knowledge and gaps on offshore wind farms impacts on biodiversity and biogeochemistry. The special event will set the scene for a follow-up discussion during a networking reception directly following the presentations.

Opening Keynote: Anthropogenic and natural impacts on North Sea sediments by Karline Soetaert, NIOZ, The Netherlands.

Regular sessions will be held on the following themes:

  • Assessing the impact of sedimentary changes on the coastal ocean physics, biodiversity and biogeochemistry. KEYNOTE Speaker: Martin Solan, University of Southampton, UK
    In coastal ecosystems, seafloor disturbance resulting from aggregate extraction, dredge disposal and beam trawling leads to “fining” of the sediment. This fining can have important implications for physical habitat characteristics, biogeochemical cycling, biodiversity and food web structure. This session focuses on contributions that increase our understanding of sediment-induced changes in the ecological, physical and chemical characteristics of the marine ecosystem. Especially, new tools to measure the fining process in situ or in laboratory conditions are welcomed.
  • Assessing the impact of hard substrate introduction on the coastal ocean physics, biodiversity and biogeochemistry. KEYNOTE Speaker: Jennifer Dannheim, AWI and HIFMB, Germany
    Introduction of hard substrates (wind farm, oil and gas, building in general, …). The offshore wind industry has seen considerable investment and a significant expansion of the sector is expected at the horizon 2030-2040. By introducing hard substrates offshore wind farms modify marine habitats with consequences for marine biodiversity and biogeochemistry that are still hardly known.
  • Assessing the impact of land-based pressures on the coastal environment, river-estuary-coastal ocean coupling. KEYNOTE Speaker: Marjorie A.M. Friedrichs, Virginia Institute of Marine Science, USA
    This session welcomes contributions, dealing with experimental, observational (including satellites) and modelling approaches, targeted at investigating the transfer of organic and inorganic (e.g nutrients, plastics, minerals) materials across the river-ocean continuum and its impacts on the coastal ocean (e.g. hypoxia, HABs, turbidity enhancement). Focus will be on the understanding and assessment of the impact of human activities (e.g. eutrophication, dredging) on this transfer and on the coastal zone health. New technologies (e.g. sensors), hyperspectral satellites and numerical models are expected to considerably advance our capacity to deliver high quality information to stakeholders and to improve our forecasting capacity of the coastal zone status under continental pressures.
  • Multiple stressors, multi-use, cumulative effect assessment, including climate change. KEYNOTE Speaker: Jean-Pierre Gattuso, Observatoire Océanologique, Laboratoire d’Océanographie, CNRS-Sorbonne Université, France
    Preserving the health of the marine environment requires a sound allocation in space and time of the multiple activities affecting the coastal zone. This needs to be grounded in a thorough understanding of the cumulative impacts of multiple activities at the ecosystem scale across borders and sectors. This section welcomes contributions with experimental or modelling approaches that deal with the combination of effects of ocean acidification, warming, hypoxia, changes in salinity, microplastics, etc. on different aspects of the marine ecosystem (biodiversity, biogeochemistry, food web dynamics). We particularly encourage contributions that target community- or ecosystem-wide responses (in space and time).
  • Ecosystem services. KEYNOTE Speaker: Tara Hooper, University of Plymouth, UK
    This session aims at addressing the currently poor link between marine processes and their societal relevance by incorporating the field of biodiversity – ecosystem functioning link into the ecosystem services concept. The biodiversity – ecosystem function field introduces the theoretical background and examines the mechanistic role of biodiversity in shaping ecosystem services. Human activities in coastal seas impact both biotic and abiotic factors that drive the link between biodiversity and ecosystem functioning, affecting the provision of ecosystem services by the marine environment. In this session, we embrace contributions bridging the gap between the fields of biodiversity-ecosystem functioning and ecosystem functioning-ecosystem services to facilitate assessing the societal implications of changes in ecosystem functioning.
  • Indicators definition for ocean health assessment in connection with SDG14 and GES assessment. KEYNOTE Speaker: Ángel Borja, AZTI, Spain
    Conservation and sustainable use of the oceans, seas and marine resources for sustainable development is the target of the sustainable development goal 14 of the United Nations. This requires tools that permit defining marine health across different marine habitats and measuring changes induced by several anthropogenic pressures. Triggered by e.g. EU environmental legislation such as the Marine Strategy Framework Directive, much scientific progress has been realised in the last decades. This session welcomes contributions on integrative assessment frameworks, new types of indicators (functional, genetic-based, …), indicator-pressure responses and appropriate spatial and temporal monitoring programs, contributing to a better assessment of the ecosystem health.
  • Science base for marine spatial planning. KEYNOTE Speaker: Vanessa Stelzenmüller, Thünen Institute, GE.
    Maritime spatial planning (MSP) works across borders and sectors to ensure human activities at sea take place in an efficient, safe and sustainable way. Nowadays, MSP is considered one of the key enablers to underpin sustainable blue growth. Ecosystem-based management (EBM) proposing tools for integrated ecosystem assessment is ever more considered outlining those principles needed for sustainable MSP. EBM differs from current management practice that usually focus on single species, sector, activity or concern. Up to date, a full-fledged uptake of the EBM principles throughout the full MSP process however is often lacking. Being a process to analyse and organise human activities in the marine space to achieve specific ecological, economic and social objectives, MSP is an example of a tool with great potential for multi-sectoral EBM, aiming to integrate sectorally driven EBM, such as EBM to fisheries or EBM to energy production. This session welcomes presentations on EBM in MSP, such as EBM-embracing MSP initiatives and science-based considerations of how to facilitate EBM-based MSP.

This session will oversee the state of science about environmental impacts of offshore wind farms, still proliferating in European waters. Special attention will be paid to the science-management-policy nexus as to best achieve an environment-friendly implementation of offshore renewables and hence, aside lessons-learned from the Belgian offshore wind farm environmental monitoring programme (WinMon.BE), we also welcome other presentations on an ecosystem-based management of offshore renewables in Europe and beyond. This session is targeted at scientists, industry, managers and policy makers. The session will set the scene for a follow-up discussion during a networking reception directly following the presentations.



  • Ulrike Braeckman (UGent, BE)
  • Arthur Capet (ULiège, BE)
  • Steven Degraer (RBINS, BE)
  • Marilaure Grégoire (ULIège, BE)
  • Tom Moens (UGent, BE)
  • Karline Soetaert (NIOZ, BE)
  • Jan Vanaverbeke (RBINS, BE)
  • Gert Van Hoey (ILVO, BE)

Scientific Committee

  • Tundi Agardy (Sound Seas, US)
  • Salvatore Arico (IOC-Unesco)
  • Silvana Birchenough (CEFAS, UK)
  • Angel Borja (AZTI, SP)
  • Denise Breitburg (Smithsonian, US)
  • Joop Coolen (Wageningen Marine Research, NE)
  • Valérie Cummins (University College Cork, Future Earth Coast, IE)
  • Farid Dahdouh-Guebas (ULB, BE)
  • Minhan Dai (Xiamen University, CN)
  • Ghada El Serafy (Deltares, NE)
  • Emmanuel Hanert (UCL, BE)
  • Stéphane Isoard (EEA)
  • Philippe Laleye, (UAC, Benin)
  • Diego Macias (JRC, IT)
  • Patrick Meire (UA,BE)
  • Angélique Mélet (MOI, FR)
  • George Petihakis (EuroGOOS)
  • Pierre Petitgas (IFREMER, FR)
  • Nadia Pinardi (UB, IT)
  • Augustin Sanchez Arcilla (Polytechnic University of Barcelona, SP)
  • Irene Schloss (University of Ushuaïa, AR)
  • Emily Smail (NOAA, US)
  • Emil Stanev (HZG, GE)
  • Adrian Stanica (GeoEcoMar, RO)
  • Vanessa Stelzenmüller (Thünen Institut, DE)
  • Michiel Vandegehuchte (VLIZ, BE)
  • Johan van der Molen (NIOZ, NE)
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