MEGASETE

Ecological and ecotoxicological impacts of an offshore floating solar farm

Project at a glance

2024-2028

Sète-Frontignan (FR)

Fish early life-stages

Biofouling communities

Settlement kinetics

Ecotoxicology

Environmental monitoring

Context

The development of marine renewable energy is creating a new generation of offshore infrastructures. While these technologies can contribute to the decarbonisation of energy production, their large-scale deployment also raises important ecological questions.

MEGASETE aims to develop and deploy the first pre-commercial 1 MWp offshore floating solar farm in France and the Mediterranean Sea. Located offshore from the commercial harbor of Sète-Frontignan, the demonstrator will occupy approximately one hectare and supply low-carbon electricity to port infrastructures. Beyond its technological objectives, MEGASETE provides a unique opportunity to study the ecological consequences of introducing a new type of large floating infrastructure into the marine environment.

The deployment of such structures can affect ecosystems through several pathways at once. They introduce new artificial surfaces that can be colonized by marine organisms, potentially modify local environmental conditions, and may also introduce or redistribute chemical contaminants associated with materials, maritime activities or surrounding sediments. MEGASETE therefore combines technological development with a comprehensive environmental assessment conducted before, during and after deployment of the solar farm.

Objectives

From infrastructure deployment to ecosystem responses

Floating offshore structures do not remain biologically inert after immersion. New submerged surfaces are progressively colonized by microorganisms, algae and invertebrates, forming complex biofouling communities. As these communities develop, they increase habitat complexity and may provide food resources, shelter and biological cues for mobile organisms, including larval and juvenile fishes.

At the same time, offshore infrastructures may alter the chemical environment. Metals, plastic additives and other contaminants can occur in seawater and sediments and may vary through time in relation to infrastructure deployment, materials, maritime activities or local environmental processes.

Within MEGASETE, the Observatoire Océanologique de Banyuls-sur-Mer combines environmental monitoring, biological observations and experimental ecotoxicology to investigate these different dimensions together. The EcoEvoDevo team at BIOM, in partnership with the LBBM lab, focus particularly on:

  • the temporal dynamics of biofouling colonization
  • the recruitment of early life stages of fishes
  • the chemical contamination of seawater and sediments
  • the effects of contaminants on biofouling communities
  • the effects of contaminants on fish metamorphosis and juvenile development
  • the effects of contaminants on fish-biofouling interactions

The objective is not only to describe what appears around the solar farm, but to identify the environmental pressures that may drive these patterns and experimentally test their biological effects.

Key questions

1. Does the deployment of the offshore solar farm modify the surrounding marine environment?

In MEGASETE, we monitor environmental conditions, assess and sample biofouling and fish communities (environmental DNA and plankton net), and investigate chemical contamination (with particular attention to contaminants such as metals and plastic-associated compounds) in seawater and sediments before, during and after the deployment of the solar farm.
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2. How do biological communities establish around the new infrastructure?

We follow the colonization dynamics of biofouling communities and the recruitment of early life stages of fishes to determine how these biological compartments progressively develop around the floating structures and whether their dynamics are interconnected.

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3. Can environmental contaminants affect these biological responses?

We perform controlled laboratory experiments to evaluate whether contaminants detected in the field can affect biofouling communities or disrupt fish metamorphosis, including associated phenotypic, physiological and endocrine processes.

4. Can laboratory experiments help explain patterns observed in the field?

By combining environmental measurements, biological monitoring and controlled exposures, MEGASETE aims to determine whether specific environmental pressures can mechanistically explain biological changes observed around the solar farm.
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A multidisciplinary demonstrator

Together, these approaches allow us to follow the ecological trajectory of a novel offshore infrastructure from its deployment onwards, while distinguishing simple changes in species presence or abundance from potential effects on organism development and biological performance. By integrating field observations with experimental ecotoxicology, MEGASETE aims to provide a mechanistic assessment of the environmental footprint of offshore floating photovoltaic technologies and contribute to their future ecological integration.

Project team and partners

MEGASETE involves a large number of partners from both the private and academic sectors, including (for the environmental impacts section of the project):

LBBM - Sorbonne Université, CNRS, Université de Perpignan Via Domitia

Raphaël Lami - Coordinator
Robin Turon
Laure Fontimpe - PhD student

BIOM - CNRS, Sorbonne Université

Marc Besson - WP Leader
Laurence Besseau - WP Leader
Robin Turon
Laure Fontimpe - PhD student
Justine Benezis - PhD student

OOB - Services Moyens à la Mer, Instrumentation, Informatique, Plongée scientifique

Renaud Vuillemin - WP Leader
Michel Groc - WP Leader
Pierre Groc
Bruno Hesse

SolarinBlue

Aurélien Croq
Antoine Retailleau
Maddalena Bozzetti

Technip Energies

Marc Cahay

IES - Université de Montpellier, CNRS

Petru Notingher
Elsa Giraud

Funding

France 2030 - ADEME

MEGASETE - CORIMER et i-démo/DEMO TASE
2024-2028

People involved in the EcoEvoDevo team

Related News

MEGASETE featured in S&A journal

Our funded research project MEGASETE has been featured in Sciences & Avenir, a french popular journal about science

Related Publications

Interested in this research?

Our projects regularly involve Master students, PhD candidates and postdoctoral researchers interested in marine Eco-Evo-Devo, ecotoxicology, behaviour and integrative biology.
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