France counts on science to save the ocean

The ocean is a climate regulator, a refuge for biodiversity and an essential resource for millions of people but is now facing growing pressures. These issues include overfishing, plastic pollution (350 million tonnes of plastic waste are produced by humans per year and by 2060 this could almost triple), deep-sea mining and acidification. Decision-makers in France and other countries now need to rethink their strategies to preserve this crucial ecosystem and anticipate future changes.

France has the world's second largest maritime exclusive economic zone (EEZ) with its 10.9 million square kilometres. "It's a huge responsibility that calls for an unprecedented mobilisation of science and politics to preserve our marine ecosystems," explains Guillaume Bordry, advisor to the French government's General Secretariat for Investment (SGPI). The France 2030 programme launched in 2021 is a €54 billion investment plan intended to enable France to catch up with its industrial competitors, make massive investments in new technologies and finance the ecological transition. In this way, it clearly embodies France's strongly held ambition in this field combining research, innovation and political action.

The CNRS has a key role to play in this dynamic by working on transforming its scientific discoveries into tools to support political action. Guillaume Bordry adds that the CNRS's "multidisciplinary expertise means it can offer an integrated approach to ocean issues." The organisation is the joint leader for several key national research programmes which makes it an essential link between science and decision-making. 

Joachim Claudet, the CNRS's Ocean Advisor explains that "what's really unique about the CNRS is that we don't focus on just one specific area of science. The CNRS covers all scientific fields so we have a very broad perspective for dealing vast and complex issues. It's a little like being able to observe an object through several prisms and then using this more overall combined vision to understand processes like socio-ecological systems".

Currently, the CNRS co-leads four national research programmes directly linked to the ocean that were set out in the France 2030 plan: BRIDGES1  which is dedicated to the sustainable management of marine resources in the South-West Indian Ocean region; Ocean and Climate2  which works on the preservation of the ocean in its broadest sense; Deep Sea3  which works on the theme of the same name; and ATLASea4  which works on sequencing the genome of marine species to enhance the protection of forms of life.

Socio-ecological resilience: the right response to the ocean's challenges

Since the start of the industrial era the world's oceans have now absorbed around 90% of the excess heat generated by greenhouse gas emissions. This massive absorption of course affects marine ecosystems and their resilience while interactions between these ecosystems and human activities like fishing, pollution or coastal developments serve to amplify disturbances in this area and could compromise the oceans' capacity to maintain their regulatory functions to face up to climate change. 

• 1Led by the CNRS, the Ifremer and the IRD.
• 2Led by the CNRS and the Ifremer.
• 3Led by the CNRS, the Ifremer and the IRD.
• 4Led by the CNRS and the CEA.

This situation highlights what researchers call socio-ecological resilience. This central concept for the BRIDGES and Ocean and Climate national research programmes refers to the capacity of a system combining our natural environment and human societies to adapt and transform when faced with change, while preserving its own essential functions. "Two problems may seem superficially similar but you can't just take a solution shown to work in a given socio-ecological system (a complex system by definition) and try to replicate it somewhere else. Local contexts dictate the approaches required to support this resilience," stresses Joachim Claudet1  who also directs the BRIDGESprogramme for the CNRS.

Researchers therefore work on identifying specific levers for action in each field which involves detailed analysis of local ecosystems combined with the integration of social, economic and cultural dynamics. To achieve this, these programmes adopt a multidisciplinary approach based on co-construction with local stakeholders.

Co-constructing sustainable solutions

Programmes like BRIDGES and Ocean and Climate are there to serve those stakeholders and others. "We're not here to impose our solutions on everyone, we need to respond to tangible requirements. Co-construction drives and speeds up the transfer of sustainable solutions to society," explains Bruno Blanke2  who directs the Ocean and Climate programme for the CNRS. This approach to co-construction thus brings together researchers, public decision-makers (from mayors to ministers), NGOs, various local stakeholders and local communities to work on a shared issue. These include the management of extreme phenomena linked to climate change in France's overseas territories or the socio-economic challenges linked to coastal erosion.

The solutions proposed generally involved decision-making tools like models or projected scenarios. Joachim Claudet explains that "we want to develop simple platforms so stakeholders can easily appropriate them and use them to model interwoven human-environment relationships like the one between fishermen and fish, for example. Platforms which also show how such relationships can evolve according to different governance, management and decision-making options." Indicators or warning systems are another sort of solution. Information of this kind could for example be used to warn local authorities about a possible marine heatwave in New Caledonia or to map areas in mainland France that are vulnerable to climate change.

The essential dialogue between science and policy-making

Constant dialogue between scientists and decision-makers is also required to transform research into tangible action. These national programmes promote such exchanges through their advisory committees, summary reports, white papers and collaborative workshops which translate research results into practical recommendations. "The CNRS's role is to make sure decision-makers possess a solid scientific basis for action while preserving the independence of research. Then, it's up to the Ministries involved with our programmes to summarise and unify our messages," underlines Bruno Blanke.

• 1CNRS research professor who specialises in the conservation and sustainability of coastal and marine socio-ecological systems at the CRIOBE (Centre for Island Research and Environmental Observatory, CNRS/EPHE-PSL/University of Perpignan Via Domitia).
• 2CNRS research professor at the Laboratory for Ocean Physics and Satellite Remote Sensing (CNRS/Ifremer/IRD/ Université de Bretagne Occidentale)

The different committees play a central role in guiding the research programmes right from their launch. For example, the Deep Sea programme launched in September 2024 is already preparing a forum for political, economic, regional, academic and community stakeholders. "This forum will combine research and legislative and societal requirements, particularly in the face of pressures on the deep sea like climate change and critical issues like mining marine mineral resources. This is all the more important because the deep sea is one of our planet's least explored ecosystems," explains Valérie Chavagnac1  who directs the programme for the CNRS. In fact, more is known about the surface of Mars than about the ocean floor! Researchers have actually mapped almost all the craters of Mars compared with around 20% of the deep sea bed. "This overall knowledge will allow us to develop new indicators to improve our management tools," she adds. 

Benefits that go beyond the public sphere

These programmes also exist within a broader framework that involves the private sector, with the ATLASeaprogramme a good example. ATLASea aims to sequence the genomes of 4500 marine species from within the French EEZ to study, understand and more effectively protect the many forms of life in all their diversity.

• 1CNRS research professor at the Géosciences Environment Toulouse Laboratory (CNES/CNRS/IRD/Université Toulouse III Paul Sabatier)

Many species naturally produce molecules of interest used in medical biology but the genomes of marine species offer plenty of ways of synthesising proteins or enzymes with potential applications in other sectors of the French economy. "For example, in agriculture they're looking to replace phytosanitary products from the oil industry with biosourced solutions derived from micro-algae. But the existing solutions are rare, expensive and polluting. The genomes sequenced in ATLASea will help us better understand how algae produce their enzymes for example so we can reproduce this synthesis more quickly, reliably and sustainably in the lab," explains Hugues Roest Crollius1 , who directs ATLASea for the CNRS.

To work more reactively to respond to user requirements, ATLASea researchers interact with competitiveness hubs made up of stakeholders from all sectors. "Many companies could benefit from genomic information on species they work with but are lost when it comes to running a genomic analysis. The competitiveness hubs mean we'll be able to sequence species that interest them and then train companies on how to do that to bolster their competitivity," adds Hugues Roest Crollius.

CNRS: a key ocean research stakeholder 

The ocean can still offer us a great deal if we take good care of it. Along with the Research Institute for Exploitation of the Sea (Ifremer), the Research Institute for Development (IRD) and the French Alternative Energies and Atomic Energy Commission (CEA), the CNRS is involved in the consortia managing many national research programmes on the world's oceans. The organisation's variety of disciplines mean it can offer cross-disciplinary input on this complex subject and involve all the scientific communities concerned. "It's a way of getting around disciplinary silos and the boundaries of CNRS Institutes. It actually should lead to a better coordination of research stakeholders who'll be in a better position to respond to the major scientific challenges linked to the oceans and the deep seabed," sums up Aida Urien, innovation advisor to the SGPI. Science is still an essential lever for guiding public policies and private initiatives towards a future in which the ocean remains a preserved common good. This is all the more important because of course there will be repercussions on land for the consequences of an 'ill' ocean.

• 1Research professor with the Institute of Biology of the Ecole Normale Supérieure (IBENS, CNRS/ENS/Inserm)

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