The ocean may be storing more carbon than estimated in previous studies

, , , ,

Our colleague Frédéric Le Moigne contributed to an international study on the efficiency of the oceanic carbon pump. The study, published this week in Nature magazine, reassesses the ocean’s capacity to store carbon, particularly through ‘marine snow’. The CNRS issued a press release about this publication :

The ocean’s capacity to store atmospheric carbon dioxide is almost 20% higher than the estimates presented in the latest IPCC report. These are the findings of a study published in the journal Nature on 6 December 2023 by an international team including a biologist from the CNRS. The scientists looked at the role played by plankton in the natural transport of carbon from the surface to the seabed.

Plankton is fond of this gas, which it transforms into organic tissue through photosynthesis during its development, and some of it is transformed into marine particles at the end of its life. Denser than seawater, this ‘marine snow’ sinks to the seabed, storing carbon and providing essential nutrients for many deep-sea creatures, from tiny bacteria to deep-sea fish.

Based on the study of a database collected from around the world since the 1970s using oceanographic vessels, the team of seven scientists were able to digitally map the fluxes of organic matter throughout the oceans. The resulting new estimate of storage capacity is 15 gigatonnes per year, an increase of around 20% on the previous studies (11 gigatonnes per year) reported by the IPCC in its 2021 report.

This reassessment of the seabed’s storage capacity represents a significant advance in our understanding of carbon exchanges between the atmosphere and the ocean at a global level. While the team stresses that this absorption process takes place over tens of thousands of years, and is therefore not sufficient to offset the exponential increase in CO2 emissions generated by global industrial activity since 1750, this study nevertheless reinforces the importance of the ocean ecosystem as a major player in regulating the global climate in the long term.

Global distribution of organic carbon flux from the surface layer of the open ocean.
© Wang et al., 2023, Nature.



Biological carbon pump estimate based on multi-decadal hydrographic data. Wei-Lei Wang, Weiwei Fu, Frédéric A. C. Le Moigne, Robert T. Letscher, Yi Liu, Jin-Ming Tang, and François W. Primeau. Nature, le 6 décembre 2023.

A look back at the EPC conference in Brest


The 8th European Phycology Congress (EPC8), co-organized by Philippe Potin (Roscoff Biological Station – SBR) and Solène Connan (LEMAR-IUEM-UBO) under the authority of the Federation of European Phycology Societies (FEPS) and the Phycological Society of France (SPF), took place from August 20 to 26 at the Brest Arena. Supported by the Brittany Region, the Finistère Departmental Council, Brest Métropole, the University of Western Brittany, and ISblue, this congress brought together nearly 600 researchers, professors, PhD students, and Master’s students from 42 countries whose research focuses on algae, whether micro or macroalgae living in freshwater or marine environments.

Plenary presentations were held each day, covering topics such as the reproduction of red macroalgae, the diversity and adaptation of phytoplankton, diatoms and light, and kelp forests (Laminariales). Oral presentations and posters were grouped into 20 symposia in 6 sessions covering taxonomy, phylogenomics, biotechnology, primary production, the role of algae in ecosystems, and algae and the general public. Several PhD students, Master’s students, and staff from LEMAR and AMURE presented their work in these different symposia. On Wednesday, excursions (Molène, Crozon, Roscoff, Plouguerneau) or workshops were offered. About twenty companies, including local algae valorization enterprises, as well as the Chambre Syndicale des Algues et Végétaux Marines and the Cluster Algues-Bretagne, were represented and sponsored this congress.

Participants also had the opportunity to admire an exhibition titled “Immersion in the Heart of Algae,” at the interface of “Arts and Sciences,” related to the fascinating world of algae, whether planktonic and microscopic or forming vast underwater forests off our coasts. This immersive exhibition featured original works by artists inspired by marine algae, such as the work IGLOO OPUS II by Caroline Desnoëttes, in which sounds recorded within kelp forests by Lucia Di Iorio were played. The exhibition also showcased beautiful photographs of macro- and microalgae (photographers: Erwan Amice, Wilfried Thomas, Sébastien Colin & Marie Walde) and the “Planctonarium” dome created as part of the Plancton Planète project.

Furthermore, on August 21, a public evening on the theme “Intriguing Algae: Cooking, Cultivating, Understanding,” hosted by Vincent Doumeizel (UN Global Seaweed Coalition), attracted nearly 300 people who came to discover the exhibition and listen to presentations by Line Le Gall (MNHN) on algae, Hugo Morel (Bord à Bord) on seaweed cuisine, which included a tasting of seaweed tartare and chips, Martial Laurans (Ifremer) on seaweed harvesting and cultivation, and Marine Landa (SBR) on their microbiome.

Congress participants left delighted with the organization (a big thank you to the student volunteers!), the scientific program of the conference devised by Inka Bartsch (AWI, Bremerhaven, Germany), and Wiebe Kooistra (Stazione Zoologica Anton Dohrn, Naples, Italy), the exhibition, the venue (Brest-Arena), the meals served during the congress (featuring many local dishes), excursions or workshops, and the gala evening organized at Les Capucins, during which they could dance to Breton music!

And now, let the preparations for EPC9 in Krakow, Poland in 2027 begin!

The Warmalis 3 oceanographic campaign!


Oceanographic Campaign Warmalis 3: Understanding the Functioning of the Pelagic Oceanic Ecosystem and Ultimately Determining its Influence on Tuna Resources in the Western and Central Pacific Region

The WARMALIS 3 campaign, taking place from September 25 to November 8 aboard the R/V ANTEA, aims to better understand the functioning of the pelagic oceanic ecosystem and determine its influence on tuna resources in the western and central Pacific region, which account for more than 50% of global catches. In particular, the campaign studies intermediate trophic levels (zooplankton and micronecton), which constitute the primary food for all large pelagic species in the Pacific. To achieve this, biological data (micronecton trawls, zooplankton nets, EK80 sonars, and acoustic profilers), as well as physical and chemical data, are collected.


Example of micronecton capture, with gelatinous organisms, small fish, and shrimp commonly consumed by tuna and other top predators (Photo: V. Allain, SPC-IRD).


WARMALIS 3 is the last in a series of three campaigns (2021, 2022, 2023) part of the MICROPAC project (Micronecton in the Pacific, 2021-2023) led by Christophe Menkès (IRD/UMR ENTROPIE) and Valérie Allain (CPS) with partner units: MIO, IMAGO, LEMAR, LOPS, LEGOS, and CLS. After exploring the western and central Pacific from south to north in previous years, the crew is undertaking a 45-day east-to-west traverse along the equator this year.
Four colleagues from LEMAR are on board: Laure Barbin, Jérémie Habasque, Anne Lebourges, and Anaïs Médieu.


Campaign plan for Warmalis 3.


You can follow the ship’s log on the mission blog.

Nawras seminar: Data science and the marine environment


On Monday 2 October 2023, a seminar was held in Marrakech on the Nawras project, led by Marie Bonnin, an IRD researcher at LEMAR, and Jihad Zahir from Cadi Ayyad University.

The aim of the seminar was to present the opportunities for collaboration between the IRD and Cadi Ayyad University in the field of data sciences and the marine environment. It brought together 15 researchers from different organisations in Marrakech, Essaouira and Safi, from Cadi Ayyad University and the Institut de Recherche pour le Développement, from different disciplines (IT, law, ecology, biogeochemistry). Each institute and organisation was able to present its link with data sciences and/or the marine environment, as well as current projects, in order to highlight opportunities for collaboration and to facilitate the co-supervision of short-term internships. The participants concluded that the opportunities for collaboration were real and stimulating, and that bilateral exchanges should enable the first collaborations to be set up quickly.

PAMPAS project exhibition: Coastal marsh heritage

, , ,

The PAMPAS project – Évolution de l’identité PAtrimoniale des Marais des Pertuis charentais en réponse à l’Aléa de Submersion marine, 2019-2023 – is a collaborative research project funded by the French National Research Agency (ANR) and led by the Littoral Environnement et Sociétés de La Rochelle laboratory (LIENSs, CNRS – La Rochelle University). It aims to understand the future of coastal wetlands, focusing on the evolution of the heritage identity of the marshes of the Pertuis Charentais in response to flooding over half a century.
The marshes of Charente-Maritime: a unique study area presenting:

  • A strong heritage identity – landscape, biodiversity, architectural heritage
  • Vulnerability to submersions,
  • Contrasted management methods and a concentration of numerous economic activities – agriculture, shellfish farming, tourism … whose sustainability can be questioned.

In a context of increasing populations and activities in coastal areas, the preservation and maintenance of these socio-ecosystems are essential to safeguard the quality and functions of these constrained environments. The project has expanded the concept of heritage identity to include the ecological and environmental functions of marshes, such as:

  • Their adaptation to the overall rise in sea level through sedimentation,
  • Their role as a buffer against marine submersions limiting the rise in sea level in adjacent areas,
  • Their role in water filtration, nutrient recycling, carbon sequestration, habitat provision, and nursery functions for numerous species.

This project chose to go beyond traditional approaches to the assessment of conservation ecology, economics, and cultural heritage management, all considered insufficient to comprehend heritage as the entirety of components contributing to the collective identity of a marsh.


  • Adopted an interdisciplinary approach applied to three study areas (the marshes of Brouage, Fier d’Ars, and Tasdon), contrasting in terms of natural, cultural, and landscape heritage, as well as management practices: in debate between laissez-faire and embankment, heavily embanked, and reconnected to the sea, respectively.
  • Built a collective approach and participatory engineering, crossing expertise in Humanities and Social Sciences, Life and Earth Sciences, and involving marsh managers, with 48 people from 13 research units and 9 disciplines.

The 3 major objectives of PAMPAS are to:

  • Characterize the natural, cultural, and landscape functions of the marshes and spatially represent these different components of heritage identity;
  • Represent the socio-ecosystem of marshes in terms of functionality, services, resilience, or adaptability to hazards;
  • Define scenarios for the evolution of the heritage identity of the three study sites facing submersion hazards and assess their adaptive potential. These results will be discussed through an interactive mapping tool.

In conclusion, based on a revised definition of heritage identity adapted to marsh areas, PAMPAS provides a new vision for sustainable marsh management by transmitting economic, cultural, and ecological knowledge. The challenges and issues of this project thus far exceed the local level and concern wetlands globally, for which it is now necessary to reconsider analysis and management frameworks, integrating heritage in its various socio-ecosystemic dimensions.

This heritage is not always visible or recognized as such by the entire population. Therefore, this exhibition aims to reveal to the general public not only the results of a research project but also the objects (animals, plants, structures, landscapes, activities, etc.) that could be recognized as full-fledged heritage in the marshes. Showing the invisible, less easily perceived objects, and highlighting the ecological functions of the marshes is the objective of this exhibition.

The exhibition will be visible from September 30 to November 4 at the Ecomuseum of Loix en Ré (Ile de Ré)