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The French overseas department of Guadeloupe is an archipelago located between Dominica and Montserrat. Like many Caribbean islands, the Atlantic coasts of the islands within the archipelago are very regularly impacted by Sargassum events, from Capesterre-de-Marie-Galante to the North of Grande-Terre.

Just like in Martinique and Saint Barthelemy, the Prefecture of Guadeloupe coordinates several services set up for the management of Sargassum.

Météo France issues daily Sargassum stranding forecast bulletins using satellite data collected from various observation satellites. These bulletins are available on the Météo France website:

Health surveillance is entrusted to the Regional Health Agency (ARS), which worked with Gwad’Air (an approved association for Air Quality Surveillance in Guadeloupe) to install a network of sensors that measure Hydrogen Sulphide and ammonia levels on 24 sites of the archipelago. Thus, it is possible to know in real time the quality of the air and the saturation rate of Hydrogen Sulphide and Ammonia. Daily data is available on the Gwad’Air website:

Mayors are responsible for collection, since they are sanitation warrants . Spreading is managed by the Littoral Conservancy and the National Office of Forests.

Finally, the Guadeloupe Region, ADEME and the Departmental Council of Guadeloupe manage experiments and the valorization of Sargassum.

The Prefecture of the Region, the ARS and Gwad’Air also manage communication and prevention about Sargassum events.

It should be noted that since August 2022 and the announcement of the creation of an anti-Sargassum public service by the French Ministry in charge of Overseas Territories, Guadeloupe opted for a Public Interest Group (GIP) named SARGIP. It will group representatives of the State, the Guadeloupe Region, the Department and the Chamber of Commerce and Industry. A mixed union will also bring together the communities affected by the phenomenon and respond for operational needs.

Comparison of seaweed events between 2018 and 2022 on a beach in Guadeloupe

Porte d'Enfer photographed by the Sentinel 2 satellite in March 2018
Porte d'Enfer photographed by the Sentinel 2 satellite in April 2022
Porte d'Enfer, Sentinel 2 satellite in March 2021
guadeloupe PORTE ENFER AVRIL-2022
Porte d'Enfer, Sentinel 2 satellite in April 2022

The groundings of 2011 and 2018 were particularly intense, but 2022 broke all records with quantities of Sargassum never recorded before. The Club Sentinelle, a Guadeloupe monitoring network, studies these groundings using satellite data and local data.

Source: Club Sentinelle, Guadeloupe


Remote sensing of Sargassum in Guadeloupe with the Sentinel Club

Founded in 2015 by the retired physics teacher Gérard Escleyne and sponsored by Juerg Lichtenegger, consultant for the European Space Agency (ESA), the Sentinel Club is a group of students from Port-Louis High School. They use satellite data to identify Sargassum slicks, monitor their movement and anticipate wash ups in Guadeloupe.

Young Guadeloupeans meet the IRD Antea expedition

In Pointe-à-Pitre (Guadeloupe), young members of the Sentinel Club of Port-Louis High School are boarding the Antea, a ship from the French oceanographic fleet. The purpose of the expedition is to carry out Sargassum sampling to understand the fauna and flora related to the seaweed beds.

Adding value to Sargassum through biogas: the hydrogen car of tomorrow?

Dominique Joly is looking into the transformation of Sargassum into methane, a high-potential gas that can be used to produce another gas: hydrogen. Those are the first conclusive tests that may allow the development of a new green economy from this complex raw material.

The transformation of Sargassum seaweed into activated carbon to clean up water

A team of scientists, led by Sarra Gaspard, is studying several ways for valuing Sargassum. One lead with strong potential: the manufacture of activated carbon based on Sargassum, which could clean the soil up and contaminate the water with Chlordecone, among other things.

Thematic Sheets



Preparation of biochar and activated carbons from invasive Sargassum algae for the reduction of chlordecone in contaminated soil

The valorization of Sargassum is a rising concern as the events are getting more and more intense. Scientists have worked on the recovery of Sargassum in biochar and activated carbon in an attempt to partially decontaminate the soil with chlordecone presence.

Comic Sargassum - Story(ies) of a brown tide

(Cf Alliance Française)


Sargassum: Story(s) of a Brown Tide

“Sargassum: Story(s) of a Brown Tide” was written in the style of a role-playing game. Researchers are invited to come out of their laboratories to meet citizens, illustrators to return to the benches of the university to question the research, screenwriters to immerse themselves in the reality of fieldwork.

Led by the Alliance Française of Santo Domingo, the creation of this Caribbean and international documentary comic strip is intended to become a space for discussion and reflection on the environmental issue of Sargassum.

Invasions versus innovations

80,000 tonnes of Sargassum 6 months a year! This is one of the faces of Guadeloupe that you will never see on a postcard! What if we could turn this adversity into an opportunity?

Writer: Jessica Oublié
Cartoonist: François Piquet
Scientist: Sarra Gaspard


Gérard Escleyne – Founder of the Club Sentinelle

Juerg Lichtennegerg – Sponsor of the du Club Sentinelle, geographer, consultant for the ESA

Sarra Gaspard – Scientist from the University of the West Indies – Sargassum based biochar and active carbon

Marie-Ange Arsène – Sargood Project – University of the West Indies

Yasmine Morice – Research engineer – Gwad’Air – +590 590 32 32 90

Mélanie Cueff – Collection and recovery engineer – ADEME – +590 690 64 63 72 –

Didier Roux – Head of Environmental Health Department – ARS
roux@ars.sante.fr – +590 590 82 52 14

Willy CEÏ, Project Manager (Sargassum theme) I.P.S (Intermunicipal Syndicate for the Development of Beaches and Tourist Sites) / PULSAR Unit ( Local Emergency Plan SARgasses)
0590 28 68 05 /

Public Health France