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Brazil, the largest country on the South American continent, has 60% of its total surface covered by the Amazonian rainforest. Its entire coastline, i.e. 8,500 kilometers, is on the Atlantic Ocean. The North of the Brazilian territory is crossed by the longest river in the world: the Amazon, which flows into the Atlantic Ocean.

There’s no official policy regarding Sargassum. The Brazilian coasts are not prone to massive events as other Caribbean territories. However, scientists, residents and professionals on the coasts of the North of the country in the Amazon estuary in the state of Pará, have observed an increase in the quantity of Sargassum since 2019. For example some fishermen mention a brown algae clinging to their nets and causing itching.

Since 2011, but even more so since 2018 when the phenomenon exploded, scientists around the world have been looking into the question of the proliferation of Sargassum and its movements in the Atlantic Ocean. The most popular theory in the scientific community regards the Congo river (one of the largest on the African continent which also flows into the Atlantic) and the Amazon river.

Both of these rivers carry an immense quantity of nutrients (mainly nitrates and phosphates), due to the mining activity, intensive cultivation and deforestation. These nutrients could be an important factor in the proliferation of Sargassum.

Observations show that the evolution of Sargassum in the Atlantic Ocean follows marine currents and nutrients carried by the two aforementioned rivers. The currents flow from the African Western coasts to the Caribbean coasts and to the Gulf of Mexico.


From intensive agriculture to sargassum blooms: research on the origins of algae in Brazil

In Brazil, Professor José Eduardo Martinelli Filho meets with fishermen who suffer from Sargassum events and with a Quilombo community next to a tributary of the Amazon River impacted by the discharges of chemicals in the water. The specialist tries to understand the connection between these different factors.

Thematic sheets



The floating sargassum of South Atlantic Ocean : likely scenarios

Scientists from several federal universities in Brazil have gathered information regarding the Sargassum biomass reaching the shores of the Southern Atlantic, to find an explanation for its origins,try to determine the main environmental factors attached to it, and possible options to manage it.

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.

A sea of opportunities

A sea of opportunities: The benefits of the Sargassum Sea for the international community.

Writer: Gabriella Gullich
Cartoonist: Daniel Bretas
Scientists: Marina Sissini / Paulo Autunes Horta


José Eduardo Martinelli Filho – Head Professor of the Oceanographic Biology Laboratory of the Federal University of Pará – +55 91 3201 7987

Federal University of Pará – +55 91 3201-7390

Silvia Keiko Kawakami – Chemical oceanography, sargassum biochemistry, metals

Vinicius Tavares Kutter – Chemical oceanography, sargassum biochemistry, metals

Flavio Alves-Junior – Associated invertebrate fauna

Mariana Cabral de Oliveira – Genetics and genomics of Sargassum

Maria Teresa Menezes de Széchy – Taxonomy, ecology, biogeography of Sargassum

João Adriano Rossignolo – Materials engineering, sustainable uses of Sargassum

Maria Beatriz B. de Barros Barreto – Genetic molecular taxonomy of Sargassum