Finding the origins of marine plastic pollution

How much plastic is found in our rivers?

Where exactly are microplastics found?

What is the origin of plastic waste in the environment?

What happens to plastic waste once it reaches the ocean?

© Anna Deniaud

We still have a lot to learn about the « plastic empire » — pollution  detected 40 years ago in every corner of the world.  

Up to 8 million tonnes of plastic are released into the ocean each year,  according to current scientific models. The number of plastic fragments  in the ocean is estimated at 5,000 billion—equal to the total quantity of  zooplankton in the Mediterranean—one of the world’s most polluted  seas.  

Why does this massive quantity of plastic, undoubtedly toxic, flow  increasingly into the waters of the Blue Planet? The schooner Tara, with  her partners and sponsors, set out to answer this question in 2019.

Carte de l'expédition Tara Microplastiques

In day-to-day life

From sea to land

This freshwater expedition, following the 9 major rivers that traverse the  countryside, cities and towns of Europe, was a reminder of our often forgotten link with the Ocean.

The Schooner
  • 7months of expedition

  • 2 700samples

  • 5proposed amendments to the circular economy law

  • 140million plastic bottles per year discarded in nature in France

« For a long time we thought that transformation of plastics into microplastics happened at sea, under the influence of sun and waves. However, the process also seems to be taking place in rivers and their catchment areas. Our research is making it possible to better understand the phenomena of plastic fragmentation, quantify what comes from rivers, and assess the nature of plastic pollution in order to guide the measures to be taken. »

Jean-François Ghiglione, director of research, CNRS

Common Idea: It’s possible to walk on the “plastic continent”. No! The image of a “continent” suggests the magnitude of the phenomenon, but does not mean dry land. Researchers speak of plastic “soup”, a mixture of large and small plastics accumulating in certain places at the ocean’s surface.

Des scientifiques discutent des échantillons de microplastiques

Plastic at sea — the solutions are on land!


All 2,700 samples collected from the rivers contain plastic,  including upstream of cities such as London, Hamburg or  Rouen. 

Upstream fragmentation 

The majority of plastic found in river water samples are in  the form of microplastics. This pollution is invisible,  impossible to collect, and calls for major actions on land to  stop the flow. 

Six actions to take ashore 

-improve collection and recycling 

-reduce single-use disposable plastics 

-reduce the number of chemicals and resins added to plastic -reinvent packaging to eliminate toxic polystyrene -reinstate a deposit system for PET bottles 

-obtain a United Nations Treaty concerning plastic

© Noelie Pansiot


A Tara mission, 100 % French

This mission on the rivers of Europe was prepared in just 6  months, with 17 French laboratories in as many scientific  disciplines. 

Labs & partners

Jean-François Ghiglione : Directeur scientifique de Tara Microplastiques, Directeur de recherche CNRS

Jean-François Ghiglione

Scientific director of the Tara Microplastics Mission, CNRS director of research

Romain troublé, Directeur général

Romain Troublé

Executive director of the Tara Ocean Foundation

Dive into the expedition

Ocean Culture

Expedition Tara Pacific, Escale à Wallis

Tara Pacific

Coral reef biodiversity with climate change

Tara mission Microbiomes

Mission Microbiomes

Understanding the invisible people of the ocean to preserve our future

Our partners

Major partner