Tara Oceans and Tara Méditerranée: "Exceptional Adventures"

The Tara Oceans expedition, from 2009 to 2013, investigated the biodiversity of plankton in all the seven seas, and the characteristics of its environment. In 2014, the schooner Tara crisscrossed the Mediterranean to analyze the impact of plastic on this ecosystem. What are the results of the studies conducted by Tara? They aren't just the prerogative of the scientific community. What is their impact on our daily lives? A review with Gaby Gorsky, Scientific Director of Tara Méditerranée and of the Villefranche-sur-Mer Oceanological Observatory.

Gaby Gorsky
Scientific Director of Tara Méditerranée and of the Villefranche-sur-Mer Oceanological Observatory.

What is the specificity of the Tara Oceans expedition?

Tara Oceans sailed through the two hemispheres for three years: no expedition has ever been as global or as detailed. The aim was to investigate the biodiversity of plankton, the microscopic organisms which drift with the ocean currents, as well as the characteristics of their environment and their role in the planet's ecological balance. We focused on plankton because it's a category of organisms neither fished nor processed by man, and therefore a reliable indicator of the state of an ecosystem. It so happens that nearly 25% of the CO2 released every year by human beings into the atmosphere is absorbed by the ocean, by mechanisms in which plankton plays an essential role. We took tens of thousands of plankton samples and recorded all the environmental parameters, including by satellite: we zoomed from the satellite view to the DNA of the organisms.

Tara Oceans ended in 2013, what can you tell us about the analysis of the samples and the data recorded in all the seven seas?

The study results are extraordinary, already published in a score of articles. Other results are being submitted today to the leading scientific reviews, Science and Nature, for publication shortly.

We compiled a database among the world's most reliable and largest. It will soon be accessible free of charge to scientists, because science can only advance if we pool our resources. The database will be used to simulate the evolution of the climate, of the circulation of carbon between the atmosphere and the oceans. To make forecasts, we are designing mathematical models from the most reliable data, such as our own, as well as data that arrive continuously from the sensors installed across the world. The data supplied by Tara are very broad, because gathered in places where no one has ever been, and improve the accuracy of these forecasts by prolonging past trends.

The very fragile plankton samples were dispatched to various laboratories in several countries for analysis. We first discovered that our sampling was complete: we sampled virtually all the species of plankton existing in the oceans. They are colonized by a gigantic number of viruses, bacteria and parasites, which also play a very important role in the biodiversity. At least 30% of these species are still unknown: in some groups sampled, 90% of the species were unknown. These new compounds and structures will be investigated to serve for pharmaceuticals, chemistry and cosmetics.

In 2014, Tara returned to the Mediterranean to address a new fundamental ecological issue?

In the Mediterranean, Tara investigated the impact of plastic pollution on this landlocked sea. We directed our researches toward plastics smaller than 2 cm to determine how they enter the plankton food chain and end up in our plates.

We found plastic in all the nets that we cast. We registered hundreds of samples to investigate the type, quantity, diversity of the plastics and everything that they transport. With the currents and wind, they move fast and convey pathogenic bacteria that cling to them, algae, shellfish, insecticides and pesticides. The hydrophobic surface of plastic attracts the active compounds of persistent organic pollutants (POP) which subsequently enter the digestive system of crustaceans and fish. Every piece of plastic is colonized and there isn't a single spot in the Mediterranean with a plastic-free surface. This makes it an extremely important environmental and societal issue.

In North Africa, Europeans are still installing polluting industries, which dump their waste directly into the sea. But the inhabitants are gaining awareness: they want clean water and not work at any ecological price. The industries have to learn the value of investing in the cleanest production and not the cheapest.

The first conference was held in Monaco in March 2015, gathering together many players in the plastic world of a dozen Mediterranean countries. After the findings, particularly all the data gathered by Tara Méditerranée, we will reflect together on the ways and means to combat this pollution. The French Parliament voted in 2014 to ban single-use plastic bags from 2016, which is a fine decision.

Thanks to the Veolia Foundation, we managed to acquire the best instruments, which enabled us to compile incomparable databases. The Foundation is a rock solid partner in these exceptional adventures.

* Photo credit: N.Sardet-TaraExpeditions


Tara Expedition website


Environment and Biodiversity | France (Morbihan)
Tara Expéditions

Environment and Biodiversity | France (Hérault)
Tara Expéditions


2014/12/01 | Projects
Pollution by plastics in the Mediterranean : Tara is back home

10/03/2015 | Projets
"Plastics in the Mediterranean: beyond the facts, what solutions?"