Modeling the Ocean ecosystem with Tara GO-SEE

© David Sauveur / Fondation Tara Océan

Ten years ago this fall, the Tara Oceans expedition set sail on a 4-year voyage across the world seas — an unprecedented mission that revolutionized marine biology. The aim was to study plankton as exhaustively as possible and compile an overview of the global planktonic ecosystem. To date, this expedition allowed scientists to discover 150 million marine genes, 100,000 species and determine the distribution factor of planktonic communities through the analysis of more than 35,000 seawater samples. And so many other discoveries. Ten years later, the scientific adventure continues with the Tara Global Ocean Systems Ecology & Evolution (GO-SEE) project. Tara Oceans’ data are now globally recognized, their exploitation continues and the horizon of knowledge keeps widening!

Building on the advances in global ecosystem achieved during the first decade of the Tara Oceans project (2009-2019), and published in the leading scientific journals, we were able to structure this project into a federation for research (FR2022), a virtual institute bringing together 22 international teams (11 in France, including the Tara Ocean Foundation) around a new odyssey: Tara GO-SEE (Global Ocean Systems Ecology & Evolution).

The goal is to understand the fundamental ecological and evolutionary principles of a first complex ecosystem on our planet, for the purpose of establishing a robust quantitative theory of its dynamics and resilience. Between atoms, cells and organisms, and climate, stars and galaxies, on which hundreds of billions of euros worth of studies were spent, are ecosystems — the self-organized, adaptive living networks interacting with the environment on multiple scales. Ecosystems may be the most complex “objects” in our universe, because they integrate all living things into their physical and chemical matrix. For this reason, they were long exempted from scientific measurements and seemed unfathomable. The results of the Tara Oceans project proved otherwise. Through systematic sampling of marine plankton on different scales — taxonomic (from viruses to animals), systemic (from genes to organisms) and spatial temporal (4 years spent sailing the world’s oceans) — we generated the largest database of DNA/RNA sequences and images of organisms at the level of the biome.

Protists-mix-Atlantic©C.Sardet_1200© Christian Sardet / Plankton Chronicles

For the first time, we can perceive the frontiers of a global ecosystem’s real complexity. We have developed concepts and methods to integrate genetic, imaging and environmental (biophysical and chemical) data, and are beginning to discover the structure and dynamics of the large planktonic life network.

In Tara GO-SEE, we propose to pursue our “pan-ecosystemic” approach over the next 10-15 years, to answer some fundamental questions. How did life become diversified and complex on an ecosystemic level? How do organisms interact and what are the rules for self-organization of living organisms in ecosystems? How do we integrate the complexity of life in modeling the ocean’s major emerging functions (carbon pump, climate, food webs and fisheries)? Our main hypothesis is that organism interactions and their collective behaviors are the basis of the mechanisms that generate biodiversity and regulate communities. However, these “symbiotic” forces have not yet been quantified or modeled in terms of ecology and evolution. An approach at the ecosystemic level is needed to develop a holistic understanding of the processes that are likely to regulate our world.

To do this, not only will we continue to exploit ecomorphogenetic data from the Tara Oceans and Tara Pacific expeditions, but we will also develop new analytical approaches to fill information gaps and to integrate and formalize heterogeneous data. Finally, we will set sail with a new oceanographic approach, flexible and responsive enough to measure the key processes of the ocean ecosystem on relevant spatial and temporal scales.

Colomban de Vargas,
Scientific coordinator of the Tara Oceans and Tara Pacific expeditions and CNRS Research Fellow at the Roscoff Marine Station (CNRS/UPMC).

 

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