Tara Oceans Expedition opens up a treasure chest for phycologists

The Tara Oceans consortium recently published five scientific papers in the journal Science revealing the initial wave of scientific results from the first six years of the project.1-5 The findings show the extraordinary diversity of plankton in the world’s oceans, uncover many of the interactions between them, and reveal how plankton impact and are influenced by the environment. This publication is accompanied by two editorials by Eric Karsenti (Director of Tara Oceans) and colleagues in the journal Molecular Systems Biology that describe the history of the project and reveal some of the challenges of translating such a vast amount of data into knowledge.6,7

The special issue of Science devoted to Tara Oceans includes five publications that unveil the vast amount of scientific data arising from a project that has grasped the attention and imagination of both scientists and the general public. Starting as a grass-roots initiative by a group of scientists, the research-enabled schooner Tara spent almost 4 years circumnavigating the globe and going around the Arctic Circle. Overall, Tara Oceans sampled plankton at more than 210 sites and at multiple depth layers in all the major oceanic regions. The scientific sampling followed protocols developed to capture the entire morphogenetic complexity of the plankton community across several orders of size (from 0.02 µm to a few mm), together with an extensive range of physico-chemical parameters. 8 Sampling typically lasted 60 hours per station. The 35,000 samples collected form the basis for extensive processing and data integration on land.

The sequencing of almost a billion genetic barcodes, short genetic sequences that help identify organisms, has revealed more than 150,000 new genetic taxa of eukaryotic plankton, a number that far surpasses previous estimates. An ocean microbial reference gene catalog of 40 million genes from marine microbes was also described, as were more than 5,000 viral communities, more than 99% of which have not been described previously. The scientists further determined the “interactome” of the plankton living in the world’s oceans – the social network between bacteria, viruses and planktonic eukaryotes. The high prevalence of parasites within this ecosystem was one of the significant findings of this hidden world. For the first time, scientists now have a picture of the structure and function of much of the global ocean microbiome. 

The depth of DNA sequencing and extensive sampling make the data set an unprecedented public resource for phycologists interested in exploring the ecology and evolution of marine plankton, and likely signals the start of a new era of omics-enabled research in microbial oceanography. Feast your eyes on the May 22 special issue of Science, it’s not every day you’ll see plankton gracing the front cover of this prestigious journal!

1. Sunagawa et al. (2015) Science 348: 1261359.
2. Villar et al. (2015) Science 348: 1261447.
3. Brum et al. (2015) Science 348: 1261498.
4. de Vargas et al. (2015) Science 348: 1261605.
5. Lima-Mendez et al. (2015) Science 348: 1262073.
6. Karsenti (2015) Molecular Systems Biology 11: 811.
7. Sunagawa et al. (2015) Molecular Systems Biology 11: 809.
8. Pesant et al. (2015) Scientific Data 2: 150023.