The Tara Oceans Project: New Opportunities and Greater Challenges Ahead

In the May 22, 2015 issue of Science magazine, several articles (including the editorial, research papers, and perspectives) were published on the Tara Oceans Project and studies related to ocean microbes [1–8]. This represents truly a milestone for studies in both ocean ecology and microbial communities. As stated on the European Molecular Biology Laboratory (EMBL) website (http://www.embl.de/tara-oceans/start/): ‘‘Tara Oceans results reveal climate change insights, and a treasure trove of novel species and genes.” The Tara Oceans project is led by the EMBL and was initiated in September 2009. Over the past few years, this project has collected more than 30,000 samples containing millions of small organisms from more than 200 ocean stations. Most samples were collected by Tara, a 110-foot research schooner that has sampled microscopic plankton at depths of up to 2000 m in all the major oceanic regions, such as the North Atlantic Ocean, during expeditions from 2009 through 2013 [8]. This project has garnered interest from numerous research groups worldwide, and received press coverage on several occasions since 2009 [9]. Three major studies related to microbial big-data mining have been performed on the samples and data collected in the Tara Oceans project. The first is a study examining the ocean microbial function and community structure [8]. The group led by Peer Bork analyzed 7.2 TB of metagenomic data (a very small fraction of the whole project) from 243 Tara Oceans samples collected from 68 locations. They discovered millions of novel sequences from viruses, prokaryotes, and picoeukaryotes, and indicated that the temperature, rather than other environmental factors, plays the most important role in shaping the microbial community compositions. The second study is of the ocean virome [3]. Brum et al. defined the upper-ocean viral community pan and core gene sets based on 43 Tara Oceans expedition samples. Their analyses support the seed-bank hypothesis, which defines ‘‘the viral community as a reservoir of dormant individuals that can potentially be resuscitated in the future under different environmental conditions” [10]. This hypothesis may help explain how oceanic viral communities maintain high local diversity. The third study is of ocean plankton interactome interpretation. Lima-Mendez et al. found that the ocean plankton interaction network is driven by both local and global patterns. Moreover, this study provided a rich resource for ocean food webs as well as biological components in ocean models [4]. Other studies published include analyses of the diversity of eukaryotic plankton [1], overview of the global ocean microbiome based on the Tara Oceans project [2], and the ways environmental characteristics of Agulhas rings affecting inter-ocean plankton transport [5].