ANSWER: To study marine microorganisms
Explanation:
- Tara expedition 2009 was to study marine microorganisms.
- Tara sailed 30,000 km across the world's oceans, with researchers collecting 35,000 samples, taking them from the very top layers of the ocean down to 1,000m below the waves.
- An international team of scientists took part in expeditions onboard the Tara schooner between 2009 and 2013.
- It travelled around the world to study CO2 captured by marine microorganisms such as plankton.