Somewhere between one-quarter and one-half of every breath you take comes from oxygen produced by microorganisms in the ocean. These tiny creatures at the bottom of the food chain are the basis for so much life on this planet, and yet we know very little about them. In an effort to rectify this, a team of scientists set sail for three years on a 110-foot schooner named Tara to collect and study samples of these microorganisms. They especially wanted to better understand how climate change affects these tiny creatures.


Click to Enlarge. © Wedodata/ Tara Expéditions

They ended up writing five papers for the journal Science about the 35,000 samples of plankton, bacteria, krill, viruses, and the mostly unicellular protists and archaea they collected from the world's oceans.

While the details are highly technical, the insights are important to everyone. "How can we save the whales if we can't save the krill?" Science editor Marcia McNutt told NPR. "There's something about the tragedy of the commons here."

Check out some of the photos of the creatures collected during this massive project involving 250 people.

©M.Ormestad/Kahikai/Tara

These parasitoid crustaceans called hyperiid amphipod eat sea salps, then use the empty gelatinous husks as protective shells.

© Christian Sardet/ CNRS/ Sharif Mirshak/ Parafilms/ Tara Expeditions

This male Sapphirina copepod collected in the Mediterranean Sea reflects and diffracts light through tiny plates in its epidermal cells.

©Christian Sardet/CNRS/Tara Expéditions

This Lauderia annulata, collected and photographed in the Indian Ocean, is one of the largest known diatoms (200 microns). Clumps of chloroplasts, which conduct photosynthesis, are visible as green and yellow particles within this cylindrical single cell creature encased in a light­-reflecting glass shell. 

©Christian Sardet/CNRS/Tara Expéditions

This is a mixture of multicellular plankton collected in the Pacific Ocean with a mesh net just 0.1mm wide. The group includes small zooplanktonic animals, larvae, and single-cell protists.

©Christian Sardet/CNRS/Tara Expéditions

The Tara  expedition collected these small zooplanktonic animals in the Indian Ocean: A molluscan pteropod on the right, and two crustacean copepods. That fleck of orange on the left is paint from Tara's hull.

©Christian Sardet/CNRS/Tara Expéditions

This small medusa collected in the Mediterranean Sea is a close relative of Turritopsis, thought to be a so-called "immortal" jellyfish.