From 2009 to 2013, the 110-foot schooner Tara sailed around the world, collecting plankton samples from more than 200 sites, some as deep as 6,500 feet down in the ocean, Science magazine reports. Fighting volatile weather, funding issues, and even the threat of pirates, the Tara expedition team still managed to cull an impressive database of plankton, the beings that produce half the planet's oxygen and include "microscopic plants and animals, fish larvae, bacteria, viruses, and other microorganisms," per Reuters. What the samples revealed, per the BBC: about 5,000 virus "communities," 35,000 bacteria species, and a stunning 150,000 protozoa—single-celled plants and creatures. Scientists believe most of the discoveries in the exhaustively culled database have never been IDed before.
"There are about 11,000 formally described species of plankton—we have evidence for at least 10 times more than that," Dr. Chris Bowler of Paris' National Center for Scientific Research tells the BBC. And what scientists have put under the microscope is only a small percentage of their complete inventory: They've pored over just 579 of the 35,000 or so plankton samples collected, the broadcaster reports. They also completed what Tara Expeditions is calling the "largest DNA sequencing effort ever done for ocean science" and found 40 million genes, only 20% of which were previously known. One (mostly) common denominator among many of the collected organisms: They're sensitive to changes in the mercury. "With changing temperatures as a result of climate change, we are likely to see changes in this community," Bowler says. (Read the latest on another amazing discovery from the deep.)