Tiny ocean creatures collectively called plankton are mostly thought of as food for whales and other large marine animals. But a four-year global study has discovered, among other things, that plankton are a major source of oxygen on our planet.
Plankton are animals, algae, bacteria and other microscopic organisms invisible to the naked eye. They inhabit the upper layers of the world’s oceans, seas and freshwater.
In a project called Tara Oceans, led by the French nonprofit organization Tara Expeditions, 200 scientists from 45 countries took turns researching plankton aboard a two-mast schooner.
Setting sail in September 2009, the ship, Tara, visited 210 sites, where scientists collected 35,000 samples, researching the lives, genetic makeup and movement of the tiny creatures.
Chris Bowler, Tara Oceans' scientific coordinator, said the researchers discovered that plankton are responsible for much of the well-being of our planet. The creatures are "generating the oxygen we breathe, removing carbon dioxide from the atmosphere and generally maintaining this Earth in a state that is habitable for us human beings,” he said.
Bowler said that close to half of the oxygen that we breathe comes from diatoms —, tiny, photosynthesizing algae that inhabit the sunlit layer of all water bodies. “That basically means every fifth time that you breathe, you're breathing oxygen which we can directly trace back to diatoms," he said. "So they're sort of as important as a tropical rain forest in terms of their global contribution.”
Expedition executive director Romain Troublé said the study clearly showed that the ocean is the Earth’s climate machine.
“We believe that the ocean is also the main driver of the climate change, the main mitigator in the way that the ocean and the life in the ocean is storing carbon dioxide, storing heat," he said. "And this machinery works because the ocean is in good health.”
Different groups of scientists studied different things. For instance, one group cataloged over 40 million previously unknown plankton genes. Another found that most of the plankton interactions were parasitic.
The collected data will be used to determine which of the organisms are most adaptable to changing water conditions.
Results of the first studies were published in the May edition of the online scientific journal Science, which said that many analyses would follow.