They are small, and you may not give them much thought, but plankton—tiny marine organisms—are absolutely vital for life on Earth, researchers say.

In addition to serving as food for many of the oceans' inhabitants, including the largest animal of all, the blue whale, plankton produce at least half the oxygen we all need to survive, say scientists who have just released the most comprehensive analysis ever conducted of the globe's ocean plankton.

During a three-year global expedition, an international team of researchers has been studying plankton collected from all the world's oceans.

Plankton is an umbrella term for drifting microorganisms in the world's oceans.

The expedition's result is an enormous database of around 150,000 single-celled plants and animals along with some 35,000 species of bacteria and 5,000 viruses, most of them new to science, scientists say.

"We have the most complete description yet of planktonic organisms to date: what's there in terms of viruses, bacteria and protozoa—we finally have a catalog of what is present globally," said Chris Bowler of the National Center for Scientific Research in Paris.

The expedition conducted from the 110-foot research schooner Tara, which collected samples from 210 global sites, has resulted in a series of studies, five in all, published in the journal Science.

During the years of research, the schooner traveled around 87,000 miles, expedition executive director Romain Troublé explained.

Taking part in the $10 million series of science cruises were around 200 researchers from 35 countries representing more than 20 different scientific specialties.

Ocean plankton is part of a rich ecosystem that is vital for life on earth, the researchers point out.

"Plankton are much more than just food for the whales," Bowler said. "Although tiny, these organisms are a vital part of the Earth's life support system, providing half of the oxygen generated each year on Earth by photosynthesis and lying at the base of marine food chains on which all other ocean life depends."

They also remove carbon dioxide from the Earth's atmosphere and, through photosynthesis, convert it into organic carbon, thus buffering the effect of the increasing amount of carbon dioxide created by the burning of fossil fuels.

The plankton database that has been assembled will be released publicly and made available to scientists around the world.

With just 2 percent of the collected plankton samples analyzed so far, there is a huge amount of future research ahead to understand the part played by plankton in the well-being of the Earth. "So it's really just the beginning of the study," Bowler said.

ⓒ 2021 All rights reserved. Do not reproduce without permission.