Planktonic organisms such as these single-celled creatures are found throughout the oceans |
The hidden world of the ocean's tiniest organisms has been revealed in a series of papers published in the journal Science.
An international team has been studying samples of plankton collected during a three-year global expedition.
They have so far found 35,000 species of bacteria, 5,000 new viruses and 150,000 single-celled plants and creatures.
They believe that the majority of these are new to science.
Dr Chris Bowler, from the National Centre for Scientific Research (CNRS), in Paris, told BBC News: "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 catalogue of what is present globally."
This tiny crustacean was found in a sample taken in the South Pacific |
Planktonic organisms are minute, but together they make up 90% of the mass of all of the marine life in the oceans.
They include viruses, bacteria, single-celled plants and creatures (protozoa).They form the very base of the food chain, and produce - through photosynthesis - half of the oxygen we breathe.
However, until now, little has been known about this unseen ocean ecosystem.The Tara expedition, primarily funded by the French fashion designer Agnes B, set out to change that.
Many of the organisms are new to science |
So far the team has analysed 579 of the 35,000 samples that were collected
An international team of scientists took part in expeditions onboard the Tara schooner between 2009 and 2013.
It sailed 30,000km 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.
The project has cost about 10m euros.
New viruses
So far the scientists have analysed 579 of the 35,000 samples collected, presenting the results in five scientific papers.
Dr Bowler said the research was transforming our understanding of these ocean communities.
"For the viruses, we describe about 5,000 virus communities - only 39 of these were previously known.
"And for protists - unicellular organisms - we estimate something like 150,000 different taxa.
"There are about 11,000 formally described species of plankton - we have evidence for at least 10 times more than that."
The analysis has revealed that many of the organisms are sensitive to temperature
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The researchers also looked at how the different organisms interacted |
Planktonic organisms such as these tiny jellyfish and fish are found throughout the oceans |