Four years of study shows plankton is more than just whale food

Scientists from the Tara Ocean expedition unveil the most comprehensive analysis ever undertaken of the world’s ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.

AT SEA (TARA OCEANS EXPEDITION) – Scientists have unveiled the most comprehensive analysis ever undertaken of the world’s ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.

The researchers spent 3-1/2 years aboard the schooner Tara, taking 35,000 samples of plankton from 210 sites globally, determining the distribution of the organisms, tracking how they interact with one another and carrying out genetic analyses.

Tara Expeditions Executive Director Romain Troublé said the Tara Oceans project was a project undertaken in the public interest, but financed by private money.

“The mission has been run on this vessel over many oceans. Over the four years of this programme the boat welcomed on board about 200 scientists from 45 countries spending their time on board to sample the very microscopic life under the ocean, the plankton,” he said.

Plankton include microscopic plants and animals, fish larvae, bacteria, viruses and other microorganisms that drift in the oceans.

Speaking in 2012 when the vessel was docked in London, Chris Bowler, a research director at France’s National Center for Scientific Research, and one of the scientists involved in the study published in the journal Science, said the importance of plankton shouldn’t be underestimated.

“When you do take a microscope and look at the average drop of water you see that it’s really teeming with all kinds of microscopic life that do incredibly important functions for managing the planet, ensuring the well-being of the planet, 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.

“Close to half of the oxygen generated by the oceans we believe comes directly from diatoms,” Bowler told Reuters, referring to the common type of algae that uses sunlight to photosynthesise and produce oxgen.

“That basically means every fifth time that you breathe you’re breathing oxygen which we can directly trace back to diatoms, so they’re sort of as important as a tropical rain forest in terms of their global contribution,” he added.

The scientists conducted the largest DNA sequencing effort ever done in ocean science, pinpointing around 40 million plankton genes, most previously unknown.

Much of the plankton was more genetically diverse than previously known. However, the genetic diversity of marine viruses was much lower than anticipated.

By removing carbon dioxide from the atmosphere and converting it into organic carbon via photosynthesis, plankton provide a buffer against the increased carbon dioxide being generated by the burning of fossil fuels, Bowler said.

The scientists found that most of the interactions between plankton organisms were parasitic. They also found evidence for widespread dispersal of viruses in the oceans.

Troublé said the schooner sailed about 87,000 miles (140,000 km) during the research voyage.

Tara Ocean’s mission, he said, “has been a joint work between the Consortium of Scientists, 21 laboratories across the world and the Foundation Tara Expedition – a non-profit enterprise that we started in 2003 and this foundation’s goals are really to support science at sea, but also to try to share and accelerate the gap between hard science and the general public, hard science and the kids, and hard science and the politicians.”

Those aboard endured hardships such as being locked for 10 days in Arctic ice, storms in the Mediterranean Sea and in the Magellan Straight, and sailing through the Gulf of Aden with protection from the French navy against pirates.

But the vessel also provided a platform for learning, with exercises including inviting children on board and local lectures during their voyages.

Politicians too were involved, including United Nations Secretary-General Ban ki-Moon.

The real value of the research though, according to Troublé, is the highlighting of the effects pollution is having on the ocean.

“The Foundation Tara Expeditions is really working hard on three main ideas – ocean and climate, ocean and biodiversity – as we did on Tara Oceans – and ocean and pollution – ocean and man, man’s impact on the ocean,” he said.

“The first results of this project, on this Tara Oceans project, are very important, especially in this year 2015, as France is welcoming the Climate Conference of the United Nations in Paris in December 2015,” he added.

“Since we really want to emphasise the role of the ocean in the 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, and this machinery works because the ocean is in good health,” he said.

The team want to use the data collected to find out which plankton are most adapted to which kinds of conditions, in terms of the pollution and acidity levels of the water they’re found in, which they hope will allow them to predict how the ocean will look hundreds of years from now.