[Global] 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 international team of researchers spent three and a half 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.
Plankton include microscopic plants and animals, fish larvae, bacteria, viruses and other microorganisms that drift in the oceans.
“Plankton are much more than just food for the whales,” says Chris Bowler, a research director at France’s National Centre for Scientific Research, and one of the scientists involved in the studies published in Science today.
“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.”
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 says.
The scientists conducted the largest DNA sequencing effort ever done in ocean science, pinpointing around 40 million plankton genes, most previously unknown.
Tara Expeditions Executive Director Romain Troublsays the schooner sailed about 140,000 km during the research voyage.
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.
The research vessel has also collected information about the oceans’ depth, temperature and salinity, and the interactions between the tiny life forms that live in the water.
“When we mapped how planktonic organisms — from viruses to small animal larvae — interact with each other, we discovered that most of those interactions are parasitic, recycling nutrients back down the food chain,” says Jeroen Raes from the Flanders Institute for Biotechnology and Free University of Brussels.
When it came to viruses, the team identified more than 5,000 viral populations throughout upper parts of the world’s oceans.
“Surprisingly despite several decades of prior marine viral research, only 39 of these 5,000 viral populations were similar to previously known viruses,” says researcher Jennifer Brum from the University of Arizona.
The new information “has generated a treasure trove of data available to anyone willing to dive in,” says an accompanying Perspective article in Science , authored by E. Virginia Armbrust at the University of Washington, Seattle and Stephen Palumbi of Stanford University.
“Together, these studies deliver compelling evidence for extensive networks of previously hidden biological interactions in the sea.”
Photo: Plankton collected in the Pacific Ocean. (CNRS/Tara Expitions: Christian Sardet)
View original article at: Huge study of tiny plankton a ‘treasure trove’