A team of international researchers has spent the last three years collecting and studying samples of the world’s plankton. So far, among their samples, the team has identified 5,000 new viruses, 35,000 bacteria species and 150,000 single celled plants and animals. The researchers believe that the majority of these are new to science.
In the minds of many people plankton are “what whales eat”. However, the microscopic organisms that drift in the top layers of the worlds oceans represent one of our most crucial ecosystems. Together, the species referred to as plankton make up 90% of the mass of all ocean creatures. They represent Earth’s largest carbon sink, produce half of our oxygen, provide the food base that all ocean ecosystems depend upon and even have an influence on the weather.
“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,” Dr. Chris Bowler of the National Centre for Scientific Research (CNRS) told the BBC.
Despite the importance of the vast, microscopic ecosystem relatively little has been known about it until now, and the research is only beginning.
An international team of scientists set sail aboard the schooner Tara B between 2009 and 2013, covering more than 18,000 miles of ocean. Altogether they collected 35,000 samples of water from the top layers of the ocean. To date they have analyzed 579 of the 35,000 samples
“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,” said Bowler.
Most of the 35,000 microbes found have been previously described, however the researchers found many new genes.
“This is the largest DNA sequencing effort ever done for ocean science: analyses revealed around 40 million genes, the vast majority of which are new to science, thus hinting towards a much broader biodiversity of plankton than previously known,“ said Patrick Wincker, from Genoscope, CEA in a statement.
Bowler also told the BBC that they have a new dataset which describes the organization of these ocean communities.
“We have thrown all of these together to see who interacts with whom,” said Dr Bower. We now have a big dataset where we can ask: ‘who do you always find with someone else?’ or ‘who do you never find with someone else’. This helps us to describe symbiosis and interactions that go beyond grazing and predator-prey relationships,” he said.
The researchers also report that these organisms and their communities could be dramatically impacted by climate change. According to Bowler, water temperature is the key factor in determining what sorts of organisms live in which community.
“We can predict with 97% probability the temperature of the water they are living in,” he said.
With only two percent of the samples collected analyzed to date, work on the project is really just beginning. However, with each step the researchers are taking scientist’s understanding of ocean ecosystems to a whole new level.
“The finding that temperature shapes which species are present, for instance, is especially relevant in the context of climate change, but to some extent this is just the beginning. The resources we’ve generated will allow us and others to delve even deeper, and finally begin to really understand the workings of this invisible world,” said Bowler.
The research may even help the world’s space agencies as they turn to water worlds in the search for extraterrestrial life.
