The oceans on the Earth contain more microorganisms than previously thought, according to scientists, who say that just one liter of any seawater can hold almost 20,000 different types of bacteria. Reporting in the journal Proceedings of the National Academy of Sciences, lead researcher Mitchell Sogin and colleagues say that the microbial biodiversity is immensely more than estimated.
"Microbiologists have formally described 5,000 microbial species. This study shows we have barely scratched the surface," said Sogin of the Marine Biological Laboratory. "In our new study, we discovered more than 20,000 in a single liter of seawater, having expected just 1,000 to 3,000. The number of different kinds of bacteria in the oceans could eclipse 5 to 10 million." The study is a part of an international venture attempting to catalogue all life forms in the oceans.
Scientists were able to find microbes at eight sites in the Atlantic and Pacific Oceans even at depths, which reached 550-4,100m (1,800-13,500ft). The eight sites included both hot and cold environments even to the extreme as well as a hydrothermal vent, which is situated on an underwater Pacific volcano off the Oregon coast. Scientists expected to discover only about 2,000 species per liter of seawater, but were amazed to find a staggering amount.
"Microbes constitute the vast majority of marine biomass and are the primary engines of Earth's biosphere," said Dr Sogin. "These observations blow away all previous estimates of bacterial diversity in the ocean. It really points to our lack of knowledge and how much more there is to learn." The researchers used a new technique called as "454 tag sequencing" to look at thousands of unusual microbes. They think that if the current species are wiped out, then a new one with a more suitable genetic makeup could follow them.
"We know there will be major ecological changes on our planet. The microbial world has to survive the changes and one way is to have a lot of novelty in your genome so that you can cope with different environmental conditions," Dr Sogin said.
