Scientists estimate around 1m species inhabit oceans

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Almost a million animal and plant species may live in the oceans, a third of which are unknown to science, experts believe.

The estimate is based on the findings of a huge survey of marine life conducted by hundreds of scientists around the world.

So far, 226,000 species of organism have been identified, with a further 65,000 in specimen collections still to be 

The World Register of Marine Species (Worms) excludes life forms such as bacteria and viruses whose genetic information is not enclosed in a cell nucleus.

By studying the rate of discovery and numbers of species found in sampled areas, the scientists made a prediction of how many species in total the oceans may contain.

They arrived at a figure of between 704,000 and 972,000. Lead scientist Dr Ward Appeltans, from the Intergovernmental Oceanographic Commission of Unesco (United Nations Educational, Scientific and Cultural Organisation), based in Belgium, said: “For the first time, we can provide a very detailed overview of species richness partitioned among all major marine groups. It is the state of the art of what we know – and perhaps do not know – about life in the oceans.”

A report is published in the journal Current Biology.