Our estimates of the number of species on the planet may be off by as much as a factor of 10, largely due to the fact that we know so little about life in our oceans, say the authors of a new study on marine life.
"There are ... [many] things, especially in the ocean, that we don't know in terms of biodiversity," said Gerhard Pohle, acting executive director of the Huntsman Marine Science Centre in St. Andrews, N.B., according to CTV News.
The World Register of Marine Life — which includes information from the 2001-2010 Census of Marine Life — is an international effort to create a common catalogue of marine plants and animals for the scientific community. The researchers' findings, published in the journal Current Biology on Nov. 15, reveal that about one million species live in the oceans. Previous estimates put the total at around ten times that amount.
"It's staggering to think that as recently as 2011, we did not know how many species there are in the world by order of magnitude," said Pohle, who participated in the Census of Marine Life.
Part of the problem is that there is no standard method of reporting species.
"When there's a child that's born, you need to go to city hall and register the name of the baby, but when you create a new species, the only thing you need to do is publish a paper in an official journal," said Ward Appeltans, project manager of the Ocean Biogeographic Information System of UNESCO's Intergovernmental Oceanographic Commission. "For every five species that were described, two were described before."
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Another problem has been 'forgotten' species.
According to Claude Nozeres, who works with the Department of Fisheries and Oceans (DFO) Canada, a species of large 'sea pen' found in the Gulf of St. Lawrence was recently 'rediscovered' in a DFO museum collection. Nozeres, who contributed to the world register, has also helped with the Canadian Register of Marine Species, which was started in 2009.
The biggest limitation, though, is just how little we know about the creatures living in our oceans. This study's estimates indicate that as many as two-thirds of ocean species still haven't been found.
The register has already catalogued around 226,000 species, with another 65,000 in various collections that are still left to be examined. Computer projects, based on the current ideas of ocean biodiversity and the information provided by more than 250 experts from around the world, put the estimated number of ocean species at between 700,000 and one million.
"Knowing what lives in the ocean is fundamental to appreciate, care and protect it," said Appeltans.
"Having a single catalogue of all known marine species is like an index in a library. We can all start using the same species names, avoid confusion over names and make less mistakes."
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