A million species of animals and plants live in the ocean, say
scientists
The first official register of what lives in the oceans has revealed
that the marine environment may be home to as many as a million species
of animals and plants, but only about a quarter of them have actually
been formally described.
Previous estimates of the number of species living in the oceans have
ranged wildly from a few hundred thousand of several million, but the
latest estimate is based on the first proper attempt to draw up an
accurate inventory of marine life.
Although more ocean species have been discovered in the past decade
than in any previous 10-year period - and about 65,000 newly
"discovered" species are still waiting to be given formal scientific
names - scientists believe that at least a third of all the marine life
forms may be completely unknown to science.
The World Register of Marine Species, an on-line international
database, has been put together by 270 marine biologists from 146
institutions in 32 countries in an attempt to answer the age-old
question: what lives in the sea?
It found that about 226,000 species have been formally described by
scientists - about 20,000 in the past decade alone - but that the total
number could be three or four times higher, although unlikely to be more
than a million as some previous estimates have suggested.
"More species than ever before are being described annually by an
increasing number of [scientists].
If the current trend continues, most species will be discovered this
century," the scientists say in a study published in the journal Current
Biology.
"The question of how many marine species exist is important because
it provides a metric of how much we do and do not know about life in the
oceans. We have compiled the first register of the marine species in the
world and used this baseline to estimate how many more species...may be
discovered," they say.
One of the biggest obstacles to working out the total number of
marine species is the problem of synonyms - many animals and plants have
been given more than one name, and in some cases multiple names."The
occurrence of as yet unrecognised synonyms is one of the most
significant problems in estimating the true number of described
species," the study says.
The sperm whale of Moby Dick fame, for instance, has 19 synonyms,
nine of which were given to the species by just three experts, the study
found.
Another problem was that some species have in fact been found when
analysed genetically to consist of two species.
The killer whale and the common bottle-nose dolphin, for instance,
have each been split into two or more species as a result of genetic
analysis.
"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 ocean," said Ward Appeltans of the Intergovernmental
Oceanographic Commission.
- The Independent
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