Ocean May Contain One Million Species Or More
November 16, 2012

Many Marine Species Remain Unidentified And Unaccounted For

Alan McStravick for redOrbit.com - Your Universe Online

A vast undertaking has been launched to catalog the life that inhabits our world´s oceans. For the first time, a comprehensive register of marine species has been compiled. This effort was part of a massive collaboration among hundreds of experts around the globe.

Findings detailed in this report claim that one-third of all species that inhabit the world´s oceans may actually still remain completely unknown to science. This is true even though more species have been identified and described in the last decade than at any other time in our history.

According to best estimates of the researchers involved, the ocean may actually contain as many as one million species in total. To date, only approximately 226,000 of those species have been identified and described. The researchers also have another 65,000 species that have been collected that are still awaiting description.

"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," says Ward Appeltans of the Intergovernmental Oceanographic Commission (IOC) of UNESCO.

Collaborating on the study with Appeltans was Enrique Macpherson and Xabier Turon, both of the Center for Advanced Studies of Blanes (CEAB-CSIC, Spain). Macpherson states, “Bringing together the leading taxonomists around the world to pool their information has been the great merit of this research.”

One of the primary benefits of this study is that it provides a focal point upon which to coordinate conservation efforts along with providing new estimates for future extinction rates, according to the researchers involved. They expect, over the course of this century, that almost all of the currently unknown species will be discovered. Most of those yet to be identified are found disproportionately among smaller crustaceans, mollusks, worms and sponges.

The newly created World Register of Marine Species (WoRMS) is an open-access, online database. In all, 270 experts who represent 146 institutions and 32 countries have compiled the register. They state it is 95 percent complete, thus far. However, it is continually being updated as new species are discovered.

"Building this was not as simple as it should be, because there has not been any formal way to register species," Costello says.

One of the problems the teams ran into is a common occurrence in the marine taxonomy world. Synonymy happens quite frequently. This is when one animal is known by multiple scientific and common names. As an example, each whale or dolphin will have, on average, 14 different scientific names.

According to CSIC researcher Damia Jaume, from the Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB), while the species is the best known scientific moniker for an animal, synonymy will occur, and with greater variances, in animals that are either greater in size or that draw interest for different commercial purposes.

When the researchers pour over their specimen records and perform careful examination of the creatures, they fully expect that upwards of 40,000 “species” will be removed from the register, as a result of this synonymy. They do state that the loss of those species from the register will most likely be offset, however, as DNA evidence will reveal previously overlooked “cryptic” species.

Appeltans claims the importance for this register is due to the fact that, while there are fewer ocean-based species than those species that live on land, they represent a much older evolutionary lineage. This ancient lineage is fundamental to our understanding of life on Earth. Appeltans believes that WoRMS is only the start of our achieving this elevated understanding.

"This database provides an example of how other biologists could similarly collaborate to collectively produce an inventory of all life on Earth," Appeltans says.

The findings have been published online this week in the Cell Press publication Current Biology.