Marine biodiversity

Researchers have published a series of papers that illustrate marine biodiversity in 25 key geographic areas around the globe – from the Mediterranean Sea to the Gulf of Mexico – providing a comprehensive "roll call" of marine life.

The species inventories released on Monday conclude work by 360 scientists to integrate both new and prior knowledge, much of it from diverse, localized sources, as well as nations' exclusive economic zones. These efforts resulted in the first comprehensive lists of marine life in diverse regions.

"The most significant thing about them is that we actually have them – and we never did before," said Ron O'Dor, co-senior scientist for the Census of Marine Life, or CoML, which commissioned the project.

CoML described the collection of biodiversity reports as a "prelude" to the main marine census findings on species distribution and abundance, scheduled for an October release in London.

Over the past decade, more than 2,700 scientists have participated in the Census of Marine Life. According to a statement summarizing the reports, CoML researchers expect the project's estimate of all known marine species to surpass 230,000 specimens.

The final figure will also include species not yet listed in the Ocean Biogeographic Information System, or OBIS – a permanent database featuring millions of records that aid both researchers and policymakers.

Biodiversity in focus – and under threat

The latest papers estimate that biodiversity levels are highest in the waters around Japan and Australia, where almost 33,000 species are known to scientists. More than 22,000 species were reported in Chinese waters.

Preserving these diverse marine ecosystems, however, requires stringent regulations. O'Dor said strict environmental protections are in place in Australian waters, but policing the thousands of islands that comprise the Philippines and Indonesia is more challenging.

But the area has other vulnerabilities: "Climate change, global warming is going to have a heavy impact in that region because it's right on the equator," he told Deutsche Welle.

Though threats to biodiversity varied across regions, the biggest challenges to marine life overall are overfishing, pollution, loss of habitat and invasive species.

"Most of the problems are associated with human influences," O'Dor said, citing as examples the creation of anoxic "dead" zones in the Gulf of Mexico due to Mississippi River runoff and mining and oil exploration.

Yet overfishing is at the top of the threat list – with much of the impact concentrated within nations' exclusive economic zones. O'Dor recommended an approach to fisheries management based on entire ecosystems, not just individual species.

"You can't manage species in isolation," he said. But crafting an approach that incorporates tens of thousands of species in waters rich in biodiversity, like those around Australia, is not easy.

Europe's enclosed seas

The Mediterranean Sea was among those regions with the "most threatened" biodiversity. It was also the region most threatened by invasive species – with 600 aliens. Most of them originated in the Red Sea and arrived via the Suez Canal.

"The problem nowadays is the velocity of this phenomenon – now species are introduced by humans more intensively," Marta Coll, lead author of the Mediterranean Sea regional synthesis, told Deutsche Welle.

Coll nevertheless described the Mediterranean as a hotspot of diverse marine life forms – with plenty still left to discover.

"For example, experts still debate how many species of fish inhabit the Mediterranean Sea," she said. Meanwhile, the threats facing this region have diversified, with climate change among the main phenomena that stand to influence marine life.

In the Baltic, another one of Europe's enclosed seas, biodiversity is also under pressure. Henn Ojaveer, lead author of the forthcoming CoML paper on the Baltic Sea, said the region has seen its biodiversity profile change over the past 40 to 50 years, and even today the situation is "completely heterogeneous."

The number of different species counted in the Baltic Sea stood at about 6,000. "This is very likely an underestimation, but the best count we have currently," Ojaveer said.

All will be revealed

On October 4, the Census of Marine Life plans to present a final count for new species discovered over the course of the decade-long project. CoML researchers would not release the number in advance, but did indicate that several thousand species were "new to science."

"The sheer number that have been discovered so far, it's amazing," said Bhavani E. Narayanaswamy, project coordinator for the CoML European Implementation Committee. "But even more so is the fact that there remains even more to be discovered."

Identifying and describing new marine species is a long, arduous process – and CoML's statement on the reports labels current knowledge of biodiversity in all regions studied as "inadequate."

Yet the census marks the most comprehensive look at the world's marine life so far, and the largest international collaboration ever between scientists in the field.

The European Commission's environment spokesman, Joe Hennon, said the Commission was grateful for CoML's contribution, calling it "an international driving force in promoting a better knowledge of the seas."

"We cannot achieve the aims of the maritime policy – exploiting new resources sustainably or protecting the marine environment – if we do not know what resources are out there to protect," Hennon said.

Open ocean, endless possibilities

The census results scheduled for release in October will take a broader view of the world's marine environment. This should yield more data on species in the open ocean beyond the continental shelf. Moreover, the data will be organized by "realm,” from ice oceans to microbes.

CoML research has also focused on both species identification and active geology in the deep sea. Maria Baker, manager of one of the realm's field projects known as "ChEss," said scientists there have listed about 190 new species since work started in 2002.

"Every time we go down to new areas, you expect to find new species," she said.

The project also led to the 2005 discovery of the first deep-sea vent south of the equator, as well as the northernmost and southernmost vents ever located. Just this year, researchers found the deepest known undersea volcanic rift in the Cayman Trough – at a depth of more than 5,000 meters.

But Baker said reaching many deepwater regions is hindered by cost and accessibility issues, and more exploration must still be done: "We're literally scraping the surface in some areas."

Author: Amanda Price
Editor: Nathan Witkop