'Biggest marine biology project in the world'

 

An Irish marine scientist has played a central role in helping to answer the question, ‘What’s in the sea?’

SCIENTISTS HAVE catalogued no fewer than 230,000 different species living in our oceans, a remarkable tally by any measure. Yet these may represent just a fifth of what is actually there, according to a major international marine census.

As of mid-February there were 16,764 distinct marine fish species known to science, yet this grows by 100 to 150 “new” fish each year. There could be as many as 21,800 marine fish actually out there, suggest the scientists behind the Census of Marine Life (coml.org).

The census has been under construction for the past 10 years, says Prof Mark Costello, an Irish marine scientist based in the Leigh Marine Laboratory at the University of Auckland in New Zealand. He has played a key role in the development and delivery of the census, which overall involved the work of 2,700 scientists from 80 countries around the world.

It got under way in 2000 after funding came from the Alfred P Sloan Foundation. The project sought to answer the disarmingly simple question, “What is in the sea?”

Coincidentally, Costello was looking at that very issue at the time. “I was trying to do something global for my MSc,” he said, and was working with Dr Simon Wilson at Trinity College Dublin to answer that question in relation to European waters.

They were working on an inventory of marine life and when he went to a workshop organised by the new census group in Washington DC, it was a perfect fit. In fact, the Census group decided to use the Irish work as a template for its own inventory.

Costello describes it as “an old-fashioned discovery programme”, akin to the work of earlier scientists who went into the wild to find undiscovered species of plants, birds animals and fish.

Yet the census was anything like old fashioned when it came to locating new species in some of the ocean’s most inaccessible places. “It is also about new technologies,” Costello said, including deep-water submersibles, satellite data transfer and GPS.

Costello is a full time lecturer and conducts research in the Leigh Marine Lab at Auckland, yet he has also spent the past 10 years contributing to the Census.

Only last month he was the lead author of a report with colleagues that provided a “roll call” of species found in 25 key ocean areas around the world. It was published in PLoS ONE.

It represented a collection of papers covering 25 “biomes”, Costello explains. These are large geographic areas, not habitats but regions that can cover huge areas and include many types of habitat. For example, the Mediterranean represented a single area and so did the waters off Antarctica.

The European Atlantic was one biome and so too was the Caribbean Sea, the Indian Ocean and the Baltic Sea. “This is the first global map of marine biomes,” he says, with the papers involving the work of 360 scientists from around the world.

Basically, the group were sampling the biome, looking to see what species were present, but not attempting to measure the quantity of any given species.

The scientists found that the species count across the 25 regions ranged from just 2,600 up to 33,000 species. About one-fifth of those found in any given location were crustaceans, with only 2 per cent of the inventory being vertebrates such as whales, sea lions, seals and turtles.

“This inventory was urgently needed for two reasons,” Costello said. “First, dwindling expertise in taxonomy impairs society’s ability to discover and describe new species. And secondly, marine species have suffered major declines – in some cases 90 per cent losses – due to human activities and may be heading for extinction, as happened to many species on land.”

The key threats include over-fishing, loss of habitat, the impact of non-native species that take hold in new locations – often via human intervention – and pollution.

Then there are the emerging threats, he adds, including rising water temperature and the gradual acidification of sea water due to carbon uptake, both linked to global warming.

This group of papers now provides a baseline against which any future rise or fall in the species count can be measured. It also shows up the marine “hot spots” where the greatest diversity appears.

For example, the waters off Australia and off Japan were particularly rich, with about 33,000 distinct species present. Other areas in which there was significant biodiversity included the oceans off China, the Mediterranean Sea and the Gulf of Mexico.

The inventory also showed up strong regional differences. For example, crustaceans – including crabs, lobsters, crayfish, shrimp, krill and barnacles – made up between 22 per cent and 35 per cent of species in places such as Alaska, at the both poles, off Brazil and other areas.

Yet this group of animals only made up 10 per cent of the inventory in the Baltic.

A few species were found in many of the biomes, with the “everyman” of the deep oceans being a fish, the manylight viperfish ( Chauliodus sloani). It was found in a quarter of the world’s marine waters.

The “most cosmopolitan” marine species, also appearing in many biomes, were forms of algae and single-celled organisms, along with seabirds and marine mammals such as the whales that travel across the oceans throughout their lives.

The Census of Marine Life has become “the biggest marine biology project in the world”, Costello says. And effectively it comes to an end this October when the final report of the Census is delivered at a conference in London.

Yet the work will go on, Costello believes. The Sloan funding has ended but the Census group will place a small secretariat for maintaining the data management systems in the International Oceanographic Commission in Paris.

A conference is also planned next year in Aberdeen to discuss what to do next. Yet even as these moves are made, marine scientists around the world will continue to do what they do best, conduct marine research. Individual teams will go on working to collect data and help to answer that little question with the big answer: “What is in the sea?”


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