Census of the Sea: What’s Really Living in Earth’s Water?

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Right now in the US, Americans are (hopefully) filling out their census forms so the government can accurately tally our population and redistribute funds and services where they’re needed. At the same time, another project that has been underway for the past decade is coming to a close: A ‘census’ aimed at counting the world’s marine life.

While ordinary folks might consider the globe as having many oceans, marine scientists tend to think of the world has having one huge ocean—most of it unexplored. In an extraordinary scientific endeavor, researchers around the world have been collaborating for the past decade to identify, classify and compile a census of all the known and unknown life that inhabit even the deepest, darkest seas—from the simplest one celled-organisms to the great blue whale. Salt water covers about 70 percent of the earth’s surface, and while those 323 million cubic miles of marine habitat provides the richest bio-diversity on the planet, it is also the least understood. Before the census got underway, the total tally of known marine life was estimated to be 230,000 species, but scientists now believe that there are at least three times that many waiting to be discovered and named. The actual number could be as high as a million or more.

The $650 million project called the Census of Marine Life, which was launched in 2000 and will issue its report in October, has garnered the expertise of 2,000 scientists from eighty countries in a never-before conducted exploration. There are 14 different field projects devoted to various categories of underwater creatures, about 90 percent of which require a microscope to see.

“There are some aspects of oceanography that really deserve treatment as a single global focus, and we think biodiversity is one of them,” says Ann Bucklin, a lead principal investigator of the zooplankton project of the Census of Marine Life and head of marine sciences at the University of Connecticut. ”That means we want to know all the marine animals that live everywhere on the earth and in the ocean, and the only way you can do that is with an international and genuinely global team of researchers.”

The Census of Marine Life has been largely underwritten by the Alfred P. Sloan Foundation and is using some of the most sophisticated technology available to gather specimens, identify and classify the species, and map their distribution and abundance. In other words, the goal of the Census of Marine Life is not only to identify species and their abundance, but also to discover where they live. “Even more than discovering new species, we’ve also extended our understanding in new places in the ocean,” Bucklin tells Tonic. “There are many questions about what lives in the deepest, darkest parts of the ocean, near the bottom, because we have rarely sampled from there.”

Bucklin says this historic first worldwide scientific collaboration is inspired by the spirit of early British explorers and expeditions. Charles Darwin ventured from England to the Galapagos Archipelago on the HMS Beagle. The British HMS Challenger launched in 1872 with 240 scientists, seamen, and crew and went around the world exploring marine life for several years. And researchers feel exceptionally lucky to have the funding to do this oceanographic work worldwide. This kind of financial support almost never happens since, most usually, scientific funding is generated within a country for its own scientists, Bucklin says.

“Discovery is difficult to fund,” she says. “The global vision is one aspect that sets this census apart. The second is the expeditionary focus. It’s discovery. It’s finding out what’s there in places we’ve never been before.”

The zoolankton project, for example, is using sophisticated equipment to identify the DNA barcode of 7000 zooplankton species. Massachusetts Institute of Technology has developed an advanced sonar system that has enabled scientists to take sonar-based snapshots of deep-sea dwelling fish. And, at the Marine Biological Laboratory in Woods Hole on Cape Cod, scientists like Linda Amaral-Zettler and colleagues are using a super-sensitive sequencing machine to map the genetic codes of thousands of microbes collected from around the globe. The bugs are dried and the DNA is extracted and delivered by mail in tubes or in liquid form packed with dry ice.

“One estimate is that there are 20,000 different type of species of bacteria in a liter of water. In the Encyclopedia of Life, there are 1.9 million known species of life on earth. We’re talking about potentially reaching that with microbes. We’re still trying to estimate that,” says Amaral-Zettler. “The tricky part is people can relate to shrimp—they have trouble relating to microbes. But bacteria is critical to life. Really, we have more bacterial cells in our bodies than human cells—about ten times more bacteria than human cells. Just because we can’t see it doesn’t mean it’s not important. Microbes can have huge consequences on the way we live in terms of even climate. Carbon dioxide in the ocean is linked to microbial life—all of this is connected and it’s important to remember that 50 to 90 percent of the biomass in the ocean is microbial.”

The project has launched hundreds of research vessels—some of them, such as an expedition to the pirate-populated area of Celebes sea in Indonesia, on board fishing boats adapted for scientific exploration. Their findings have been surprising: marine life in the most inhospitable places, ranging from dark, cold waters 5,000 meters down—or more than 3 miles below the surface—to a hot undersea vent blowing 764 degrees Fahrenheit in the mid-Atlantic. (Remember the amazing shrimp that showed up just last month in Antarctic waters that scientists previously thought were too cold and dark to be inhabited by any life form at all?)

“We are going to these places in new corners of the ocean and finding out what’s there. We’ve seen more of the ocean than we would ever have ever been able to expect to see. That, for an oceanographer, is just a huge adventure,” says Bucklin.

The hope here is nothing short of making marine life count.

Originally published on Tonic


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