Marine scientists have completed the first ever census of the myriad creatures living in the world’s deep blue seas, a monumental accomplishment that took 2,700 researchers 10 years to accomplish. While the scientists didn’t count every single fish head, they now know more than ever before about what kinds of life inhabit the oceans, what lives where, and the number of creatures that remain. They hope that this sound science will produce sound decisions on environmental policy and fishery management.
The Census of Marine Life was officially launched in 2000. After a decade of work, some of the most interesting findings are the delineations of the ocean’s unknowns. For example, the Census upped the estimate of the number of known marine species to nearly 250,000, but still couldn’t estimate the total number of species in the ocean. It might be millions, the report says, or tens or hundreds of millions, when all the ocean’s microbes are accounted for.
The information gathered by the census has been organized into a global marine life database, but it’s far from a complete reckoning of the ocean’s denizens. A summary report of the Census’s findings says that “for more than 20 percent of the ocean’s volume, the Census database still has no records at all, and for vast areas very few.” Still, researchers say this information will provide a rough baseline, a reference point against which to measure the changes to the ocean’s populations. That will help researchers measure the impact of the warming water temperatures brought on by climate change, and can help them assess the impact of oil spills.
Some of the news from the census was ominous. A study of 10 groups of large, commercially important marine animals (such as reef fish, whales, sharks, and open ocean fish like tuna) found that at their lowest point, these groups had declined by nearly 90 percent from their historic baselines. However, after reaching their low points a few of these groups have shown signs of recovery–a hopeful indication that conservation programs can work. On the other end of the food chain, researchers found evidence of a global but patchy decline in phytoplankton, the tiny photosynthetic organisms that are a crucial source of food for many ocean critters.
Despite such worrisome news, the Census is also a celebration of the ocean’s diverse wonders. As the summary report says:
The Census found living creatures everywhere it looked, even where heat would melt lead, seawater froze to ice, and light and oxygen were lacking. It expanded known habitats and ranges in which life is known to exist. It found that in marine habitats, extreme is normal. [Highlights of a Decade of Discovery (pdf)]
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