Climate & environment - Feb 15
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Total human impact on oceans mapped for the first time
Alok Jha, Guardian
Fishing, climate change and pollution have left an indelible mark on virtually all of the world's oceans, according to a huge study that has mapped the total human impact on the seas for the first time. Scientists found that almost no areas have been left pristine and that more than 40% of the world's oceans have been heavily affected.
"This project allows us to finally start to see the big picture of how humans are affecting the oceans," said Ben Halpern, assistant research scientist at the University of California, Santa Barbara, who led the research. "Our results show that when these and other individual impacts are summed up, the big picture looks much worse than I imagine most people expected. It was certainly a surprise to me."
Human impact is most severe in the North Sea, the South and East China Seas, the Caribbean, the Mediterranean, the Red Sea, the Gulf, the Bering Sea, along the eastern coast of North America and in much of the western Pacific.
The oceans at the poles are less affected, but melting ice sheets will leave them vulnerable, researchers said.
Different ecosystems have been affected to differing degrees: the study found that almost half of the world's coral reefs have been heavily damaged. Other areas of concern are seagrass beds, mangrove forests, seamounts, rocky reefs and continental shelves. Soft-bottom ecosystems and the open ocean fared best, but even these were not pristine in the majority of locations.
(14 February 2008)
Graphics at original. Related from National Geographic: No Pristine Oceans Left, New Map Shows
Climate changing faster than predicted: Picture gallery
Six dramatic photos
(15 February 2008)
Venture to Use Sea to Fight Warming Runs Out of Cash
Andrew C. Revkin, New York Times
Planktos, a California company that is trying to turn a profit by fertilizing the ocean with iron dust, canceled planned field tests on Wednesday, citing a lack of funds. At the company’s Web site, planktos.com, a notice blamed a “highly effective disinformation campaign” for the cancellation.
The business plan had been to sell carbon offset credits earned by creating blooms of phytoplankton that, in theory, would absorb a certain amount of the climate-warming gas carbon dioxide through photosynthesis and then sink to the seabed.
The credits would be sold in the growing market for such offsets to compensate for unavoidable emissions of carbon dioxide.
Plankton blooms happen naturally when dust containing iron settles on ocean waters, where a lack of iron otherwise prevents plankton from thriving. Huge blooms have resulted when dust from the Sahara Desert blows over the Atlantic, for example.
But efforts to replicate the process artificially have met with strong opposition from environmental groups and some marine and climate scientists.
(14 February 2008)
Good commentary from Alex Steffens at WorldChanging.
Swimmers' Sunscreen Killing Off Coral
Ker Than, National Geographic News
The sunscreen that you dutifully slather on before a swim on the beach may be protecting your body-but a new study finds that the chemicals are also killing coral reefs worldwide.
Four commonly found sunscreen ingredients can awaken dormant viruses in the symbiotic algae called zooxanthellae that live inside reef-building coral species.
The chemicals cause the viruses to replicate until their algae hosts explode, spilling viruses into the surrounding seawater, where they can infect neighboring coral communities.
Zooxanthellae provide coral with food energy through photosynthesis and contribute to the organisms' vibrant color. Without them, the coral "bleaches"-turns white-and dies.
(29 January 2008)
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