http://www.wired.com/wiredscience/2010/05/gulf-tippingGulf Coast May Be Permanently Changed by Oil Spill
By Brandon Keim May 5, 2010 | 1:49 pm(snip)
But if oil flows continue, plant and animal populations may be pushed to species-level tipping points, their numbers so low that replenishment is impossible. When this happens, food webs change. Some remaining species become more common, and others less. Disruption favors low-level opportunists that rush into newly open niches. Local ecosystems tip. If that keeps happening, an entire region can tip.
This seems to have happened in the northwest Atlantic, where overfishing for cod led to their permanent replacement by crabs and baitfish. In the northwest Mediterranean, a confluence of overfishing, pollution and climate change fueled the reign of algae and jellyfish. There’s no going back from such transformation, at least not at human-relevant timescales. That degree of change is now conceivable across much of the Gulf of Mexico.
“If a perturbation is extensive enough, and lasts long enough, you can shift an ecosystem to an entirely different state,” said John Valentine, senior marine scientist at Alabama’s Dauphin Island Sea Lab. He called ecosystem tipping “the most extreme of possibilities,” but said if the oil flow continues for several months, it could well happen in many areas. “There could be serious consequences for foundation species,” he said.
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“The system is already becoming degraded,” said University of New Orleans ecologist Denise Reed. It’s too soon to know if local systems will tip, but “oil could push a marsh that’s already hanging by its fingernails over the edge,” she said.
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So not only were past decisions (like not including the $500,000 safety cutoff (
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x8273121 ) critically important in determining the effects of the blowout, decisions made daily right now are also critical. And it appears that the choices are not always being based on wise criteria.