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2018-08-08. Dinosaur-Killing Asteroid Impact Made Huge Dead Zones in Oceans.

posted Aug 11, 2018, 9:15 PM by Alan Gould
By Lucas Joel, Eos/AGU. For GSS A Changing Cosmos chapter 1, Life and Climate chapter 9, Climate Change chapter 8. Excerpt: About 66 million years ago, an asteroid roughly 10 kilometers wide hit Earth in what is today the Gulf of Mexico. It brought annihilation: All the dinosaurs except for the birds went extinct; forests around the planet vanished temporarily, killing off all bird species that lived in trees; dust and other aerosols blocked the Sun, and global temperatures took a nosedive. The world plunged into a state analogous to nuclear winter. Another fallout effect of the impact, according to new work, was a depletion of oxygen in the oceans triggered by rapid global warming following the impact and nuclear winter. Such anoxia, the researchers behind the work report, devastated marine life. What’s more, this episode of anoxia may have parallels to the rapid global warming and resulting ocean anoxia being wrought by human-driven climate change today. “The global warming following the impact is one of the most rapid warmings in Earth’s history,” said Johan Vellekoop, a geologist at KU Leuven in Belgium who led the new research. “It’s on a human timescale.” He described that the postimpact warming happened over the course of only a few hundred to a few thousand years....https://eos.org/articles/dinosaur-killing-asteroid-impact-made-huge-dead-zones-in-oceans