One of the most dramatic mass extinctions in history, the End Permian event 250 million years ago, took out 95 percent of species on Earth. Scientists have long believed this holocaust began when a mega-volcano erupted in what is now Siberia, polluting the atmosphere and causing acid rain for possibly thousands of years. But now a new study suggests that the first wave of extinctions after the volcano were self-perpetuating.
When biological diversity is hobbled from too many species extinctions, it sets up a feedback cycle that prevents new species from evolving to fill empty nodes in the food web. Scientists call this "carbon chaos" because it's a way of using chaos theory to explain the carbon cycles that drive all life.
Over at Wired, environmental journalist Brandon Keim has a fantastic article about this new study, which presents persuasive evidence that carbon chaos amplified and worsened the extinctions during the End Permian.
During that time, the carbon cycle - the flow of life's essential element through all Earth's systems - oscillated wildly, a period known as a "chaotic carbon interval." And rather than rebounding and steadily filling suddenly open niches, as might be expected, life appears to have entered a boom-and-bust cycle. Species flourished and collapsed, over and over, a planet-level version of the jellyfish bloom-and-bust cycles now seen in overfished oceans.
One seemingly plausible explanation is ongoing Permian-Triassic volcanic activity, which could have decimated new species as they arose. However, carbon chaos continued for millions of years after volcanoes cooled. A newer explanation, favored by Whiteside, draws from the work of ecological theorists who say that, at planetary scales as well as local, complexity generates resilience.
Applied to mass extinctions, this idea is somewhat radical - but in a coral reef or rainforest, or even a computer network, it's an accepted notion. Just as distributed systems are more secure than a handful of mainframes, ecosystems composed of many interlocking and sometimes redundant species are especially sturdy. Because they're stable, they in turn nourish life's diversification over evolutionary time. It's a biological catch-22: A richness of life requires stability to develop, but stability requires a richness of life.
Obviously this has dramatic implications for us today, since we are rapidly erasing nodes from our food web as animals become extinct or endangered. If biological diversity collapses and we enter a period of carbon chaos, it may be over a million years before our ecosystems recover.
Read the whole article via Wired
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