David Grinspoon Quote
Yet among the multiple animal inventions at the dawn of the Cambrian were new forms of mobility. A number of critters began burrowing into these mats and braving the toxic soils beneath them. These digging, tunneling creatures are known as bioturbators, basically life that stirs up the ground. In fact, the fossils that officially define the beginning of the Cambrian in the geological record, Trichophycus pedum, are identified by the looping, burrowing patterns they left in the seafloor. Once this bioturbating disturbance of the Cambrian seafloor got started, it began changing the texture and chemistry of the dirt in ways that made it more inviting for other burrowing creatures. Oxygen began penetrating the loosened soil beneath the mats, neutralizing the lethal hydrogen sulfide. This started a positive feedback.
Yet among the multiple animal inventions at the dawn of the Cambrian were new forms of mobility. A number of critters began burrowing into these mats and braving the toxic soils beneath them. These digging, tunneling creatures are known as bioturbators, basically life that stirs up the ground. In fact, the fossils that officially define the beginning of the Cambrian in the geological record, Trichophycus pedum, are identified by the looping, burrowing patterns they left in the seafloor. Once this bioturbating disturbance of the Cambrian seafloor got started, it began changing the texture and chemistry of the dirt in ways that made it more inviting for other burrowing creatures. Oxygen began penetrating the loosened soil beneath the mats, neutralizing the lethal hydrogen sulfide. This started a positive feedback.
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About David Grinspoon
His research focuses on comparative planetology, with a focus on climate evolution on Earth-like planets and implications for habitability. He has also studied, written and lectured on the human influence on Earth, as seen in cosmic perspective.
He has published four books, Venus Revealed, which was a finalist for the Los Angeles Times book prize, Lonely Planets: The Natural Philosophy of Alien Life, which won the 2004 PEN literary award for nonfiction, Earth in Human Hands, which was named one of NPR's Science Friday "Best Science Books of 2016" and Chasing New Horizons: Inside the Epic First Mission to Pluto, co-authored with Alan Stern. He is adjunct professor of Astrophysical and Planetary Science at the University of Colorado, a former Fellow of the Institute for Cross-Disciplinary Engagement at Dartmouth College and a former Distinguished Visiting Scholar in the College of the Environment at Wesleyan University.