Dr. Christopher Reinhard, assistant professor in Earth & Atmospheric Sciences, has been published in the journal Nature.
From the Georgia Tech news story:
For three billion years or more, the evolution of the first animal life on Earth was ready to happen, practically waiting in the wings. But the breathable oxygen it likely required wasn’t there, and a lack of simple nutrients may have been to blame.
Then came a fierce planetary metamorphosis. Roughly 800 million years ago, in the late Proterozoic Eon, phosphorus, a chemical element essential to all life, began to accumulate in shallow ocean zones near coastlines widely considered to be the birthplace of animals and other complex organisms, according to a new study by geoscientists from the Georgia Institute of Technology and Yale University.
Along with phosphorus accumulation came an oceanic chemical chain reaction, which included other nutrients, that powered organisms to pump oxygen into the atmosphere and waters. Shortly after that transition, which in geohistorical terms can mean about 100 million years, waves of climate extremes swept the globe, freezing it over twice for tens of millions of years each time, a highly regarded theory holds.
The elevated availability of nutrients and bolstered oxygen also likely fueled evolution’s greatest lunge forward.
After billions of years, during which life consisted almost entirely of single-celled organisms, animals evolved. At first, they were extremely simple, resembling today’s sponges or jellyfish, but Earth was on its way from being, for eons, a planet less than hospitable to complex life to one bursting with it.
You can read the entire Georgia Tech article here.
Dr. Chris Reinhard’s background is originally in evolutionary biology, but his past and current research is best characterized as falling under the label of 'deep time biogeochemistry' — He is fascinated and astonished by the observation that our planet has come to support a pervasive biosphere, and seek to reconstruct how we got here. This involves combining techniques from aqueous geochemistry, geology, and biogeochemical modeling in an effort to reconstruct Earth surface environments as they have changed over long timescales through Earth's deep history and how this evolution has been coupled with the evolution of microbial and macroscopic life. He received his Ph.D. in Earth Sciences from the University of California, Riverside in 2012 and joined Georgia Tech as an Assistant Professor in 2014.