Nav: Home

Lake bed reveals details about ancient Earth

July 18, 2018

Sleuthing by a Rice University postdoctoral fellow is part of a new Nature paper that gives credence to theories about Earth's atmosphere 1.4 billion years ago.

Rice's Justin Hayles and his colleagues, led by Peter Crockford at McGill University in Montreal, analyzed samples from an ancient Canadian lake bed that turned up anomalous oxygen isotopes embedded in deposits of sulfate. The oxygen provides hints at the extent of life on ancient Earth's surface.

The researchers found the planet's gross primary production - a measure of processes like photosynthesis - was a small fraction of modern levels during a stretch of the Proterozoic eon known to researchers as the "Boring Billion" because of the planet's environmental and evolutionary stability.

"The Boring Billion is called boring because it seemed for a long time that nothing remarkable was occurring on Earth's surface, but the evolution of Earth and the life on its surface continued," Hayles said.

Hayles, a National Science Foundation postdoctoral fellow, did the work as a Ph.D. student at Louisiana State University. He joined the Rice lab of Laurence Yeung, an assistant professor of Earth, environmental and planetary sciences, two years ago.

Hayles' analysis with specialized mass-spectrometry equipment was part of the effort to analyze cores taken from the lake bed. "When the project started, we were just looking to see what sulfates looked like through Earth's history," he said. "In the process, we analyzed this one set of samples and found an anomaly."

That anomaly was an unexpected amount of oxygen-17, one of three stable isotopes of oxygen. "This was shocking because we thought this anomaly could only exist when atmospheric carbon dioxide concentrations are extremely high, such as during a 'snowball Earth' event," Hayles said. "It turns out that this condition is not needed if concentrations of atmospheric oxygen (O2) and bioproductivity are much lower than today."

Because oxygen is highly reactive, it easily combined with sulfide in what was then a lake at Ontario's Sibley Basin. "When you form sulfate from sulfide, you get a little bit of O2 incorporated," he said. "That is preserved as a capsule of the ancient atmosphere, so it contains oxygen from back in the Proterozoic, 1.4 billion years ago."

The researchers suggested their discovery is the oldest direct measurement of atmospheric oxygen isotopes by nearly a billion years, taken from a time when microorganisms, including bacteria and algae, were beginning to ramp up production through photosynthesis but had not yet reached the fertile period that triggered a second "oxygenation event."

"It has been suggested for many decades now that the composition of the atmosphere has significantly varied through time," said Crockford, now a postdoctoral fellow at Princeton. "We provide unambiguous evidence that it was indeed much different 1.4 billion years ago."

The researchers said their discovery could help in the search for clues to life on other planets.

"Earth during the Proterozoic was like an alien world compared with the modern Earth," Hayles said. "The atmosphere had only a small amount of oxygen and the environment was arguably much warmer.

"Knowing how well microbial life thrived tells us what to expect on a hypothetical planet with a similar environment," he said. "There is potential that if Mars was ever sufficiently Earth-like and the right material found its way to Earth, this technique could provide similar evidence."
-end-
Scientists at McGill University, Louisiana State University, Lakehead University, the Weizmann Institute of Science in Israel, Peking University, Yale University, Princeton University and the University of California, Riverside took part in the study.

The research was supported by the Natural Sciences and Engineering Research Council of Canada, the Fonds de Recherche du Quebec-Nature et Technologies and the University of Colorado Boulder.

Read the abstract at http://dx.doi.org/10.1038/s41586-018-0349-y

This news release can be found online at http://news.rice.edu/2018/07/18/lake-bed-reveals-details-about-ancient/

Follow Rice News and Media Relations via Twitter @RiceUNews.

Related materials:

Yeung Lab: https://www.yeunglab.org

Rice Department of Earth, Environmental and Planetary Sciences: https://earthscience.rice.edu

Wiess School of Natural Sciences: https://naturalsciences.rice.edu

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,970 undergraduates and 2,934 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for quality of life and for lots of race/class interaction and No. 2 for happiest students by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview.

Rice University

Related Atmosphere Articles:

Physics: An ultrafast glimpse of the photochemistry of the atmosphere
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
Using lasers to visualize molecular mysteries in our atmosphere
Molecular interactions between gases and liquids underpin much of our lives, but difficulties in measuring gas-liquid collisions have so far prevented the fundamental exploration of these processes.
The atmosphere of a new ultra hot Jupiter is analyzed
The combination of observations made with the CARMENES spectrograph on the 3.5m telescope at Calar Alto Observatory (Almería), and the HARPS-N spectrograph on the National Galileo Telescope (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma) has enabled a team from the Instituto de Astrofísica de Canarias (IAC) and from the University of La Laguna (ULL) to reveal new details about this extrasolar planet, which has a surface temperature of around 2000 K.
An exoplanet loses its atmosphere in the form of a tail
A new study, led by scientists from the Instituto de Astrofísica de Canarias (IAC), reveals that the giant exoplanet WASP-69b carries a comet-like tail made up of helium particles escaping from its gravitational field propelled by the ultraviolet radiation of its star.
Iron and titanium in the atmosphere of an exoplanet
Exoplanets can orbit close to their host star. When the host star is much hotter than our sun, then the exoplanet becomes as hot as a star.
Astronomers find exoplanet atmosphere free of clouds
Scientists have detected an exoplanet atmosphere that is free of clouds, marking a pivotal breakthrough in the quest for greater understanding of the planets beyond our solar system.
Helium detected in exoplanet atmosphere for the first time
Astronomers have detected helium in the atmosphere of a planet that orbits a star far beyond our solar system for the very first time.
Mountain erosion may add CO2 to the atmosphere
Scientists have long known that steep mountain ranges can draw carbon dioxide (CO2) out of the atmosphere -- as erosion exposes new rock, it also starts a chemical reaction between minerals on hill slopes and CO2 in the air, 'weathering' the rock and using CO2 to produce carbonate minerals like calcite.
The changing chemistry of the Amazonian atmosphere
Researchers have been debating whether nitrogen oxides (NOx) can affect levels of OH radicals in a pristine atmosphere but quantifying that relationship has been difficult.
Hubble observes exoplanet atmosphere in more detail than ever before
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b.
More Atmosphere News and Atmosphere Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.