by California Institute of Technology, October 22, 2018 in ScienceDaily
A team led by scientists at Caltech and the Jet Propulsion Laboratory (JPL), which Caltech manages for NASA, has calculated that if liquid water exists on Mars, it could — under specific conditions — contain more oxygen than previously thought possible. According to the model, the levels could even theoretically exceed the threshold needed to support simple aerobic life.
That finding runs contrary to the current, accepted view of Mars and its potential for hosting habitable environments. The existence of liquid water on Mars is not a given. Even if it is there, researchers have long dismissed the idea that it might be oxygenated, given that Mars’s atmosphere is about 160 times thinner than that of Earth and is mostly carbon dioxide.
by McGill University, July 18, 2018 in ScienceDaily
The findings, published in the journal Nature, represent the oldest measurement of atmospheric oxygen isotopes by nearly a billion years. The results support previous research suggesting that oxygen levels in the air during this time in Earth history were a tiny fraction of what they are today due to a much less productive biosphere.
“It has been suggested for many decades now that the composition of the atmosphere has significantly varied through time,” says Peter Crockford, who led the study as a PhD student at McGill University. “We provide unambiguous evidence that it was indeed much different 1.4 billion years ago.”
The study provides the oldest gauge yet of what earth scientists refer to as “primary production,” in which micro-organisms at the base of the food chain — algae, cyanobacteria, and the like — produce organic matter from carbon dioxide and pour oxygen into the air.
by Florida State University, June 11, 2018 in ScienceDaily
Global climate change, fueled by skyrocketing levels of atmospheric carbon dioxide, is siphoning oxygen from today’s oceans at an alarming pace — so fast that scientists aren’t entirely sure how the planet will respond.
Millions of years ago, scientists discovered, powerful volcanoes pumped Earth’s atmosphere full of carbon dioxide, draining the oceans of oxygen and driving a mass extinction of marine organisms.
La géologie, une science plus que passionnante … et diverse