A scientific team led by Professor Robert Frei at the University of Copenhagen in Denmark, and including scientists from Newcastle University, UK, and universities in Uruguay and Southern Denmark, have for the first time managed to plot the rise and fall of oxygen levels in the Earth's atmosphere over the last 3.8 billion years.
By analysing the isotopes of chromium in iron-rich sediments formed in the ancient oceans, the team has found that a rise in atmospheric oxygen levels 580 million years ago was closely followed by the evolution of animal life.
Published today in the academic journal Nature, the data offers new insight into how animal life – and ultimately humans – first came to roam the planet.
"Because animals evolved in the sea, most previous research has focussed on oceanic oxygen levels," explains Newcastle University's Dr Simon Poulton, one of the authors of the paper.
"Our research confirms for the first time that a rise in atmospheric oxygen was the driving force for oxygenation of the oceans 580 million years ago, and that this was the catalyst for the evolution of large complex animals."
Distinctive chromium isotope signals occur when continental rocks are altered and weathered as a result of oxygen levels rising in the atmosphere.
The chromium released by this weathering is then washed into the seas and deposited in the deepest oceans - trapped in iron-rich rocks on the sea bed.
Using this new data, the research team has not only been able to establish the trigger for the evolution of animals, but have also demonstrated that oxygen began to pulse into the atmosphere earlier than previously thought.
"Oxygen levels actually began to rise 2.8 billion years ago" explains Dr Poulton.
"But instead of this rise being steady and gradual over time, what we saw in our data was a very unstable situation with short-lived episodes of free oxygen in the atmosphere early in Earth's history, followed by plummeting levels around 2 billion years ago.
"It was not until a second rise in atmospheric oxygen 580 million years ago that larger complex animals were able to get a foothold on the Earth."
Dr. Simon Poulton | EurekAlert!
Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University
NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
19.02.2018 | Information Technology
19.02.2018 | Ecology, The Environment and Conservation
19.02.2018 | Life Sciences