Snowball Earth May Have Spawned Early Animals

New data collected in scientific studies lend additional credence to the Snowball Earth theory, a daring idea that state the planet was covered pole-to-pole by a thick layer of ice hundreds of millions of years ago.

This theory states that glacial events associated with this planetary state led to the appearance of the earliest animals. A new study by biogeochemists at the University of California in Riverside (UCR) supports this belief with new evidence.

The thick sheet of ice that covered Snowball Earth returned time and again throughout our planet's history, experts say, and each of these glacial instances lasted for millions of years at a time.

The recurring glaciations may have take place between 750 and 580 million years ago, when life as we know it began to develop and flourish, and biodiversity appeared where there was none before.

UCR scientists now explain that the main effect the glaciation periods had was enrich the ocean with the chemical element phosphorus, which experts believe played a huge role in the development of life.

“In the geological record, we found a signature for high marine phosphorus concentrations appearing in the immediate aftermath of the Snowball Earth glacial events,” explains Noah Planavsky.

“Phosphorus ultimately limits net primary productivity on geological timescales. Therefore, high marine phosphorus levels would have facilitated a shift to a more oxygen-rich ocean-atmosphere system,” the expert adds.

“This shift could have paved the way for the rise of animals and their ecological diversification. Our work provides a mechanistic link between extensive Neoproterozoic glaciations and early animal evolution,” he says.

Planavsky is the first author of a new research paper detailing the findings, which appears in the October 28 issue of the top scientific journal Nature. He is also a graduate student in the UCR Department of Earth Sciences.

The team conducted its investigation by measuring the concentrations of phosphorus in iron-rich chemical precipitates, which were recuperated from core samples and drill carried out around the world.

Elevated levels of phosphorus, experts believe, can be linked to spikes in global oxygen production patterns, which were caused by photosynthesis.

“High phosphorus levels would have increased biological productivity in the ocean and the associated production of oxygen by photosynthesis,” the UCR student says.

“Much of this organic matter is consumed, in turn, as a result of respiration reactions that also consume oxygen. However, the burial of some proportion of the organic matter results in a net increase of oxygen levels in the atmosphere,” Planavsky concludes, quoted by SpaceRef.