Algal explosion allowed human and animal life to evolve, according to researchers

Scientists from ANU say that an explosion of algae 65 million years ago resulted in life on earth.
By Angela Heathcote August 17, 2017 Reading Time: 2 Minutes Print this page

ANCIENT SEDIMENTARY rock from central Australia has revealed how animals first appeared on earth, pointing to an explosion of algae that occurred 650 million years ago, which researchers say revolutionised our ecosystems.

The new study published in Nature today provides long awaited answers to one of the biggest questions in science: how did animals and humans first appear on earth?

The team of researchers from the Australian National University (ANU) crushed a portion of rock dating back to the period just after the earth began thawing and extracted ancient molecules.

“What we found was quite spectacular and was really, totally unexpected,” Jochen Brocks told ABC News.

“We found out that these molecules of more complicated algae increased in a big burst around 650 million years ago,” around the time when animals first started appearing.

“The reason why that is so exciting is it is just before animals appeared and also exciting because it happened after the biggest climatic catastrophe in Earth’s history,” he explained.

algal explosion

Sedimentary rock from central Australia was crushed to extract molecules of ancient organisms.(Image Credit: ANU)

Snowball earth

Brocks explained that prior to the algal bloom there was a dramatic event that he describes as ‘snowball earth’.

“The Earth was frozen over for 50 million years. Huge glaciers ground entire mountain ranges to powder that released nutrients, and when the snow melted during an extreme global heating event, rivers washed torrents of nutrients into the ocean.”

This cooling of the earth’s temperatures and the high levels of nutrients being deposited into the ocean fostered perfect conditions for algae to bloom.

“It appears this huge release of nutrients after the melting of this snowball Earth event triggered the evolution of these larger algae and replaced bacteria.”

“Algae are incredibly large in comparison to bacteria. And you need large and nutritious organisms at the base of the food webs to create the burst of energy towards higher and bigger organisms,” Jochen said. 

Amber Jarret, co-author of the study could tell they were onto something big.

“We immediately knew that we had made a ground-breaking discovery that snowball Earth was directly involved in the evolution of large and complex life,” she said.