SYDNEY, Oct. 28 (Xinhua) -- Scientists in Australia have revealed how the breakup of an ancient supercontinent 1.5 billion years ago transformed Earth's surface environments, paving the way for the emergence of complex life, the University of Sydney said on Tuesday.
The research, published in Earth and Planetary Science Letters, challenges the notion of the "Boring Billion" -- a time of supposed stasis, or biological and geological inactivity, in Earth's history, according to a statement of the university.
Instead, it shows that plate tectonics was reshaping the planet, triggering the conditions that supported oxygen-rich oceans and the appearance of the first eukaryotes, the ancestors of all complex life.
The study shows how plate tectonics has helped shape Earth's habitability, providing a new way to think about "how tectonics, climate and life co-evolved through deep time," according to Professor Dietmar Muller of the University of Sydney.
"Our work reveals that deep Earth processes, specifically the breakup of the ancient supercontinent Nuna, set off a chain of events that reduced volcanic carbon dioxide emissions and expanded the shallow marine habitats where early eukaryotes evolved," Muller said.
The study indicates that the appearance of the first fossil eukaryotes about 1.05 billion years ago coincided with continental dispersal and expanded shallow seas. All plants, animals and fungi are eukaryotes.
Researchers discovered that as Nuna fragmented around 1.46 billion years ago, the total length of shallow continental shelves more than doubled to about 130,000 kilometers. These shallow-water environments likely hosted extensive oxygenated and temperate seas, providing long-lived, stable environments for complex life to flourish.
"This dual effect -- reduced volcanic carbon release and enhanced geological carbon storage -- cooled Earth's climate and altered ocean chemistry, creating conditions suitable for the evolution of more complex life," said the study's co-author Associate Professor Adriana Dutkiewicz from the University of Sydney. ■
