Washington, January 30 (ANI): In a new research, scientists have determined that plant evolution led to permanent changes to the way rivers looked and behaved about 420 million years ago.
During the period, the planet's land mass was mostly dusty and barren, and rivers were more like great expanses of water sliding into the ocean.
According to Martin Gibling, professor with Dalhousie's Department of Earth Sciences, "There was bare rock and sand, with crusts of bacteria and algae over the rock surfaces. And ancient rivers were very different, like big sheets of water carrying sand and gravel. They weren't like channels whatsoever."
Dr. Gibling and postdoctoral researcher Neil S. Davies wanted to find out more about those big rivers and what happened during the evolution of the Earth to throw them for a loop.
For the answers to one of the most significant environmental changes in the Earth's history, they turned to the fossil record using a literature compilation and fieldwork.
Their research took them to 35 sites around the globe, including Port-au-port, Newfoundland, the Gaspe Peninsula of Quebec, the Channel Islands off the coast of France and Death Valley in California.
The difference, they discovered, was the earliest plants, stretching their roots down and stabilizing river banks.
Instead of wide and sheet-like, rivers evolved to become more confined and narrower.
"Once the plants started to get a toehold, they sent spores into more inland areas," said Dr. Davies.
"The entire process took about 50 million years, with vegetation spreading until it dominated every landscape except total desert. The Earth could never be the same again," he added. (ANI)
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