Rivers in barren landscapes are restless, according to an analysis of dozens of rivers around the globe. Waterways devoid of vegetation shift their beds ten times more quickly than do those with plants stabilizing their banks — a finding that could help researchers to better understand the evolution of arid terrain, such as that of early Earth and Mars.
Meandering rivers play a crucial part in sculpting planetary surfaces. But scientists know little about how rivers behaved before land plants arose around 440 million years ago, forever altering Earth’s surface.
Alessandro Ielpi at Laurentian University in Sudbury, Canada, and Mathieu Lapôtre at Stanford University in California studied images of 41 rivers that meander through environments ranging from the Arctic to the Amazon. The tally includes often-overlooked rivers in the arid centres of continents.
The researchers found that unvegetated rivers’ meanders moved much faster than did those of vegetated rivers. River movement could have drastically altered ancient landscapes by shifting carbon between the soil and the atmosphere, setting the stage for the rise of life on land.