Did the snowball Earth give complex life a boost?
Seven-hundred million years ago, Earth was a frozen, white sphere, its rocky surface buried kilometers under ice. Despite the barren landscape, the evolution of complex life in the oceans was about to pick up steam. New research published this week in Geology suggests that the two realms were more connected than previously thought.
As massive glaciers scratched and scarred Earth’s rocky surface, they freed less-common minerals, which were later flushed into the seas as the ice melted into giant glacial rivers. These minerals in turn may have spurred nutrient cycling in the oceans, boosting the metabolism of microbial life.
“In retrospect, I’m surprised it took [researchers] so long to go and do a study like this,” says Galen Halverson, a stratigrapher at McGill University who was not involved in the work. “It fits with what we understand” about the glaciated Earth.
