A rapid increase and expansion of ocean life 471 million years ago was not caused by asteroid fragments hitting the Earth in the form of meteorites, according to a new study published in the journal Nature Communications.
Known as the Great Ordovician Biodiversification Event (GOBE), this increase in ocean life, which produced high levels of biodiversity, has long been attributed to a bombardment of the Earth by meteorites, possibly as a result of collisions of asteroids in the belt between Mars and Jupiter.
That bombardment was believed to have altered Earth’s environment enough to spark a high level of diversification among existing ocean life.
Now, a team of scientists from Sweden and Denmark, after having conducted new dating of crystals that contain meteorite sediments, argue the expansion of ocean life actually occurred two million years before the meteorites impacted the Earth.
The researchers concluded there is no correlation between the increase in ocean life and the meteorite bombardment and “no measurable ‘extraterrestrial’ influence on biodiversity,” according to study co-author Anders Lindskog of Lund University in Sweden.
Preceded by the Cambrian expansion about 540 million years ago, the GOBE was the second major eruption of life on Earth, occurring 70 million years after the Cambrian period.
A combination of several factors rather than just one triggered the GOBE expansion of ocean life, the researchers noted. These included the division of Earth’s landmasses into small continents, which fostered species diversification, and a cooling climate that produced conditions favorable for the proliferation of life.
High sea levels meant more room for life to grow and thrive, Lindskog added.