Biogeochemists have found new evidence linking “Snowball Earth” glacial events to the rise of early animals. The research was funded by the National Science Foundation (NSF). Study results appear in this week’s issue of the journal Nature.
The controversial Snowball Earth hypothesis posits that, on several occasions, the Earth was covered from pole to pole by a thick sheet of ice lasting for millions of years.
These glaciations, the most severe in Earth history, occurred from 750 to 580 million years ago.
In the aftermath, the researchers discovered, the oceans were rich in phosphorus, a nutrient that controls the abundance of life in the oceans.
The team, led by scientists at the University of California Riverside, tracked phosphorus concentrations through Earth’s history by analyzing the composition of iron-rich chemical precipitates. These precipitates accumulated on the seafloor and “scavenged” phosphorus from seawater.
The analyses revealed that there was a pronounced spike in marine phosphorus levels in the mid-Neoproterozoic (from ~750 to ~635 million years ago).