Deep freeze may have spawned complex life on Earth

October 28th, 2010 - 1:35 pm ICT by ANI  

London, Oct 28 (ANI): The rise of complex life on Earth may have been given a boost by a spike in ancient marine phosphorus concentrations from 750 to 635 million years ago, University of California, Riverside, researchers say.

They found new evidence linking ‘Snowball Earth’ glacial events to the rise of early animals.

The controversial Snowball Earth hypothesis posits that the Earth was covered from pole to pole by a thick sheet of ice lasting, on several occasions, for millions of years.

These glaciations, the most severe in Earth history, occurred from 750 to 580 million years ago. The researchers argue that the oceans in the aftermath of these events were rich in phosphorus, a nutrient that controls the abundance of life in the oceans.

The UC Riverside team and colleagues tracked phosphorus concentrations through Earth’s history by analyzing the composition of iron-rich chemical precipitates that accumulated on the seafloor and scavenged phosphorus from seawater.

Their analyses revealed that there was a pronounced spike in marine phosphorus levels in the mid-Neoproterozoic (from ~750 to ~635 million years ago).

To explain these anomalously high concentrations, the researchers argue that the increase in erosion and chemical weathering on land that accompanied Snowball Earth glacial events led to the high amounts phosphorus in the ocean.

The abundance of this nutrient, which is essential for life, in turn, led to a spike in oxygen production via photosynthesis and its accumulation in the atmosphere, facilitating the emergence of complex life on Earth.

The study results appear in the Oct. 28 issue of Nature. (ANI)

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