Less life: Limited phosphorus recycling suppressed early Earth’s biosphere

A person wearing a green jacket at the base of a very large wall of red and black rock. — As Earth’s oxygen levels rose to near-modern levels over the last 800 million years, phosphorus levels also increased, according to modeling led by the UW’s Michael Kipp and others. Accordingly, Kipp said, large phosphate deposits show up in abundance in the rock record at about this time. This is a Wyoming portion of The Phosphoria Formation, a deposit that stretches across several states in the western United States and is the largest source of phosphorus fertilizer in the country.

The amount of biomass — life — in Earth’s ancient oceans may have been limited due to low recycling of the key nutrient phosphorus, according to new research by the University of Washington and the University of St. Andrews in Scotland.

The research, published online Nov. 22 in the journal Science Advances, also comments on the role of volcanism in supporting Earth’s early biosphere — and may even apply to the search for life on other worlds. The paper’s lead author is Michael Kipp, a UW doctoral student in Earth and space sciences; coauthor is Eva Stüeken, a research fellow at the University of St. Andrews and former UW postdoctoral researcher. Roger Buick, UW professor of Earth and space sciences, advised the researchers.

“We were interested in [how] phosphorus [levels have changed throughout Earth’s history] because it is thought to be the nutrient that limits the amount of life there is in the ocean, along with carbon and nitrogen,” said Kipp. “You change the relative amount of those and you change, basically, the amount of biological productivity.”