Nickel down, oxygen up

A new idea on what set the stage for the rise of oxygen in Earth's early atmosphere

A decrease in the amount of dissolved nickel in ocean waters beginning 2.7 billion years ago could have stifled methane-producing bacteria and set the scene for oxidation of the Earth’s atmosphere, researchers report in the April 9 Nature.

LAYERED STORIES These banded iron formations, found in Ontario, Canada, contain layers of iron, silica and trace metals formed billions of years ago from sediments in ancient ocean waters.