Aerobic Nitrogen Cycling at the Surface of Paleoproterozoic Oceans
Researchers have uncovered new information about nutrient cycling and redox conditions on the ancient Earth by analyzing nitrogen isotope ratios from marine sedimentary rocks dating to the Paleoproterozoic. The study helps to fill in knowledge gaps in the Precambrian sedimentary nitrogen isotope record.
The samples examined span the Great Oxidation Event, a time when biological activity is thought to have spurred a dramatic increase in atmospheric oxygen some 2.45 billion years ago (2.45 Ga). This event was a major redox transition for the planet, and marks a dramatic step in the evolution of life on Earth. The study reports nitrogen isotope ratios that are similar to those seen in recent marine sediments, which indicates that aerobic nitrogen cycling was likely occurring at the surface of the oceans.
The study, “Pervasive aerobic nitrogen cycling in the surface ocean across the Paleoproterozoic Era,” was published in the journal Earth and Planetary Science Letters. The work was supported by NASA Astrobiology through the Exobiology Program.