Earth’s Oxygen Surge 2.4 Billion Years Ago Wiped Out Most Life, Enabling Complex Cells
Updated
Updated · spacedaily.com · May 30
Earth’s Oxygen Surge 2.4 Billion Years Ago Wiped Out Most Life, Enabling Complex Cells
2 articles · Updated · spacedaily.com · May 30
Around 2.4 billion years ago, free oxygen began building up in Earth’s atmosphere, triggering the Great Oxidation Event and what is considered the earliest mass extinction in the rock record.
Cyanobacteria drove the shift by releasing oxygen through photosynthesis; for hundreds of millions of years that oxygen was soaked up by iron, rocks and volcanic gases until those sinks became saturated.
Studies cited in the report say early oceans rich in nickel and urea favored methane-producing archaea over cyanobacteria, delaying atmospheric oxygenation until volcanic activity waned and ocean chemistry changed.
For Earth’s largely anaerobic biosphere, oxygen was toxic, forcing surviving microbes into oxygen-free refuges such as deep sediments, hydrothermal settings and animal digestive tracts.
The oxygen rise also cut methane, helping trigger the 2.4-2.1 billion-year Huronian glaciation, while eventually enabling aerobic respiration and the later evolution of eukaryotes and animals.
How did life’s deadliest pollution event create the conditions necessary for our own existence?
How did the rise of oxygen paradoxically prevent Earth from losing its oceans to space?
Did a molecule delivered by meteorites help trigger the greatest chemical shift in Earth's history?
The Great Oxidation Event (2.4–2.1 Billion Years Ago): How Cyanobacteria Reshaped Earth's Atmosphere and Life
Overview
The Great Oxidation Event (GOE), which happened between 2.4 and 2.1 billion years ago, was Earth's first major climate crisis. It began when cyanobacteria evolved and developed oxygenic photosynthesis, producing oxygen as a byproduct of splitting water. At first, the oxygen released into seawater was absorbed by elements like iron, keeping atmospheric oxygen low. Over hundreds of millions of years, as cyanobacteria spread, oxygen levels in seawater rose until it started to escape into the atmosphere. This dramatic change shows how life can reshape the planet, offering important lessons for understanding today's environmental challenges.