Yellowstone’s Hot Springs May Reveal Clues About Earth’s Early Oxygen Use

Recent research from Montana State University suggests that microbial life in Yellowstone’s Lower Geyser Basin could provide insight into the evolution of how life adapted to use oxygen.

The microorganisms living in the Octopus and Conch Springs thrive in kelp-like, gelatinous structures known as “streamers,” which move rapidly in the superheated waters around 88°C (190°F). These microbes share genetic similarities with ancient bacteria and archaea, offering a glimpse into the early stages of life on Earth.

Key Differences Between the Springs’ Environments

Despite the similar structures of the microbial communities, the environments of the two springs differ significantly. Octopus Spring contains significantly higher levels of dissolved oxygen (about 20 micromolar), whereas Conch Spring has almost no oxygen, with less than 1 micromolar present. In contrast, Conch Spring has much higher concentrations of dissolved sulfide (more than 120 micromolar), while Octopus Spring has only 2-3 micromolar.

Understanding Life Before and After the Great Oxidation Event

The stark chemical differences between the springs provide valuable insights into how life on Earth adapted before and after the Great Oxidation Event (GOE), which occurred around 2.5 billion years ago. The GOE was a critical period when Earth’s nearly oxygen-free atmosphere was flooded with oxygen, a significant shift in the planet’s biochemistry.

Before the GOE, Earth’s earliest microbes likely found ways to incorporate small amounts of oxygen into their biochemical processes. However, the emergence of molecular oxygen, which is highly reactive, required organisms to develop new defense strategies. Additionally, high concentrations of sulfides, which can interfere with respiration in modern aerobic organisms, raise important questions about how ancient lifeforms in hot springs may have evolved mechanisms to cope with both rising oxygen levels and toxic sulfides.

The Springs as Proxies for Life’s Response to Changing Oxygen Levels

Due to the varying levels of oxygen and sulfide, the springs serve as ideal natural models for studying life before and after the GOE, offering a unique opportunity to explore how life adapted to increasing oxygen concentrations in Earth’s atmosphere.

Read the original article on: Science Alert

Read more: The Great Oxidation Event: A 200-Million-Year Pathway to Oxygenation