A groundbreaking study of ancient stromatolites has revealed that ammonium reservoirs in early Earth’s oceans, likely influenced by volcanic activity, may have supported microbial life before the Great Oxidation Event. The research team, led by Dr. Ashley Martin of Northumbria University, analyzed fossilized stromatolites dating back over 2.5 billion years to shed new light on Earth’s environmental conditions before the emergence of oxygen.
The study focused on understanding nitrogen cycling processes in early Earth’s ecosystems, which is essential for life. The team found unusual nitrogen isotope patterns in southern Zimbabwe that can offer insights into the mechanisms at play in Earth’s early marine environment. This has significant implications for our understanding of the Great Oxidation Event, which occurred around 2.5 to 2.3 billion years ago and saw the first rise of oxygen concentration in the atmosphere.
The team believes that a large ammonium reservoir would have been beneficial for early life, providing the nitrogen source needed for biological processes to occur. These conditions, likely in an ocean depleted of dissolved oxygen with a strong volcanic or hydrothermal influence, may have helped support microbial growth and paved the way for the Great Oxidation Event.
The research team suggests that volcanic activity played a key role in fueling early life. Dr. Eva Stüeken from the University of St Andrews explained that the unusual nitrogen isotope values found in the rocks suggest a strong linkage to hydrothermal nutrient recycling, which may have fueled the development of life. Professor Axel Hofmann from the University of Johannesburg added that volcanicism was exceptionally active 2.75 billion years ago and left a lasting impact on the evolution of life at that time.
The study’s findings support an earlier proposal by Dr. Martin and colleagues that large quantities of bioavailable nitrogen in the form of ammonium may have accumulated in ancient oceans due to volcanic activity and fueled the development of life.
Source: https://scitechdaily.com/2-75-billion-year-old-rocks-rewrite-the-story-of-earths-early-life