Together with an international team, two researchers from LUH, Ashley Martin (now at Northumbria University, UK) and Stefan Weyer (Institute of Earth System Sciences) investigated 2.7 billion years old fossilised microbial mats from Zimbabwe – so-called stromatolites. Their motivation was to get new insights on the co-evolution of life and oxygen of Earth’s early oceans and atmosphere. The focus of their geological and geochemical investigations was on the early nitrogen cycle. Nitrogen, the main ingredient of the current atmosphere, is vital for all life on Earth but must first be converted into useable, bioavailable forms for uptake by plants and animals.
The research team found unusual nitrogen isotope patterns (together with other geochemical and isotopic signatures) in the investigated stromatolites, offering new insights on the mechanisms at play in Earth’s early marine habitats before the atmosphere became oxygenated during the Great Oxidation Event (at 2.5 to 2.3 billion years ago). Likely, enhanced volcanic activity resulted in a large ammonium reservoir and stimulated biological activity that generated the observed isotopic anomalies.
A paper published in the prestigious scientific journal, Nature Communications, outlines the findings of the international team with expertise in geology, microbiology, and geochemistry, which includes researchers from LUH, the University of St Andrews (UK), the University of Kaiserslautern-Landau, the Max Planck Institute for Chemistry in Mainz and the University of Johannesburg in South Africa. The article can be found here: https://doi.org/10.1038/s41467-025-57091-3.
