High resolution techniques reveal clues in 3.5 billion-year-old biomass

To learn about the first organisms on our planet, researchers must analyze the rocks of the earliest Earth. They are found in only a few places on Earth’s surface. The Pilbara Craton in Western Australia is one of those rare places. There are rocks that are about 3.5 billion years old that contain traces of the microorganisms that lived back then.

A research team led by the University of Göttingen has now found new clues about the composition and composition of this ancient biomass, providing insight into the oldest ecosystems on Earth. Here are the results. published In the journal Precambrian research.

Using high resolution techniques eg Nuclear Magnetic Resonance Spectroscopy (NMR) and near-edge X-ray absorption fine structure (NEXAFS), the researchers analyzed the carbonaceous particles found in rocks made of barium sulfate. This enabled scientists to gain important information about the structure of microscopically small particles and show that they are of biological origin. It is likely that the particles were deposited as sediment in a body of water in a “caldera” – a large crater-shaped hollow that formed laterally. Volcanic activity.

In addition, some particles may have been transported and altered by hydrothermal waters just below the volcano’s surface. This indicates the tumultuous history of the sedimentary deposits. By analyzing different carbon isotopes, the researchers concluded that different types of microorganisms were already living around volcanic activity, such as those found in Iceland’s geysers today. hot springs in Yellowstone National Park.

The study not only sheds light on Earth’s past, but is also methodologically interesting. “It was exciting to be able to combine a range of high-resolution techniques, which enabled us to gain information about the history of how organic particles formed,” explains first author Lina Weimann, Geosciences Center at the University of Göttingen. Accumulations and their origins. As our results show, traces of the first organisms can still be found in very old materials.”