Life on Mars: the need for sample return

What makes life possible in extreme environments? That is the research field of Dr. Florence Schubotz at MARUM – Center for Marine Environmental Sciences at the University of Bremen. Extreme habitats are found in the deep sea and even thousands of meters beneath the ocean floor. But they are also present in outer space – on Mars, for example. The rocket was launched from the Earth in July 2020, and since February 2021 the rover Perseverance has been roaming our neighboring planet taking measurements and collecting samples. Researchers will use the Martian rock samples to reveal the geological processes on Mars, as well as the planet’s geological history and to study potential biosignatures. The space agencies NASA and ESA are planning the return transport of selected samples in 2030, which will then be examined more closely in laboratories on Earth. One of the questions scientists hope to answer is whether there has ever been life on Mars.

For a number of years, both with international colleagues and at MARUM, the co-author and organic geochemist Florence Schubotz has been working on the question of the possibility for life on other planets or moons, and how extraterrestrial life may be detected with the help of biosignatures. “There are also extreme habitats on the Earth. And we know that there has been water on Mars – so it is not totally unrealistic,” according to Schubotz.

The Rover has already carried out some initial analyses on Mars. However, certain methods, such as isotope analyses of larger molecules, are only possible on Earth, according to Schubotz. They could, for example, reveal evidence of biotic and abiotic signals, thus suggesting the presence of life – or maybe not. “So far, the data does not rule it out. Organic material was actually found in an ancient lake bed that was possibly formed millions of years ago. But the detected molecules detected could have also been formed abiotically. Until now, it has not been possible to either confirm or rule out any of these scenarios,” Schubotz points out. And that is precisely the reason that analysis of samples on Earth is essential – adhering to strict protocols for sterile and contamination-free treatment of the samples.

For this purpose, the team of authors, including researchers from Imperial College London (UK), the Carnegie Institution of Washington (USA), CNRS – Centre de Biophysique Moléculaire (France), and MARUM, summarized the options for potential analyses and inquired: Which instruments and technology are available and how can they be applied for the samples from Mars? “These include, for example, particle accelerators, scanning electron microscopy, and high-resolution imaging mass spectrometry. The idea is to disperse expertise for examination of the samples,” says Schubotz. MARUM and the University of Bremen also possess appropriate state-of-the-art technologies. However, an application process carried out by the ESA will determine who ultimately receives samples for analysis.

More informationen:

Website Mars Sample Return mission: https://science.nasa.gov/mission/mars-sample-return/

Publication on biomarkers: https://pubs.geoscienceworld.org/msa/elements/article/18/2/100/617863/Biomarkers-in-Extreme-Environments-on-Earth-and