Oldest fossils of methane-cycling microbes expand frontiers of habitability on early Earth
July 14, 2021

Oldest fossils of methane-cycling microbes expand frontiers of habitability on early Earth 

EUROPLANET/UNIVERSITY OF BOLOGNA PRESS RELEASE

A team of international researchers, led by the University of Bologna, has discovered the fossilised remains of methane-cycling microbes that lived in a hydrothermal system beneath the sea floor 3.42 billion years ago. 

The microfossils are the oldest evidence for this type of life and expand the frontiers of potentially habitable environments on the early Earth, as well as other planets such as Mars. 

The study, published today in the journal Science Advances, analysed microfossil specimens in two thin layers within a rock collected from the Barberton Greenstone Belt in South Africa. This region, near the border with Eswatini and Mozambique, contains some of the oldest and best-preserved sedimentary rocks found on our planet. 

The microfossils have a carbon-rich outer sheath and a chemically and structurally distinct core, consistent with a cell wall or membrane around intracellular or cytoplasmic matter.

Prof Barbara Cavalazzi, the lead author of the study, said: “We found exceptionally well-preserved evidence of fossilised microbes that appear to have flourished along the walls of cavities created by warm water from hydrothermal systems a few meters below the sea floor. Sub-surface habitats, heated by volcanic activity, are likely to have hosted some of Earth’s earliest microbial ecosystems and this is the oldest example that we have found to date.”

The interaction of cooler sea-water with warmer subsurface hydrothermal fluids would have created a rich chemical soup, with variations in conditions leading to multiple potential micro-habitats. The clusters of filaments were found at the tips of pointed hollows in the walls of the cavity, whereas the individual filaments were spread across the cavity floor.

Chemical analysis shows that the filaments include most of the major elements needed for life. The concentrations of nickel in organic compounds provide further evidence of primordial metabolisms and are consistent with nickel-content found in modern microbes, known as Archaea prokaryotes, that live in the absence of oxygen and use methane for their metabolism.

“Although we know that Archaea prokaryotes can be fossilised, we have extremely limited direct examples. Our findings could extend the record of Archaea fossils for the first time into the era when life first emerged on Earth,” said Prof Cavalazzi. 

She added: “As we also find similar environments on Mars, the study also has implications for astrobiology and the chances of finding life beyond Earth.”

‘‘Cellular remains in a ~3.42 billion-year-old subseafloor hydrothermal environment’, B. Cavalazzi (Università di Bologna, Italy/ University of Johannesburg, South Africa), L. Lemelle (LGL-TPE, ENS de Lyon, Université de Lyon, CNRS, France), A. Simionovici (ISTerre, University of Grenoble-Alpes, CNRS, France), S.L. Cady (Pacific Northwest National Laboratory, USA), M.J. Russell (Università degli Studi di Torino, Italy), E. Bailo (WITec GmbH, Germany), R. Canteri (Fondazione Bruno Kessler, Italy), E. Enrico (Istituto Nazionale di Ricerca Metrologica, Italy), A. Manceau (ISTerre, University of Grenoble-Alpes, CNRS, France), A. Maris (Università di Bologna, Italy), M. Salomé (European Synchrotron Radiation Facility, France), E. Thomassot (Université  de Lorraine, CNRS, CRPG, France), N. Bouden (Université  de Lorraine, CNRS, CRPG, France), R. Tucoulou (European Synchrotron Radiation Facility, France), A. Hofmann (University of Johannesburg, South Africa), Science Advances, 2021. https://advances.sciencemag.org/content/7/29/eabf3963.

The research was carried out with the support of Europlanet 2024 RI, which received funding from the European Union’s Horizon 2020 programme (Grant No 871149).

Images

1) Image of the locality of the study area in the Barberton Greenstone Belt in South Africa. Credit: A. Hofmann.
1) Image of the locality of the study area in the Barberton Greenstone Belt in South Africa. Credit: A. Hofmann.

https://www.europlanet-society.org/wp-content/uploads/2021/07/Barberton-Greenstone-Belt-South-Africa-Credit-A-Hofmann-scaled.jpg

2) Image of the outcrop from which the rock sample was taken in the Barberton Greenstone Belt in South Africa. Credit: Cavalazzi et al.
2) Image of the outcrop from which the rock sample was taken in the Barberton Greenstone Belt in South Africa. Credit: Cavalazzi et al.

https://www.europlanet-society.org/wp-content/uploads/2021/07/Outcrop-in-the-Barberton-Greenstone-Belt-South-Africa-Credit-Cavalazzi-et-al.tif

3) Optical microscope image of the filamentous microfossils. Credit: B. Cavalazzi.
3) Optical microscope image of the filamentous microfossils. Credit: B. Cavalazzi.

https://www.europlanet-society.org/wp-content/uploads/2021/07/Microfossil-filaments-Credit-B-Cavalazzi.tif

4) Raman spectra image of filamentous microfossils in boxed area in Image 3. The turquoise and blue show the carbonaceous matter associated with the filaments. Credit: Cavalazzi et al.

https://www.europlanet-society.org/wp-content/uploads/2021/07/Raman-spectra-image-filamentous-microfossils-Credit-B-Cavalazzi-et-al.tif

Science Contact

Barbara Cavalazzi
University of Bologna
barbara.cavalazzi@unibo.it

Media Contacts

Matteo Benni
Ufficio Stampa
Università di Bologna
+39 051 20 99327
+39 338 7866108
matteo.benni@unibo.it

Anita Heward
Press Officer
Europlanet 2024 Research Infrastructure
aheward@europlanet-society.org
+44 7756 034243

About Europlanet

Since 2005, Europlanet has provided Europe’s planetary science community with a platform to exchange ideas and personnel, share research tools, data and facilities, define key science goals for the future, and engage stakeholders, policy makers and European citizens with planetary science.

The Europlanet 2024 Research Infrastructure (RI) has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149 to provide access to state-of-the-art research facilities and a mechanism to coordinate Europe’s planetary science community. The project builds on a €2 million Framework 6 Coordination Action (EuroPlaNet), a €6 million Framework 7 Research Infrastructure (Europlanet RI) and a €10 million Horizon 2020 Research Infrastructure (Europlanet 2020 RI) funded by the European Commission. 

The Europlanet Society promotes the advancement of European planetary science and related fields for the benefit of the community and is open to individual and organisational members. The Society’s aims are:

  • To expand and support a diverse and inclusive planetary community across Europe through the activities of its 10 Regional Hubs
  • To build the profile of the sector through outreach, education and policy activities
  • To underpin the key role Europe plays in planetary science through developing links at a national and international level. 

Europlanet 2024 RI project website: www.europlanet-2024-ri.eu

Europlanet Society website: www.europlanet-society.org   

Follow on Twitter via @europlanetmedia

About University of Bologna

The University of Bologna has very ancient origins: founded in 1088 it is considered the first University of the Western World. It counts over 87,000 students, 232 degree programs, 84 of which are international, distributed over 5 Campus: Bologna, Cesena, Forlì, Ravenna and Rimini.

It has 32 Departments, 48 PhD courses, 53 Postgraduate Schools, 86 first and second level Masters and an average of 11,000 research products per year. The University of Bologna is among the first universities in Europe for the number of students participating in exchange programs, both outgoing and incoming.

Новости Новости Беларусь Любовь и семья Общество Люди и события Красота и здоровье Дети Диета Кулинария Полезные советы Шоу-бизнес Огород Гороскопы Авто Интерьер Домашние животные Технологии Идеи для творчества на каждый день