Bacterial growth could reveal Earth’s origins

For years, geologists have analyzed modern microbial mats to decipher how cells functioned as far back as 3 billion years.

Now, researchers have found a way to garner new information from cells by linking the even spacing between the thousands of tiny cones that dot the surfaces of stromatolite-forming microbial mats.

Nutrient-exchanging bacteria grow mostly on moist surfaces and collect dirt and minerals that crystallize over time.

Stromatolites are the bacteria that turn to stone just beneath the crystallized material, thereby recording their history within the crystalline skeletons.

They are considered to be the oldest fossils on Earth with patterns that also appear in cross-sectional slices of stromatolites that are 2.8 billion years old — to photosynthesis.

Scientists at MIT''s Department of Earth, Atmospheric and Planetary Sciences (EAPS) and the Russian Academy of Sciences suggest that the characteristic centimeter-scale spacing between neighboring cones that appears on modern microbial mats and the conical stromatolites they form occurs as a result of the daily competition for nutrients between neighboring mats.

By analyzing the length of the triangular patterns seen in an ancient stromatolite, for example, geologists can now infer more details about the environment in which the microbial mat lived, such as whether it lived in still or turbulent water. ...

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