Microbes and minerals: How microorganisms accelerate calcification

Microorganisms are everywhere and have been influencing the Earth's environment for over 3.5 billion years. Researchers from Germany, Austria and Taiwan have now deciphered the role they play in the formation of lime - for the first time in the deep sea rather than in the laboratory. A five-meter-long limestone core obtained during an expedition served as the basis.

Microorganisms are usually associated with decomposition and degradation processes, but they also facilitate and accelerate the formation of minerals that would otherwise only form very slowly or not at all.

It is precisely this phenomenon that interests researchers in geology, geochemistry and materials science, as it can be used for topics in basic and applied research. Limestone minerals, for example, bind carbon dioxide (CO) from the atmosphere as a solid over long periods of time.

Methane leaks as a natural laboratory

Methane and other hydrocarbons are released from the ocean floor at so-called cold seeps, forming the basis for ecosystems independent of sunlight. The basic process is methane oxidation without oxygen, which is carried out jointly by archaea and bacteria. "This metabolic reaction indirectly leads to calcification in sediments near the ocean floor. Marine methane sources are therefore excellent ecosystems to study microbial processes and their influence on mineral formation," explains first author Daniel Smrzka from MARUM - Center for Marine Environmental Sciences and the Faculty of Geosciences at the University of Bremen.

The results of the study confirmed previous experimental studies based on microbial cultivation and mineral formation, but for the first time provide quantitative estimates of rock formation over thousands of years. According to the team of authors, these results are an important step towards better understanding the phenomenon of microbial-influenced mineral formation and quantifying its influence for the first time, as microbial activity influences the formation of minerals in almost all ecosystems and environmental conditions.

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Source: University of Bremen