(ORDO NEWS) — While studying Hawaiian caves, scientists discovered an unexpected number of previously unknown bacteria and their complex communities. Such ecosystems help to understand what life was like on our planet in the past – and what it could be on Mars.
American biologists turned their attention to the volcanic caves of Hawaii because they expected to find a wide variety of microbes there.
However, the results exceeded expectations – so much so that there was talk of “dark bacterial matter”, which scientists had not noticed before.
A total of 70 samples collected in various lava caves are studied – these are microbes that live in lava tubes, hydrotherms and other habitats that formed from 400 to 800 years ago.
Nothing says more about a bacterium than its genome, so scientists have obtained the DNA sequence that codes for their ribosomal RNA.
This is a very conservative sequence, i.e. slowly changing in the course of evolution, by which it is easy to understand the systematic affiliation.
To their surprise, under these extreme conditions, the researchers found many diverse and previously unknown bacteria.
Moreover, they form complex and unique ecosystems because they actively interact with each other. At the same time, some communities contained fewer systematic groups, but were intertwined with more complex ecological relationships.
Meanwhile, neighboring caves, pipes and channels can vary greatly in their microbial population despite similar conditions. Scientists suggest that the richness of the living in the caves arose precisely because of the difficult conditions for survival.
The “connecting link” of many ecosystems, actively interacting with other cave populations, turned out to be specific bacteria.
“This work shows that older groups of bacteria like the phylum Chloroflexi could have taken on important ecological functions or roles,” says Rebecca D. Prescott, who works at NASA and the University of Hawaii (USA).
Chloroflexi are an extremely diverse group of bacteria : they are known to play a wide variety of roles in different habitats, but are not yet well understood and their significance to communities is unknown. Some scientists call such bacteria “dark matter” – they are invisible in nature and obscure to us.
Interesting in themselves, the ecosystems of the Hawaiian caves have also attracted the attention of astrobiologists.
The fact is that from the point of view of geology, they strongly resemble caves on ancient Mars, where there could also be active volcanoes and fumaroles – cracks from which hot gas escapes.
It is possible that similar microbial communities once existed on the Red Planet (as well as on the ancient Earth).
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