Scientists, hiding in the depths of ancient lava caves in Hawaii, have discovered a completely unknown bacterial species. This in itself is special, but they also provide insight into how life can exist in extreme conditions, such as on Mars.
Lava caves in Hawaii are home to many more bacterial species than scientists previously thought, they write in a new study published in Frontiers in Microbiology has been published. It’s an example of life in extreme environments like Mars and on Earth as early as long ago, he says. The researchers studied the diversity and interaction within existing microbial ecosystems. One of the surprising results was that the group of bacteria, the Chloroflexion, which often acts as a “hub” type. That is, they are related to many other species and usually play a major ecological role in the bacterial community.
black matter
“There may be ancient genera of bacteria, such as Chloroflexi-which have an important environmental role,” said lead researcher Rebecca Prescott NASA Johnson Space Center and the University of Hawaii. “The Chloroflexion They are a very diverse group of bacteria that have many different roles in all kinds of environments, but they haven’t been studied much, so we don’t know what they do in these communities. Some scientists call these groups “microbial dark matter,” or microorganisms that are invisible and have never been studied in nature.”
Invisible volcanic life
To get a picture of the evolution of bacterial communities, Prescott and colleagues took 70 samples from a variety of locations in and around lava caves, including active fumaroles, ancient and young lava tunnels, and caves less than 400 years old and between 500 and 800 years old. They looked at the diversity and quantity of bacterial groups in each sample. The networks of other bacteria present there also provided insight into how these microbes interact with each other.
The researchers expected that there would be less diversity in the harshest conditions – geothermal sites – and more in habitable lava tunnels. While this was true, the team was surprised that interactions between bacterial communities were more complex in extreme conditions than at sites of high diversity. “This leads us to ask whether the harsh environment helps create a more interactive microbial community with microorganisms more dependent on each other,” Prescott said. “And if so, what is the reason for this in these extreme places?”
A formation of stalactites in a Hawaiian cave containing copper minerals and white bacterial colonies. Although copper is toxic to many organisms, these microbes can tolerate it. Photo: Kenneth Engham
Ago Chloroflexion and another tribe, acid called, they have been present in all places, and may play an important role in these bacterial communities. However, these were not the largest groups of bacteria. In addition, individual communities at different sites showed wide variation in the diversity and complexity of microbial interaction. Contrary to what researchers believe, the most abundant bacterial groups are Oxyphotobacteria and the radialare usually not ‘pivotal’ species, so they may be many, but their role is less important for the overall structure of the bacterial community.
More questions than answers
The study has not yet been able to correctly identify the bacterial species or its role in the community. This requires more research. “Overall, this study highlights the importance of studying microbes in the company of other species rather than in isolation in the laboratory,” Prescott said. “In the real world, microbes do not grow in isolation. They grow, live and interact with many other microorganisms in a sea of chemical signals from those other microbes. This can alter their gene expression and affect their societal functions.”
Green and purple biofilms (a layer of microorganisms with mucus) and microbial sediments are common at geothermal active sites in caves. They often contain the unique cyanobacteria Gloeobacter kilaueensis. Photo: Stuart Donacci
As mentioned, studying bacterial species in a volcanic environment can provide us with more insight into life in challenging conditions, such as those that existed during the early existence of Earth and possibly on Mars. But it is also useful, for example, to understand how microbes transform igneous rocks (basalt) into soil. Furthermore, research could play a role in biotechnology, among other things.
