Scientists from Greece, Germany and Canada believe they are closer to unlocking the secrets of how life can survive and even evolve under extreme conditions, thanks to a recent study of microorganisms living in the sub-seafloor of Santorini’s largest submarine volcano.
The results of their study, published on Frontiers in Microbiology, indicate that this specific area within the active Kolumbo crater creates a distinct niche where microorganisms with adaptation strategies to withstand heat stresses can thrive in temperatures that may exceed 120C.
Such extreme sub-seafloor microorganisms were the first representatives of life on Earth and they are responsible for the genesis of geological structures during the evolution and creation of all currently known ecosystems.
Santorini volcanic field best candidate for cutting-edge research
The Hellenic Volcanic Arc, consisting of five islands in the Aegean Sea (Methana, Milos, Santorini, Nisiros, and Kos), contains unique hydrothermal vents developed as a response to the subduction of the African plate beneath the active margin of the European plate, the paper explains.
The Santorini volcanic field, in particular, includes more than 20 submarine cones.
The largest one, Kolumbo, is located 505 m below sea level.
High and low temperature polymetallic chimneys and vents (70C-220C) cover the seafloor at the norther part of the Kolumbo crater.
Scientists believe that, of all the potentially habitable environments on Earth, submarine volcanoes with active hydrothermal vents like this one are among the most intriguing, extreme, and challenging environments to investigate the origins and importance of sub-seafloor communities and the development and maintenance of life, and to uncover its valuable genetic resources.
Therefore, the active Santorini-Kolumbo volcanic complex serves as the best candidate to face these “quite exciting and cutting-edge research challenges.”
Santorini volcano unveils novel factors about the evolution of life
Active hydrothermal vents of volcanic origin provide a remarkable manifestation of life on Earth under extreme conditions, which may have consequences for our understanding of habitability on other terrestrial bodies as well, the paper explains.
Researchers analysed samples that were collected during R/V POSEIDON cruise P510 in March 2017 along the Kolumbo line in the area of hydrothermal venting in the Kolumbo crater, and throughout the North basin of the Santorini caldera.
About 1 g of material from each sample was used to extract genomic DNA from microbial communities.
This was the first time that microbial communities inhabiting the sub-seafloor of the Santorini-Kolumbo volcanic system were examined.
“We uncovered the presence of diverse microbiota in this system with unique adaptation strategies, including resistant forms to withstand heat stresses, such as endospores,” the researchers state.
Previous investigations already suggested that the high concentration of reductants in Kolumbo volcano, like metal enrichment, may have provided selective pressure in microorganisms to maintain resistance mechanisms including those for antibiotic resistance.
“Given the high and unique diversity of the sub-seafloor, we are expecting that such mechanisms can be activated in the deeper sediment layers of this volcanic system,” research concluded.
Now the scientific team are hoping that the exploration of the deep sub-seafloor through the International Ocean Discovery Program (Expedition 398 at the Hellenic Arc Volcanic Field), will allow them to learn more about the factors that shape and limit life in the deep sub-seafloor of active volcanic systems, and to reveal novel factors about the evolution of life on Earth.