An extreme bacterium has adapted to living in the open sea

An Italian-led study has found a bacterium able to live in extreme conditions and which uses hydrogen as an energy source. It is called Sulfurimonas pluma and, although it comes from hydrothermal springs on the bottom of the ocean, it has evolved by adapting to the environment of the open ocean. The study, published in the Nature Microbiology journal, was led by the Italian Massimiliano Molari of Germany’s Max Planck Institute and it helps us understand the impact on oceans of the many micro-organisms that live in extreme conditions. "In the oceans and in particular near ocean ridges, or the undersea mountain ranges formed by the upsurge of magma, there are fractures from which fluids rich in gas e metals emerge, around which live micro-organisms in extreme conditions", Molari told ANSA.

These micro-organisms use the energy taken from sulfur and hydrogen to support the food chain in these full-blown oases of life and biodiversity. Furthermore, the hydrothermal fluids, whose temperature is extremely high, mix with the deep and cold sea waters and generate plumes that can stretch for thousands of kilometres. The micro-organisms that live there are still very little known, despite having a key role in modifying both the chemistry of the oceans and the organisms that live there. In water samples taken from some of the plumes, researchers have identified the new bacterium which, unlike its closest relatives, can use hydrogen as a prime energy source.

"Finding bacteria of the genus Sulfurimonas in that environment and in such quantities was a surprise", said Molari. The new species probably derives from a common ancestor shared with the hydrothermal species, but which has probably acquired a greater tolerance to oxygen, allowing it to live in the oceans too, and not only in the environs of the springs that produce the gases of the Earth’s crust. "It is a discovery which on the one hand allows us to understand something new on microbic diversity and the complex mechanisms that take place in the oceans, and on the other,” concludes the Italian researcher, “gives us a lot of information to imagine similar environments which may be present in other heavenly bodies, like Enceladus or Europa".