Whenever humans think they have found the limits of life, they find extreme microbes thrive under previously excluded conditions, according tomedia, most recently from the study of cores drilled from the Indian Ocean’s seabed, where microbes are found to live nearly half a mile under rocks.
These findings were made by the International Ocean Discovery Project (IODP), which studies rock and sediment samples collected from the seabed. Usually, it was used to investigate historical climate records preserved there, but this time an international team of scientists found evidence of life.
The researchers examined rock samples taken from the lower ocean crust and looked for genetic material and organic molecules. They performed cell counting and then cultured samples in laboratory petri dishes. These reveal a relatively small but diverse number of microbes living at depths of 2,600 feet (792 meters) below the sea floor.
“They’re small, about 1 micron,” said Jason Sylvan, one of the study’s authors. We believe this is the first time that active microorganisms have been found in this environment and can use such a wide range of data streams to describe their way of life. “
But life must not be very comfortable under neath. There is no light, food is scarce, and even by microbial standards, space is very limited. The researchers were curious about how these creatures handled these conditions, so they analyzed the genetic expression of the messenger RNA they found. This could help researchers understand some of the survival strategies that microbes might use.
Some organisms seem to be able to store carbon in cells to store it when needed. Others use nitrogen and sulfur as energy sources. Some may be able to recover amino acids. Some invest in breaking down hard-to-break compounds to get carbon locked inside.
The team notes that the study reveals the viability of microorganisms, even in environments that may be considered very harsh.
“This environment and the lower oceanic crust are mainly made up of a substance called the glowing and olive rocks that makes it possible to have chemical reactions that are likely to exist in the early earths and on other planets where water and volcanic rocks interact,” Sylvan explains. Microbes may survive anywhere they have space, and they evolve to live in difficult circumstances. “
The study was published in Nature.