FAR comes from Under the sunlight that sustains life, the deep sea floor appears barren and desolate. However, its appearance obscured a thriving bacterial ecosystem, which may contain up to 45% of the world’s microbial biomass. This ecosystem is propelled by the so-called ocean snow-the constant spraying of a small number of nutrient-rich particles that fall from the surface of the sea where photosynthesis are carried out like mannan.
However, not all snow is digestible. The indigestible parts are piled up layer after layer and buried in the layers below them. To study the survival of these bacteria in the assemblage, a group of researchers led by Morono Yuki of Japan̵
For many microorganisms, burial is a direct death sentence. However, some people can enter a dormant state-reduce their metabolism to almost (but not completely) to zero. They can maintain this state for a long time. But exactly how long the debate has been.
The sample chosen by Dr. Morono and Dr. D’Hondt for inspection came from a location in the Pacific Ocean where the seabed is 6,000 meters below the surface of the water. This brings challenges to drilling. However, the expedition was able to recover the sediment core that extended to the underlying rock, in some cases 100 meters thick. The oldest material in these cores can be traced back to 101.5 million years, until the mid-Cretaceous period, the heyday on land.
Examination of the sediments showed that even the oldest ones still contained some bacteria. The question is, are these creatures dead or alive? To find out, the researchers incubated the samples and then slowly fed them with carbon and nitrogen-rich compounds to coax any living microorganisms out of their dormant state.
This result shocked Dr. Morono, “At first I was skeptical, but we found that 99.1% of the microorganisms in the sediments 101.5 million years ago still exist.” And there are many types of them. The research team discovered representatives of the phylum called Actinomyces, Bacteroides, Sclerosus and Proteus, and microbiologists are familiar with these representatives. In one sample (found only 13.5 million years ago), they also found representatives of archaea. Archaea are a group of organisms that are similar to bacteria under the microscope but have different biochemical properties, so they are regarded as living An independent field of
It is unusual to find such living fossils from the Cretaceous period of ancient times. Given the length of time involved, it is impossible to be certain that they have not experienced any growth and cell division. However, if any, this situation will be minimal given the lack of nutrients in the slime found. It is impossible for them to migrate there from the upper level. The so-called slime is sealed by a bacteria-resistant layer of a stone-like material called wollastonite.
Therefore, this discovery will provide interesting enlightenment for the evolution of bacteria on earth. This will also inspire the spirits of those who wish to find life elsewhere in the solar system. The sediment will be biologically inspected perseverance, Is the age of the U.S. Mars rover that took off from Cape Canaveral, Florida on July 30. It is 35 times older than the Mars rover studied by Dr. Morono and Dr. D’Hondt, and has not been buried and protected from environmental degradation The protection is a few meters under the cover of the seafloor. However, the future Martian rover will burrow into the formations below the surface of the earth, which have the same level of protection for the rocks above them and even the seawater. Although the factor of 35 is large, it sounds not insurmountable.■
This article appeared in the “Science and Technology” section of the print edition under the title “Errors forgotten at that time”