Deputy Director of Japan Agency for Marine-Earth Science and Technology, Atsushi Takano, and Research Student of Atsushi Urai of Shinshu University, in collaboration with Kanto Natural Gas Development Co., Ltd. and the University of Tokyo, analyzed samples collected from the South Kanto Gas Field and lived in deep fluids. It was revealed that Archaea (archaea) continue to produce methane.It was also found that a diverse microbial community exists in the deep fluid.
In the deep underground of the Kanto region, a stratum made of seafloor sediments from about 300 to 40 years ago is distributed, and the groundwater in the stratum contains water-soluble natural gas and high-concentration iodine.The natural gas produced is said to be the decomposition of organic matter buried in the ground by microorganisms, and in fact, the gene for methanogenic archaea has been detected in the groundwater around Mobara City, Chiba Prefecture.However, it was difficult to accurately evaluate the abundance and activity of methanogenic archaea living deep underground.
In the research, self-spraying gas and groundwater samples were collected from the deep underground aquifer at two survey points around Mobara City, Chiba Prefecture.As a result of extracting and measuring the coenzyme F2 from this sample, a high concentration of F430 was observed. F430 is an unstable compound that rapidly isomerizes (epimerizes) or degrades when released extracellularly from methanogenic archaea.However, no epimer of F430 was detected in this sample, and it was considered that the methanogenic archaea in the deep subterranean aquifer had high methanogenic activity.
Furthermore, by performing ribosomal RNA gene analysis, the existence of a wide variety of microorganisms in the deep subterranean aquifer in addition to methanogenic archaea was confirmed.In addition, the deep underground aquifer had almost no carbon supply from the surface layer due to rainwater or seawater, forming an independent underground biosphere.
This discovery is expected to elucidate the ecology of prokaryotes in the subterranean area and the methanogenic process in deep subterranean aquifers.