Proving the occurrence of electrical current generation across the Black Smoker Chimney (2010)

The SUGAR Program has worked in collaboration with Prof. Kazuhito Hashimotofs group of Tokyo University, and carried out an electrochemical analysis with the sample collected from the chimney from the deep sea hydrothermal vent. From this experiment, it made clear of the chimney composed by Black Smoker, made of sulfide minerals possessing a high electrical conductivity. In addition, the presence of electrical current across the wall of the Chimneys was proved. This electrical current occurs due to the chemical reactions similar to the battery between inside and outside of the Chimney in natural environment. These experimental results are the world-first proof of the Earthfs internal energy being converted into electrical energy, when released at the seafloor. This gHydrothermal Chimney Battery phenomenonh will surely explain more about the origin- of-life mechanisms, as well as deep sea biological activity and material circulation.

Nakamura, R., Takashima, T., Kato, S., Takai, K., Yamamoto, M., & Hashimoto, K. (2010) Electrical Current Generation across a Black Smoker Chimney. Angew.Chem.Int.Ed, 122:7858-7860

(Fig. Left) A piece of Black Smoker Chimney used in experiment (Labels; Left: Chimneyfs outer surface, Right: inner surface, Bottom: cross section)
(Fig. Top right) An enlarged photo of Chimneyfs inner wall (scanning electron microscopy)
(Fig. Bottom right) A concept diagram of the Chimneyfs cross electrical current


Challenging an armored monster eScaly-Footf gastropod (2009)

Since its discovery in 2001, escaly-footf gastropod has been popular among varieties of deep-sea creatures. It is actually the only living organism with scales made of iron sulfide. One of the reasons we are so attracted to escaly-footf gastropod is probably due to its rarity. Although there are numerous deep-sea hydrothermal fields in the world, escaly-footf gastropod is found only in one specific chimney in the Kairei Field in the Indian Ocean. SUGAR project team discovered escaly-footf gastropod under a large quantity of Rimicaris shrimp or Alviniconcha during the expedition in the Indian Ocean in 2009. This is how we got this opportunity to analyze why escaly-footf gastropod is so popular in the deep-sea. Thus, we decided to do further researches on escaly-footf gastropod with the teamwork of SUGAR project and Precambrian Ecosystem Laboratory.

Look forward to our exciting updates!


Establishing a new record for organism's maximum proliferation temperature and discovering unusually heavy isotopic methane compositions (2008)(2009)

We succeeded in breaking the record of upper temperature limits of life and biosphere by isolating a hyperthermophilic methanogen from Kairei Field, in Indian Ocean. This achievement enabled us to know more about the possibilities and conditions of life in the universe. SUGAR (Subsurface Geobiology and Advanced Research Program) and Precambrian Ecosystem Laboratory at JAMSTEC have developed a high temperature & pressure cultivation method (Takai method), and verified cell proliferation at 122‹C. Another evolutionary achievement was to find out methane composition made in the deep-sea condition by microorganisms are actually isotopically heavy, rather than the commonly known fact in Earth Science that often said the opposite. These achievements will surely lead us to further search for origin of methane on Earth and Mars.

Takai, K., Nakamura, K., Toki, T., Tsunogai, U., Miyazaki, M., Miyazaki, J., Hirayama, H., Nakagawa, S., Nunoura, T., & Horikoshi, K. (2008) Cell proliferation at 122‹C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation. Proc. Natl. Acad. Sci. USA, 105:10949-10954.

Fig. Electron microscopic photograph of strain 116@of Methanopyrus kandleri (Left), and history of fifty years record on upper temperature limit of life (Middle). Classification scheme of carbon isotope ratio for methane in natural environment, on organic geochemistryfs textbook (Right). We used to believe that all organisms on Earth can be gkilledh at 121‹C, however, this organism proved that our belief was wrong (Middle). The conventional statement, gMethane made by microorganisms is isotopically lighth also begged us to think once more and prove it again (Right).


Elucidation of geological, geochemical and microbiological interaction in the global deep-sea hydrothermal systems (1999-2009)

Since 1977, when the deep-sea hydrothermalism was discovered, it has been considered as one of the biggest 20th centuryfs discoveries in earth sciences. Many scientists have been attracted to this new research topic, as it also can be considered that life actually originated in those parts of the ancient Earth. However, the questions and mysteries have remained for more than thirty years since the discovery. Why are there most cosmopolitan and some regionally different microorganisms living at each active hydrothermal area? How do those microorganisms live in such extreme habitats around the active hydrothermal fields? JAMSTEC SUGAR Project has been investigating numerous active hydrothermal fields and their different habitats in a field in the Pacific, Atlantic, and Indian Ocean by showing the interdisciplinary and comprehensive research strategy and exploring skills. The outcomes of investigations conducted a potential general rule of geological, geochemical and microbiological interaction in the deep-sea hydrothermal systems, called gGeochemical control on deep-sea hydrothermal vent microbial communities by mean s of chemolithotrohic energy potentialsh. The key chemical factor is molecular hydrogen, not hydrogen sulfide and methane.

Inagaki, F., Kuypers, M. M. M., Tsunogai, U., Ishibashi, J., Nakamura, K., Treude, T., Ohkubo, S., Nakaseama, M., Gena, K., Chiba, H., Hirayama, H., Nunoura, T., Takai, K., Jørgensen, B. B., Horikoshi, K., & Boetius, A. (2006) Microbial community in a sediment-hosted CO2 lake of the southern Okinawa Trough hydrothermal system. Proc. Natl. Acad. Sci. USA, 103:14164-14169.

Fig. (Left) Distribution map of active hydrothermal fields investigated by JAMSTEC SUGAR Project. By comparing the hydrothermal vent microbial communities all over the world, it became clear that the microbial communities differ not due to the geographic locality, but geological settings. As a result, a hypothetical model of "geochemical control on deep-sea hydrothermal vent microbial communities by mean s of chemolithotrohic energy potentials " was proposed, which states that the each hydrothermal field's microbial productivity depends on the molecular hydrogen concentration.
Fig. (Upper Right) Photos of the Okinawa Trough Yonaguni Knoll IV hydrothermal field. Under strange structure called gflangeh is the jet of hydrothermal fluid containing a large amount of carbon dioxide; looks like it is boiling. Grape-like structures of carbon dioxide, turned into lumps after being separated from hydrothermal fluid, for the exceptionally high concentration of carbon dioxide in the fluid. Carbon dioxide separated from hydrothermal fluid is accumulated into surrounding sediments, then creates liquid carbon dioxide pools.
Fig. (Upper Middle) Photo of the Mariner hydrothermal field discovered by JAMSTEC SUGAR Program in the south-west Pacific Ocean. Research was started at the same season with American research group; initially found by SUGAR.
Fig. (Lower Right) Photos of gBlue Smokerh, the worldfs first-discovered gblue hydrothermal fluidh by SUGAR Project, JAMSTEC. Discovered in the Okinawa Trough Hatoma Knoll hydrothermal field. At first, it was much debated that the blue color was related to the magmatic activities; however, the later researches proved that it is due to the supercritical carbon dioxidefs optical phenomenon.


The most dreaded pathogensf ancestor, gthe previously unknownh deep-sea Epsilon proteobacteria, were cultivated and characterized comprehensively, and their genomes were determined for the first time in the world (2003-2007)

Since the late 1990s, it has been gradually revealed that the global deep-sea hydrothermal environment is overwhelmingly dominated by a specific group of microorganisms, Epsilonproteobacteria. The closest isolated strains of deep-sea Epsilonproteobacteria were the Campylobacter and the Helicobacter pylori, which cause stomach cancer and diarrhea, and they were not known much for their mysterious predominance and their relationship with the relative pathogens. Here, in SUGAR Project at JAMSTEC, we decided to tackle this mystery by encouraging two of our good-looking research scientists (Satoshi Nakagawa, finally got married in 2010, and Ken Takai, already taken) to engage in this puzzle-solving! Not only good-looking, but these two scientists were surely smart enough to solve this mystery; they gracefully took the lead in isolating deep-sea Epsilonproteobacteria in advance to the worldfs researches in this area, and proved these unknown bacteria were of the chemolithoautotrophic microorganisms, which generate energy from molecular hydrogen and sulfur compounds in the hydrothermal fluids. Moreover, they carried out genome analyses, and found out that these deep-sea bacteria possess genetic characteristics and molecular biological mechanisms in order to win in their competitions to dominate in the deep-sea hydrothermal environments. Now, thanks to their analyses, it can be said that these are the inherited harmful ancestral characteristics from the ancient world...!

Nakagawa, S., Takaki, Y., Shimamura, S., Reysenbach. A-L., Takai, K., & Horikoshi, K. (2007) Deep-sea vent epsilon-proteobacterial genomes provide insights into emergence of pathogens. Proc. Natl. Acad. Sci. USA, 104:12146-12150.

Fig. (Bottom Left) Dominance of Epsilonproteobacteria in the global deep-sea hydrothermal systems
Fig. (Bottom Right) Phylogenetic tree to show Epsilonproteobacteria (marked in yellow) being a close relative to Helicobacter pylori and Campylobacter.
Fig. (Bottom) Two genome sequences of Epsilonproteobacteria decoded by SUGAR Project at JAMSTEC. One is of mesophilic Epsilonprobacterium, and another is of thermophilic Epsilonbacterium. The mesophilic Epsilonproteobacterium is quite a close relative strain to the ones that live symbiotically inside of Alviniconchafs gills. The genome analyses of symbiotic Epsilonproteobacteria are currently on the process, and in the near future, the comparison of free-living and symbiotic Epsilonproteobacteria will be possible in genomic level.


The worldfs first elucidation of genetic diversity and biogeography in unknown functional groups of microorganisms in subseafloor sediments of the East Pacific Continental Margins (2006)

At Integrated Ocean Drilling Program (IODP), finding out all the details about deep-ocean biosphere has been the cornerstone of the scientific research plans. However, not much was discovered regarding the microbial biomass that exists beneath the deep-ocean. One of the first attempts at an ODP research programs was gSub-sea floor microbial biosphere drilling research voyageh, in which SUGAR program sent out Fumio Inagaki (a handsome, single guy back then) who gracefully won the scrambling of getting the best samples from the deep subseafloor. He analyzed the genetic diversity of deep subseafloor microbial components. His results showed that the microbial communities in the subseafloor sediments consisted of the totally phylogenetically different microorganisms from the surface world even though they were functionally unknown.@

Inagaki, F., Nunoura, T., Nakagawa, S., Teske, A., Lever, M., Lauer, A., Suzuki, M., Takai, K., Delwiche, D., Colwell, F. S., Nealson, K. H., Horikoshi, K., DfHondt, S., & Jørgensen, B.B. (2006) Biogeographical distribution and diversity of microbes in methane hydrate-bearing deep marine sediments on the Pacific Ocean Margin. Proc. Natl. Acad. Sci. USA, 103:2815-2820.

Fig. (Right) The ODPfs first gmicrobiology-dedicated drilling research voyageh was done at the locations of Peru Margin and Cascadia Margin. Vertical diagrams show the archaeal and bacterial community structure changes in a few hundred meters of the sediments. The phylogenetic trees represent the systematic characteristics of such subseafloor Archaea and Bacteria. We can see that most of the dominant microorganisms in the deep subseafloor are genetically greatly different from the ones in the surface environments. In other words, we can say that the subseafloor microbial world is considerably isolated from the surface world by a large (geologic) time scale. This will lead us to gain deeper understanding of how the functionally unknown microorganisms in the subseafloor are associated with the global scale of circulations of elements and energy sources in both surface and subsurface.


Proposing the Earth-Life interactive system gUltraH3 Linkage Hypothesish that supported the oldest ecosystem on Earth (2006)

We proposed the existence of "Ultramafics-Hydrothermalism-Hydrogenesis-HyperSLiME (UltraH3) linkage", assuming that the life was born in deep-sea hydrothermal fields and this linkage has spread to play the role of the very first and the sustainable ecosystem in deep-sea. We estimated that the HyperSliME has been existing only at the seabed hydrothermal fields until today where peridotite is exposed and Earth in its primitive condition is still represented. Furthermore, we brought forward a new theory for the first time that in Hadean eon (approximately four billion years ago from today), HyperSLiME seems to have generally existed in komatiite.

Takai, K., Nakamura, K., Suzuki, K., Inagaki, F., Nealson, K. H., & Kumagai, H. (2006) Ultramafics-Hydrothermalism-Hydrogenesis-HyperSLiME (UltraH3) linkage: a key insight into early microbial ecosystem in the Archean deep-sea hydrothermal systems. Paleontological Res. 10:269-282.

Fig.(Left): Models of ocean, Earth's crust, and mantle structure with deep-sea hydrothermalism interactions of four billion years ago and today.
Fig.(Right): Images of deep-sea hydrothermalism supported by komatiite, four billion years ago.


Discovery of the oldest survivor of ecosystem on Earth in the deepest part of the active hydrothermal field in Indian Ocean (2004)

HyperSLiME is the abbreviation for the Hyperthermophilic Subsurface Lithoautotrophic Microbial Ecosystem. We assumed this sunlight-independent ecosystem to be the oldest ecosystem on the Earth. Thus, we investigated several active deep-sea hydrothermal fields in different parts of the world, and discovered the HyperSLiME, Earth's oldest ecosystem in the active deep-sea hydrothermal field in Central Indian Ridge.

Takai, K., Gamo, T., Tsunogai, U., Nakayama, N., Hirayama, H., Nealson, K. H., & Horikoshi, K. (2004) Geochemical and microbiological evidence for a hydrogen-based, hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) beneath an active deep-sea hydrothermal field. Extremophiles, 8:269-282.

HyperSLiME is the abbreviation for the Hyperthermophilic Subsurface Lithoautotrophic Microbial Ecosystem. We assumed this sunlight-independent ecosystem to be the oldest ecosystem on the Earth. Thus, we investigated several active deep-sea hydrothermal fields in different parts of the world, and discovered the HyperSLiME, Earth's oldest ecosystem in the active deep-sea hydrothermal field in Central Indian Ridge.
Photo (Right): An electron microscope image of Methanotorris formicicum, a kind of hyperthermophilic methanogen, which is the primary producer of HyperSLiME.

Copyright (c) 2007 JAMSTEC. All rights reserved.