Springs In Japan Research Articles

Isotopic analysis of nickel, copper, and zinc in various freshwater samples for source identification

Nickel (Ni), copper (Cu), and zinc (Zn) are commonly used in human activities and pollute aquatic environments including rivers and oceans. Recently, Ni, Cu, and Zn isotope ratios have been measured to identify their sources and cycles in environments. We precisely determined the Ni, Cu, and Zn isotope ratios in rain, snow, and rime collected from Uji City and Mt. Kajigamori in Japan, and investigated the potential of isotopic ratios as tracers of anthropogenic materials. The isotope and elemental ratios suggested that road dust is the main source of Cu in most rain, snow, and rime samples and that some of the Cu may originate from fossil fuel combustion. Zinc in the rain, snow, and rime samples may be partially attributed to Zn in road dust. Zinc isotope ratios in the Uji rain samples are lower than those in the road dust, which would be emitted via high temperature processes. Nickel isotope ratios are correlated with V/Ni ratios in the rain, snow, and rime samples, suggesting that their main source is heavy oil combustion. Furthermore, we analyzed water samples from the Uji and Tawara Rivers and the Kakita River spring in Japan. Nickel and Cu isotope ratios in the river water samples were significantly heavier than those in rain, snow, and rime samples, while Zn isotope ratios were similar. This is attributed to isotopic fractionation of Cu and Ni between particulate-dissolved phases in river water or soil.

Creating a Unique Hot Spring Resort of Global Repute ─ Maximizing the “Best Carbonated Spring in Japan” Gushing in the Area ─

Creating a Unique Hot Spring Resort of Global Repute ─ Maximizing the “Best Carbonated Spring in Japan” Gushing in the Area ─

Conexivisphaera calida gen. nov., sp. nov., a thermophilic sulfur- and iron-reducing archaeon, and proposal of Conexivisphaeraceae fam. nov., Conexivisphaerales ord. nov., and Conexivisphaeria class. nov. in the phylum Thaumarchaeota

A thermoacidophilic, anaerobic, and iron- and sulfur-reducing archaeon, strain NAS-02T, was isolated from a terrestrial hot spring in Japan, as previously reported. This organism is the first non-ammonia-oxidizing isolate in the phylum Thaumarchaeota. Here, we propose Conexivisphaera calida gen. nov., sp. nov. to accommodate this strain. The type strain of the type species is NAS-02T (=JCM 31663T=DSM 105898T). The values of 16S rRNA gene similarity and average amino acid identity between NAS-02T and its closest relatives are <86 and <42 %, respectively. Based on the phylogeny and physiology, we propose the family Conexivisphaeraceae fam. nov., the order Conexivisphaerales ord. nov. and the class Conexivisphaeria class. nov. to accommodate the novel genus.

Competitive Structure of Accommodations in a Traditional Japanese Hot Springs Tourism Area

This paper investigates the competitive structure of prices in a traditional hot springs resort area in Japan from a spatial econometric perspective. This perspective has not been addressed in hot springs—or “onsen” in Japanese—tourism areas, which have been gradually losing momentum due to the ageing of operators and diversification of leisure activities. The study area is one of the three oldest hot springs in Japan, the Dogo Onsen area in Matsuyama, where hotels and ryokans are clustered. First, we present a conceptual framework that characterizes two strategies, namely, differentiation and partnership strategies. Then, spatial error models are employed to test the hypothesis that spatial closeness intensifies price competition, while social closeness mitigates price competition. The estimation results reveal that our hypothesis was verified, in that the social network which has been nurtured for generations in the study hot spring area mitigates price competition, in comparison with the non-hot spring area in Matsuyama. Thus, good partnerships among local operators based on social networks should be more closely scrutinized for the revitalization of traditional hot springs areas.

Anthocyanin regulatory and structural genes associated with violet flower color of Matthiola incana

MiMYB1 and MibHLH2 play key roles in anthocyanin biosynthesis in Matthiola incana flowers. We established a transient expression system using Turnip mosaic virus vector in M. incana. Garden stock (Matthiola incana (L.) R. Br.) is a popular flowering plant observed from winter to spring in Japan. Here we observed that anthocyanin accumulation in 'Vintage Lavender' increased with flower development, whereas flavonol accumulation remained constant throughout flower development. We obtained five transcription factor genes, MiMYB1, MibHLH1, MibHLH2, MiWDR1, and MiWDR2, from M. incana floral cDNA contigs. Yeast two-hybrid analyses revealed that MiMYB1 interacted with MibHLH1, MibHLH2, and MiWDR1, but MiWDR2 did not interact with any transcription factor. Expression levels of MiMYB1 and MibHLH2 increased in petals during floral bud development. Their expression profiles correlated well with the temporal profiles of MiF3'H, MiDFR, MiANS, and Mi3GT transcripts and anthocyanin accumulation profile. On the other hand, MibHLH1 was expressed weakly in all organs of 'Vintage Lavender'. However, high expression levels of MibHLH1 were detected in petals of other cultivars with higher levels of anthocyanin accumulation than 'Vintage Lavender'. MiWDR1 and MiWDR2 maintained constant expression levels in petals during flower development and vegetative organs. Transient MiMYB1 expression in 1-month-old M. incana seedlings using a Turnip mosaic virus vector activated transcription of the endogenous anthocyanin biosynthetic genes MiF3'H, MiDFR, and MiANS and induced ectopic anthocyanin accumulation in leaves. Therefore, MiMYB1 possibly interacts with MibHLH2 and MiWDR1, and this trimeric protein complex activates the transcription of anthocyanin biosynthetic genes in M. incana flowers. Moreover, MibHLH1 acts as an enhancer of anthocyanin biosynthesis with the MiMYB1-MibHLH2-MiWDR1 complex. This study revealed the molecular mechanism involved in the regulation of anthocyanin accumulation levels in M. incana flowers.

Complete Genome Sequences of Rhodothermus marinus Strains AA2-13 and AA3-38, Isolated from Arima Onsen Hot Spring in Japan.

We isolated Rhodothermus marinus strains AA2-13 and AA3-38 from Arima Onsen, a hot spring in Japan, and sequenced their genomes. The average nucleotide identity between their genomes was 99.2%, and that with the genome of R. marinus strain DSM 4252T (isolated from Iceland) was ∼95.2%, suggesting close relationships among these strains.

Candidatus Anthektikosiphon siderophilum OHK22, a New Member of the Chloroflexi Family Herpetosiphonaceae from Oku-okuhachikurou Onsen.

We report the draft metagenome-assembled genome of a member of the Chloroflexi family Herpetosiphonaceae from microbial biofilms developed in a circumneutral, iron-rich hot spring in Japan. This taxon represents a novel genus and species—here proposed as Candidatus Anthektikosiphon siderophilum—that expands the known taxonomic and genetic diversity of the Herpetosiphonaceae and helps orient the evolutionary history of key traits like photosynthesis and aerobic respiration in the Chloroflexi.

Draft Genome Sequences of Two Thermophilic Moorella sp. Strains, Isolated from an Acidic Hot Spring in Japan.

The thermophilic Moorella sp. strains E308F and E306M were isolated from an acidic hot spring in Japan. Here, we report the draft genome sequences of E308F (3.06 Mbp; G+C content, 54.0%) and E306M (2.99 Mbp; G+C content, 54.4%), to advance the genomic information available on the genus Moorella.

Depositional processes of microbially colonized manganese crusts, Sambe hot spring, Japan

Abstract Relative contribution of microbially mediated and purely abiotic processes during Mn(II) oxidation is evaluated by investigating microbially colonized manganese deposits at the Sambe hot spring in Japan. Microscopic observations and DNA analyses suggest that manganese-oxidizing bacteria are present in the deposits at all of the sites investigated, while thick microbial mats, which consist mainly of phototrophic microorganisms, are developed at only one site. Microelectrode measurements (pH, O2 concentration, and Mn(II) concentration) near the deposit surface indicate that microbially mediated processes are dominant at all sites. These microbially mediated processes exceed the purely abiotic process by more than 2–24 times. At sites without abundant phototrophs, the major microbially mediated process that is occurring is light-independent oxidation (e.g., direct/indirect oxidation via manganese-oxidizing bacteria/fungi). In contrast, the site with abundant phototrophs is characterized by the occurrence of light-independent oxidation (mostly indirect oxidation by oxygenic phototrophs), and the contribution of light-independent oxidation is subordinate. Chemical gradients, which are established within a diffusive boundary layer and microbial mat, drive indirect oxidation by oxygenic phototrophs, and the O2 concentration gradient is particularly important when the concentration of dissolved inorganic carbon is higher than ca. 3 mM. X-ray diffraction and X-ray absorption fine-structure spectrometry analyses indicate that microbially mediated processes yield poorly-crystalline birnessite (i.e., vernadite) regardless of their relative contribution. The observations of this study imply that (1) photosynthetic increases in the O2 concentration drive indirect oxidation by oxygenic phototrophs at high concentrations of dissolved inorganic carbon like the Precambrian ocean, and that (2) the contribution of indirect oxidation by oxygenic phototrophs to ancient manganese oxides can be evaluated via geochemical redox proxies.

四季成り性イチゴ品種の暖地冬春季栽培における開花およびランナー発生特性の解明と適正品種の選定

四季成り性イチゴ品種の暖地冬春季栽培における開花およびランナー発生特性の解明と適正品種の選定

Sulfide-dependent Photoautotrophy in the Filamentous Anoxygenic Phototrophic Bacterium, Chloroflexus aggregans.

Chloroflexus aggregans is a thermophilic filamentous anoxygenic phototrophic bacterium frequently found in microbial mats in natural hot springs. C. aggregans often thrives with cyanobacteria that engage in photosynthesis to provide it with an organic substrate; however, it sometimes appears as the dominant phototroph in microbial mats without cyanobacteria. This suggests that C. aggregans has the ability to grow photoautotrophically. However, photoautotrophic growth has not been observed in any cultured strains of C. aggregans. We herein attempted to isolate a photoautotrophic strain from C. aggregansdominated microbial mats in Nakabusa hot spring in Japan. Using an inorganic medium, we succeeded in isolating a new strain that we designated “ACA-12”. A phylogenetic analysis based on 16S rRNA gene and 16S-23S rRNA gene internal transcribed spacer (ITS) region sequences revealed that strain ACA-12 was closely related to known C. aggregans strains. Strain ACA-12 showed sulfide consumption along with autotrophic growth under anaerobic light conditions. The deposited elemental sulfur particles observed by microscopy indicated that sulfide oxidation occurred, similar to that in photoautotrophic strains in the related species, C. aurantiacus. Moreover, we found that other strains of C. aggregans, including the type strain, also exhibited a slight photoautotrophic growing ability, whereas strain ACA-12 showed the fastest growth rate. This is the first demonstration of photoautotrophic growth with sulfide in C. aggregans. The present results strongly indicate that C. aggregans is associated with inorganic carbon incorporation using sulfide as an electron donor in hot spring microbial mats.

Relative influence of biotic and abiotic processes on travertine fabrics, Satono‐yu hot spring, Japan

AbstractThe relative influences of biotic and abiotic processes on travertine fabrics are still not well understood, despite increasing interest in the last decade to better understand the record of ancient microbial life and sedimentary fabrics in microbial hydrocarbon reservoirs. This study examines travertines at Satono‐yu hot spring in Japan (the temperature of water flowing over the travertine was ca 35°C), to better understand the interaction between depositional, hydrochemical and microbial parameters at different flow settings. Characteristics of the bulk hydrochemistry, mineralogy (exclusively aragonite) and the driving force for precipitation (primarily abiotic CO2 degassing with some photosynthetic microbial contribution) were similar among all of the flow settings. Conversely, the increase in flow velocity suppressed the influence of photosynthesis and enhanced the abiotic precipitation due to the thinner diffusive boundary layer at the travertine surface–water interface. Additionally, the increase in flow velocity changed the microbial composition and decreased the bacterial diversity by reflecting their adhesion efficiency on the travertine substrate. The acidity of the cyanobacterial sheaths controls the aragonite nucleation rate and the resulting calcification, even at significantly high equilibrium CO2 partial pressure (ca 22 to 28 matm), high dissolved inorganic carbon concentration (ca 35 to 38 mmol l−1), and elevated aragonite saturation state (ca 20‐fold to 34‐fold). Therefore, the increase in flow velocity suppresses the microbial influence with respect to the increase in the saturation state, the nucleation site supply and pore space generation. Overall, this results in the predominance of abiotic precipitation under high flow velocities. Consequently, a sparse‐micritic fabric with abundant interlamina porosity forms under lower flow velocity where the microbial influence is effective, while a dense‐sparitic fabric with little inter‐crystalline porosity forms under higher flow velocity where abiotic precipitation prevails. These findings provide an essential base for assessing the formation processes of ancient travertines and comparable deposits from petrological fabrics.

Effect of light wavelength on hot spring microbial mat biodiversity.

Hot spring associated phototrophic microbial mats are purely microbial communities, in which phototrophic bacteria function as primary producers and thus shape the community. The microbial mats at Nakabusa hot springs in Japan harbor diverse photosynthetic bacteria, mainly Thermosynechococcus, Chloroflexus, and Roseiflexus, which use light of different wavelength for energy conversion. The aim of this study was to investigate the effect of the phototrophs on biodiversity and community composition in hot spring microbial mats. For this, we specifically activated the different phototrophs by irradiating the mats with different wavelengths in situ. We used 625, 730, and 890 nm wavelength LEDs alone or in combination and confirmed the hypothesized increase in relative abundance of different phototrophs by 16S rRNA gene sequencing. In addition to the increase of the targeted phototrophs, we studied the effect of the different treatments on chemotrophic members. The specific activation of Thermosynechococcus led to increased abundance of several other bacteria, whereas wavelengths specific to Chloroflexus and Roseiflexus induced a decrease in >50% of the community members as compared to the dark conditions. This suggests that the growth of Thermosynechococcus at the surface layer benefits many community members, whereas less benefit is obtained from an increase in filamentous anoxygenic phototrophs Chloroflexus and Roseiflexus. The increases in relative abundance of chemotrophs under different light conditions suggest a relationship between the two groups. Aerobic chemoheterotrophs such as Thermus sp. and Meiothermus sp. are thought to benefit from aerobic conditions and organic carbon in the form of photosynthates by Thermosynechococcus, while the oxidation of sulfide and production of elemental sulfur by filamentous anoxygenic phototrophs benefit the sulfur-disproportionating Caldimicrobium thiodismutans. In this study, we used an experimental approach under controlled environmental conditions for the analysis of natural microbial communities, which proved to be a powerful tool to study interspecies relationships in the microbiome.

Fe(II) oxidation processes at the surface of bacterially colonized iron deposits

Fe(II) oxidation processes at the surfaces of bacterially colonized iron deposits are examined at three hot springs in Japan for which the chemical profiles of the pH, redox, and O2 and Fe(II) concentrations at the water/deposit interface are measured via microelectrodes. The three hot springs share similar bulk chemistry with a weakly acidic pH of 5.7–6.3, a high iron concentration of 50–130μM, and a high dissolved inorganic carbon concentration of 20–60mM. At the Sambe and Shionoha hot springs where the bulk water O2 concentration is ca. 80μM, abiotic Fe(II) oxidation via autocatalysis prevails. At the Okuoku-hachikurou hot spring where the bulk water O2 concentration is ca. 50μM, autocatalytic Fe(II) oxidation is suppressed and biotic Fe(II) oxidation induced by cyanobacterial photosynthesis is effective. These observations indicate that an O2 concentration of ca. 50μM is the threshold of reversing the relative contribution of biotic and abiotic Fe(II) oxidation. Protons from Fe(II) oxidation are compensated by reactions among the dissolved inorganic carbon species, which sustain the pH condition and continuous Fe(II) oxidation at the deposit surface. The observations of this study provide implications for understanding the deposition of banded iron formations in the geological past.

Characterization of thermotolerant phototrophic bacteria, Rhodoplanes tepidicaeni sp. nov. and Rhodoplanes azumiensis sp. nov., isolated from a geothermal spring.

Two strains of thermotolerant phototrophic alphaproteobacteria, designated strains TUT3542T and TUT3581T, were isolated from sediment mud and cyanobacterial mats in a geothermal spring in Japan, respectively, and taxonomically characterized. Both the strains were budding motile rods and were able to grow at 45 °C. Phototrophically grown cells of strains TUT3542T and TUT3581T produced pink and brownish red cultures, respectively, and showed in vivo absorption maxima at 800, 858-859 and 892-895 nm in the near infrared region, indicating the presence of a core reaction centre and peripheral pigment complexes with bacteriochlorophyll a. The intracytoplasmic membrane system was of the lamellar type parallel to the cytoplasmic membrane. 16S rRNA gene sequence comparisons showed that strains TUT3542T and TUT3581T had the highest similarity level to Rhodoplanes oryazae NBRC 109406T (99.6 %) and Rhodoplaneselegans AS130T (99.3 %), respectively. Genomic DNA-DNA reassociation studies revealed that strains TUT3542T and TUT3581T had hybridization levels of less than 62 and 56 % to the type strains of all established species of the genus Rhodoplanes, respectively. The G+C contents of genomic DNA were 67.7 mol% for strain TUT3542T and 70.4 mol% for strain TUT3581T. Results of phenotypic studies showed that the two novel strains could be differentiated from any of the previously described Rhodoplanes species. Thus, the author proposes the names Rhodoplanes tepidicaeni sp. nov. for strain TUT3542T and Rhodoplanes azumiensis sp. nov. for strain TUT3581T. The type strain of Rhodoplanes tepidicaeni is TUT3542T (=KCTC 15602T=NBRC 112815T) and the type strain of Rhodoplanes azumiensis is TUT3581T (=KCTC 15603T=NBRC 112816T).

Draft Genome Sequence of Chloracidobacterium sp. CP2_5A, a Phototrophic Member of the Phylum Acidobacteria Recovered from a Japanese Hot Spring.

ABSTRACTThe phylum Acidobacteria contains a single known phototrophic member, Chloracidobacterium thermophilum, which was recovered from a hot spring metagenome from Yellowstone National Park. Here, we expand the diversity of the genus Chloracidobacterium with a genome recovered from a hot spring in Japan, extending the known range of this lineage to a new continent.

Sulfodiicoccus acidiphilus gen. nov., sp. nov., a sulfur-inhibited thermoacidophilic archaeon belonging to the order Sulfolobales isolated from a terrestrial acidic hot spring.

A novel thermoacidophilic archaeon, strain HS-1T, was isolated from the Hakone Ohwaku-dani hot spring in Japan. Cells of strain HS-1T in exponential phase were cocci to irregular cocci with a diameter of 0.8-1.5 µm. The strain grew within a temperature range of 50-70 °C (optimal: 65-70 °C), a pH range of pH 1.4-5.5 (optimal: pH 3.0-3.5) and a NaCl concentration range of 0-2.5 % (w/v). The novel strain grew in aerobic conditions but did not grow anaerobically. Moreover, this strain utilized various complex substrates (beef extract, casamino acids, peptone, tryptone and yeast extract) and sugars (arabinose, xylose, galactose, glucose, maltose, sucrose, raffinose and lactose) as sole carbon sources. No chemolithoautotrophic growth occurred on elemental sulfur, pyrite, K2S4O6, Na2S2O3 or FeSO4 . 7H2O; however, growth by the oxidation of hydrogen occurred weakly. The core lipids were calditoglycerocaldarchaeol (CGTE) and caldarchaeol (DGTE). The DNA G+C content of the strain was 52.0 mol%, which was remarkably higher than those of known species of the order Sulfolobales(31-46.2 %). The growth of the strain was significantly inhibited in the presence of elemental sulfur. Analyses of 16S rRNA and 23S rRNA gene sequences showed that HS-1T belonged to the order Sulfolobales; however, it was distantly related to all known species of the order Sulfolobales (less than 89 % sequence similarity). On the basis of these results, we propose the novel genus, Sulfodiicoccus, in the order Sulfolobales (in the family Sulfolobaceae). The type species of the genus is Sulfodiicoccus acidiphilus sp. nov., and the type strain of the species is HS-1T (=JCM 31740T=InaCC Ar79T).

Compound– and position–specific carbon isotopic signatures of abiogenic hydrocarbons from on–land serpentinite–hosted Hakuba Happo hot spring in Japan

It has been proposed that serpentinite–hosted hydrothermal/hot spring systems played a significant role in the origin and early evolution of life on early Earth because abiogenic synthesis of organic compounds may accompany serpentinization. However, production mechanisms for apparently abiogenic hydrocarbons that have been observed in the ongoing serpentinizing systems are still poorly constrained. We report a new geochemical study of hydrocarbons in an on–land serpentinite–hosted hot spring in Hakuba Happo, Japan. We have conducted both compound–specific and position–specific carbon isotopic analyses of the observed C1 to C5 hydrocarbons. A positive linear relationship between the δ13C values and the inverse carbon number is found in C1 to C5 straight–chain alkanes in the Happo sample. This isotopic trend is consistent with a simple polymerization model developed in this study. Our model assumes that, for any particular alkane, all of the subsequently added carbons have the same isotopic composition, and those are depleted in 13C with respect to the first carbon in the growing carbon chain. The fit of this model suggests that Happo alkanes can be produced via polymerization from methane with a constant kinetic isotopic fractionation of –8.9±1.0‰. A similar carbon isotopic relationship among alkanes has been observed in some serpentinite–hosted seafloor hydrothermal systems, indicating that the same process is responsible for the abiological hydrocarbon in general serpentinization fields, not only in the Hakuba Happo hot spring. Moreover, our model is also applicable to other potentially abiogenic natural gases and experimentally synthesized hydrocarbon products. For the first time, the intramolecular 13C composition of propane from a natural sample derived from a serpentinite-hosted system was determined. The intramolecular 13C distribution in propane shows the important potential to identify different polymerization mechanisms that cannot be discriminated by compound–specific isotopic analysis.

道後温泉における地震後の水位上昇について

The Dogo hot spring, situated in Matsuyama City, Ehime Prefecture, Japan, is one of the oldest and most famous hot springs in Japan. The well water level or discharge at the spring often decreased coseismically and increased postseismically related to the past Nankai earthquakes. We analyzed well water level data recorded at the spring immediately after the 1946 Nankai earthquake and over the period from 1985 to 2015. From this analysis, we have got five postseismic well water level increases related to the earthquakes whose seismic intensities were four or greater at Matsuyama city in JMA scale. The pattern of the five postseismic increases is very similar and shows a tendency of exponential convergence. We found that these postseismic increases can be explained by a basic equation of groundwater motion, which is a kind of diffusion equation. We also tried to detect the change in the diffusion coefficient or hydraulic diffusivity. However we did not detect it.

Nonconventional cation-coupled flagellar motors derived from the alkaliphilic Bacillus and Paenibacillus species.

Prior to 2008, all previously studied conventional bacterial flagellar motors appeared to utilize either H+ or Na+ as coupling ions. Membrane-embedded stator complexes support conversion of energy using transmembrane electrochemical ion gradients. The main H+-coupled stators, known as MotAB, differ from Na+-coupled stators, PomAB of marine bacteria, and MotPS of alkaliphilic Bacillus. However, in 2008, a MotAB-type flagellar motor of alkaliphilic Bacillus clausii KSM-K16 was revealed as an exception with the first dual-function motor. This bacterium was identified as the first bacterium with a single stator-rotor that can utilize both H+ and Na+ for ion-coupling at different pH ranges. Subsequently, another exception, a MotPS-type flagellar motor of alkaliphilic Bacillus alcalophilus AV1934, was reported to utilize Na+ plus K+ and Rb+ as coupling ions for flagellar rotation. In addition, the alkaline-tolerant bacterium Paenibacillus sp. TCA20, which can utilize divalent cations such as Ca2+, Mg2+, and Sr2+, was recently isolated from a hot spring in Japan, which contains a high Ca2+ concentration. These findings show that bacterial flagellar motors isolated from unique environments utilize unexpected coupling ions. This suggests that bacteria that grow in different extreme environments adapt to local conditions and evolve their motility machinery.