Acidic Hot Springs Research Articles

Xe in amorphous silica: A new thermometer in geothermal systems

We measured noble gases in amorphous silica of geothermal origin. These samples were formed by precipitation from geothermal water in neutral pH, and by the leaching of rocks in acid hot springs. The concentration of 132Xe has a negative correlation with the temperature of geothermal water although 36Ar and 84Kr show no such correlation. The relationship between 132Xe content A (×10−8cm³STP/g) and temperature T(°C) is approximated by the equation A=−(4.5×10−3)T +0.50. The obtained equation should be useful for estimating the silica‐forming temperature that cannot be easily measured by other methods.

Isolation and Characterization of Acidothermus cellulolyticus gen. nov., sp. nov., a New Genus of Thermophilic, Acidophilic, Cellulolytic Bacteria

Twelve isolates of thermophilic, acidophilic, cellulolytic bacteria were obtained from three different primary enrichment cultures from acidic hot springs at Yellowstone National Park, Wyo. The three isolates which had the highest cellulolytic activity, as shown by the diameter of clearing zones surrounding colonies on cellulose agar plates, were selected for intensive study. All were gram-variable, nonsporulating aerobic rods which formed no pigment. They grew at 37 to 65°C, with optimum growth at 55°C. The pH range for growth was 3.5 to 7, with an optimum pH of 5. The guanine-plus-cytosine content of the deoxyribonucleic acid was 60.7 ± 0.6 mol%. The organisms are resistant to penicillin G at 100 μg/ml. They share several important features with Thermus strains, namely heterotrophic, aerobic, and thermophilic mode of growth; morphological features; sensitivity to lysozyme; and presence of catalase. They differ in other important aspects, such as the pattern of carbon sources utilized for growth, the pH and temperature profiles of growth, the pattern of sensitivity to antibiotics, the guanine-plus-cytosine content of DNA, the composition of amino acids in the cell walls, and the structure of the cell walls. Thermus species are very sensitive to penicillin G, whereas our strains are resistant. Our strains also are different, in important respects, from the genus Thermomicrobium. Therefore, we designate the organism Acidothermus cellulolyticus gen. nov., sp. nov., of which the type strain is our strain 11B, ATCC 43068.

Iron-silica crystallite nucleation by bacteria in a geothermal sediment

The recognition of microfossils in ancient sedimentary rocks has confirmed that microorganisms which strongly resemble presentday prokaryotes existed at least 3 × 109 years ago1. Identification of these structures is a difficult task, complicated not only by the simple morphology of microorganisms, but also by our limited understanding of the processes leading to the mineralization of individual cells and their component parts2–4. We have investigated these processes in a natural setting, by examining sediment samples from an acidic hot spring in Yellowstone National Park. Electron microscopy and energy-dispersive X-ray spectroscopy of thin-sectioned specimens revealed remains of bacteria inside accumulations of iron and silica. Bacterial-like forms in successive stages of mineral preservation by silica were also found

Isolation and characterization of a methanol-utilizing phototrophic bacterium, Rhodopseudomonas acidophila M402 and its growth on vanillin derivatives.

A methanol-utilizing phototrophic bacterium, strain M402, was isolated from surface water of an acidic hot spring. The isolated strain was identified as Rhodopseudomonas acidophila from its morphological and physiological characters. Profiles of the utilization of non-aromatic compounds as carbon sources by this strain were in good agreement with those of some strains of R. acidophila reported by Pfennig [J. Bacteriol., 99, 597 (1969)]. However, strain M402 was found to be capable of utilizing vanillic acid, vanillin, vanillyl alcohol, ferulic acid, veratric acid, syringic acid, syringal-dehyde and benzyl alcohol as carbon sources under anaerobic-light conditions. Although Pfennig did not refer to these abilities of his strains, these notable characters of strain M402 seem to be additional new characters of R. acidophila.

Desulfurococcaceae, the Second Family of the Extremely Thermophilic, Anaerobic, Sulfur-Respiring Thermoproteales

Two novel species of anaerobic thermophilic archaebacteria isolated from acidic hot springs of Iceland, Desulfurococcus mucosus and Desulfurococcus mobilis , representing a second family, termed Desulfurococcaceae , of the order Thermoproteales are described. They utilize yeast extract or casein or its tryptic digest, but not casamino acids, as carbon sources, by sulfur respiration with the production of H 2 S and CO 2 , or by fermentation. The pH optimum of growth is pH 5.5 to 6, the temperature optimum 85 °C. The archaebacterial nature of the Desulfurococcaceae is evident from their insensitivity towards vancomycin, streptomycin and chloramphenicol, the lack of a murein cell wall, the presence of phytanol and polyisoprenoid dialcohols in the lipids, and the composition and the properties of the DNA dependent RNA polymerase. They are closely related to the recently described anaerobic thermoacidophilic sulfur-respiring Thermoproteus tenax representing the first family, Thermoproteaceae of the Thermoproteales . Of the other divisions of archaebacteria, Sulfolobus is the nearest relative. Desulfurococcus mucosus has a slimy polymer attached to its envelope. Desulfurococcus mobilis possesses flagellae in monopolar polytrichous arrangement.

Chemical and isotopic compositions of acid hot spring waters around Kusatsu-Shirane volcano

Chemical and isotopic compositions of acid hot spring waters around Kusatsu-Shirane volcano

Thermoanaerobacter ethanolicus gen. nov., spec. nov., a new, extreme thermophilic, anaerobic bacterium

Two strains, JW 200 and JW 201, of an extreme thermophilic, non-spore-forming anaerobic bacterium were isolated from alkaline and slightly acidic hot springs located in Yellowstone National Park. Both strains were peritrichously flagellated rods. Cell size varied from 0.5–0.8 by 4–100 μm; coccoid-shaped cells of about 1 μm in diameter frequently occurred. Division was often unequal. Spheroplast-like forms were visible at the late logarithmic growth phase. The Gram reaction was variable. The DNA base composition of the two strains was between 37 and 39 mol% guanine plus cytosine as determined by buoyant density measurements and approximately 32% by the thermal denaturation method. The main fermentation products from hexoses were ethanol and CO2. Growth occurred between 37 and 78°C and from pH 4.4 to 9.8. The name Thermoanaerobacter ethanolicus gen. nov., spec. nov. was proposed for the two, new isolates. Strain JW 200 was designated as the type strain.

Thermoacidophilic Algae of North and Central America

Two species of unicellular, eukaryotic, thermoacidophilic algae were found near the acid hot springs of North and Central America. One species has a cell diameter that ranges from 1.5 to 5 μm, contains one mitochondrion and one cup-shaped chloroplast bounded by a single membrane, lacks vacuoles, and multiplies by always forming four autospores. The other species has cells with diameters from 2 to 8 μm, contains numerous mitochondria and one cup-shaped chloroplast also bounded by a single membrane but with a different thylakoid configuration, a vacuolar system, and multiplies by forming 4, 8, 16, or 32 autospores. The species have been identified as Cyanidium caldarium and Protococcus sulphurarius, respectively. The latter species, however, may not belong in genus Protococcus.

Helium isotope ratios in Yellowstone and Lassen Park volcanic gases

Helium isotope ratios (³He/4He) in Lassen Park and Yellowstone Park volcanic gases show large ³He enrichments relative to atmospheric and crustal helium indicating the presence of a dominant mantle‐helium component. The ratios in Lassen helium are 8 times atmospheric in acid hot spring gases, and about 3 times atmospheric in the gas phase in near‐neutral high‐temperature waters; the acid‐spring helium is thus isotopically similar to helium in island‐arc and other continental‐margin orogenic areas. At Yellowstone, however, the isotopic ratio in helium from the Mud Volcano area, in the eastern part of Yellowstone caldera, is 15.6 times atmospheric, similar to the ratio in helium from Kilauea and Iceland. These high ratios, 15 times atmospheric or greater, are probably distinctively associated with deep‐mantle plumes under hot‐spots, while ratios about 10 times atmospheric characterize mantle helium in basalt glasses at the crests of mid‐ocean rises. The presence of “Kilauea‐type” helium at Yellowstone indicates that at least in certain areas the continental crust is essentially transparent to mantle volatiles.

Petrographic and isotopic studies of the altered acid volcanics of the Tolfa-Cerite area, Italy: the genesis of the clays

AbstractAlunite-kaolinite deposits occur in argillized zones in acid volcanic rocks at Tolfa. Over seventy samples were examined by one or more of the following methods: thin section, DTA, X-ray, IR, TG, SEM, chemical, and hydrogen and oxygen isotope analysis. Kaolinite and dickite, of high structural order, are the dominant clays with micamontmorillonite and halloysite subordinate. In many samples kaolinite and dickite coexist; their relative amounts are variable but the dickite content tends to increase with depth. SEM studies show that dickite crystals—up to 30 µm—are bigger than kaolinite.The D/H and18O/16O ratios of six clays, a whole rock, two biotites from fresh host rock, two chalcedony veins and three local meteoric waters indicate that the clays formed in a meteoric-hydrothermal environment of acid hot spring type at about 80°C. The fresh volcanic host rocks are strongly enriched in18O relative to ‘normal’ igneous rocks due to derivation from or exchange with18O-rich sedimentary rocks at depth prior to hydrothermal and solfataric activity. In the absence of present-day geothermal activity the life of this hot spring system was less than 4 m.y.

Biochemical studies on an acidophilic, thermophilic bacterium, Bacillus acidocaldarius: isolation of bacteria, intracellular pH, and stabilities of biopolymers.

Acidophilic, thermophilic bacteria were isolated from Japanese acidic hot springs. They were spore-forming rods, identified as Bacillus acidocaldarius. DNA extracted from these acido-thermophiles showed no abnormality in chemical structure; it was instantly denatured and gradually decomposed giving rise to apurinic acid in a hot acid environment milder than the optimal conditions for the growth of the acido-thermophiles. Glyceraldehyde-3-phosphate dehydrogenase extracted from B. acidocaldarius was not active at pH 5 or less, and was resistant to heat at neutral but not acid pH. The intracellular pH was computed to be neutral by using dimethyl-2,4-oxazolidinedione. When uncouplers or inhibitors of respiration were added to the cells suspended in hot acid solution, the estimated pH was not changed and glyceraldehyde-3-phosphate dehydrogenase in the cells was not denatured. These results suggest that the cytoplasm of B. acidocaldarius is a hot neutral environment, and that a pH gradient across the cell envelope can be maintained even when oxidative phosphorylation or respiration is inhibited.

DNA-dependent RNA polymerase from the thermophilic bacterium Caldariella acidophila. Purification and basic properties of the enzyme.

A DNA-dependent RNA polymerase has been isolated from Caldariella acidophila, a thermophilic bacterium living in acidic hot springs at temperatures ranging from 63 to 89 degrees C. The enzyme was purified 180-fold and is composed of five different subunits having the following molecular weights: a = 127000, b = 120000, c = 72000, d = 65000, and e = 38000. The enzyme is activated by Mn2+ and Mg2+ and exhibits optimal activity in the presence of 0.5 mM Mn2+. The activity depends on ionic strength, with a maximum at 0.25 M KCl, and exhibits a pH optimum at 7.8 in the presence of Tris-HCl buffer. The enzyme shows a high degree of thermophilicity, its temperature optimum being 80 degrees C in the in vitro assay. The thermophilicity of C. acidophila RNA polymerase allows studies on enzyme-template interactions to be performed in a temperature range where many templates are close to their Tm.

SURVIVAL OF BACTERIA AT LOW pH AND HIGH TEMPERATURE1

In most acid hot springs examined Sulfolobus was the predominant organism above 75°C at pH 2–3. It was found from 65–93°C at pH values from 1.6 to 3. The temperature optimum for growth was 70–75°C, whereas the pH optimum for 14C‐glutamate uptake was from 2 to 5. Survival and growth were demonstrated by slide immersion studies and electron microscopy of natural samples. Rod‐shaped bacteria live in the same habitat at 75–80°C and arc distinguished from Sulfolobus by their morphology and cell wall structure.

Attachment of Bacteria to Sulphur in Extreme Environments

SUMMARY: Sulfolobus attaches to sulphur deposited in acid hot springs by means of pili characterized as follows: (i) generally irregular shape with slight curves and bends; (ii) adhesiveness that enables bacteria to attach to sulphur; (iii) acid-stable, resistant to pH values as low as 2; (iv) heat-stable, resistant to temperatures as high as 75 °C. Sulfolobus attached to sulphur in nature and in culture eroded the sulphur crystal where the bacteria were attached. Sulfolobus undergoes the following two forms of attachment: (i) to sulphur by pili which separate the bacterium from the sulphur crystal and permit lateral movement of bacteria; (ii) to glass slides by firm adhesion of the wall to the surface of the slide. Attachment to sulphur in flowing springs enables Sulfolobus to colonize these low pH (2 to 3) high temperature (70 to 75 °C) habitats.

Bacterial Origin of Sulfuric Acid in Geothermal Habitats

Natural populations of Sulfolobus, a new genus of bacteria occurring in sulfur-rich, acid hot springs and soils, were found to oxidize large amounts of sulfur to sulfuric acid at temperatures up to 85 degrees C. These bacteria are important high-temperature geochemical agents in solfatara soils.

Investigation on the river water polluted with acidic hot spring water

Tamagawa hot spring in Akita Prefecture gushes hot water of 1 pH hydrochloric acid at some 140 1 s −1. This quantity flows into the River Tama with the result that the river has been denied use for any significant hydropower development thus far. For the purpose of mitigating the acidity of the river water, the hot spring water is carried away through channels and infiltrated into the soil of a mountainside for chemical neutralizing through seepage before flowing into the river. The following facts have been obtained by field geochemical investigation (1951–1963). The neutralization effect following the injection of hot-spring water into the soil is about 80 per cent, the larger part of which effect is due to the function of dissolution of Al 3+; the pH values of the water in the reservoir of Yoroibata dam to be constructed downstream of the river do not exceed 5; and even in the absence of hot-spring water injection treatment there is acidity reduction due to the alkalinity of the tributary waters as well as due to the dissolution of river-bed components by the acid during seepage.

A chemoautotrophic and thermophilic microorganism isolated from an acid hot spring.

A pleomorphic, acidophilic, and chemoautotrophic microbe is described. The cell is bound by a membrane and a diffuse, amorphous layer. The isolate used either sulfur or iron as a source of energy. Morphological and nutritional similarities as well as corresponding thermophilic and acidophilic requirements suggest a relationship to Sulfolobus. The organism tolerates 80 °C for longer than 2 h, but heat resistance is not attributed to a bacterial spore. The maximum temperature for growth is 70 °C; the minimum about 45 °C.The DNA base composition is 57 ± 3 mole % GC. Yeast extract enhances growth of the isolate on iron and sulfur substrates, but does not significantly enhance the isolate's respiration rate on these same substrates.The isolate requires induction by sulfur or iron for maximum respiration on these substrates, respectively. Optimum oxidation of elemental sulfur occurred at pH 2.0 and gave a [Formula: see text] of 163; oxidation on iron gave a maximum [Formula: see text] of 879.

The Dissolution of Olivine in Aqueous Solutions of Inorganic Acids

Abstract The dissolution of olivine was studied in aqueous solutions of inorganic acids at temperatures of 35, 50, and 65°C in order to obtain basic information about the alteration and leaching processes in acid hot spring regions. The rates of dissolution have been determined by measuring the change in the concentrations of silica, magnesium, and the total iron leached in the solutions as a function of the time. Olivine dissolved in stirred aqueous solutions of 0.05–2n perchloric, hydrochloric, and sulphuric acids without any selective dissolution of components in the mineral. The rate at which olivine dissolved was found to be two-thirds of the reaction order with respect to the sample-powder (10–20 μ in diameter) weight (i.e., first order with respect to the surface area) and to decrease in the order of H2SO4>>HCl>HClO4. HSO4− enchanced the rate remarkably. The complexing affinity of the anions did not play an important part in the reaction with olivine powder.

The Physiological Ecology of Cyanidium caldarium

Summary: The distribution and physiology of Cyanidium caldarium in its natural habitat in acidic hot springs and hot soils have been studied. This eucaryotic alga was the sole photosynthetic organism in habitats with pH less than 5 and temperatures greater than 40°. The upper temperature limit of the alga was 55° to 56° and the optimum temperature for growth was 45°. Temperature strains such as are found in blue-green algae of alkaline thermal habitats were not found for Cyanidium caldarium. In aquatic habitats the lower temperature limit was about 35° to 36°, the organism apparently being unable to compete at temperatures below this with other algae. In soils the alga was found at temperatures as low as 10°, apparently because in terrestrial habitats competition with other algae was less significant. The pH range at which the alga has been found in nature was from 0·05 to 5·0 and growth in culture occurred over this whole range. The optimum pH for growth was between 2 and 3. In nature the alga was found in habitats of widely varying light intensity, up to 7000 ft-candles. The alga became adapted to reduced light intensity by increasing its photopigment concentrations. Photosynthesis in populations adapted to reduced light intensities was inhibited by high light intensities. The alga grew well on glucose in the dark, and the concentration of photosynthetic pigments was reduced. When such bleached cells were transferred to the light in the presence of glucose, pigments were not synthesized and heterotrophic growth continued; when glucose was omitted, pigment synthesis occurred and photosynthetic growth resumed. Glucose did not inhibit pigment synthesis when added to cells growing in the light.

The Mercury Content of Several Acid Hot Springs in Japan

The Mercury Content of Several Acid Hot Springs in Japan