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1.
The composition of sulfur isotopes in sedimentary sulfides and sulfates traces the sulfur cycle throughout Earth's history. In particular, depletions of sulfur-34 ((34)S) in sulfide relative to sulfate exceeding 47 per mil (‰) often serve as a proxy for the disproportionation of intermediate sulfur species in addition to sulfate reduction. Here, we demonstrate that a pure, actively growing culture of a marine sulfate-reducing bacterium can deplete (34)S by up to 66‰ during sulfate reduction alone and in the absence of an extracellular oxidative sulfur cycle. Therefore, similar magnitudes of sulfur isotope fractionation in sedimentary rocks do not unambiguously record the presence of other sulfur-based metabolisms or the stepwise oxygenation of Earth's surface environment during the Proterozoic. 相似文献
2.
The observed mass-independent sulfur isotopic composition (Delta33S) of volcanic sulfate from the Agung (March 1963) and Pinatubo (June 1991) eruptions recorded in the Antarctic snow provides a mechanism for documenting stratospheric events. The sign of Delta33S changes over time from an initial positive component to a negative value. Delta33S is created during photochemical oxidation of sulfur dioxide to sulfuric acid on a monthly time scale, which indicates a fast process. The reproducibility of the results reveals that Delta33S is a reliable tracer to chemically identify atmospheric processes involved during stratospheric volcanism. 相似文献
3.
Johnston DT Wing BA Farquhar J Kaufman AJ Strauss H Lyons TW Kah LC Canfield DE 《Science (New York, N.Y.)》2005,310(5753):1477-1479
The environmental expression of sulfur compound disproportionation has been placed between 640 and 1050 million years ago (Ma) and linked to increases in atmospheric oxygen. These arguments have their basis in temporal changes in the magnitude of 34S/32S fractionations between sulfate and sulfide. Here, we present a Proterozoic seawater sulfate isotope record that includes the less abundant sulfur isotope 33S. These measurements imply that sulfur compound disproportionation was an active part of the sulfur cycle by 1300 Ma and that progressive Earth surface oxygenation may have characterized the Mesoproterozoic. 相似文献
4.
Atmospheric influence of Earth's earliest sulfur cycle 总被引：1，自引：0，他引：1
Mass-independent isotopic signatures for delta(33)S, delta(34)S, and delta(36)S from sulfide and sulfate in Precambrian rocks indicate that a change occurred in the sulfur cycle between 2090 and 2450 million years ago (Ma). Before 2450 Ma, the cycle was influenced by gas-phase atmospheric reactions. These atmospheric reactions also played a role in determining the oxidation state of sulfur, implying that atmospheric oxygen partial pressures were low and that the roles of oxidative weathering and of microbial oxidation and reduction of sulfur were minimal. Atmospheric fractionation processes should be considered in the use of sulfur isotopes to study the onset and consequences of microbial fractionation processes in Earth's early history. 相似文献
5.
Precipitation of sulfide ores and organic matter: sulfate reactions at pine point, Canada 总被引：1，自引：0，他引：1
Bitumen is a common associate of carbonate-hosted lead-zinc deposits. On the Pine Point lead-zinc property, Northwest Territories, Canada, there are two forms of bitumen. Unaltered bitumens have atomic hydrogen/carbon ratios of about 1.4, sulfur contents of about 7.8 percent, and sulfur isotope ratios ( section sign(34)S) of approximately +4.6 per mil. Altered bitumens occur in proximity to sulfide ore bodies and white sparry dolomite. Their hydrogen/carbon ratios are about 1.02, the sulfur contents average 22 percent, and the section sign(34)S values are about +12.4 per mil. These data indicate that some bitumen has participated in the thermochemical reduction of sulfate to produce hydrogen sulfide required to precipitate the ores. Mass balance considerations show that the amount and degree of alteration of bitumen is more than adequate to account for the reduced sulfur species (lead, zinc, and iron sulfides) deposited at Pine Point. These reactions may provide an important means of generating the large volumes of sulfide necessary to precipitate ore bodies in carbonate rocks. 相似文献
6.
The currently known upper temperature limit for growth of organisms, shared by a number of archaebacteria, is 110 degrees C. However, among the sulfate-reducing bacteria, growth temperatures of greater than 100 degrees C have not been found. A search for high-temperature activity of sulfate-reducing bacteria was done in hot deep-sea sediments at the hydrothermal vents of the Guaymas Basin tectonic spreading center in the Gulf of California. Radiotracer studies revealed that sulfate reduction can occur at temperatures up to 110 degrees C, with an optimum rate at 103 degrees to 106 degrees C. This observation expands the upper temperature limit of this process in deep-ocean sediments by 20 degrees C and indicates the existence of an unknown group of hyperthermophilic bacteria with a potential importance for the biogeochemistry of sulfur above 100 degrees C. 相似文献
7.
一株硫酸盐还原菌DSRBa的分离鉴定及特性分析 总被引：1，自引：0，他引：1
从内循环厌氧反应器颗粒污泥中分离、纯化得到一株硫酸盐还原菌命名为DSRBa,经形态和基于16SrDNA序列分析,该菌株归属于脱硫弧菌属(Desulfovibrio)。分别以甲酸钠、乙醇、乳酸钠、葡萄糖等为碳源,以硫酸盐、硫代硫酸盐、亚硫酸盐、单质硫为硫源,研究了不同温度、pH及不同硫酸根浓度对该菌株的影响。结果表明,菌株最适宜生长温度为30～35℃,最佳生长pH为7.0,无需绝对严格厌氧,当溶液中氧化还原电位(ORP)≤-40mV时,该菌株能较好生长,且生长4d后使溶液内氧化还原电位值达到-380mV,随后溶液内氧化还原电位基本保持不变。当系统内乳酸钠和酵母提取物浓度分别为3.5g·L-1和1g·L-1时,硫酸根浓度在1～4.5g·L-1范围对菌株生长无明显影响,且当SO24-浓度≤3g·L-1时,菌株生长4d对硫酸根的去除率达到90%以上。 相似文献
8.
The isotope record of sedimentary sulfides can help resolve the history of oxygen accumulation into the atmosphere. We measured sulfur isotopic fractionation during microbial sulfate reduction up to 88 degrees C and show how sulfate reduction rate influences the preservation of biological fractionations in sediments. The sedimentary sulfur isotope record suggests low concentrations of seawater sulfate and atmospheric oxygen in the early Archean (3.4 to 2.8 billion years ago). The accumulation of oxygen and sulfate began later, in the early Proterozoic (2.5 to 0.54 billion years ago). 相似文献
9.
含硫尾矿废水对水田土壤的污染 总被引：2，自引：0，他引：2
研究受铜矿尾矿废水影响的受害农田之结果表明，虽然废水硫化物含量低于排放标准，但其硫酸盐含量却比水库水高出１０倍，受废水影响，土壤全硫含量（特别是水溶性和吸附性硫部分）显著增加，同时，土壤的Ｃ／Ｓ比值显著下降，有机质含量高的土壤在渍水条件下形成强烈的还原性环境，使土壤中硫化物含量迅速增加，从而对水稻根系造成毒害，因此，笔者建议在我国的废水排放标准及农田灌水水质标准中，增加硫酸根监测项目和标准。 相似文献
10.
The chemical speciation of sulfur in geological fluids is a controlling factor in a number of processes on Earth. The two major chemical forms of sulfur in crustal fluids over a wide range of temperature and pressure are believed to be sulfate and sulfide; however, we use in situ Raman spectroscopy to show that the dominant stable form of sulfur in aqueous solution above 250°C and 0.5 gigapascal is the trisulfur ion S(3)(-). The large stability range of S(3)(-) enables efficient transport and concentration of sulfur and gold by geological fluids in deep metamorphic and subduction-zone settings. Furthermore, the formation of S(3)(-) requires a revision of sulfur isotope-fractionation models between sulfides and sulfates in natural fluids. 相似文献
11.
本文对甘肃省不同类型滩羊产区饮水中含硫量进行了测定,结果表明:1.各类型滩羊产区饮水pH范围为7.65—7.90.而作为对照的蒙古羊产区饮水pH为8.6,饮水中均无硫化氢(H_2S),亦无其它硫化物形式的硫。2.不同类型产区滩羊饮水中的蕊。主要以硫酸盐形式存在。3.典型滩羊产区饮水中的流含量平均为4.8毫克当量/升,为对照区0.59毫克当量/升的8倍;一般产区和过渡产区分别为20和26.9倍。 相似文献
12.
长期施用硫酸盐肥料对土壤性质和水稻生长的影响 总被引：12，自引：0，他引：12
本文就长期施用硫酸盐肥料对土壤性质和水稻生育的影响进行了系统研究。实践证明,硫酸盐肥料能促使土壤有机质缓慢积累,能提高土壤中磷的有效性,能活化粘土矿物晶格中所固结的钾素,改善土壤钾素供应状况。土壤中速效氮、磷、钾动态变化的趋势是一致的,在早稻生育期间（5月底6月初）速效氮、磷、钾有一个高峰期。一般说,铵态氮的高峰期比较早,速效磷、钾的高峰期比铵态氮略迟。在晚稻生育期间,这些养分的动态变化与早稻生育期间不同,有效磷保持相对稳定,有效钾直线下降。其原因及其对水稻生育的影响有待进一步研究。长期施用硫酸盐肥料,对稻米蛋白质含量和氨基酸组成也有影响,优化施肥能提高稻米蛋白质含量。含硫氨基酸如蛋氨酸,胱氨酸的含量,早稻比晚稻高;碱性氨基酸的含量,晚稻比早稻高。 相似文献
13.
In the permanently stagnant depths of Green Lake (near Syracuse, N.Y.), sulfide made by bacteria is depleted in heavy sulfur (S(34)), and sulfate is enriched. The fractionation factor, 1.0575, is the greatest yet observed. Isotopic resemblance to salt-dome sulfur deposits is evident, and, like saltdome calcite, the lake's carbon dioxide is depleted in heavy carbon (C(13)). 相似文献
14.
不同无机硫对内蒙古白绒山羊消化代谢的影响 总被引：3，自引：1，他引：3
选用9只装有瘤胃和十二指肠近端瘘管的内蒙古白绒山羊羯羊（2周岁左右），随机分成3组，分别饲喂氮硫比相同而硫源不同（分别为硫磺，硫化钠和硫酸钠）的3种日粮，进行消化代谢试验和测定食糜流通量，以探讨不同无机硫对氮和硫的沉积量以及硫的流通规律，试验结果表明：硫酸钠组氮的进食量和沉积量均显著高于硫磺组和硫化钠组（P＜0．05），但各组间氮的表观消化率差异不显著（P＞0．05），硫化钠组和硫酸钠组硫的沉积量以及表观消化率均显著高于硫磺组（P＜0．05），硫酸盐在瘤胃吸收量很少，主要在肠道被吸收；硫化物在瘤胃和小肠均可被吸收利用，元素硫（硫磺）主要在瘤胃和小肠前段被分解利用，元素硫的生物学效价显著低于硫酸钠和硫化钠（P＜0．05）。总之，添加硫酸钠对内蒙古白绒山羊的效果好于硫磺和硫化钠。 相似文献
15.
Philippot et al. (Reports, 14 September 2007, p. 1534) interpreted multiple-sulfur isotopic compositions of approximately 3.5-billion-year-old marine sulfide deposits as evidence that early Archaean microorganisms were not sulfate reducers but instead metabolized elemental sulfur. However, their data can be better explained by a scenario involving poor mixing of photochemical and surface sulfide sources. 相似文献
16.
Sulfides from four achondrite meteorite groups are enriched in 33S (up to 0.040 per mil) as compared with primitive chondrites and terrestrial standards. Stellar nucleosynthesis and cosmic ray spallation are ruled out as causes of the anomaly, but photochemical reactions in the early solar nebula could produce the isotopic composition. The large 33S excess present in oldhamite from the Norton County aubrite (0.161 per mil) suggests that refractory sulfide minerals condensed from a nebular gas with an enhanced carbon-oxygen ratio, but otherwise solar composition is the carrier. The presence of a mass-independent sulfur effect in meteorites argues for a similar process that could account for oxygen isotopic anomalies observed in refractory inclusions in primitive chondrites. 相似文献
17.
Multiple stable isotopes used to trace the flow of organic matter in estuarine food webs 总被引：2，自引：0，他引：2
The use of a combination of the stable isotopes of sulfur, carbon, and nitrogen allows the flow of organic matter and trophic relations in salt marshes and estuaries to be traced while eliminating many ambiguities that accompany the use of a single isotopic tracer. Salt-marsh grasses take up the isotopically light sulfides formed during sulfate reduction, and the transfer of this light sulfur through the marsh food web is illustrated with data on the ribbed mussel (Geukensia demissa) from various locations in a New England marsh. The multiple isotope approach shows that this filter feeder consumes both marsh grass ( Spartina) detritus and plankton, with the relative proportions of each determined by the location of the mussels in the marsh. 相似文献
18.
A thiosulfate shunt in the sulfur cycle of marine sediments 总被引：1，自引：0，他引：1
Jørgensen BB 《Science (New York, N.Y.)》1990,249(4965):152-154
The oxidation of sulfide, generated by bacterial sulfate reduction, is a key process in the biogeochemistry of marine sediments, yet the pathways and oxidants are poorly known. By the use of (35)S-tracer studies of the S cycle in marine and freshwater sediments, a novel shunt function of thiosulfate (S(2)O(3)(2-)) was identified. The S(2)O(3)(2-) constituted 68 to 78 percent of the immediate HS(-)-oxidation products and was concurrently (i) reduced back to HS(-), (ii) oxidized to SO(4)(2-), and (iii) disproportionated to HS(-) + SO(4)(2-). The small thiosulfate pool is thus involved in a dynamic HS(-) - S(2)O(3)(2-) cycle in anoxic sediments. The disproportionation of thiosulfate may help account for the large difference in isotopic composition ((34)S/(32)S) of sulfate and sulfides in sediments and sedimentary rocks. 相似文献
19.
鸡粪中的含硫有机物在微生物作用下会释放出大量的硫化氢气体,危害畜禽的健康及污染环境。试验以减少鸡粪中硫化氢释放量为目的,从菹草内分离得到1株具有异养硫氧化作用的细菌,命名为JS3。16S rRNA序列分析表明菌株JS3与杀鲑气单胞菌的亲源关系最近。以硫代硫酸钠为唯一硫源时菌株JS3的硫氧化特征:碳源优先利用顺序为葡萄糖柠檬酸钠乙酸钠;氮源优先利用顺序为硝酸钠氯化铵;菌株JS3氧化硫的最佳碳氮比为15∶1,此时77.82%的硫代硫酸根被转化为硫酸根;pH从4.05增加到10.05,菌株的氧化硫能力先增强后下降,当pH为9.05时,硫酸根的积累量最高,可达到4.33 g/L;当氯化钠添加量达到4.0%时对菌株JS3才产生明显影响,说明株菌具有一定的耐盐性;最佳硫代硫酸根初始浓度为2 810 mg/L,此时83.22%的硫代硫酸根被转化为硫酸根;250 mL三角瓶中装液量为75 mL时,菌株JS3是硫氧化能力最强。在硫化氢减释模拟试验中,与对照相比,菌株JS3可降低84.53%的硫化氢释放量。 相似文献
20.
Extremely thermophilic archaebacteria are known to be metabolizers of elemental sulfur and the methanogens. A novel group of extremely thermophilic archaebacteria is described, which consists of sulfate-respiring organisms that contain pure factor 420 and that have been isolated from marine hydrothermal systems in Italy. They possess a third type of archaebacterial RNA polymerase structure previously unknown, indicating an exceptional phylogenetic position. Most likely, this group represents a third major branch within the archaebacteria. The existence of sulfate reducers at extremely high temperatures could explain hydrogen sulfide formation in hot sulfate-containing environments, such as submarine hydrothermal systems and deep oil wells. 相似文献