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1.
Kerr RA 《Science (New York, N.Y.)》2000,289(5487):2021a-2022a
Archaeologists are mulling over tantalizing images of what appears to have been a house of wood and mud littered with human artifacts now 91 meters beneath the Black Sea. The find lends further credence to the claims of two oceanographers that a torrent equaling 200 Niagara Falls cascaded from the Mediterranean Sea 7500 years ago, driving Neolithic peoples living along the Black Sea coastline inland. But whether the catastrophe gave rise to the biblical account of Noah's Flood and spread farming into central Europe, as the researchers speculate, we can't yet say.  相似文献   

2.
Mediation of sulfur speciation by a black sea facultative anaerobe   总被引:1,自引:0,他引:1  
Shewanella putrefaciens, a respiratory facultative anaerobe isolated from the Black Sea, can reduce thiosulfate, sulfite, and elemental sulfur to sulfide readily and quantitatively. This widespread and anaerobically versatile microorganism, which is incapable of reducing sulfate, uses oxidized sulfur intermediates as electron acceptors during the respiratory oxidation of organic matter. Because of its widespread distribution and abundance, it may play a significant role in sulfur and trace metal cycling in the Black Sea and in other marine and freshwater anaerobic environments.  相似文献   

3.
屈海利 《油气储运》1998,17(5):39-42
介绍了GIS数据库及从地图、航空照相、卫星遥感获得GIS数据的三种方法及管道工业成功应用GIS的两个事例。美国的西北天然气公司利用GIS使其许多工作自动化,如计算机辅助泄漏检查、管网模型分析、紧急事故响应和系统规划等,GIS已使该公司的工作环境远远超过CAD时代。Bechtel公司在铺设从里海到黑海的原油输送管道时,利用GIS和卫星遥感建立一个最小费用线路的计算机模型。结果表明,利用GIS软件的地面覆盖自动辨别能力和遥感卫星生成的地面覆盖地图建立的线路模型选线,将比在里海与黑海之间采用直线线路的费用少14%。  相似文献   

4.
乐清湾海域鱼类中多溴联苯醚的分布特征   总被引:1,自引:0,他引:1  
陈树科  沈晓飞  江锦花 《安徽农业科学》2009,37(23):11040-11043
使用气相色谱-质谱-化学离子源(GC—MS-NCI)检测法对持久性有机污染物多溴联苯醚(PBDEs)的10种同系物(∑10PBDEs)在海洋鱼类(红鲈、黑鲷、鲈鱼)中的含量进行了检测。结果表明,红鲈、黑鲷、鲈鱼肌肉中∑10PBDEs的含量分别为252.6~662.2、454.6~1413.4、147.4-760.5ng/kg湿重(ww)。鱼肌肉样品中BDE47的相对含量最高。鱼肝对多溴联苯醚的富集能力强于鱼肉。  相似文献   

5.
A 7000-year record of Coccolithovirus and its host, the calcifying haptophyte Emiliania huxleyi, was reconstructed on the basis of genetic signatures preserved in sediments underlying the Black Sea. The data show that the same virus and host populations can persist for centuries. Major changes in virus and host populations occurred during early sapropel deposition, ~5600 years ago, and throughout the formation of the coccolith-bearing sediments of Unit I during the past 2500 years, when the Black Sea experienced dramatic changes in hydrologic and nutrient regimes. Unit I saw a reoccurrence of the same host genotype thousands of years later in the presence of a different subset of viruses. Historical plankton virus populations can thus be included in paleoecological and paleoenvironmental studies.  相似文献   

6.
Copper porphyrins have been isolated from deep-sea sediments collected during six legs of the Deep Sea Drilling Project-International Program of Ocean Drilling. These pigments are present in depositional areas receiving high inputs of terrestrially derived oxidized organic matter. Such areas include the Black Sea, the Bay of Biscay, the Blake-Bahama Basin, and slumped Miocene deposits off Cape Bojador on the west coast of Africa.  相似文献   

7.
Multichannel seismic-reflection data show that the Victoria Land-basin, unlike other sedimentary basins in the Ross Sea, includes a rift-depression 15 to 25 kilometers wide that parallels the Transantarctic Mountains and contains up to 12 kilometers of possible Paleozoic to Holocene age sedimentary rocks. An unconformity separates the previously identified Cenozoic sedimentary section from the underlying strata of possible Mesozoic and Paleozoic age. Late Cenozoic volcanic rocks intrude into the entire section along the eastern flank of the basin. The Victoria Land basin is probably part of a more extensive rift system that has been active episodically since Paleozoic time. Inferred rifting and basin subsidence during Mesozoic and Cenozoic time may be associated with regional crustal extension and uplift of the nearby Transantarctic Mountains.  相似文献   

8.
Deuser WG 《Science (New York, N.Y.)》1970,168(3939):1575-1577
A combination of measurements of carbon-13 and the hydrogen sulfide content in Black Sea waters with available data on the total carbon dioxide in these waters indicates that the contribution of organic sulfur to the hydrogen sulfide lies between 3 and 5 percent and increases with depth. Likely causes for the increase are increasing productivity or upward movement of the anoxic zone during the facts last 2000 year.  相似文献   

9.
Analyses of the stable isotopes of the organic carbon and microscopic examination of the sediment particles suggest that up to 90 percent of the organic matter in Ross Sea sediments is derived from the igneous and ancient metamorphic and sedimentary rocks that are being glacially eroded on the Antarctic continent and transported seaward.  相似文献   

10.
张潇潇  房伟明  周玉珍  王纪军 《安徽农业科学》2013,(32):12566-12567,12569
[目的]对引进的8个路易斯安娜鸢尾品种的物候期、生长特性、结实性、分生能力等进行观察测定。[方法]8个品种分别为‘B1ackGamecock’、‘RegalRicochet’、‘Teven’、‘SeaWisp’、‘WaihiWedding’、‘HotAndSpicy’、‘SeriouslyBlue’和‘Gunner’。[结果]8个引进品种在苏州均能正常开花,叶片冬季绿色,品种间在花期、花色、花茎高度等方面的差异为园林应用提供了丰富的植物材料;5个品种人工授粉后,大田开放授粉植株的结实率高于设施内隔离授粉的植株,‘SeaWisp’结实率最高达70.4%,可用于实生苗生产;‘BlackGamecock’品种在大田自然生长环境中分生系数最高达9,可用于分生苗生产;‘HotAndSpicy’不结实,分生系数低,需要依靠组培方式生产种苗。[结论]根据品种的不同特性选择不同种苗生产途径,可为苏州地区种苗生产提供参考。  相似文献   

11.
Massive microbial mats covering up to 4-meter-high carbonate buildups prosper at methane seeps in anoxic waters of the northwestern Black Sea shelf. Strong 13C depletions indicate an incorporation of methane carbon into carbonates, bulk biomass, and specific lipids. The mats mainly consist of densely aggregated archaea (phylogenetic ANME-1 cluster) and sulfate-reducing bacteria (Desulfosarcina/Desulfococcus group). If incubated in vitro, these mats perform anaerobic oxidation of methane coupled to sulfate reduction. Obviously, anaerobic microbial consortia can generate both carbonate precipitation and substantial biomass accumulation, which has implications for our understanding of carbon cycling during earlier periods of Earth's history.  相似文献   

12.
In the 9 years since my first survey of early metallurgy appeared in this journal (65) metallurgy has become a major battleground between those who argue independent invention and those who argue diffusion in the evolution of urban civilization. In this new article I contend that: 1) The upland belt and debouching river valleys of southwestern Asia have a clear priority in the beginnings of copper metallurgy and extractive metallurgy generally, suggesting that the forces of urbanization contributing to the rise of metallurgy there were more massive, widespread, and better integrated than elsewhere. 2) The trend to polymetallism, against the background of pyrotechnology generally and the other important technologies of urbanism, established a necessary sequence to early metallurgy. This sequence was a prerequisite to the coming of the Iron Age, which was uniquely contained at first within the environment of Anatolia and the eastern Mediterranean and spread outward from there. 3) The course of metallurgy and possibly of the other urbanizing technologies can best be understood through a process of diffusion and multiple innovation interrelating metallurgical evolution over much of Eurasia, but with the area defined by the Black Sea, the Caspian Sea, the Red Sea, and the eastern Mediterranean as its center. Only in this fashion can we place metallurgy in its proper role as an important subsystem in the rise of civilization.  相似文献   

13.
The aim of this research was to identify long-term changes in the material composition of arable and fallow lands in the agricultural district of an ancient center in the Northern Black Sea region. Geochemical features of changes in the upper mineral soil horizon of different-aged arable and fallow lands near the ancient city of Kerkinitis were studied. The multitemporal boundary between arable lands of different ages was identified, and indicators to diagnose residual signs of former agricultural loads were revealed in the material composition of agrozems using geostatistical methods. The use of such unique objects of study as soils of ancient agricultural areas is related to the potential evaluation of risks of fertility loss because of slow but practically irreversible processes of pedogenesis and the opportunity to prevent or reduce their negative manifestations in arable land.  相似文献   

14.
Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.  相似文献   

15.
Based on laboratory modeling, a conclusion has been made that contamination of soddy-calcareous typical soil of the Black Sea Coast of the Caucasus by Cr, Cu, Ni, Pb, and oil results in its poorer biological properties. The total number of bacteria drops, the activity of catalase and dehydrogenase and celluloselytic activity become smaller, the amount of bacteria of the Azotobacter genus decreases, and the parameters of germination and initial growth of radish become poorer. With respect to the adverse effect on the biological properties of the investigates soil, heavy metals may be arranged into the following series: Cr > Cu ≥ Ni = Pb. Qualitative benchmarks of the regional maximum permissible contents of Cr, Cu, Ni, Pb, and oil in soddycalcareous typical soils of this region were determined on the basis of changes in ecological soil functions.  相似文献   

16.
Soluble manganese(III) [Mn(III)] has been thought to disproportionate to soluble Mn(II) and particulate Mn(IV)O2 in natural waters, although it persists as complexes in laboratory solutions. We report that, in the Black Sea, soluble Mn(III) concentrations were as high as 5 micromolar and constituted up to 100% of the total dissolved Mn pool. Depth profiles indicated that soluble Mn(III) was produced at the top of the suboxic zone by Mn(II) oxidation and at the bottom of the suboxic zone by Mn(IV)O2 reduction, then stabilized in each case by unknown natural ligands. We also found micromolar concentrations of dissolved Mn(III) in the Chesapeake Bay. Dissolved Mn(III) can maintain the existence of suboxic zones because it can act as either an electron acceptor or donor. Our data indicate that Mn(III) should be ubiquitous at all water column and sediment oxic/anoxic interfaces in the environment.  相似文献   

17.
朱永雄 《湖北农业科学》2012,51(9):1824-1827
海南黑牛是利用良种日本黑毛和牛的冷冻精液与海南黄牛(雷琼黄牛)母牛进行人工授精所产的杂交后代.通过对海南黑牛进行外貌观察和体尺测量,研究其体型外貌与双亲的差异.结果表明,海南黑牛的多项体尺指标与母、父本相比都发生了变化.其外貌主要特征表现为头小颈短、面部清秀,体躯紧凑,背腰平直,无肩峰,毛呈黑色;而体尺测量除管围和管围指数外,体重、体高、胸围、体长等指标均比海南黄牛要小.即在外貌特征上,海南黑牛总体表现双亲的特性,毛色呈现日本和牛黑毛,体型接近海南黄牛小而清秀,但前期生长发育缓慢,表现出当地小型黄牛的特性.  相似文献   

18.
The shared hopes of farm ownership in America motivated many Black farmers and educators during the nineteenth and early twentieth centuries. Although an independent Black yeomanry was not to be, and a host of factors have combined to remove Black Americans from farming, the quest has not been a vain one. Black land-grant institutions continue to redefine their mission in a changing world and in the process maintain their relevancy.  相似文献   

19.
关于黑土分类和分布问题的探讨   总被引:5,自引:0,他引:5  
黑土的分布面积在文献中有不同的记载,这主要是由于不同的分类体系产生的,论述了在国内有影响的五个土壤分类体系对黑土的界定,并说明不同分类体系黑土的面积。  相似文献   

20.
本研究是《推广瘦肉型杂交猪》重点科技承包项目的重点配套研究课题。1987—1989年分别对杜×甘白、杜×甘黑、汉×甘白、汉×甘黑、长×甘白、长×甘黑、大约×甘白(杜:杜洛克猪;汉:汉普夏猪;长:长白猪;大约:大约克夏猪;甘黑:甘肃黑猪;甘白:甘肃白猪。)的七个杂交组合和甘白×甘白、甘黑×甘黑、甘白×甘黑三个母本专试组进行了测定。育肥试猪共178头,屠宰试猪共114头。结果表明,杂交组合的肥育和屠宰各项指标均高于母本纯繁对照,日增重高55.18克相似文献   

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