Sedimentary phosphate method for estimating paleosalinities

The widespread occurrence of sedimentary phosphate in argillaceous sediments provides the basis for a new method of paleosalinity estimation. Sedimentary phosphate contains iron- and calcium-phosphate fractions, the relative proportions of which are sensitive to salinity of the water at sites of deposition. The sedimentary phosphate method provides direct estimates of paleosalinity throughout the freshwater to marine range.     

Strontium isotopic composition of estuarine sediments as paleosalinity-paleoclimate indicator

The strontium isotopic composition of biogenic precipitates that occur in estuarine sediments can be used as proxy indicator of paleosalinity and for assessing precipitation and river discharge rates over thousands of years. In the San Francisco Bay estuary, river water with low (87)Sr/(86)Sr ratio (average, 0.7065) and low Sr concentration (0.13 parts per million) mixes with seawater with a higher (87)Sr/(86)Sr ratio (0.7092) and Sr concentration (7.9 parts per million). The predicted mixing relation between salinity and Sr isotopic composition is confirmed by measurements of modern estuarine surface waters. A paleosalinity record obtained from foraminifera for the ancestral San Francisco Bay during oxygen isotope substage 5e of the last interglacial reflects a global rise and fall of sea level, and short time-scale variations related to fluctuations in discharge rates of the Sacramento and San Joaquin rivers.     

Sedimentary phosphate method for estimating paleosalinities: a paleontological assumption

Paleosalinity values in certain rocks determined by the sedimentary phosphate method differ from salinity estimates based upon contained fossil assemblages, geochemical methods, and existing stratigraphic controls. Some anomalous values are related to the abundance of fossil organisms known to be concentrators of calcium phosphate. Because of the abundance and diversity of organisms which might introduce significant errors into paleosalinity estimates, the sedimentary phosphate method seemingly is of limited applicability.     

Marine Diagenesis of Shallow Marine Lime-Mud Sediments: Insights from dgrO18 and dgrC13 Data

Shallow marine lime-mud sediments of the Ste. Genevieve Formation (Mississippian), in part of the Illinois Basin, underwent at least three diagenetic changes: (i) local dolomitization in seawater or a brine, producing dolostone having average deltaC(13) of +2.5 per mille and deltaO(18) of +1.9 per mille (versus PDB-1); (ii) more usually cementation of unreplaced CaCO(3), in intrasediment seawater, yielding isotopically marine lime mudstone mainly composed of calcite, 4-micron or finer, with deltaO(18) of from -1 to +1 per mille; (iii) later partial alteration of CaCO(3), in permeable dolomitic rocks, by isotopically "lighter" waters, to calcite with an estimated deltaO(18) of -10 per mille or less. Isotope data appraised by petrographic analysis thus suggest "submarine" cementation of these carbonates in shallow marine conditions.     

Glacier oxygen-18 content and pleistocene ocean temperatures

The mean oxygen-18 content of continental ice sheets during the last glacial maximum is estimated to deltaO(18)=-30 per mille or less, and the consequent change in the isotopic composition of the oceans at that time to 1.2 per mille or more. This means that at least 70 percent of the oxygen-18 variations found in shells of planktonic foraminifera from deep-sea cores between times of glacial maximums and minimums are due to isotopic changes in ocean water, and at most 30 percent to changes in ocean surface temperature. Hence, Emiliani's "paleotemperature" curve rather depicts the amount of ice on the continents in excess of that present today. In this sense it may be renamed a "paleoglaciation" curve.     

High-pressure dissociation of carbonic and boric acids in seawater

The apparent dissociation constants of carbonic and boric acids were determined for pressures up to 654 atmospheres in seawater of 34.8 per mille salinity at 22 degrees C. Our values for the ratios of the apparent dissociation constants at 654 atmospheres to the constants at 1 atmosphere are 1.84 1.48, and 1.94 for K'(1), K'(2), and K'(B), respectively. At this pressure the commonly accepted values of Buch and Gripenberg for these ratios are 2.03 and 1.30 for K'(1) and K'(2), respectively.     

Oxygen-18 variations in sulfate ions in sea water and saline lakes

A new method measures the oxygen-isotopic composition of dissolved sulfate ions and barium sulfate. Sulfate ions in the oceans are enriched in oxygen-18 by 9.5 per mille relative to mean ocean water and show only minor variations, probably because the exchange rate with water is slow enough to prevent local equilibrium with surface waters. Sulfate ions in saline lakes and brines have oxygen-18 enrichment of from 7 to 23 per mille relative to mean ocean water;the value of the highest enrichment observed is about the same as that of atmospheric oxygen.     

Marine dolomite of unusual isotopic composition

A piston core taken off of the coast of Oregon in 358 meters of water contained an indurated calcareous layer composed partly of dolomite with a composition Ca(58.7)Mg(41.3). Dolomites of this chemical composition are typical of the supratidal environment. However, the dolomite has isotopic composition delta0(18) = 5.8 per mille, deltaC(13) = 35.1 per mille relative to the Chicago PDB-I standard. The unusual carbon isotope ratio is similar to that of calcites produced as a byproduct of bacterial breakdown of hydrocarbons.     

柴胡不同部位中8种微量元素的综合评价

[目的]综合评价柴胡不同部位中的8种微量元素。[方法]采用因子分析方法对柴胡的花、叶、茎、根中微量元素含量数据进行分析,找出了柴胡中Ca、Mg、Na、K、Fe、Mn、Cu、Zn8种元素之间的关系,结合SPSS统计软件,对柴胡不同部位中微量元素进行定量定性综合评价。[结果]Fe与Mg、Na、K相关极显著,Mn与Ca显著相关。第1公共因子F1在指标Mg、Na、K、Fe、Zn上有较大的载荷,第2公共因子F2在指标Ca、Mn、Cu上有较大的载荷。柴胡不同部位中8种微量元素含量高低顺序为：根〉叶〉花〉茎。[结论]该研究为大规模合理开发柴胡资源,以及为柴胡的药物功效学和微量元素的研究提供科学的依据和理论基础。     

Carbon isotope composition of carbonaceous matter from the precambrian of the witwatersrand system

Polymerized hydrocarbons occurring in the gold-uranium conglomerates of the Witwatersrand System (South Africa) show deltaC(13) values between -22.4 and -32.8 per mille, their isotopic composition thus falling into the range of sedimentary organic carbon. Accordingly, organic derivation of the material seems very probable. This conclusion is consistent with a model of the existence of organic evolution and biologic activity in times certainly older than 2.15 x 10(9) years.     

盐胁迫对玉蕊幼苗生长及矿质元素吸收和转运的影响

【目的】探明盐胁迫对玉蕊幼苗生长和矿质元素吸收及转运的影响,从离子转运机制角度解析玉蕊的盐胁迫耐受性,为玉蕊的野生种群保护、迁地保育、推广利用及造林的立地选择提供科学参考。【方法】以二年生玉蕊实生苗为试验材料,采用自动潮汐模拟全日潮装置,对玉蕊幼苗设0（CK）、15‰、20‰、25‰、30‰、35‰和40‰共7种盐度胁迫处理,对比分析玉蕊在盐胁迫下根、茎、叶对钙（Ca）、镁（Mg）、铁（Fe）、氯（Cl）、钠（Na）5种矿质元素的吸收量、转运系数及生长指标与矿质元素吸收的相关性。【结果】低盐度（0~15‰）胁迫下,玉蕊植株生长良好,高盐度（30‰~40‰）胁迫导致玉蕊叶片急剧脱落,生物量下降,严重抑制玉蕊植株的生长发育。盐胁迫使玉蕊体内Na和Cl元素的积累量升高,玉蕊幼苗根部对Ca和Mg元素的吸收量下降,而叶片部位对Ca、Mg和Fe元素的吸收量升高,茎段部位对Ca、Mg和Fe元素的吸收量无明显差异。盐胁迫下玉蕊幼苗对Ca、Mg和Cl元素的转运系数均大于1.0,对Fe元素的转运系数小于1.0,对Na元素的转运系数在盐度为35‰~40‰时大于1.0。相关分析结果表明,玉蕊生物量与地上部分各元素间均呈负相关,叶片脱落率、根冠比与地上部分各元素间均呈正相关。【结论】全日潮淹浸6 h/d的环境下,玉蕊幼苗在水体盐度为0~15‰范围内生长良好,在20‰~25‰盐度范围内有一定的耐受能力,而当水体盐度≥30‰时,玉蕊幼苗无法正常生长。其耐盐性主要是通过根系对Na元素的聚积,限制Na元素向茎叶运输,同时增强Ca、Mg、Fe和Cl元素向茎叶的转运来实现。在玉蕊迁地保育过程中,可将盐度作为立地选择的一个重要因素,同时在热带亚热带地区进行半红树林人工造林时应选择高潮位、中低盐度区域种植玉蕊。     

Anomalous carbon-isotope ratios in nonvolatile organic material

Organic mats are associated with sulfur deposits in Upper Pleistocene sand ridges of the coastal plain of southern Israel; black, brittle, and non-volatile, they show parallel layering but no other apparent cellular structure. Two independent carbon-14 determinations yielded ages of 27,750+/-500 and 31,370+/-1400 years. Four carbon-13:carbon-12 determinations fell within the range deltaC(13) =-82.5 to -89.3 per mille relative to the PDB standard; these appear to be the lowest values yet reported for naturally occurring high-molecular-weight organic material. The origin of the carbon is probably complex; it must have passed through at least one biologic cycle before final deposition.     

不同产地矮地茶微量元素的形态分析

[目的]对不同产地矮地茶水煎液中微量元素进行形态分析。[方法]采用微量元素形态分析流程、原子吸收光谱法对7个产地矮地茶中微量元素Ca、Fe、Zn、Mn、Cu、Pb、Cd的初级及次级形态进行研究。[结果]7个产地野生矮地茶中微量元素含量为CaFeZnMnCuPb,Cd未检出,7种元素的提取率在33.05%~72.33%、浸留比在0.32~7.29、悬浮态颗粒吸附率在0.36%~25.30%,该法对各元素的加标回收率为90.5%~110.2%,相对标准偏差5%。[结论]7个产地矮地茶中7种微量元素均符合药用植物绿色行业标准,不同产地矮地茶同种微量元素含量有差异。     

Manganese and related elements in the interstitial water of marine sediments

Analyses for manganese, nickel, iron, cobalt, sodium, and lithium in the interstitial water of cores from the southern California borderland and six deep-sea cores in the area of the East Pacific Rise show great variation in concentration of trace elements. Oxidizing near-shore sediments showed a 50-fold enrichment in manganese in contrast to sulfide-rich reducing sediments, which showed no enrichment. Deep-sea sediments were variable in their concentration of the trace metals. All but one core showed a high enrichment in dissolved manganese, with a maximum of 6.6 parts per million. Two cores showed a 100-fold enrichment in nickel and cobalt. The manganese appears to be in solution either as Mn(2+) or as a complex. The results appear to support manganese nodule formation in deep-sea sediments through a diffusion of manganese from depth to the surface.     

霍山石斛不同部位中必需微量元素与必需氨基酸的相关性研究

求文对名贵中药材霍山石斛各部位中必需微量元素和必需氨基酸的含量进行了测定，对人体和植物共同的必需微量元素与人体必需氨基酸间的相关性进行了研究。结果发现，Ｃｕ、Ｚｎ、Ｆｅ与必需氨基酸呈负相关；Ｍｇ、Ｃａ、Ｍｎ与必需氨基酸呈正相关。欲提高霍山石斛中必需氨基酸含量，建议少施Ｃｕ、Ｚｎ、Ｆｅ粪肥料，适当多施Ｍｇ、Ｃａ、Ｍｎ类微肥。     

Hyperfine zeeman effect atomic absorption spectrometer for mercury

A new type of atomic absorption spectrometer-one that detects trace mercury in host material, based on hyperfine structure lines in a magnetic field-was developed and tested on various substances. This device can detect trace mercury to about 0.04 part per million (40 parts per billion) in about 1 minute. No chemical separation from the host material is necessary.     

禾谷类杂粮作物耐逆和栽培技术研究新进展

禾谷类杂粮作物谷子、高粱、黍稷等是旱作生态农业的主栽作物,也是中国传统农耕文化的载体作物,在膳食结构多样化和人民健康保障方面有着不可或缺的作用。禾谷类杂粮多栽培在旱薄地、盐碱地和粮食主产区的边际田块,品种的耐逆性尤其重要。本文作为本期《中国农业科学》20篇禾谷类杂粮的抗旱耐盐和栽培耕作技术研究文章的导读,在对谷子高粱和黍稷进行概况介绍的基础上,展示了这些文章的核心内容和创新点,比较了这些结果和国内外高度相关的同类文章在关键发现上的异同,以拓展读者的阅读视野,同时对谷子高粱黍稷的抗旱耐逆研究进行了展望。     

油茶幼林营养元素吸收及其分配特征

[目的]了解油茶各器官和营养元素吸收、累积及分配特征,为油茶林地施肥管理提供科学依据.[方法]以长势较好的5.5年生油茶林为调查对象,测定其树干、树枝、树叶、主根和侧根的营养元素含量,分析营养元素吸收及分配特征.[结果]油茶各器官营养元素含量的排列顺序大致为N>K、Ca>Mg>P>Fe、Mn>Zn>B>Cu.油茶不同器官营养元素总含量的排列顺序:树叶>侧根>树枝>主根>树干.油茶树体营养元素贮藏总量为14.65g/株,其中,N、K、Ca的贮存量最高,其次是P、Mg、Fe、Mn,Cu、Zn、B最低.油茶各器官营养元素贮存量的顺序排列:树叶>树干>主根>树枝>侧根.[结论]油茶树体N、K、Ca元素的吸收和累积量最高,营养元素的分配与各器官的生物量不成比例关系,树叶和树干营养元素贮存量最高.     

Progresses in Stress Tolerance and Field Cultivation Studies of Orphan Cereals in China

Small cereal crops, including foxtail millet (Setaria italica), sorghum (Sorghum bicolor) and broomcorn millet (Panicum miliaceum), are important in northern China’s arid and semi-arid dry land agriculture, which are main components for a diversified food system and considered as traditional healthy food. Because they are mainly cultivated in dry land and salinity soils, natural and human selection had made those crops with super capability for drought and salt tolerant. This issue of Scientia Agricultura Sinica published 20 papers focus on drought tolerance, salinity tolerance, disease resistance and cultivation of those orphan crops in China. Nearly all these papers were conducted by the scientific researcher of the Chinese Agricultural Research System, Millet and Sorghum Section. This is a brief introduction of these 20 papers, and some comparisons between conclusions of those researches with the known published ones are also included. Foxtail millet, sorghum and broomcorn millet are considered as models for drought and salinity study in the grasses family, the papers published here will push the progress of this system.     

内江市土壤和蔬菜中微量元素的相关性研究

[目的]研究土壤和蔬菜中微量元素的相关性。[方法]采用梅花形布点法采样,用火焰原子吸收分光光度法和石墨炉原子吸收法测定土壤和蔬菜中的Zn、Fe、Cu、Mn、Ca、Mg和Pb含量。[结果]试验地土壤中含有丰富的微量元素,其含量大小依次为:Ca>Fe>Mn>Mg>Zn>Cu,所测蔬菜中微量元素含量大小依次为:Ca>Mg>Fe>Cu。所测蔬菜对土壤中微量元素的吸收具有选择性,所测蔬菜中Mg含量明显高于土壤,Cu含量明显低于土壤,说明蔬菜对Mg有富积作用,对Cu无富积作用。蔬菜不同部位同一元素的含量有很大差别,莴笋叶中微量元素含量都比莴笋茎中高。70%蔬菜中Pb含量均未超过国家标准限量。[结果]土壤中微量元素和蔬菜中微量元素有较好的相关性。