Distributions of inorganic nutrients in the bohai sea of china

1　Introduction　TheBohaiSeaislocatedinthenorthernChinawithlongitudesofbetween 117°38′Eand 12 2°31′Eandlat itudesofbetween 37°0 8′Nand 4 1°0 2′N .Itisashal lowseawithanaveragewaterdepthof 18m (LiuandZhang ,2 0 0 0 ) .Severalbigrivers ,suchastheLiaoheRiver,theHaiheRiverandtheYellowRiver ,findtheirwaysintotheBohaiSeaandtransportlargeamountofnutrientsandsuspendedmattersfromthecontinentintothesea (Zhangetal.,1994 ;Zhang ,1996 ) .Duringthelasttwodecades ,marineenviron mentintheBohai…     

Form changes and bio-effect of cadmium in the alkaline soil operated by inorganic salts

Four soluble inorganic salts were used to examine their influences upon cadmium forms in the alkaline soil and the contents of cadmium absorbed by plants. After KCl solution added in the soil, the contents of effective form of cadmium in the soil increased from 28% to 122%, carbonate form decreased from 2% to 47%, iron-manganese oxidation form increased from 20% to 150%. As to the organic combination form, when the KCl solution of lower concentration was added in the soils, the organic combination form contents of cadmium would decrease, while the KCl solution of higher concentration was added in the soils, the organic combination form contents of cadmium would increase. After CaCl2 solution was added in the soils, the contents of effective form of cadmium in the soils increased from 7% to 33%, the carbonate form contents of cadmium decreased from 10% to 60%, the contents of the iron-manganese oxidation form of cadmium increased from 5% to 90%, the organic combination form of cadmium increased from 5% to 73%. After KH2PO4 solution was added in the soils, the contents of effective form of cadmium in the soils decreased from 20% to 46%, the carbonate form contents of cadmium decreased from 14% to39%, the contents of the iron-manganese oxidation form of cadmium increased from14% to 95%, the organic combination form of cadmium increased from 5% to 65%. After K2CO3 solution was added in the soil, the effective form contents of cadmium decreased from 5% to 22%, the carbonate form contents of cadmium increased from 12% to 64%, the contents of organic combination form of cadmium in the soils were similar to those of the carbonate form, increasing by 3%-38%. The content variation of the iron-manganese oxidation form of cadmium was slight after K2CO3 solution was added in the soils.     

气相色谱法测定岩矿中有机碳无机碳及石墨碳

介绍了测定岩矿样品中不同形态碳的方法。样品中加入ＭｎＯ２作氧化剂，在气相色谱仪内热解，测定结果是总碳。有机碳、石墨碳是由样品分别除去碳酸盐碳、碳酸盐碳与有机碳后，按总碳测定法测出。无机碳（碳酸盐碳）是在气相色谱仪密封系统内加酸分解碳酸盐，不用附加系统分离Ｈ２Ｏ与ＣＯ２，直接经色谱柱分离测定。也可分别测定总碳、有机碳或无机碳，用差减法计算无机碳或有机碳。     

The acoustic signature of fluid flow in complex porous media

Effective medium approximations for the frequency-dependent and complex-valued effective stiffness tensors of cracked/porous rocks with multiple solid constituents are developed on the basis of the T-matrix approach (based on integral equation methods for quasi-static composites), the elastic–viscoelastic correspondence principle, and a unified treatment of the local and global flow mechanisms, which is consistent with the principle of fluid mass conservation. The main advantage of using the T-matrix approach, rather than the first-order approach of Eshelby or the second-order approach of Hudson, is that it produces physically plausible results even when the volume concentrations of inclusions or cavities are no longer small. The new formulae, which operates with an arbitrary homogeneous (anisotropic) reference medium and contains terms of all order in the volume concentrations of solid particles and communicating cavities, take explicitly account of inclusion shape and spatial distribution independently. We show analytically that an expansion of the T-matrix formulae to first order in the volume concentration of cavities (in agreement with the dilute estimate of Eshelby) has the correct dependence on the properties of the saturating fluid, in the sense that it is consistent with the Brown–Korringa relation, when the frequency is sufficiently low. We present numerical results for the (anisotropic) effective viscoelastic properties of a cracked permeable medium with finite storage porosity, indicating that the complete T-matrix formulae (including the higher-order terms) are generally consistent with the Brown–Korringa relation, at least if we assume the spatial distribution of cavities to be the same for all cavity pairs. We have found an efficient way to treat statistical correlations in the shapes and orientations of the communicating cavities, and also obtained a reasonable match between theoretical predictions (based on a dual porosity model for quartz–clay mixtures, involving relatively flat clay-related pores and more rounded quartz-related pores) and laboratory results for the ultrasonic velocity and attenuation spectra of a suite of typical reservoir rocks.     

Environmental records of carbon in recent lake sediments

Based on careful sampling and accurate analysis of recent sediments in Lake Chenghai, this paper discusses the staggered positive/negative correlation between organic carbon (OC) concentration and inorganic carbon (IC) concentration. The result indicates that temperature change, and its induced relative changes are the main factors affecting the relationship between IC concentration, δ¹³C of carbonate and OC concentration. When temperature and its induced photosynthesis strength change control autochthonous calcite precipitation, OC concentration is positively correlated with IC concentration and δ¹³C of carbonate. When temperature and its induced physical/chemical changes dominate, OC concentration displays negative correlation with IC concentration and δ¹³C of carbonate. IC concentration and δ¹³C of carbonate in sediments of Lake Chenghai are good proxies for climatic warm/cold changes.     

Lower Triassic Inorganic Carbon Isotope Excursion in Chaohu, Anhui Province, China

This paper reports a Lower Triassic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was stituated in a deep part of the Lower Yangtze carbonate rapm. The δ(^13C) excursion shows two periods from the Permian-Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end-Permian mass extinction and related events.The first period starts at the δ(^13C) depletion caused by the mass extinction and evolves with a gradual δ(^13C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ(^13C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ(^13C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the eratic ecosystem that followed the great end-Permian mass extinction.     

上海滨岸潮滩水沉积物中无机氮的季节性变化

对长江口南翼上海滨岸带3个站点潮滩上覆水，沉积物和间隙水中的3态无机氮的含量分布的年度季节性监测研究表明：潮滩上覆水中溶解无机氮以NO3－N为主：表层沉积物中可交换态无机氮以NH4－N为主，约占70％－85％，沉积物间隙水中主要无机氮为NH4－N和NO3－N。潮滩水体中NH4－N的季节性变化幅度不大，而NO3－N和NO2－N的季节性变化明显，在冬季含量明显降低；但沉积物和间隙水中氮氨和硝态氮的浓度在冬季则有较大增加。初步探讨了潮滩水和沉积物中无机氮分布季节性变化的主要影响因素，估算了潮滩表层沉积物－水界面无机氮的扩散通量，指出NH4－N的扩散释放对滨岸水环境质量影响较大。     

鱼类在海洋碳循环中的作用及研究展望

碳中和是应对气候变化的必由之路,海洋负排放是实现碳中和的重要途经。海洋作为地球最大碳库,研究发现越来越多的海洋和海岸带生物参与碳循环,并对海洋碳汇产生重要贡献。鱼类作为海洋生态系统中最重要组成部分之一,其在海洋碳循环中的作用还没有引起足够的重视。最新研究表明海洋鱼类在无机碳循环中发挥了重要作用,深化对鱼类参与碳循环过程的认识、量化其固碳潜力将有助于丰富海洋碳循环研究。本文首先系统梳理了鱼类参与碳循环的过程和机制等研究进展。鱼类通过产生碳酸盐粪便、水平和垂直迁移运输、生物扰动、生物碳和“尸体”碳以及食物网消耗与传输等方式参与海洋碳循环。鱼类参与碳循环的证据和参与海洋碳循环的重要性逐渐凸显。其次,本文提出目前鱼类参与碳循环研究存在的问题与挑战,包括渔业捕捞源汇之争、水产养殖业的机遇和挑战以及准确量化鱼源碳酸盐的困难,仍有待理论和方法学的深化研究和技术的革新去解决。最后本文提出鱼类参与碳循环的研究展望,及其在全球气候变化背景下的潜在机遇,同时结合当前渔业碳汇的发展进程以及行业需求,提出渔业减排固碳发展路径建议。本文旨在提升鱼类在海洋碳循环贡献和服务生态系统的潜力的认识,为海洋碳汇和渔业碳汇研究提供新的视角。     

不同温度下长茎葡萄蕨藻无机碳利用

【目的】阐明长茎葡萄蕨藻对无机碳的利用方式。【方法】运用pH漂移技术,探索藻体质量、藻体部位、照度和海水体积对长茎葡萄蕨藻(Caulerpa lentillifera)的pH补偿点的影响,并研究在3种不同温度(20、25、30℃)下,乙酰唑胺(AZ)、乙氧苯丙噻唑磺胺(EZ)、4,4′-二异硫氰基芪2,2′-二磺酸(DIDS)、钒酸盐(Van)4种抑制剂对长茎葡萄蕨藻无机碳的利用影响。【结果】藻体质量、藻体部位、照度和海水体积对长茎葡萄蕨藻的pH补偿点均无显著性影响(P>0.05),在一定范围内藻体质量或照度越大,达到pH补偿点时间越短,且pH补偿点均大于9。20℃下各抑制剂的抑制作用最大,其次为30℃,25℃最小,但3种温度下各抑制剂的抑制率无显著差别(P> 0.05)。4种抑制剂中DIDS对长茎葡萄蕨藻pH补偿点和无机碳利用均无显著影响(P> 0.05),剩余3种抑制剂的抑制作用依次为EZ>AZ>Van。【结论】藻体质量、藻体部位、照度和海水体积对长茎葡萄蕨藻pH补偿点无影响。温度对长茎葡萄蕨藻吸收利用无机碳没有明显影响。长茎葡萄蕨藻能利用HCO_3^-作为无机碳源进行光合作用。     

SiCp/Mg复合材料的制备及其阻尼特性研究

采用搅拌铸造法在真空度为200 Pa的条件下制备得到含有微量氧化物的SiCp/Mg复合材料,通过显微组织观察和动态热机械分析等对其阻尼特性进行了研究。结果表明,所制备的SiCp/Mg复合材料基体晶界处分布着附着有氧化物的网状结构,且随着SiCp含量的增加,网状结构增多,且分布更加分散。此结构增大了位错密度和晶粒界面滑移,位错脱钉和界面滑移在振动过程中耗能量增大,因此所制备的SiCp/Mg复合材料具有理想的阻尼性能。