Air-sea CO₂ fluxes in the southern Yellow Sea: An examination of the continental shelf pump hypothesis   总被引：1，自引：0，他引：1  

Liang Xue  Longjun Zhang  Wei-Jun CaiLi-Qing Jiang 《Continental Shelf Research》2011,31(18):1904-1914

The southern Yellow Sea (SYS), located to the north of the East China Sea (ECS), was considered part of the ECS when Tsunogai et al. (1999) proposed the “continental shelf pump” (CSP) hypothesis. However, the original CSP carbon dioxide (CO₂) uptake flux (2.9 mol C m⁻² yr⁻¹) appears to have been overestimated, primarily due to the differences between the SYS and the ECS in terms of their CO₂ system. In this paper, we estimated air-sea CO₂ fluxes in the SYS using the surface water partial pressure of CO₂ (pCO₂) measured in winter, spring, and summer, as well as that estimated in fall via the relationship of pCO₂ with salinity, temperature, and chlorophyll a. The results indicate that overall, the entire investigated area was a net source of atmospheric CO₂ during summer, winter, and fall, whereas it was a net sink during spring. Spatially, the nearshore area was almost a permanent CO₂ source, while the central SYS shifted from being a CO₂ sink in spring to a source in the other seasons of the year. Overall, the SYS is a net source of atmospheric CO₂ on an annual scale, releasing ∼7.38 Tg C (1 Tg=10¹² g) to the atmosphere annually. Thus, the updated CO₂ uptake flux in the combined SYS and ECS is reduced to ∼0.86 mol C m⁻² yr⁻¹. If this value is extrapolated globally following Tsunogai et al. (1999), the global continental shelf would be a sink of ∼0.29 Pg C yr⁻¹, instead of 1 Pg C yr⁻¹ (1 Pg=10¹⁵ g).The SYS as a net annual source of atmospheric CO₂ is in sharp contrast to most mid- and high-latitude continental shelves, which are CO₂ sinks. We argue that unlike the ECS and the North Sea where carbon on the shelf could be exported to the open ocean, the SYS lacks the physical conditions required by the CSP to transport carbon off the shelf effectively. The global validity of the CSP theory is thus questionable.  相似文献   

内蒙古敖仑花斑岩铜钼矿床花岗岩类地质地球化学特征   总被引：5，自引：0，他引：5  

邹滔  王京彬  王玉往  袁继明  林龙军  窦金龙 《地质学报》2011,85(2)

敖仑花斑岩铜钼矿床位于大兴安岭南段西拉木伦河断裂北侧,矿床赋存于花岗闪长斑岩岩体及长英质角岩中.矿区脉岩发育,多形成于花岗闪长斑岩体及成矿之后.岩石地球化学表明,赋矿斑岩具有高Si、富Al、Na,低Ca、Mg和Fe2OT3,A/CNK值小于1.1等特征,为偏钠质的高钾钙碱性Ⅰ型花岗岩;稀土元素具微弱负Eu异常,轻重稀土分异比较明显,LREE/HREE值在11.43～18.33,LaN/YbN值在14.64～37.55;岩石具高Sr(＞400×10-6),低Y(≤18×10-6)和Yb(≤1.9×10-6),显示出典型的埃达克岩特征.矿区后期的脉岩中,流纹斑岩与赋矿斑岩的地球化学特征差别较大,具有低Sr,高Y和Yb,明显的负Eu异常等特征,反映其构造背景为张性环境;英安斑岩具有弱的负Eu异常,轻重稀土分异度高于流纹斑岩,但略低于花岗闪长斑岩.通过分析矿区花岗岩岩类的地球化学特征及形成构造环境,认为敖仑花铜钼矿床具有有利的成矿条件和很大的找矿潜力.  相似文献   

Sr speciation in producing SrCO3 with celestite     

Chenglun Liu  Li Zhang  Longjun Xu  Zhimin Su  Taiping Xie  Yuan Wang 《中国地球化学学报》2014,33(3):244-247

Strontium speciation transferring in strontium residue and mixing strontium ore are investigated with extracting experiment, X-ray powder diffraction （XRD）, X-ray fluorescence spectrometer （XRF） and Atomic Absorption Spectroscopy （AAS）. The results show that there are strontium carbonate, strontium sulfate, strontium sulfide, and a little amount of strontium silicate and strontium ferrite in strontium residue. Impurities in strontium residue mainly contain carbonate and oxide of calcium, iron, magnesium and aluminum etc. The amount of strontium sulfide in strontium residue is larger than that in strontium ore. And a little strontium silicate and strontium ferrite are found in strontium ore. It is concluded that acid soluble method is used firstly in the process of producing strontium carbonate from mixing strontium ore. In addition, mechanical smash method and surface active treatment to strontium samples are beneficial to the ratio-leaching increase of strontium. The research achievement helps to save energy and decrease pollutants emission in strontium processing industry.  相似文献   

Preparation of Mn₃O₄ from low-grade rhodochrosite ore by chemical bath deposition method     

Jing Zhao  Longjun Xu  Taiping Xie  Chao Xie 《中国地球化学学报》2015,(1):55-61

Mn3O4was prepared with the chemical bath deposition(CBD) method. A Mn SO4 solution was obtained by the leaching and purifying of low-grade rhodochrosite ore(LGRO), which was used as raw material. The prepa ration procedures were studied and promoted. The result showed that the Mn3O4 with the highest purity and highes specific surface area could be obtained under the following processes. An Mn SO4 solution of 1.0 mol/L was added into a beaker under a flow rate of 30 m L/h. The p H of the reaction solution was adjusted to 10 using NH3 H2 O a80 °C. Then the solids were washed and dried at 200 °C fo2.5 h. The total Mn content(TMC) of Mn3O4 was 72.0 %The ionic distributions was formulated as [Mn2?[Mn2??0.3024Mn30.2937Mn4?h0.37860.0254]2O4. The average crys tallite size of Mn3O4 with a tetragonal hausmannite struc ture was found to be about 35 nm by X-ray diffraction(XRD) analysis. The BET specific surface area of the Mn3O4 measured was 32 m2/g.  相似文献   

Kinetics analysis of the enzymatic hydrolysis of cellulose from straw stalk     

CHEN Kun  XU Longjun  BI Zhiming  FU Zhilei 《中国地球化学学报》2013,32(1):41-46

The effects of several parameters on the simultaneous saccharification and fermentation of straw stalk for ethanol fuel production were investigated on the basis of orthogonal experiments. The parameters include temperature and time of fermentation, quantity and proportion of yeast inoculation, as well as cellulase dosage. An ethanol yield of 0.183 g/g was obtained from the straw stalk pretreated with diluted acid under determined optimum conditions. These conditions were: fermentation temperature: 38℃; fermentation time: 72 h; yeast inoculation quantity: 15%; yeast inoculation proportion: 2:1; and cellulose enzyme dosage: 20 U/g. The relationship between ethanol concentration c and fermentation time t is presented as follows, c=abt/(1+bt). The rate constant k of straw stalk hydrolysis by the cellulose enzyme depends on hydrolysis time, as described by k=k1t-h. Therefore, straw stalk hydrolysis reaction by the cellulose enzyme is fractal-like.  相似文献   

Preparation of chemical manganese dioxide from low-grade rhodochrosite ore     

ZHAO Jing  XU Longjun  XIE Chao 《中国地球化学学报》2013,32(4):380-384

The preparation of chemical manganese dioxide(CMD) from low-grade rhodochrosite ore(LGRO) in Xiushan,Chongqing,was studied and improved,including leaching with sulfuric acid,purifying,crystallizing and decomposing of MnCO3,and refining of primary MnO2.The product was characterized by X-ray diffraction.The results showed that the extraction ratio,the manganese recovery ratio of purifying,crystallization and refining reached 96.8%,93.9%,97.7%and 85.4%,respectively.The optimum conditions of refining were described as follows:liquid(H2SO4)/solid(primary MnO2) ratio was 3 L/g,the concentrations of NaClO exceeded 20%,and reaction time was 3 hours.Under the above conditions,the contents of MnO2and Mn in the obtained manganese dioxide were respectively 85.1%and 53.9%.The refined MnO2can be used as the super grade manganese dioxide mine powder in chemical industry.The XRD indicated that the structure of the product wasγ-MnO2.  相似文献   

高浑浊度河口沉积物的沉积机理评述   总被引：2，自引：0，他引：2  

王飞  张龙军 《海洋湖沼通报》2004,(2):21-29

该文主要介绍了潮流对沉积作用的影响，沉积物的再悬浮和最大浑浊带的形成机制以及影响沉积物絮凝沉降的因素。潮流是搬运河口泥沙的主要动力，沉积在河口拦门沙的泥沙会在潮流的作用下向河口外继续搬运。沉积物的再悬浮和最大浑浊带密不可分，正是由于沉积物在周期性潮流的作用下引起再悬浮，为最大浑浊带的形成提供了条件。影响沉积物絮凝沉降的因素很多，有内因，也有外因。内因是颗粒物自身的性质；外因如盐度、流速、pH值等。  相似文献   

潮间带沉积物中重金属的AVS归一化研究   总被引：5，自引：0，他引：5  

张向上  张龙军  吴玉科 《中国海洋大学学报(自然科学版)》2003,33(3):420-424

采集胶州湾河套镇养殖区潮间带高、中、低潮带的沉积物样品 ,将重金属 AVS归一化法应用于粘土质潮间带沉积物研究 ,测定了酸可挥发硫 (AVS)和酸化过程中溶解释放的重金属 (SEM) ,并根据 SEM与 AVS的摩尔浓度关系评价二价重金属 (Cu、Pb、Zn、Cd、Ni)的化学活性和生物可获得性。结果表明 :河套镇养殖区除各潮带表层 0～ 2 cm外 ,SEM/ AVS均小于 1,重金属的生物活性小 ,不会对养殖的底栖生物造成影响。 8cm以下 AVS平均含量高潮带 >中潮带 >低潮带 ,在同一潮位 AVS随深度增加而增加 ;相同潮位的 SEM垂直变化趋势相同  相似文献   

南黄海夏季表层海水中pCO2分布的初步探讨     

王峰  张龙军  张经 《中国海洋大学学报(自然科学版)》2002,32(6):1007-1011

作者在 1 999年夏季的航次中 ,获得了南黄海表层海水 p CO2 的实测数据。本文结合水文、化学和生物等要素的同步观测资料 ,对影响 p CO2 分布和变化的某些重要现象进行了初步探讨。研究表明南黄海表层海水 p CO2 的分布存在较大的不均匀性 ,这是边缘海区海水中生物、物理和化学因素复合作用的结果。除长江口门外的 p CO2 高值区外 ,南黄海表层海水的 p CO2 值与叶绿素、水温大体呈负相关 ,而与海水的盐度基本上呈正相关。  相似文献   

Three-dimensional water quality model based on FVCOM for total load control management in Guan River Estuary,Northern Jiangsu Province     

Li Zhang  Weibo Lin  Keqiang Li  Jianming Sheng  Aihong Wei  Feng Luo  Yan Wang  Xiulin Wang  Longjun Zhang 《中国海洋大学学报(英文版)》2016,15(2):261-270

Guan River Estuary and adjacent coastal area (GREC) suffer from serious pollution and eutrophicational problems over the recent years. Thus, reducing the land-based load through the national pollutant total load control program and developing hydrodynamic and water quality models that can simulate the complex circulation and water quality kinetics within the system, including longitudinal and lateral variations in nutrient and COD concentrations, is a matter of urgency. In this study, a three-dimensional, hydrodynamic, water quality model was developed in GREC, Northern Jiangsu Province. The complex three-dimensional hydrodynamics of GREC were modeled using the unstructured-grid, finite-volume, free-surface, primitive equation coastal ocean circulation model (FVCOM). The water quality model was adapted from the mesocosm nutrients dynamic model in the south Yellow Sea and considers eight compartments: dissolved inorganic nitrogen, soluble reactive phosphorus (SRP), phytoplankton, zooplankton, detritus, dissolved organic nitrogen (DON), dissolved organic phosphorus (DOP), and chemical oxygen demand. The hydrodynamic and water quality models were calibrated and confirmed for 2012 and 2013. A comparison of the model simulations with extensive dataset shows that the models accurately simulate the longitudinal distribution of the hydrodynamics and water quality. The model can be used for total load control management to improve water quality in this area.  相似文献