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101.
N_2O是大气中最重要的温室气体之一,目前已经有大量的研究对海洋N_2O循环及海洋对N_2O收支的贡献进行追踪报道。然而,极区相关研究仍然十分有限。本研究利用中国第25、26次南极科学考察的机会,对南大洋进行的采样以及实验室分析,结果显示,南大洋表层海水存在亚热带锋附近N_2O过饱和,亚南极锋附近接近饱和,和极锋以南洋面的不饱和的特征。海冰融化后,其融冰水的注入是N2O不饱和特征形成的主要原因。运用正态分布选取站观测风速95%以上的风速范围进行平局估算出极锋以南洋区海气通量,结果显示,极锋区以南表层海水是大气N_2O的汇区,年吸收通量约为3.5×10~(-4)—7.7×10-4Tg·a-1(百万吨氮/年)。 相似文献
102.
桂西南锰矿赋存于上泥盆统五指山组中段,产锰矿三层,大多由锰质豆鲕粒组成。笔者研究了下雷锰矿床的锰质豆鲕粒,按其形态、结构构造和矿物成份划分为16种类型,并据①其沉积环境属断陷深水台沟相;②富集于几个矿段;③其碳酸锰矿物δC~(13)值为-6.23~-7.78‰,说明碳源于深部岩浆;④豆鲕粒由菱锰矿,蔷薇辉石、黑云母、锰铁叶蛇纹石、绿泥石、柘榴石等热液矿物组成。因此认为,锰质豆鲕粒形成于海底热气液喷溢口及其附近热水流动带,而低温滞水带不易形成豆鲕粒。 相似文献
103.
The mixing behaviour of iron, manganese, phosphate and humic acid in a Delaware salt marsh creek was studied using field data, laboratory mixing experiments, and geochemical mass balance equations. Property-salinity diagrams for field data indicated that the removal of iron is 56–70% in the 0–10‰ salinity range. A proposed mechanism of removal is the flocculation of colloidal iron, perhaps with humic acid. Phosphate, however, undergoes 195% addition in the same low salinity region, which may be due to release of phosphate from resuspended sediments. Dissolved manganese is conserved, as is humic acid throughout the salt marsh mixing zone. Within the uncertainty of the data the maximum possible removal of humic acid is 23%.Laboratory mixing experiments that simulated salt marsh mixing along the same salinity gradient as observed in the field (5–25‰) showed only small-scale additions and removals compared to the field results. Such small-scale changes occurred largely at salinities >10‰ in the laboratory experiments, whereas most removals and additions occurred at salinities <10‰ in the field. Mixing studies also showed little difference between prefiltered and unfiltered mixes. The studies suggest that simple mixing of salt marsh waters, with or without suspended material, does not strongly influence the observed behaviour of dissolved constituents in salt marshes, and that other processes (e.g. sediment or intertidal exchange) must dominate their behaviour. 相似文献
104.
FENG Xionghan LIU Fan TAN Wenfeng LIU Xiangwen & HU Hongqing . College of Resources Environment Huazhong Agricultural University Wuhan China . Testing Center China University of Geosciences Wuhan China 《中国科学D辑(英文版)》2004,47(8):760-768
Todorokite is one of the common manganese ox-ides in manganese ore deposits, weathering product of manganese-bearing rocks, soils and sediments. It is also an important component in the abundant marine manganese nodules. Since todorokite was firstly found in Japanese Todoroki mine in 1934, its properties and origination have appeared to be very interesting to many researchers[1—3]. It has a stable structure similar to porous molecular sieves, constructed of triple MnO6 octahedral chains. Th… 相似文献
105.
Jia?RongfenEmail author Peng?Xianzhi Zhou?Zheng Liu?Dehan Wang?Guanxin Wang?Deqiang 《中国地球化学学报》2004,23(3):197-206
Relatively strongly magnetic fine components (< 30μm, XS-4J and DS-4J) which are most environmentally sensitive were separated from layer S5-1 in the Xifeng and Duanjiapo loess sections and analyzed by MPV-3 for their morphometric characteristics and reflectance, SEM-ESD for their element contents and XRD for their mineral phases, respectively. The results showed that minerals in both samples are dominated by detrial Fe-Ti oxides of aeolian origin. In sample XS-4J the reflectance and iron contents of magnetic minerals are usually high. In addition to magnetite (Fe3O4), maghemite (γFe2O3) and hematite (Fe2O3), some Fe-high oxide (72.25 wt%–86.67 wt%), ilmenite (FeTiO3), and magnetite-ulvöspinel [Fe(FeCr)O4, Fe (FeNi)O4] were also detected. In sample DS-4J obvious negative linear correlations were found between Ti and Fe, and the contents of Mn, Si, Al and Ca are usually high and the minerals are dominated by magnetite (maghemite), goethite (FeOOH) and limonite (containing Si and OH). In addition, the signs of corrosion of magnetic minerals and newly crystallized magnetite (maghemite) were recognized. Differences in the composition and assemblage characteristics of magnetite minerals between XS and DS reflect significant differences in source rocks and preserving conditions. 相似文献
106.
In this paper, the application of a homemade Nation and Co(Salen) modified platinum microelectrode and an ISO-NOPMC microsensor (World Precision Instruments, USA ) to measure nitric oxide in natural seawater is reported. These two microelectrodes are suitable for the measurement. In natural seawater, the sensitivity and stability of the ISO-NOPMC microsensor are higher than that of the homemade Nation and Co(Salen) modified platinum microelectrode. 相似文献
107.
原子吸收分光光度法快速测定铬铁矿中钙、镁、锰 总被引:2,自引:0,他引:2
通过在标液中加入相应的Sr来消除离子干扰,采用原子吸收分光光度法快速测定CaO、MgO、MnO的含量,方法经国家标准物质验证,其RSD<2%(n=6)。其结果与标准值相符。方法达到了准确、简便、快速、实用性强。 相似文献
108.
应用EDTA间接滴定法测定铝土矿、高岭土、黏土等矿石中的三氧化二铝,试验了不同种类的酒石酸掩蔽钛对三氧化二铝测定结果的影响。建议选择左旋体或右旋体酒石酸作掩蔽剂,尽量不要选择内消旋体酒石酸,更不能选择外消旋体酒石酸。采用酒石酸钾钠作掩蔽剂,三氧化二铝的测定结果良好,方法快速、简便。 相似文献
109.
110.
Peter W. L. Vojak Clive Edwards Martin V. Jones 《Estuarine, Coastal and Shelf Science》1985,20(6):661-671
Water samples from the Tamar Estuary oxidized manganese when supplemented with Mn2+ (2 mgl−1). The rates of oxidation were depressed in the presence of various metabolic inhibitors. The effect of Mn2+ and temperature on the rate of manganese oxidation suggested that a biological process was largely responsible for converting Mn2+ to Mn4+. Rates of manganese oxidation were much higher in freshwater (3·32 μgl−1 h−1 in water containing 30 mgl−1 of suspended matter) than in saline water (0·7 μgl−1 h−1 in water of salinity 32‰) containing the same amount of particulate matter. The rate of manganese oxidation was proportional to the particulate load (up to 100 mgl−1 particulates). 相似文献