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He,Ne and Ar isotopic composition of Fe-Mn crusts from the western and central Pacific Ocean and implications for their genesis

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Science China Earth Sciences 2007年第6期50卷 857-868页

作者： G. P. GLASBY Department of Geochemistry GZG Goldschmidtstrasse 1 D-37077 Gttingen Germany

The noble gas nuclide abundances and isotopic ratios of the upmost layer of Fe-Mn crusts from the western and central Pacific Ocean have been determined. The results indicate that the He and Ar nuclide abundances and isotopic ratios can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type is characterized by high 4He abundances of 191×10?9 cm3·STP·g?1 on average, with variable 4He, 20Ne and 40Ar abundances in the range (42.8?421)×10?9 cm3·STP·g?1, (5.40?141)×10?9 cm3·STP·g?1, and (773?10976)×10?9 cm3·STP·g?1, respectively. The high 3He/4He samples are characterized by low 4He abundances of 11.7×10?9 cm3·STP·g?1 on average, with 4He, 20Ne and 40Ar abundances in the range of (7.57?17.4)×10?9 cm3·STP·g?1, (10.4?25.5)×10?1 cm3·STP·g?1 and (5354?9050)×10?9 cm3·STP·g?1, respectively. The low 3He/4He samples have 3He/4He ratios (with R/RA ratios of 2.04?2.92) which are lower than those of MORB (R/R A=8±1) and 40Ar/36Ar ratios (447?543) which are higher than those of air (295.5). The high 3He/4He samples have 3He/4He ratios (with R/R A ratios of 10.4?12.0) slightly higher than those of MORB (R/R A=8±1) and 40Ar/36Ar ratios (293?299) very similar to those of air (295.5). The Ne isotopic ratios (20Ne/22Ne and 21Ne/22Ne ratios of 10.3?10.9 and 0.02774?0.03039, respectively) and the 38Ar/36Ar ratios (0.1886?0.1963) have narrow ranges which are very similar to those of air (the 20Ne/22Ne, 21Ne/22Ne, 38Ar/36Ar ratios of 9.80, 0.029 and 0.187, respectively), and cannot be differentiated into different groups. The noble gas nuclide abundances and isotopic ratios, together with their regional variability, suggest that the noble gases in the Fe-Mn crusts originate primarily from the lower mantle. The low 3He/4He type and high 3He/4He type samples have noble gas characteristics similar to those of HIMU (High U/Pb Mantle)-and EM (Enriched Mantle)-type mantle material, respectively. The low 3He/4He type samples with HIMU-type noble gas isotopic rati

关键词： Fe-Mn crusts noble gases isotope geochemistry mantle heterogeneity Pacific Ocean

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New index of ferromanganese crusts reflecting oceanic environmental oxidation

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Science China Earth Sciences 2007年第3期50卷 371-384页

作者： WU GuangHai ZHOU HuaiYang ZHANG HaiSheng LING HongFei MA WeiLin ZHAO HongQiao CHEN JianLin LIU JieHong Key Laboratory of Marine Ecosystem&Biogeochemistry of State Oceanic Administration Hangzhou 310012China Key Laboratory of Submarine Geoscience of State Oceanic Administration Hangzhou 310012China Geochemistry Institute of Guangzhou Chinese Academy of SciencesGuangzhou 510640China State Key Laboratory for Mineral Deposit Research Nanjing UniversityNanjing 210093China

Ferromanganese crusts (hereinafter crusts) form in aerobic environment and the environmental oxida-tion degree is recorded by the redox sensitive element Co in the crusts. The ages of the layers from the surface to bottom of the crusts are determined, and main element contents at high resolution along the depth sections of three crusts from the Pacific Ocean are analyzed by an electron microprobe. Thus the variations of Co/(Fe+Mn) and Co/(Ni+Cu) with age/depth of the crust layers are obtained. By comparing the ratios of Co/(Fe+Mn) and Co/(Ni+Cu) with the δ 18O curves of the Pacific benthic foraminifera, we find that these two ratios can reflect the variation of the environmental oxidation state under which the crust layers deposit. The evolution of the oxidation degree reflected by the two indexes resembles the evo-lution of temperature since the Oligocene reflected by the δ 18O curves of the Pacific benthic foraminif-era. This suggests that the crust-forming environment after the Oligocene is controlled mainly by the oxygen-rich bottom water originated from the Antarctic bottom water (AABW). However it is not the case prior to the Oligocene. Furthermore it suggests that the environmental oxidation degree controls the formation of the crusts and the Co contents in the crusts. This explains why the Co contents in the crusts increase with time up to now.

关键词： ferromanganese crusts the Pacific Ocean oxidation degree of environment the Oligocene AABW

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Effects of sand burial on biomass, chlorophyll fluores-cence and extracellular polysaccharides of man-made cyanobacterial crusts under experimental conditions

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Science China(Life Sciences) 2007年第4期50卷 530-534页

作者： WANG WeiBo1,2, YANG CuiYun1,2, TANG DongShan1,2, LI DunHai1, LIU YongDing1& HU ChunXiang1 1 State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100039, China 1. State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China 2. Graduate University of Chinese Academy of Sciences Beijing 100039 China

Soil cyanobacterial crusts occur throughout the world, especially in the semiarid and arid regions. It always encounters sand burial, which is an important feature of mobile sand dunes. A greenhouse study was conducted to determine the effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts in six periods of time (0, 5, 10, 15, 20 and 30 d after burying) and at five depths (0, 0.2, 0.5, 1 and 2cm). The results indicated that with the increase of the burial time and burial depth extracellular polysaccharides content and Fv/Fm decreased correspondingly and there were no significant differences between 20 and 30 burial days under dif-ferent burial depths. The degradation of chlorophyll a content appeared only at 20 and 30 burial days and there was also no significant difference between them under different burial depths. It was also observed a simultaneous decrease of the values of the Fv/Fm and the content of extracellular poly-saccharides happened in the crusted cyanobacterium Microcoleus vaginatus Gom. It may suggest that there exists a relationship between extracellular polysaccharides and recovery of the activity of pho-tosystem II (PS II) after rehydration.

关键词： Microcoleus vaginatus Gom. man-made cyanobacterial crusts sand burial biomass photosynthetic activity extracellular polysaccharides

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GEOCHEMICAL CHARACTERISTICS OF Fe-Mn NODULES AND crusts FROM THE MARIANA RIDGE AND THE WEST PHILIPPINE BASIN

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Chinese Science Bulletin 1991年第14期36卷 1190-1193页

作者：何良彪 First Institute of Oceanography State Oceanography Administration Qingdao 266003 PRC

I. INTRODUCTIONA lot of work on marine Fe-Mn nodules has been done. However, few reports about the study of Fe-Mn nodules in the Mariana Ridge and the West Philippine Basin are known. The purpose of this note is to re... 详细信息

关键词： the Mariana Ridge the West Philippine Basin Fe-Mn nodules and crusts the transition of geochemical characteristics.

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Shifts in community structure and function of ammoniaoxidizing archaea in biological soil crusts along a revegetation chronosequence in the Tengger Desert

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Research in Cold and Arid Regions 2019年第2期11卷 139-149页

作者： LiNa Zhao XinRong Li ShiWei Yuan YuBing Liu Shapotou Desert Research and Experiment Station Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Remote Sensing of Gansu Province Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences

Metagenomic studies have demonstrated the existence of ammonia-oxidizing archaea(AOA) and revealed they are responsible for ammoxidation in some extreme environments. However, the changes in compositional structure and ammonia-oxidation capacity of AOA communities in biological soil crusts(BSCs) of desert ecosystems remain poorly ***, we utilized Illumina MiSeq sequencing and microbial functional gene array(GeoChip 5.0) to assess the above changes along a 51-year revegetation chronosequence in the Tengger Desert, China. The results showed a significant difference in AOA-community richness between 5-year-old BSCs and older ones. The most dominant phylum during BSC development was Crenarchaeota, and the corresponding species were ammonia-oxidizing_Crenarchaeote and environmental_samples_Crenarchaeota. Network analysis revealed that the positive correlations among dominant taxa increased, and their cooperation was reinforced in AOA communities during BSC succession. Redundancy analysis showed that the dominant factor influencing the change in AOA-community structure was soil texture. GeoChip 5.0 indicated that the amoA gene abundances of AOA and ammonia-oxidizing bacteria(AOB) were basically the same, demonstrating that AOA and AOB played an equally important role during BSCs development. Our study of the long-term succession of BSC demonstrated a persistent response of AOA communities to revegetation development in desert ecosystems.

关键词： ammonia-oxidizing archaea biological soil crusts GeoChip 5.0 network analysis

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Deep-Sea Cobalt crusts Water Jet Cutting Ability

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Geomaterials 2011年第2期1卷 41-45页

作者： Zhonghua Huang Ya Xie 不详

Deep-sea cobalt crusts water jet cutting method is proposed to avoid cutter impact load. With simulation calculations and experimental tests, water jet system parameters and its cutting ability were studied. Simula-tion results show that working pressure, ejection range and ejection angle of water jet system are main parameters of its cutting ability. Its important degree is in turn the working pressure, ejection range and ejection angle. Increasing water jet system working pressure is the most effective way to improve its cutting ability. When water jet working pressure is constant, in order to improve its cutting ability, the ejection range should be less than 4mm (four times of nozzle diameter) and the ejection angle should be about 13o. Experimental results show that there is a threshold pressure during water jet cutting cobalt crusts simulation material. With the increase of water jet working pressure, its cutting ability increases dramatically. With the increasing of water jet ejection range, its cutting ability decreases sharply. The optimal ejection angle is about 13o

关键词： Water Jet System Parameters Deep-Sea Cobalt crusts Cutting Ability

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