黄海透光层悬浮半导体矿物组成及其促进微生物胞外电子传递过程初探     

刘佳  孙元  任桂平  鲁安怀  李艳  丁竑瑞 《岩石矿物学杂志》2020,39(1):96-104

在地球上最为活跃的海洋透光层体系中,矿物-微生物交互作用的形式十分丰富。系统采集了黄海近海透光层水体样品,测试分析发现其中分布大量悬浮半导体矿物及微生物群落。通过电感耦合等离子质谱仪(ICP-MS)、环境扫描电子显微镜(ESEM)及配有的EDX能谱仪,从宏观到微区对悬浮颗粒矿物的化学元素组成进行了测试分析,发现其主要矿物组成元素为Si、O、Na、K、Ca、Al等,且含有较高含量的Mn、Fe、Ti等金属元素;通过X射线衍射光谱(XRD)、拉曼光谱(Raman)测试从整体到局部分析悬浮颗粒矿物的物相组成,发现其主要组成矿物为石英、钠长石、方解石、云母和绿泥石等,还有锐钛矿、金红石、板钛矿、针铁矿等铁、钛金属氧化物半导体矿物。通过16S rRNA高通量测序分析海水中主要微生物群落为Proteobacteria、Actinobacteria、Bacteroidetes、Planctomycetes、Woeseia、Fluviicola等,并通过构建双室反应体系对海水微生物与悬浮矿物间氧化还原作用及胞外电子传递过程进行了表征,结果显示增加海水悬浮矿物作为电子受体后,体系开路电压由330. 80 mV提升至426. 59 mV,提升比率达130%,最大输出功率由8. 376 9 mW/m^2提升至12. 096 8 mW/m^2,为原体系的1. 44倍。实验研究表明,海水透光层悬浮矿物能有效参与并促进微生物胞外电子传递过程,为后续深入研究基于电子能量传递利用的半导体矿物-微生物协同作用以及元素循环调控机制奠定初步基础。  相似文献   

海南岛海岸带土地利用强度与生态承载力分析     

李通  闫敏  陈博伟  张丽  宋茜茜 《测绘通报》2020,(9):54-59

随着海南省进一步开放发展，海岸带区域的土地利用强度逐渐加强，生态保护需求日益增强。利用4期（1990、2000、2009、2015年）海岸带土地利用分类数据，研究海岸带土地开发利用强度，并分析了其生态承载力。结果表明：①耕地和林地是海南岛海岸带地区的主要土地类型。②25年间，海南岛海岸带土地利用强度整体较高且逐年上升，2000—2009年土地利用强度增速最高，达2.03%；海口市和澄迈县土地利用强度4期均值最大，分别为300.5和286.1。③25年来海南岛海岸带生态状况呈下降趋势，57%的海岸带市县实际生态承载压力增长了1倍以上。  相似文献   

郯庐断裂带南段继承性断裂构造控矿模式研究及其应用效果——以皖东北五河金矿整装勘查为例     

汪青松  张顺林  张金会  张家嘉  尤淼 《地质学报》2020,94(10):2965-2977

郯庐断裂带南段的皖东北地区地质构造复杂，多为厚覆盖区，找矿难度大。由于控矿条件难以调查清楚，缺乏具有区域特色的勘查理论指导，区内金矿勘查长期没有取得突破成果。笔者依托五河金矿整装勘查项目，进行了区域重磁异常特征和成矿规律分析研究，发现皖东北地区北东- 北北东向重力低异常具有弧形条带特征，并以郯庐断裂带为界，大致具有旋转对称性。重磁异常保存印支期构造格架痕迹信息，反映了郯庐断裂带南段时空演化特征，显示了北东- 北北东向主要断裂构造具有继承性，形成于印支期，燕山期继续活动，控制白垩纪“红层盆地”和燕山期成岩成矿作用。中低温热液型金多金属矿床和矽卡岩型铜金矿床是皖东北地区主要矿床类型，均受继承性断裂构造控制。结合郯庐断裂的演化特征，利用物探成果引领地质理论创新，提出了郯庐断裂带南段矿床的“继承性断裂构造控矿模式”。根据继承性断裂构造形成机理分析其空间分布规律，总结了矿化蚀变构造带的物探异常标志，解决了皖东北覆盖区成矿预测与找矿靶区圈定难题，在五河金矿整装勘查区应用取得了重要找矿成果，圈定6个金矿找矿靶区，得到了钻探验证，已发现中型规模金矿床2处、小型3处，估算潜在资源量可达特大型规模，实现了安徽省境内郯庐断裂带金矿找矿的重大突破。  相似文献   

Conversion relationship of rainfall-soil moisture-groundwater in Quaternary thick cohesive soil in Jianghan Plain,Hubei Province,China     

《China Geology》2020,3(3):462-472

The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain, the transition zone between the Dabie Mountain Area and Jianghan Plain. It’s a great field test site to study the material and energy exchange among rainfall, soil moisture, and groundwater of the Earth ’s critical zone in subtropical monsoon climate plain areas. This paper analyzed the connection between rainfall and volume water content (VWC) of soil at different depths of several soil profiles, and the dynamic feature of groundwater was discussed, which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata. The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge, while the lateral recharge is the main supplement source. There were 75 effective rainfall events among 120 rainfall events during the monitoring period, with an accumulated amount of 672.9 mm, and the percentages of effective rainfall amount and duration time were 62.50% and 91.56%, respectively. The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m. The soil profile was divided into four zones: (1) The sensitive zone of rainfall infiltration within 1.4 m, where the material and energy exchange frequently near the interface between atmosphere and soil; (2) the buffer zone of rainfall infiltration between 1.4 m and 3.5 m; (3) the migration zone of rainfall infiltration between 3.5 m and 5.0 m; and (4) the rainfall infiltration and groundwater level co-influenced zone below 5.0 m. The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth ’s critical zone, which is of great theoretical and practical significance for groundwater resources evaluation and development, groundwater environmental protection, ecological environmental improvement, drought disaster prevention, and flood disaster prevention in subtropical monsoon climate plain areas.  相似文献   

尼日尔三角洲东部深水区构造特征及其形成机理     

赵江  王秋良  卢圣力  付博  杜峰 《大地测量与地球动力学》2019,39(7):691-695

研究尼日尔三角洲东部深水区块发现，整个盆地从陆向洋具有3个大的构造分区：伸展拉张区、过渡区和挤压逆冲区。伸展区以大型同沉积断层伴生大量滚动背斜构造为特征，过渡区发育大量泥底辟构造，挤压区以复杂的逆冲叠瓦构造为主。通过分析形成机理，揭示东部深水转换带上M研究区构造特征，按构造的演化特征将该区构造分为泥底辟型、冲断-泥底辟混合型、逆冲型3种类型，提出研究区内的圈闭主要以构造-岩性圈闭为主，为尼日尔三角洲盆地深水勘探提供新的理论指导。  相似文献   

Drying increases organic colloidal mobilization in the karst vadose zone: Evidence from a 15-year cave-monitoring study     

Jin Liao  Chaoyong Hu  Xiuli Li  Jiaoyang Ruan 《水文研究》2021,35(4):e14163

Understanding the hydrological processes of colloids within the karst vadose zone is vital to the security of karst groundwater and providing appropriate paleohydrological explanations of colloid-facilitated metals in speleothem. This study addresses the mobilization mechanisms driving colloidal organic matter (COM) transport in the karst vadose zone using a 15-year long monthly monitoring dataset from a cave drip point (HS4) in Heshang Cave, Qingjiang Valley, China. Variations in COM concentrations were reported as the fluorescence difference values of raw and filtered (<0.22 μm) samples at an excitation wavelength of 320 nm and emission wavelength of ~400 nm. A fluorescence humification index (HIX) lower than 0.8 and an autochthonous index (BIX) higher than 1.2 indicated that the origin of COM was mainly from the karst vadose zone, rather than the soil zone. The COM concentration varied from 0.001 to 0.038 Raman Unit (RU), with evident seasonal fluctuations. Rising limbs for COM values occurred prior to rising limbs within a dripwater hydrograph; moreover, the COM peak values corresponding to the beginning of the increasing hydrograph generally suggested that the mobilization of COM reflected the movement of the air–water interface (AWI) in the karst vadose zone rather than rainfall intensity or flow velocity. COM peak values were positively correlated with the antecedent drying duration and negatively correlated with HIX values. These phenomena may be explained by the increased amount of organic matter that was aggregated and absorbed on the surface of carbonate in the karst vadose zone during a longer drying duration. Moreover, the longer drying duration was also beneficial to autochthonous biological activity, which subsequently decreased the HIX value of the organic matter in the karst vadose zone. The movement of AWI and the drying duration are both controlled by the outside weather conditions. This study is therefore conducive to evaluating the security of karst groundwater in response to climate change, and challenges prevailing paleoclimate interpretations of colloid-facilitated metal abundance timeseries reported from speleothems.  相似文献   

Wave-forced dynamics in the nearshore river mouths,and swash zones     

Maurizio Brocchini 《地球表面变化过程与地形》2020,45(1):75-95

The role of wave forcing on the main hydro-morphological dynamics evolving in the shallow waters of the nearshore and at river mouths is analyzed. Focus is mainly on the cross-shore dynamics that evolve over mildly sloping barred, dissipative sandy beaches from the storm up to the yearly timescale, at most. Local and non-local mechanisms as well as connections across three main inter-related subsystems of the nearshore – the region of generation and evolution of nearshore bars, river mouths and the swash zone – are analyzed. The beach slope is a major controlling parameter for all nearshore dynamics. A local mechanism that must be properly described for a suitable representation of wave-forced dynamics of all such three subsystems is the proper correlation between orbital velocity and sediment concentration in the bottom boundary layer; while specific dynamics are the wave–current interaction and bar generation at river mouths and the sediment presuspension at the swash zone. Fundamental non-local mechanisms are both infragravity (IG) waves and large-scale horizontal vortices (i.e. with vertical axes), both influencing the hydrodynamics, the sediment transport and the seabed morphology across the whole nearshore. Major connections across the three subsystems are the upriver propagation of IG waves generated by breaking sea waves and swash–swash interactions, the interplay between the swash zone and along-river-flank sediment transport and the evolution of nearshore sandbars. © 2019 John Wiley & Sons, Ltd.  相似文献   

Beaver dam analogues drive heterogeneous groundwater–surface water interactions     

Jeffrey Wade  Laura Lautz  Christa Kelleher  Philippe Vidon  Julianne Davis  Julio Beltran  Casey Pearce 《水文研究》2020,34(26):5340-5353

Beaver dam analogues (BDAs) are a cost-effective stream restoration approach that leverages the recognized environmental benefits of natural beaver dams on channel stability and local hydrology. Although natural beaver dams are known to exert considerable influence on the hydrologic conditions of a stream system by mediating geomorphic processes, nutrient cycling, and groundwater–surface water interactions, the impacts of beaver-derived restoration methods on groundwater–surface water exchange are poorly characterized. To address this deficit, we monitored hyporheic exchange fluxes and streambed porewater biogeochemistry across a sequence of BDAs installed along a central Wyoming stream during the summer of 2019. Streambed fluxes were quantified by heat tracing methods and vertical hydraulic gradients. Biogeochemical activity was evaluated using major ion porewater chemistry and principal component analysis. Vertical fluxes of approximately 1.0 m/day were observed around the BDAs, as was the development of spatially heterogeneous zones of nitrate production, groundwater upwelling, and anaerobic reduction. Strong contrasts in hyporheic zone processes were observed across BDAs of differing sizes. This suggests that structures may function with size-dependent behaviour, only altering groundwater–surface water interactions after a threshold hydraulic step height is exceeded. Patterns of hyporheic exchange and biogeochemical cycling around the studied BDAs resemble those around natural beaver dams, suggesting that BDAs may provide comparable benefits to channel complexity and near-stream function over a 1-year period.  相似文献   

A critical zone observatory dedicated to suspended sediment transport: The meso-scale Galabre catchment (southern French Alps)     

Cédric Legout  Guilhem Freche  Romain Biron  Michel Esteves  Oldrich Navratil  Guillaume Nord  Magdalena Uber  Thomas Grangeon  Nico Hachgenei  Brice Boudevillain  Céline Voiron  Lorenzo Spadini 《水文研究》2021,35(3):e14084

The 20 km² Galabre catchment belongs to the French network of critical zone observatories (OZCAR; Gaillardet et al., Vadose Zone Journal, 2018, 17(1), 1–24). It is representative of the sedimentary lithology and meteorological forcing found in Mediterranean and mountainous areas. Due to the presence of highly erodible and sloping badlands on various lithologies, the site was instrumented in 2007 to understand the dynamics of suspended sediments (SS) in such areas. Two meteorological stations including measurements of air temperature, wind speed and direction, air moisture, rainfall intensity, raindrop size and velocity distribution were installed both in the upper and lower part of the catchment. At the catchment outlet, a gauging station records the water level, temperature and turbidity (10 min time-step). Stream water samples are collected automatically to estimate SS concentration-turbidity relationships, allowing quantification of SS fluxes with known uncertainty. The sediment samples are further characterized by measuring their particle size distributions and by applying a low-cost sediment fingerprinting approach using spectrocolorimetric tracers. Thus, the contributions of badlands located on different lithologies to total SS flux are quantified at a high temporal resolution, providing the opportunity to better analyse the links between meteorological forcing variability and watershed hydrosedimentary response. The set of measurements was extended to the dissolved phase in 2017. Both stream water electrical conductivity and major ion concentrations are measured each week and every 3 h during storm events. This extension of measurements to the dissolved phase will allow progress in understanding both the origin of the water during the events and the partitioning between particulate and dissolved fluxes of solutes in the critical zone. All data sets are available at https://doi.osug.fr/public/DRAIXBLEONE_GAL/index.html .  相似文献   

微生物勘探技术在潮汕坳陷油气勘探中的应用初探     

赵忠泉  孙鸣  万晓明  陈胜红  赵静  宋立军  李辉  强昆生  梁永兴 《中国地质》2020,47(3):645-654

东沙海域潮汕坳陷中生界研究程度相对较低,油气分布规律不明,为了加强对该区油气分布和富集规律的研究,针对潮汕坳陷西部地质目标首次应用微生物地球化学勘探技术(MGCE),探讨其含油气性。MGCE技术以轻烃微渗漏理论为基础,采用地质微生物学方法和地球化学方法检测研究区海底表层的微生物异常和吸附烃异常,预测研究区下伏地层中油气的富集区及其油气性质。检测结果显示研究区西部凹陷的斜坡区微生物异常呈块状发育,轻烃微渗漏强度变化大,可能为潜在油气富集区,酸解吸附烃成果显示可能的油气性质为干气和凝析油气。  相似文献