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藻类作为水体中的初级生产力,通过生物积累、生物矿化等生理功能与环境中的重金属相互作用、对重金属地球生 物化学循环起到关键作用。为了探讨藻类生物矿化去除水体中重金属的现象,文中研究了淡水微藻FZUL-321对Pb2+的去除 及矿化。结果表明：微藻FZUL-321对Pb2+有较强的去除能力,且是一个快速去除的过程。随着Pb2+浓度增大,该微藻对Pb2+ 的去除效果也增大。在弱酸性条件下（pH5.0）,其去除Pb2+的效果较好。如在Pb2+初始浓度为100mg/L,pH5.0,去除时间 为40min,此时Pb2+的去除量为423.2×10-3干重。原子力显微镜（AFM）对细胞表面的形貌进行观察,发现微藻FZUL-321与 Pb2+作用后,细胞形貌和尺寸变化较大,如细胞褶皱并塌陷,细胞表面变得粗糙等。傅里叶红外光谱（FT-IR）结果表明藻 细胞表面的羧基、氨基和磷酸基团等官能团参与前期Pb2+的吸附沉淀。最终,通过一系列生化作用,微藻FZUL-321将离子 态的Pb2+矿化,X射线衍射（XRD）分析显示,矿化产物为Pb5(PO4)3OH。 相似文献
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生态系统科学研究与生态系统管理 总被引：4，自引：2，他引：2
中国科学院地理科学与资源研究所生态系统学科以生态系统生态学研究为核心,通过研制生态系统观测和模拟分析的技术和方法,探索解决区域性/大尺度生态学问题的理论和方法,监测生态系统变化,认知生态系统变化规律,推动生态系统生态学、生物地理生态学、全球变化生态学和生态信息科学技术的发展,创新生态系统管理模式,服务于国家和地方的生态建设、应对全球变化及区域可持续发展。面向国家重大需求,在中国华北平原农业区、南方红壤丘陵林业区、青藏高原农牧区以及黄土高原区等典型区域开展生态系统管理技术与模式的集成与创新研究,着力解决国家生态文明建设和应对全球气候变化中的重大生态学问题,推动区域生态系统管理领域的科技进步。围绕生态系统生态学学科前沿,着重在① 生态系统联网观测、模拟与信息管理,② 生态系统结构、过程与功能,③ 生态系统空间格局与机制,④ 生态系统对全球变化的响应与适应,⑤ 生态系统管理与生态系统服务等五大主要研究方向,系统开展生态系统生态学前沿理论和实践的创新研究,研究成果处于国内和国际生态学研究的科学前沿。 相似文献
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ZHANG Mengshao PANG Yanchun YANG Ben HE Yangjian LIANG Siyu HU Qiang LIN Li 《《地质学报》英文版》2023,97(6):1587-1603
A study of the morphological and microstructural characteristics of helcionelloids from the Nanjiang area (north Sichuan, China) at the northern Yangtze Platform was undertaken, in order to understand their phylogenetic position. Helcionelloids fossils from the Kuanchuanpu Formation of the Changtanhe–Maolinzi section include 7 genera and 11 species. There are distinct differences in the degree of shell bending, the apical morphology and apex position, the outline of the aperture and the height of the shell, all of which constitute important identification features. Although helcionelloid apices exhibit varying degrees of rotation towards the aperture, they do not show any signs of evident distortion. A pair of basally-symmetrical muscle scars are discovered on the shells of helcionelloids (such as Bemella simplex), showing a distinct difference when compared with those of the stem-group gastropod (e.g., Pelagiella). The prismatic shell layer of helcionelloids has been observed, which are common components in Cambrian molluscs, but differ significantly from the dense layer microstructure found in contemporary molluscs. The microstructures, muscle scars and morphological characteristics demonstrate that helcionelloids represent a stem-group of molluscs. 相似文献
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关于厄尔尼诺成因的新认识 总被引：2，自引：0，他引：2
据前人统计,厄尔尼诺出现于地球自转速度急剧变慢的第二年。造成这种现象的主因,是地球间歇性不对称膨胀,引起自转速度几年一次的准周期性急剧变慢。在该时期南北半球岩石圈产生强烈的离开赤道的体力,使赤道地区发生东西向张性断裂活动。位于阻力较小的软流层之上的太平洋岩石圈,不仅规模大、动力强,而且存在着东太平洋海隆薄弱带,并与秘鲁海沟应变空间毗邻,故现今太平洋东部赤道地区的东西向张性断裂最为发育,形成规模宏大的卡内基断裂带和加拉帕戈斯断裂带。它们活动促使海底的岩浆和热水喷溢,导致厄尔尼诺的海水升温多从秘鲁－厄尔多尔沿岸开始。地球自转速度变慢过程中,赤道地区的大气和海水获得较多的向东角动量,造成该地区的信风和向西流动洋流减弱、东太平洋冷水上翻涌升流衰缓,加速赤道东太平流海域温度变暖,助长厄尔尼诺的形成。全球大气角动量的季节性变化,也引起地球自转速度冬季慢夏季快的周年项变化,使厄尔尼诺年增温盛期一般出现于年末前后。 相似文献
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FANG Xiaoqian SU Dan WU Qing WANG Jiayi ZHANG Yangjian LI Guoyu CAO Yu 《地理学报(英文版)》2023,33(4):760-778
Relatively coordinated development among cities can typically promote the integration of the whole urban agglomeration, while urbanization of land has been found important to economic development in developing countries. Numerous studies have measured the urban land expansion in urban agglomerations. However, urban land spatial inequality under a specific spatial structure remains poorly understood. Here, we combined the β-convergence model and the core-periphery structure to explore the dynamic... 相似文献
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Biologists have considered both winter coldness and temperature seasonality as major determinants of the northern limits of plants and animals in the Northern Hemisphere,which in turn drive the well-known latitudinal diversity gradient.However,few studies have tested which of the two climate variables is the primary determinant.In this study,we assess whether winter coldness or temperature seasonality is more strongly associated with the northern latitudinal limits of tree species and with tree species richness in North Amedca.Tree species were recorded in each of 1198 quadrats of 110 km × 110 km in North America.We used correlation and regression analyses to assess the relationship of the latitude of the northern boundary of each species,and of species richness per quadrat,with winter coldness and temperature seasonality.Species richness was analyzed within 38 longitudinal,i.e.,north-south,bands (each being ＞1100 km long and 110 km wide).The latitudes of the north-ern range limits of tree species were three times better correlated with minimum temperatures at those latitudes than with temperature seasonality.On average,minimum temperature and temperature seasonality together explained 81.5％ of the variation in the northern range limits of the tree species examined,and minimum temperature uniquely explained six-fold (33.7％versus 5.8％) more of this variation than did temperature seasonality.Correlations of tree species richness with minimum temperatures were stronger than correlations with tempera-ture seasonality for most of the longitudinal bands analyzed.Compared to temperature sea-sonality,winter coldness is more strongly associated with species distributions at high lati-tudes,and is likely a more important driver of the latitudinal diversity gradient. 相似文献
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ZHANG Yu ZHANG Yangjian CHENG Liang CONG Nan ZHENG Zhoutao HUANG Ke ZHANG Jianshuang ZHU Yixuan GAO Jie SUN Yihan 《地理学报(英文版)》2023,33(1):99-120
Recently, whether drylands of Northwest China (NW) have become wetting has been attracting surging attentions. By comparing the Standard Precipitation Evapotranspiration Indices (SPEI) derived from two different potential evapotranspiration estimates, i.e., the Thornthwaite algorithm (SPEI_th) and the Penman-Monteith equation (SPEI_pm), we try to resolve the controversy. The analysis indicated that air temperature has been warming significantly at a rate of 0.4°C decade?1 in the last five decades and the more arid areas are more prone to becoming warmer. Annual precipitation of the entire study area increased insignificantly by 3.6 mm decade?1 from 1970 to 2019 but NW presented significantly increasing trends. Further, the SPEI_th and SPEI_pm demonstrated similar wetting-drying-wetting trends (three phases) in China’s drylands during 1970-2019. The common periodical signals in the middle phase were identified both by SPEI_th and SPEI_pm wavelet analysis. Analysis with different temporal intervals can lead to divergent or even opposite results. The attribution analysis revealed that precipitation is the main climatic factor driving the drought trend transition. This study hints that the wetting trend’s direction and magnitude hinge on the targeted temporal periods and regions. 相似文献
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YU Guirui CHEN Zhi ZHANG Leiming PENG Changhui CHEN Jingming PIAO Shilong ZHANG Yangjian NIU Shuli WANG Qiufeng LUO Yiqi CIAIS Philippe BALDOCCHI D. Dennis 《资源与生态学报(英文版)》2017,8(2):115-120
As the Earth entering into the Anthropocene, global sustainable development requires ecological research to evolve into the large-scale, quantitative, and predictive era. It necessitates a revolution of ecological observation technology and a long-term accumulation of scientific data. The ecosystem flux tower observation technology is the right one to meet this requirement. However, the unique advantages and potential values of global-scale flux tower observation are still not fully appreciated. Reviewing the development history of global meteorological observation and its scientific contributions to the society, we can get an important enlightenment to re-cognize the scientific mission of flux observation. 相似文献
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略论地台区的海进、海退与相邻地槽区的造盆、造山运动伴生的原因 总被引：1，自引：0，他引：1
地台区的海进、海退 ,分别与相邻地槽区的造盆和造山运动伴生这一普遍现象 ,主要是在重力均衡作用下 ,上地幔流变层 (软流层 ,异常地幔 )物质侧向迁移所致。地槽区造盆运动 ,造成该区地壳减薄 ,从而在重力均衡作用下 ,相邻地台区的上地幔流变层物质便向该区顺层流入 ,促使其上地幔隆起。地台区上地幔流变层物质大量他流 ,势必引起地壳沉降 ,产生海进。华北地台中石炭世早二叠世早期整体沉降 ,形成了中国重要的石炭二叠纪聚煤区 ,便与其南北两侧秦岭和中亚蒙古地槽区在该时期的造盆运动有关。地槽区的造山运动 ,造成该区地壳加厚 ,从而在重力均衡作用下 ,该区隆起的上地幔流变层物质 ,又流回相邻地台区 ,促使地台区地壳抬升 ,产生海退。华北地台区晚奥陶世早石炭世的抬升剥蚀和从早二叠世晚期起转入陆相沉积发展阶段 ,便分别与南北两侧的秦岭和中亚蒙古地槽区于加里东早期和华力西晚期的造山运动相联系。 相似文献