Who is the “murderer” of the bloom in coastal waters of Fujian,China, in 2019?

Journal of Oceanology and Limnology - On May 24–29, 2019, a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish (Plectorhinchus cinctus and...     

澜沧江-湄公河重金属污染评价及大坝影响(英文)

The resource development and changes of hydrological regime,sediment and water quality in the Mekong River basin have attracted great attentions.This research aimed to enhance the study on transboundary pollution of heavy metals in this international river.In this study,eight sampling sites were selected to collect the bed sand samples along the mainstream of the Mekong River.In addition,the contents of 5 heavy metal elements and their spatial variability along the mainstream of the river were analyzed.The geoaccumulation index(I geo) and potential ecological risk analysis were employed to assess heavy metal pollution status in the mainstream of the Mekong River.The results show that the average content of the heavy metal elements Zn is 91.43 mg/kg,Pb is 41.85 mg/kg,and As is 21.84 mg/kg in the bed sands of the Upper Mekong River,which are higher than those(Zn 68.17 mg/kg,Pb 28.22 mg/kg,As 14.97 mg/kg) in the Lower Mekong.The average content of Cr in the Lower Mekong is 418.86 mg/kg,higher than that in the Upper Mekong(42.19 mg/kg).Luang Prabang has a very high Cr concentration with 762.93 mg/kg and Pakse with 422.90 mg/kg.The concentration of Cu in all of the 8 sampling sites is similar,except for in Jiajiu with 11.70 mg/kg and Jiebei with 7.00 mg/kg.The results of the geoaccumulation index reveal that contaminations caused by Zn and Pb while Pb and As are more than those by Zn in Upper Mekong.Cr is the primary pollutant in the Lower Mekong,especially at Luang Prabang and Pakse.Slight pollution with As also occurs in Pakse.The potential ecological risk index indicates that the potential ecological risk of heavy metals in the mainstream of the Mekong River is low.We argue that the pollution of water quality and contamination of heavy metals in bed sediment caused by mining of mineral resources or geochemical background values in the Mekong is not transmitted from the Upper to the Lower Mekong because of the reservoir sedimentation and dilution along the river.     

焊接所致力学性能不均匀性对卷管法安装管道完整性影响

管道由于热加工影响,其焊缝处及邻域的热影响区管段材料性能将与其余管段存在差异,即管道存在力学性能不均匀性。分别采用各向同性硬化材料模型与Ramberg-Osgood材料模型,应用ABAQUS仿真模拟卷管过程,并对仿真结果进行对比,表明使用Ramberg-Osgood材料模型能够更真实地模拟管道的力学行为,获得更接近真实值的管道力学响应。基于此模型采用控制度量法研究力学性能不均匀性的影响。研究表明:管道力学性能不均匀性水平越高,对管道结构完整性造成的不良影响也越大。     

三维Voronoi图在三维方向关系计算中的应用

提出一种基于三维Voronoi图的三维方向关系计算方法。在分析二维方向关系的基础上,提出一种三维空间中的\     

环北极沉积盆地结构与构造演化特征——来自环北极地质长剖面的证据

通过对北极地区不同盆地结构的系统研究与对比分析,绘制了环北极沉积盆地群长剖面,剖面全长约13 000 km,涉及季曼-伯朝拉盆地等15个盆地和微陆。由于整个剖面尺度巨大,在若干缺乏详细资料的地区采用将邻近地区的其他剖面平移到本剖面中,或由其两侧的剖面地层和构造形式推测。剖面涉及的盆地多属叠合性质,涵盖克拉通盆地、裂谷盆地、前陆盆地、被动大陆边缘盆地等多种盆地类型;各区域沉积厚度差异显著,最厚的东巴伦支海等盆地沉积了自古生界至新生界的地层,沉积厚度可达近15 km ,而沉积最薄处的拉普捷夫海等盆地则只发育了从中生界上白垩统至新生界的沉积,厚度不超过4 km。以北大西洋—北冰洋洋中脊为界,北极地区分属欧亚板块和北美板块,很多盆地为大陆的一部分或大陆向北冰洋的延伸部分（大陆架）。各盆地的发育主要受波罗的板块、西伯利亚板块与劳伦古陆显生宙以来的构造演化控制;加里东运动、埃尔斯米尔运动、海西运动（乌拉尔运动）及大西洋洋脊自南向北的扩张对环北极盆地均有显著影响,具体表现为造成盆地类型的改变、改变盆地沉降速率等。     

青藏高原东部高寒草甸区放牧家畜粪花粉组合特征及其环境指示意义

青藏高原是我国重要的高寒草甸分布区和畜牧区,畜牧活动对区域植被和生态的影响作用受到众多学者的广泛关注.通过采集青藏高原东部高寒草甸区共49个放牧家畜粪样品(牦牛粪样品30个、马粪样品11个、羊粪样品8个),并在区域植被调查的基础上,对粪样品开展了花粉分析.结果 表明:这3种类型的粪样品花粉组合以莎草科(Cyperace...     

A Preliminary Discussion on the Mechanism of Abnormal Intensity Zones of the M5.1 Wen＇an Earthquake in 2006

An earthquake measuring 5.1 on the Richter scale struck Wen'an county,Hebei Province on July 4,2006. No casualties have been reported,with only slight damage. The disaster level of this event is the slightest on the M4.9～5.1 events record tally since the CCDSN (China Center of Digital Seismic Network) was built in 1999. The epicenter intensity of this earthquake was low,while in areas like Beijing,which is 100km far away,abnormal high intensity zones appeared. This article discusses the reasons behind this abnormal phenomenon,with the diagrams of intensity isolines drawn by the intense seismic stations and networks in the capital circle area as references,as well as the seismogenic mechanism in the source,the seismic histories,the geological structures and the ray pathways of seismic waves in areas within 150km around the epicenter. It was concluded that the special dynamic and geological situations were the main causes for the lower intensity degree and slight damage in the epicenter area,but higher intensity in the surrounding areas.     

松嫩平原全新世黑土14C年龄-深度关系空间格局

准确评估土壤有机碳储量及其变化的一个关键,是明确全新世土壤形成年龄-深度关系的空间格局。本文利用松嫩平原12个典型黑土剖面的56个AMS 14C年龄数据,尝试重建全新世黑土14C年龄与形成深度的空间分布模式。结果显示：1）研究区黑土大范围形成时间不晚于8.5 cal.ka B.P.;2）研究区黑土形成年龄的分布由深度40 cm以下阶段性均匀分布转为40 cm以上南北向"三明治"模式（南北老,中部新）;3）研究区黑土形成深度分布在4 cal.ka B.P.之前和降水梯度变化密切相关,4~3 cal.ka B.P.在研究区东南部显著变浅,3~0 cal.ka B.P.几乎阶段性呈均匀分布,而在1~0 cal.ka B.P.研究区近中心区域反而出现低谷。结合区域气候变化、地貌演化和人类活动历史,推测松嫩平原黑土大范围形成与东亚夏季风边缘区全新世早期-适宜期植被大范围生长扩张有关,研究区黑土形成年龄的分布在40 cm以上可能主要受毗邻沙丘活动影响,在40 cm以下可能主要受全新世适宜期稳定气候影响,黑土形成深度的分布可能主要由4 cal.ka B.P.之前的降水控制转变为之后的自然风力侵蚀和人类活动影响。     

Karlodinium elegans sp. nov. (Gymnodiniales,Dinophyceae), a novel species isolated from the East China Sea in a dinofl agellate bloom

Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were set up from seawater samples taken during the bloom.The cultures were examined for morphological features,ultrastructure characters,photosynthetic pigments,the large subunit(LSU)of the rRNA gene,and the internal transcribed spacer(ITS)sequences,as well as acute toxicity analysis.The cell was unarmored,small-sized,and ovoid,and was characterized by elaborate striations on the epicone and hypocone.The nucleus was large,ellipsoid to oval or kidney-shaped,and centrally located in the cell.A long linear apical groove originated above the sulcus in the ventral epicone and extended to the dorsal side.An elongate,slit-like“ventral pore”was located on the left of the epicone,well away from the apical groove.The chloroplasts were yellowish brown,numerous,band like,and irregularly distributed in the cell periphery.Fucoxanthin was the main accessory pigment composition.Phylogeny topology reconstructed on partial LSU rDNA showed that the unknown dinofl agellate branched as a sister species to Karlodinium sp.(strain IFR981&IFR797,from France)and Karlodinium corrugatum(strain KDGSO08,from Australia),with genetic divergences of 0.6%and 3.3%,respectively.Based on the morphological and molecular phylogenetic analysis,we describe the novel dinofl agellate as Karlodinium elegans sp.nov.A toxicity assay revealed that the clonal culture of K.elegans(strain PTB601)had no adverse eff ect on brine shrimp(Artemia salina)and marine medaka(Oryzias melastigma),indicating it may not be a toxic species.     

中国可持续减贫的发展地理学研究

中国2020年减贫转向后相对贫困将贯穿于现代化全过程,减贫的可持续性面临着巨大挑战。论文在梳理中国贫困地理研究的基础上,从发展地理学视角阐述了可持续减贫的内涵、尺度分析模式、对象划分、评价监测,以及路径设计和发展干预。主要结论为：① 可持续减贫是在建立家庭和地方发展潜力与动力基础上的持续减少贫困,并缩小发展差距的思想和实践范式;② 可持续减贫结合自下而上和自上而下尺度分析模式,研究减贫的尺度转换过程,反映减贫要素和决策实施在空间的尺度解构和重构;③ 可持续减贫对象分为绝对贫困家庭、相对贫困家庭、相对贫困村、相对贫困乡(镇)和相对贫困县,并提出了绝对贫困线和相对贫困线标准;④ 运用“五维地理资本指数”和欧氏空间距离,分析县域可持续减贫成效与区域收敛性;⑤ 可持续减贫通过地方化、区域化和全球化空间整合,推动区域贫困治理由传统模式向高质量发展转型;⑥ 可持续减贫突出以地方为主的“内源—外源”融合的发展干预。