胶州湾浮游纤毛虫丰度和生物量的周年变化   总被引：3，自引：1，他引：2  

于莹  张武昌  赵楠  孙晓霞  张翠霞  丰美萍  肖天 《海洋与湖沼》2011,42(5):690-701

于2007年1—12月在胶州湾搭载＂创新号＂考察船完成了12个航次的浮游纤毛虫丰度和生物量调查。结果表明,胶州湾纤毛虫丰度的范围为41—31077ind/L,生物量范围为0.06—99.37μgC/L。表层纤毛虫平均丰度于6月达到全年最高值（6065ind/L）,12月为最低值（843ind/L）;平均生物量8月达全年...  相似文献   

辽宁省岩石地球化学研究新进展     

张耀华  高新国  宋昌锦  李星云 《国土资源》1990,(3)

辽宁地球化学场研究,是根据辽宁全域41种元素丰度及各种地球化学参数,论述了辽宁不同地质时代和构造分区表壳岩石元素分配特点,指出了辽宁重要成矿元素的高值时代;建立了辽宁早前寒武纪变质岩、超变质岩,全域沉积岩,火成岩不同岩类的主元素地球化学模型和元素富集型式;并对Au、Pb、Zn、B等主要成矿元素的分布、分配以及与有关元素的相关特征进行了讨论;指出了成矿元素的主要载体岩石和高值地质单元。根据大地构造分区、元素组合,将辽宁全域划分为4个地球化学省,11个地球化学区,35个地球化学分区。  相似文献   

Assessment of marine debris on the Belgian Continental Shelf   总被引：2，自引：0，他引：2  

Lisbeth Van Cauwenberghe  Michiel Claessens  Michiel B. Vandegehuchte  Jan Mees  Colin R. Janssen 《Marine pollution bulletin》2013

A comprehensive assessment of marine litter in three environmental compartments of Belgian coastal waters was performed. Abundance, weight and composition of marine debris, including microplastics, was assessed by performing beach, sea surface and seafloor monitoring campaigns during two consecutive years. Plastic items were the dominant type of macrodebris recorded: over 95% of debris present in the three sampled marine compartments were plastic. In general, concentrations of macrodebris were quite high. Especially the number of beached debris reached very high levels: on average 6429 ± 6767 items per 100 m were recorded. Microplastic concentrations were determined to assess overall abundance in the different marine compartments of the Belgian Continental Shelf. In terms of weight, macrodebris still dominates the pollution of beaches, but in the water column and in the seafloor microplastics appear to be of higher importance: here, microplastic weight is approximately 100 times and 400 times higher, respectively, than macrodebris weight.  相似文献   

保山地区下仁和桥组页岩气成藏条件分析     

陈志柱  张宗羲  杨楠  白鹏 《云南地质》2014,(2):180-184

通过野外调查及室内测试,对云南省保山地区早志留世浅海较深水环境沉积的下志留统下仁和桥组黑色笔石页岩进行了分析研究.初步认为下仁和桥组黑色页岩沉积厚度大且稳定,有机质丰度高、岩石成熟度高、有机质类型好、演化程度高、裂缝发育,具备页岩气藏的形成条件.  相似文献   

Enhancing the relative Fe-to-proton abundance in ultra-high-energy cosmic rays     

Carl BlaksleyEtienne Parizot 《Astroparticle Physics》2012,35(6):342-345

We study a generic class of models for ultra-high energy cosmic ray (UHECR) phenomenology, in which the sources accelerate protons and nuclei with a power-law spectrum having the same index, but with different values for the maximum proton energies, distributed according to a power-law. We show that, for energies sufficiently lower than the maximum proton energy, such models are equivalent to single-type source models, with a larger effective power law index and a heavier composition at the source. We calculate the resulting enhancement of the abundance of nuclei, and find typical values of a factor 2-10 for Fe nuclei. At the highest energies, the heavy nuclei enhancement ratios become larger, and the granularity of the sources must also be taken into account. We conclude that the effect of a distribution of maximum energies among sources must be considered in order to understand both the energy spectrum and the composition of UHECRs, as measured on Earth.  相似文献   

Toxicity of Arsenic to Photobacterium phosphoreum,Daphnia magna,and Danio rerio at Different pH Levels          下载免费PDF全文

Qun He  Ruijuan Qu  Xinghao Wang  Zhongbo Wei  Ping Sun  Zunyao Wang 《洁净——土壤、空气、水》2016,44(1):72-77

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黄海水母旺发区浮游鞭毛虫和纤毛虫群落结构分布及其与水母发生关系初探   总被引：2，自引：2，他引：0  

丁军军  徐奎栋 《海洋与湖沼》2012,43(3):527-538

鞭毛虫和纤毛虫在海洋微食物环和经典食物链间的能量流动中起着重要的枢纽作用,但其在水母暴发过程中的作用仍然不明。本研究基于2011年春季以及水母旺发的夏季黄海专项航次,通过荧光染色技术和定量蛋白银法研究了南黄海水母频发海域3个断面(E:33°N,G:34°N,I:35°N)的鞭毛虫和纤毛虫的群落结构和时空分布特点,对其与水母的发生关系进行了初步探讨。结果表明,春夏两季的微型鞭毛虫丰度均以近岸水域为最高,向外海递减,高值区大多出现在水体表层及底层附近。夏季总微型鞭毛虫的丰度和生物量较春季略高,且异养微型鞭毛虫比例升高。纤毛虫丰度的水平分布与鞭毛虫正相反,以近岸较低,向外海递增,主要分布在表层及10m水层。在水母出现的E和G断面,夏季纤毛虫数量显著降低,丰度仅为春季的30%—40%;而未见水母的I断面夏季较春季的数量升高了一个数量级。推测夏季水母发生的E、G断面纤毛虫丰度明显降低系因水母的捕食压力所致,纤毛虫数量的减少导致对鞭毛虫的摄食压力降低,鞭毛虫数量增加;而未见水母的I断面纤毛虫则维持较高的丰度值。本研究表明,水母作为浮游生态系统的顶级捕食者,可通过营养级联效应对微小型浮游动物群落产生影响。  相似文献   

Temporal and spatial patterns of tenebrionid beetle diversity in NW Patagonia, Argentina   总被引：1，自引：0，他引：1  

P. Sackmann  G.E. Flores   《Journal of Arid Environments》2009,73(12):1095-1102

Spatial and temporal variation in abundance, richness and composition of Tenebrionidae beetle assemblages were described for north-western Patagonia. Beetles were collected using 450 pitfall traps arranged in 50 plots across an area of about 22,500 km² representative of the Subantarctic-Patagonian transition of Argentina. The study area included three different habitats: forest, scrub, and steppe. Beetles were trapped at five, eight day sampling periods in spring-summer between November 2004 and March 2006. A total of 30 species and 938 individuals were collected. Total abundance was higher in November and January than in March, and species richness did not change among samplings. Species richness was greater in the steppe than scrub. Assemblages differed between the northern and southern transects. There was little correlation between the measured environmental variables and species composition. Historical factors might explain the observed patterns, but other environmental variables such as soil characteristics may be more informative in explaining the present distribution of tenebrionid species.  相似文献   

乌蒙山区毕节市耕地土壤养分丰缺评价及其变化趋势          下载免费PDF全文

骆珊  张德明  彭成龙  安亚运  龚桂源 《贵州地质》2020,37(3):258-258

碱浸脱硅处理高硅铝土矿时,会产生大量的含硅碱液,要实现其循环利用,需对含硅碱液进行脱硅。本文分别以初始硅渣、焙烧硅渣、硅渣与石灰混合为脱硅剂,对比考查含硅碱液的脱硅效果,并分析脱硅机理。结果表明,当添加25g/L的初始硅渣时,脱硅率仅为47.96%;将硅渣在600℃焙烧后,脱硅率提升至66.67%。焙烧后的硅渣明显提升了脱硅活性,当混合添加25g/L焙烧硅渣和钙硅比为1的CaO,脱硅率达到93%,主要是硅渣作为异相成核的晶核 ,在脱硅过程中的晶体生长以及CaO的协同脱硅作用,混合添加焙烧渣和CaO的高脱硅能力为氧化铝工业生产提供了再循环脱硅剂,并为含硅碱液的循环利用提供了可能性。  相似文献   

The Acceleration of Charged Particles in Corotating Interaction Regions (Cir) – a Review with Particular Emphasis on the Ulysses Mission     

Erhard Keppler 《Surveys in Geophysics》1998,19(3):211-278

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