紫色土母质的分布及其地质环境——紫色土再研究     

青长乐  牟树森  朱波  王定勇  魏朝富  谢德体  段文霞  王文富 《山地学报》2009,27(6)

紫色土的分布决定于其母质--紫色岩石的分布.紫色岩石是红层的主要部分.红层的形成有一定的水热条件限制,当今地表红层的分布状况却与当地的现实水热条件不完全相符.因此,只有从地质历史演进的角度看待今日红层岩石的分布规律.通过讨论红层分布的历史原因,认为紫色岩石的分布是全球性的,紫色土亦然.  相似文献   

四川紫色土地区鹤鸣观小流域分布式侵蚀产沙模型   总被引：4，自引：0，他引：4  

袁再健  蔡强国  褚英敏  冯明汉  李双喜 《地理研究》2006,25(6):967-976

从四川省南部县鹤鸣观小流域Ⅱ号支沟为研究区,构建了适合紫色土地区小流域分布式侵蚀产沙模型。该模型以20m×20m栅格为空间步长,以10min为时间步长,定量分析鹤鸣观小流域Ⅱ号支沟水土流失程度,模拟了各时段每个栅格次降雨侵蚀产沙过程,计算了每个栅格次降雨径流量、侵蚀量与沉积量,并且运用递归算法计算出整个流域次降雨侵蚀产沙量,模型能够评价流域下垫面各因子空间分布不均匀性和人类活动的影响。在鹤鸣观小流域Ⅱ号支沟进行了模型的检验,模拟过程与实测结果符合较好。  相似文献   

豫西二叠系煤成气的运移和紫斑岩的形成     

陈传诗 《煤田地质与勘探》1995,23(5):6-10

成煤作用可生成大量气体和液体。这些气体和液体在岩层中运移时,可使岩石中的高价氧化物还原成低价氧化物,生成次生矿物如菱铁矿鲕粒或结核,同时使岩石的颜色改变,由红色变为灰色,或者变为紫斑岩。由于上述改变属于煤成气运移过程留下的遗迹,可以用来追索煤成气的运移,寻找浅层煤成气藏。   相似文献   

Responses of marine-derived Trichoderma fungi to seawater and their potential antagonistic behaviour     

SONG Yinping  MIAO Fengping  LIU Xianghong  JI Naiyun 《海洋湖沼学报（英文）》2019,(2):525-534

To explore the metabolic responses of marine-derived Trichoderma fungi to environmental stresses, the survivability, metabolism, and antagonism of ten marine isolates have been examined. Their survival in both freshwater and seawater indicates them to be facultative marine fungi, but they are more adaptable to marine environment. Most of them feature strain-specific and positive metabolic responses to seawater, which also usually result in the higher proportions of heteroatom-bearing and unsaturated units in mycelial constituents. Seawater factors can promote many strains to produce bioactive metabolites, including plant pathogen- and marine phytoplankton-inhibitory and marine animal-toxic ones, but the eff ects of NaCl are often weak or negative. The inhibition of marine phytoplankton corresponds to the intracellular accumulation of heteroatom-bearing and unsaturated units under seawater condition, and the varied toxicities to marine animals further signify the divergences of lipophilic exudates under diff erent conditions. The results may contribute to further understanding and mining the structural diversity and biological activity of secondary metabolites from marine-derived Trichoderma fungi.  相似文献   

A new probabilistic approach to estimating marine gastropod densities from baited traps          下载免费PDF全文

Jennifer Coston‐Guarini  Jean‐Marc Guarini  Frederike Ricarda Boehm  Thomas R. H. Kerkhove  Frances C. Rivera  Karim Erzini  François Charles  Tim Deprez  Laurent Chauvaud 《Marine Ecology》2018,39(3)

A new probabilistic approach is proposed to assess muricid species population abundances at scales relevant to both Ancient and Modern coastal fisheries. Motivated by the long‐term goal of reconstructing the dynamics of exploited murex populations during Antiquity, the objective was to estimate the population density of the banded dye‐murex, Hexaplex trunculus (Linnaeus, 1758) from successive captures with baited traps, using a method similar to the technique employed in the Mediterranean purple dye industry. The stochastic model developed simulates cumulative captures while accounting for high variability. It was calibrated with data acquired during a field trapping experiment (Crete Island, Greece). Traps’ catchability and Effective Area of Attraction (EAA) were estimated using the individual speed and behavioural response towards bait from laboratory experiments. Average density of H. trunculus was estimated as 2.2 ± 1.4 SE individuals per square metre, with no significant differences between seagrass and rocky habitats. The clearing time of successive capture experiments averaged 84 ± 6 SE hr. Clearing ca. 0.4 ha of subtidal area would be necessary to produce ca. 1.0 g of pure Tyrian purple pigment. The method described is generalizable to making population abundance estimates for similar groups, such as whelks, in modern fisheries.  相似文献   

Comparative study on rain splash erosion of representative soils in China   总被引：5，自引：0，他引：5  

Qinjuan Cheng  Qiangguo Cai  Wenjun Ma 《中国地理科学(英文版)》2008,18(2):155-161

As the first event of soil erosion, rain splash erosion supplies materials for subsequent transportation and entrainment. The Loess Plateau, the southern hilly region and the Northeast China are subject to serious soil and water loss; however, the characteristics of rain splash erosion in those regions are still unclear. The objectives of the study are to analyze the characteristics of splash erosion on loess soil, red soil, purple soil and black soil, and to discuss the relationship between splash erosion and soil properties. Soil samples spatially distributed in the abovementioned regions were collected and underwent simulated rainfalls at a high intensity of 1.2mm/min, lasting for 5, 10, 15, and 20min, respectively. Rain splash and soil crust development were analyzed. It shows that black soil sample from Heilongjiang Province corresponds to the minimum splash erosion amount because it has high aggregate content, aggregate stability and organic matter content. Loess soil sample from Inner Mongolia corresponds to the maximum splash erosion amount because it has high content of sand particles. Loess soil sample from Shanxi Province has relatively lower splash erosion amount because it has high silt particle content and low aggregate stability easily to be disrupted under rainfalls with high intensity. Although aggregate contents of red soil and purple soil samples from Hubei and Guangdong provinces are high, the stability is weak and prone to be disrupted, so the splash erosion amount is medium. Splash rate which fluctuates over time is observed because soil crust development follows a cycling processes of formation and disruption. In addition, there are two locations of soil crust development, one appears at the surface, and the other occurs at the subsurface.  相似文献   

坡地过程及退化坡地恢复整治研究——以三峡库区紫色土坡地为例   总被引：12，自引：0，他引：12  

郑度  申元村 《地理学报》1998,(2)

本文以长江三峡库区紫色土坡地的定点试验研究成果为依据,阐明了该类坡地退化的关键因子中的坡度,以及土壤粒径、有机质及Ｎ、Ｐ、Ｋ流失的规律。研究表明,坡面片蚀最大侵蚀量的坡度为２４°～２９°;侵蚀的主要粒径为粉砂和粘粒,土壤有机质及速效Ｎ、Ｐ、Ｋ主要是随粉砂和粘粒流失而流失。在对工程的（石坎梯田）、农业的（等高耕作）和生物的（植物篱技术）措施对比后,认为采用植物篱技术是退化坡地恢复整治可供选择的良好途径。  相似文献   

Linking soil thickness and plot‐scale hydrological processes on the sloping lands in the Three Gorges Area of China: a hydropedological approach     

Zhiyong Fu  Zhaoxia Li  Chongfa Cai  Ying Zhao  Zhihua Shi  Qinxue Xu  Xiaoyan Wang 《水文研究》2012,26(15):2248-2263

  相似文献   

紫色土坡地壤中流特征   总被引：10，自引：0，他引：10       下载免费PDF全文

徐勤学  王天巍  李朝霞  蔡崇法  史志华 《水科学进展》2010,21(2):229-234

壤中流是紫色土坡地径流的重要组成部分。通过野外人工模拟降雨试验,研究了不同降雨条件下紫色土坡地壤中流特征和地表状况变化对壤中流的影响,结果表明:①未扰动荒坡地壤中流径流系数是裸露坡耕地的3～15倍,平均流量是坡耕地的7～33倍,荒坡地和坡耕地壤中流特征差异在大雨强条件下表现更为明显;②坡耕地壤中流径流系数随降雨强度的增加而显著减少,但荒坡地壤中流受雨强的影响不明显;③荒坡地壤中流随地表状况变化而改变,植被覆盖的减少和降雨对疏松地表的压实导致壤中流明显减少。  相似文献   

海洋真菌Neosartorya fischeri 1008F₁的次级代谢产物抑菌及抗肿瘤活性的研究     

沈硕 《海洋科学》2014,38(11):35-40

通过抑菌及抗肿瘤活性实验,明确海洋真菌Neosartorya fischeri 1008F1次级代谢产物中的活性有效组分。应用对峙培养法和生长速率法,对菌株的抑菌活性进行测定。应用MTT法,对菌株的抗肿瘤活性进行测定。应用凝胶(Sephadex LH-20)柱层析的方法,对菌株发酵产物的提取物进行分离。结果发现,海洋真菌Neosartorya fischeri 1008F1的水溶性提取物对番茄早疫菌(Alternaria solani)具有一定的抑制活性。菌株的粗提物浸膏经Sephadex LH-20柱梯度洗脱后,得到的组分B、C、D、E和F。在0.5 g/L的供试浓度下,组分B、C和D对胃癌细胞SGC-7901的抑制率均高于80%,而组分B、C、D、E和F对肝癌细胞BEL-7404的抑制率均高于70%。  相似文献