近百年来我国西南地区酸沉降背景下湖泊环境变化——来自四面山龙潭湖沉积硅藻证据     

管锡东  蒋宏忱  姜颖  陈旭 《湖泊科学》2021,33(6):1940-1950

大气酸沉降会导致地表水体酸化和富营养化,同时气候变暖也会影响湖泊水体环境,湖泊生态系统如何响应二者相互作用是全球变化研究的热点之一.我国西南地区是全球酸沉降负荷最高的地区之一,然而目前对酸沉降影响下地表水环境变化规律知之甚少.本文以重庆四面山龙潭湖为研究对象,通过沉积岩芯的²¹⁰Pb测年和硅藻分析,并结合流域历史资料数据,揭示龙潭湖过去近百年来水环境变化及其主要驱动因子.结果表明,1926-1968年,龙潭湖以Achnanthidium minutissimum和Encyonema silesiacum占优势;随后,Lindavia bodanica快速增加至峰值后逐渐减少,伴随Aulacoseira alpigena和Aulacoseira ambigua含量上升.硅藻组合中以适应中性和弱碱性水体的属种为主,嗜酸性属种含量很少,表明目前水体总体维持弱碱性,这得益于当地紫色砂页岩和森林土壤对于酸沉降的缓冲作用.尽管目前龙潭湖仍维持弱碱性,1980s以来硅藻推导水体酸碱度下降、中富营养种增加,表明酸沉降降低水体碱度并提高营养水平.气候变暖加剧水体热力分层和营养富集,导致适应扰动、贫营养环境的L.bodanica减少.2010年以来,中富营养属种略有减少反映湖泊富营养化有所减缓.  相似文献   

江苏省酸雨时空分布特征及酸雨潜势预报因子   总被引：8，自引：0，他引：8  

刘梅  濮梅娟  尹东屏  张备 《气象科技》2008,36(4):462-467

通过对江苏4个酸雨监测点近13年观测数据统计分析发现:江苏酸雨发生的年平均天数、酸雨出现次数、年平均酸雨量等都具有自北向南逐渐增加的趋势,酸雨发生次数和酸雨量具有明显的年际分布特征和月变化规律,发生天数和酸雨量的月变化均呈现抛物线形分布.根据发生酸雨时前期污染物浓度和气象因子平行分析,探讨了南京地区酸雨发生时污染物浓度和气象因子的变化规律,总结出了产生酸雨的有利条件:前一天污染物浓度为NO2≥0.04 mg/m3,PMlO N02≥0.085 mg/m3,S02 N02≥0.08 mg/m3,850 hPa主导风向以西南风为主,次之是东南风,风速小于等于12 m/s.900 hPa以下出现逆温层.在此基础上提出了南京地区酸雨潜势预报方法并进行了预报结果验证.  相似文献   

Effect of Long-term Experimental Warming on the Nutritional Quality of Alpine Meadows in the Northern Tibet     

SUN Wei  LI Shaowei  ZHANG Yangjian  FU Gang 《资源与生态学报(英文版)》2020,11(5):516-524

The nutritional quality of grasslands is closely related to recruitment of young and population dynamics of livestock and wild herbivores. However, the response of nutritional quality to climate warming has not been fully understood in the alpine meadow on the Tibetan Plateau, especially in the Northern Tibet. Here, we investigated the effect of experimental warming ( beginning in 2008) on nutritional quality in three alpine meadows (site A: 4313 m, B: 4513 m and C: 4693 m) in the Northern Tibet. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude ash (Ash), ether extract (EE) and water-soluble carbohydrate (WSC) were examined in 2018-2019. Experimental warming only increased the content of CP by 27.25%, ADF by 89.93% and NDF by 41.20%, but it decreased the content of Ash by 57.76% in 2019 at site B. The contents of CP and WSC both increased with soil moisture (SM). The content of CP decreased with vapor pressure deficit (VPD). The combined effect of SM and VPD was greater than air temperature (T_a) in controlling the variations of the CP content, ADF content and nutritional quality. Compared to T_a, VPD explained more of the variation in NDF and Ash content. All of these findings suggest that warming effects on nutritional quality may vary with site and year, and water availability may have a stronger effect on the nutritional quality than temperature in the alpine meadow of the Northern Tibet.  相似文献   

舒心片的质量标准研究          下载免费PDF全文

刘明智  梁宏  郝旭 《应用海洋学学报》2020,36(12):157

目的：建立中药舒心片中丹酚酸B含量的测定方法。方法：采用高效液相色谱法（HPLC）测定舒心片中丹酚酸B的含量,色谱柱为Agilent TC-C₁₈（2）色谱柱（4.6 mm×250 mm,5 μm）,以乙腈-0.1%的磷酸溶液（25∶75）为流动相;检测波长为286 nm;柱温为25℃;流速为1.0 ml/min。结果：供试品和对照品溶液中丹酚酸B与他峰分离度良好;在0.050～1.642 μg之间丹酚酸B呈良好线性关系,R=0.9993,丹酚酸B平均加样回收率为97.58%,RSD=0.25%。结论：经方法学验证,本法可用于舒心片的质量控制。  相似文献   

海洋动物营养生态位研究方法及其应用     

李云凯  陈子昂  贡艺  陈新军 《热带海洋学报》2021,40(4):143-156

食物资源对海洋动物的生存和繁衍至关重要。海洋动物的营养生态位描述了其在海洋生态系统中的生态地位及功能, 对分析种间关系和资源分配模式、了解群落结构与功能具有重要的指示作用。本文在整理近30年来国内外相关研究的基础上, 系统归纳了当前海洋动物营养生态位研究的主要方法(胃含物分析、整体组织稳定同位素分析、脂肪酸组成分析和特定化合物稳定同位素分析)及其应用领域, 着重归纳总结了量化营养生态位宽度和重叠的生态模型, 并分析了各营养生态位评估方法的优势和局限性。同时在此基础上, 对今后研究方向提出了展望, 以期为我国海洋动物摄食生态学相关研究工作提供参考。  相似文献   

高灵敏靶标自环化滚环扩增检测的动态接头构建     

王晨儒  安然  梁兴国 《中国海洋大学学报(自然科学版)》2021,(5)

针对靶标自环化滚环扩增(TC-RCA)难以高灵敏度检测的难题,本文探究了扩增过程中靶标环化效率低的原因,并构建了新型动态接头以提高靶标DNA的环化灵敏度。通过采用含有发卡结构的动态接头(18 nt),使接头的两端产生连接活性差异,探讨发卡接头打开与闭合的动态平衡在提高环化灵敏度中的作用。具体研究了发卡动态接头的稳定性和磷酸化对连接及环化效率的影响。研究表明,增加接头两端的连接活性差异可提高环化灵敏度(106 copies/μL),从而揭示了TC-RCA灵敏度低的根本原因。由于许多过量的接头同时连接到靶标DNA两端后,靶标无法环化,造成仅有少部分靶标环化为RCA模板,导致极低浓度的靶标无法发生RCA。在此基础上,采用另一种10 nt的短链动态接头,使检测灵敏度提高了两个数量级(达104 copies/μL)。本研究为TC-RCA中接头的设计提供了新思路,对双链DNA环化机理的深入研究具有重要意义。  相似文献   

Fecundity of the snapper Chrysophrys auratus (Pisces: Sparidae) from the Hauraki Gulf     

James Crossland 《新西兰海洋与淡水研究杂志》2013,47(4):767-775

Fecundity estimates were made for snapper Chrysophrys auratus, a serial spawning fish, for the 1974–75 and 1975–76 spawning seasons. Weighed sub‐samples of ovaries were used, and eggs were counted manually. All eggs >0.1 mm diameter were considered potentially capable of being spawned; estimates of these eggs were made at the beginning and end of spawning, and their difference was considered to be the actual fecundity. A log‐log transformation of egg numbers against length offish gave a linear relationship. Fecundity estimates ranged from 297 000 at 25 cm to 4 528 000 at 50 cm in 1974–75, and from 83 000 at 25 cm to 6 164 000 at 50 cm in 1975–76. Counts of ripe eggs were also made, and batch sizes ranging from 13 000 at 25 cm to 104 000 at 50 cm were predicted. By combining these data with fecundity estimates the number of batches spawned was estimated to be 23–44 in 1974–75, depending on and increasing with length; and 6–59 in 1975–76.  相似文献   

Key genes expression of reductive tricarboxylic acid cycle from deep-sea hydrothermal chemolithoautotrophic Caminibacter profundus in response to salinity, pH and O₂     

HE Peiqing  LIU Yan  YUE Wenjuan  HUANG Xiaohang 《海洋学报(英文版)》2013,32(2):35-41

CO2 fixation pathway of Caminibacter profundus, a chemolithoautotrophic -Proteobacteria from deep-sea hydrothermal vent, was determined and characterized by genetic and enzymatic analyses. Gene expression of key enzymes for CO2 fixation in response to salinity, pH and O2 in Medium 829 were also investigated. The results demonstrate that C. profundus contained aclB, porA and oorA, the genes encoding key enzymes of reductive tricarboxylic acid (rTCA) cycle. However, genes fragments of cbbL and cbbM encoding key enzyme of Calvin cycle were not recovered. Key enzymatic activities of ATP citrate lyase (ACL), pyruvate: ferredoxin oxidoreductase (POR) and 2-oxoglutarate: ferredoxin oxidoreductase (OOR) were also present in C. profundus. The combination of genetic and enzymatic analyses confirm that C. profundus adopted rTCA cycle for carbon assimilation. The results of aclB and oorA relative expressions of C. profundus demonstrate that the ranges of environmental factors for high genes expression were sea salt 3.0%-5.0% (optimum 3.0%), pH 5.0-6.5(optimum pH 6.5), anaerobic to microaerobic conditions (optimum 1.0% O2 ). Gene expression patterns under different conditions show similar patterns with bacterial growth, revealing that key rTCA cycle genes provided molecular basis for bacterial growth and propagation. Our results suggest that C. profundus could regulate key genes of rTCA cycle for carbon assimilation and energy metabolism in response to environmental fluctuations in hydrothermal vent.  相似文献   

不同溶剂对沉积物碳酸盐组分中硼的提取和硼同位素组成的影响研究          下载免费PDF全文

杨剑  马云麒  彭章旷  李海军  柴小丽  肖应凯  张艳灵 《盐湖研究》2018,26(4):64-72

实验研究了不同溶剂(盐酸、醋酸、饱和EDTA-2Na盐等)对沉积物样品中的碳酸盐组分硼元素提取和硼同位素组成的影响。结果表明,1 mol/L的醋酸是溶解沉积物样品中碳酸盐组分的最佳溶剂,能将沉积物中的碳酸盐完全溶解,并有效避免样品中石膏、硅酸盐等矿物的溶出,对其中铁的氧化物等影响也比较小;同时,在过硼特效树脂前将溶液调至弱碱性所用的亚沸氨水的量较少,从而引入的本底较少。采用盐酸和饱和EDTA-2Na溶液溶解沉积物,容易将沉积物中除碳酸盐以外的矿物中的硼溶出,如石膏、硅酸盐矿物等,不利于碳酸盐组分中硼的提取。  相似文献   

大别山燕山期中酸性小岩体钼成矿模型     

唐中刚 《四川地质学报》2012,32(3):299-303

大别山北麓钼(钨)矿带上的钼矿化,成因多与集中分布的中生代中酸性小岩体(花岗质斑岩)有关.信阳～汤家坪一带已知燕山期中酸性小花岗(斑)岩体40余处,且多具钼矿化,历经数年地质工作,已探明中型以上的钼矿床7处.该区内斑岩型钼矿床地质特征不尽相同,但成矿时代、围岩蚀变、岩体与矿化空间上的联系,都有一般斑岩钼矿床的共同特点.总结该区成矿酸性小岩体地质特征,成矿作用、成因、地球化学特征及成矿规律的研究成果,可为该区找矿提供借鉴作用.  相似文献