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1.
三峡水库香溪河库湾主要营养盐的入库动态   总被引:15,自引:0,他引:15  
李凤清    叶麟  刘瑞秋  曹明    蔡庆华   《生态学报》2008,28(5):2073-2073~2079
基于香溪河及其主要支流高岚河的5a监测数据,估算三峡水库香溪河库湾氮磷营养盐的入库通量,并分析了氮磷营养盐的浓度及其通量的逐月动态.研究发现,每年大约有1623.49 t总氮和331.85 t总磷汇入香溪河库湾,其中,香溪河贡献了68.50%的总氮和91.74%的总磷.在这两条河流中,溶解无机氮是氮的主要存在形式;氮通量表现出夏季7月份偏高、春秋季次之、冬季较低的规律;面源污染是氮进入河道的主要途径.磷酸盐是香溪河磷的主要存在形式,而高岚河磷酸盐的含量则较低;香溪河磷通量的月均波动规律不明显,高岚河磷通量的高峰期出现在春末和夏季;高岚河的磷主要通过面源途径进入河道,而香溪河的磷则存在点源污染.水土流失可能是香溪河流域面源污染的主要途径,磷矿和磷化工厂的排污则是磷点源污染的主要途径.从保护三峡水库香溪河库湾的生态学角度考虑,应重点控制香溪河磷的点源污染.  相似文献   

2.
第1期三峡水库蓄水前后水生态系统动态的初步研究………………………………………………………………胡征宇蔡庆华(1)三峡水库富营养化问题与对策研究……………………………………………………………………………蔡庆华胡征宇(7)三峡水库库首初期蓄水前后理化因子的比较研究…………………………曹明蔡庆华刘瑞秋渠晓东叶麟(12)三峡水库及香溪河库湾理化特征的比较研究………………………………曹明蔡庆华刘瑞秋渠晓东叶麟(20)三峡水库蓄水前后香溪河氮磷污染状况研究…………………………………………方涛付长营敖鸿毅邓南圣(26)三峡水库香溪河库湾沉积物对磷的吸附特征研究…………………………付长营陶敏方涛敖鸿毅邓南圣(31)三峡库区藻类水华调查及其毒理学研究……………………………………周广杰况琪军刘国祥汤宏波胡征宇(37)香溪河库湾浮游藻类种类演替及水华发生趋势分析…………………………………周广杰况琪军胡征宇蔡庆华(42)三峡库区高岚河甲藻水华的初步研究……………………………………………………………汤宏波刘国祥胡征宇(47)香溪河库湾轮虫现状及水质评价初探…………………………………………………周淑婵黄祥飞唐涛蔡庆华(52)三峡水库坝前...  相似文献   

3.
2003年三峡水库蓄水后,香溪河入库区段形成典型的水库型库湾,磷污染严重,导致水华频发。异养细菌是水体物质循环的重要参与者,其中无机磷细菌释放结合态磷加重了水体富营养化。为了研究异养细菌和无机磷细菌对水体富营养化的影响,在库湾设置7个采样点,2015年4月、6月、9月和12月分别采集水样,测定样品总氮(TN)、总磷(TP)、磷酸盐(PO_4-P)及表层(水面下方0.5 m)水体叶绿素a(Chl.a)浓度,实验室培养异养细菌及无机磷细菌。利用SPSS 17.0对水体可培养异养细菌和无机磷细菌的时空变化进行单因素方差分析,并用SPSS软件分析细菌含量与总氮浓度、总磷浓度、磷酸盐浓度和叶绿素a浓度的相关性。结果显示:异养细菌和无机磷细菌含量与叶绿素a浓度无显著相关性;无机磷细菌与氮磷相关性均高于异养细菌,说明香溪河库湾无机磷细菌与水体氮磷关联性大于异养细菌。  相似文献   

4.
三峡水库香溪河库湾沉积物对磷的吸附特征研究   总被引:5,自引:1,他引:4  
通过三峡水库香溪河库湾的3个采样点沉积物中磷的自然吸附实验和不同粒径下沉积物的胁迫吸附试验,研究了沉积物对磷的吸附特征。结果表明:上覆水中的磷浓度与沉积物中的总磷含量有很好的相关性,沉积物中的总磷含量对上覆水的水质有很大的影响;三点的临界平衡浓度为C1:0.188mg/L,C2:0.147mg/L,C3:0.188mg/L;各点增加的量即饱和吸附量不同(ΔQ1:268.16mg/kg,ΔQ2:57.96mg/kg,ΔQ3:267.27mg/kg),恰恰与三点的临界平衡浓度之间的关系一致;粒径对沉积物对磷的吸附量影响程度与沉积物理化参数也存在很大的关系;三个样点的吸附量,分别接近于1.5mg/g,0.8mg/g及1.4mg/g。结果还表明:最大吸附量大的地方,饱和吸附量不一定就大,二者之间不存在必然的关系;香溪河沉积物中的磷在现有条件下表现为“源”,不排除外在条件改变时转化为“汇”。如果最大吸附容量、饱和吸附容量及平衡浓度能够很好的与数学相结合,可为当地的环保部门管理香溪附近工厂提供科学依据。  相似文献   

5.
于超  储金宇  白晓华  刘伟龙 《生态学报》2011,31(23):7104-7111
入湖河流携带污染物对洱海水环境的影响日益明显,对洱海入湖水量最大的河流——弥苴河下游水体氮磷进行了连续采样分析,以期为河口湿地建设和水质改善提供基础数据.结果表明:1)弥苴河水质介于地表水Ⅲ-Ⅴ类之间,主要污染物为氮和磷,其中总氮平均浓度为1.17 mg/L,最高浓度达到2.00 mg/L;总磷平均浓度为0.06 mg/L;2)弥苴河下游总氮、总磷浓度丰水期高于枯水期,并呈现出季节性变化规律;3)弥苴河下游水体总氮、总磷年均浓度远高于洱海水体总氮、总磷年均浓度,其中总氮高出2.10倍,总磷高出2.90倍;4)弥苴河下游河段非点源污染占据主导地位.  相似文献   

6.
三峡水库及香溪河库湾理化特征的比较研究   总被引:6,自引:0,他引:6  
根据2003年6月三峡水库初期蓄水后对香溪河库湾的常规监测,对该水域的理化特征及其动态进行了分析,并与三峡水库库首的数据进行了比较研究。结果显示库湾TN、NO3-N浓度要显著低于库首,前者两周年平均值为1.29mg/L,0.88mg/L,后者两周年平均值为1.62mg/L,1.22mg/L。而PO4-P则是库湾显著高于库首,并且在7—9月库首的TP/PO4-P有显著提高。结果同时表明库首的水土流失较严重,而库湾则有较好的水土保持。最后对TSIM的计算结果表明,由于TP、TN都处于高水平,库首呈现中营养化(TSIM>37),而库湾则呈现严重富营养化(TSIM>53)。  相似文献   

7.
香溪河库湾春季水华期间悬浮颗粒物粒度动态的初步研究   总被引:1,自引:1,他引:0  
水体中的悬浮颗粒物是物质在水环境中迁移转化的载体和蓄积库,是营养成分在水相、沉积物相和食物链中循环的重要载体,是河流生态系统物质循环和能量流动的重要组成部分[1—3],很多学者研究了悬浮物的组成、结构和粒度之间的关系,发现其粒度特征对于了解生态系统内部物质和能量循环转化过程具有重要意义[4,5]。三峡水库蓄水后,香溪河下游部分河段成为库区的一部分,相对于河流来说,流速的减小使更多的悬浮颗粒物发生沉降,营养物质富集,易暴发水华[6]。本研究在三峡水库香溪河库湾水华暴发过程中对不同水深的悬浮颗粒物在24h内的动态分布特征进…  相似文献   

8.
香溪河库湾春季叶绿素a 浓度动态及其影响因子分析   总被引:30,自引:3,他引:27  
2005年3月至4月,对三峡水库香溪河库湾的叶绿素a动态及其与TN、TP等环境因子的关系进行了研究。结果表明,从香溪河库湾下游到上游,叶绿素a存在明显的水平分布。在时间分布上,3月17日暴发一次大规模的水华,4月份水华的暴发有一个明显的平面推移的过程。叶绿素a浓度与TN、TP之间存在着一定的负相关关系,TN与叶绿素a浓度的相关性较显著。香溪河库湾极可能是N限制型水体,而不受P限制。叶绿素a与透明度存在反双曲线关系,与溶解氧呈显著正相关关系。  相似文献   

9.
香溪河库湾春季水华期间硝酸盐、磷酸盐的时空分布   总被引:14,自引:2,他引:12  
在三峡水库香溪河库湾春季水华连续暴发期间(2005年2月26日—4月28日)对香溪河与长江汇合处(河口)至香溪河库湾上游库尾处总计14个采样点进行连续监测,结果表明硝酸盐和磷酸盐在库湾中存在明显的时空分布规律。在空间上,河口的硝酸盐浓度高,库尾浓度低,其变化趋势是随着与河口距离的增加而降低;磷酸盐的分布规律是库尾的浓度高,河口的浓度低,其变化趋势与硝酸盐恰好相反。各采样点硝酸盐和磷酸盐浓度在时间上也呈现出明显的规律。河口硝酸盐的浓度在不同时间变化幅度较小,库尾采样点的硝酸盐浓度的变化幅度较大,随着与河口距离的增加硝酸盐浓度在不同时间的变化幅度逐渐增大。各样点磷酸盐在时间上的变化趋势是样点S04-S08的变化幅度较大,位于香溪河库湾河口和库尾的变化幅度较小。  相似文献   

10.
三峡水库蓄水后香溪河库湾底栖动物群落结构的变化   总被引:7,自引:1,他引:6  
2003年8月到2004年8月对长江三峡水库香溪河库湾的底栖动物进行了定量研究。共采到底栖动物26种,隶属4门6科,总平均密度为276ind./m2,总平均生物量为0.301g/m2,优势种为霍甫水丝蚓和前突摇蚊幼虫。与其他同类型的水库比较香溪河库湾的现存量相对较低。研究结果同时显示随着蓄水时间的延长,底栖动物的现存量在逐渐增加。霍甫水丝蚓和前突摇蚊幼虫等耐污种发展为优势种,表明水质有恶化的趋势,寡毛类的平缓发展说明目前香溪河库湾的沉积情况尚不严重。  相似文献   

11.
The electrophoretical polymorphisms of some blood proteins were studied in the Talysh population of Pirasora situated in South-East Azerbaidjan. We calculated the gene frequencies of these polymorphisms and determined the genetic distances between the Talyshes and some Iranian populations of North, Central and South Iran, Afghans, and three populations of Azerbaijan. The Talyshes are very close to Iranians of Shiraz, whereas they are distant from the Azerbaijanians. Anthropological investigations showed that the Caucasoids and Mongoloids lived in the Aragvi Basin since the Eneolithic period. This was stated by Alexeev (1974), who emphasized the mixture of the Caucasus populations from ancient times on. We calculated the genetic distances between the Caucasus populations and numerous populations of other geographic regions, considering 28 alleles of 12 loci of blood group, serum protein and red cell enzyme polymorphisms and constructed the dendrogram of these populations. The position of the Caucasus populations in the dendrogram corresponds on principle to the earlier anthropological observations. The clustering of the Caucasoid populations corresponds completely with anthropological and historical data, and supports our earlier hypothesis (Nazarova 1999) concerning the differentiation of Caucasoids, Northern Mongoloids and Amerinds from the populations, which inhabitated Asia in palaeolithic times.  相似文献   

12.
人类基因组及后基因组研究进展及其应用与开发研究现状   总被引:9,自引:0,他引:9  
人类对自身基因组的研究,随着人类基因组工作草图的绘制完成和对基因功能研究的深入已加快进入了实质性、关键性的开发利用阶段。本文概述了人类基因组及后基因组的研究进展及依此开展基因治疗及基因(组)药物研制等应用开发研究的现状。  相似文献   

13.
The systematic position ofthe Ebenaceae, Sapotaceae, Styracaceae, Ochnaceae, Stachyuraceae, Dipterocarpaceae, Clusiaceae and Hypericaceae has been investigated using serological comparisons of sets of antigenic determinants. The results show that the Sytracaceae and Sapotaceae are undoubtedly more closely associated with the Actinidiaeceae and Theaceae, respectively, than with each other. We found no corresponding determinants betnween antigen systems from the Ebenaceae and systems from any other family whose relations to this family have been proposed. As discovered previously, investigations of antigen systems from the Ochnaceae, Dipterocarpaceae, Stachyuraceae, Clusiaceae and Hypericaceae are against the idea of a natural order “Theales” in which these families, or at least some of them, are combined with the Theaceae and Actinidiaceae. This paper completes our previous investigations which largely support a superorder Ericanae sensu Ehrendorfer and Takhtajan. We propose to include the Actinidiaceae and Theaceae in this superorder, assigning them a central position laong with the Sapotaceae and Sytracaeae on one side and the Primulales and Ericales on the other. Another most interesting finding is that there are corresponding determinants between antigen systems from the members of the Ericanae and representatives of the Polemoniaceae and Loasaceae.  相似文献   

14.
In order to analyze the complicated movements of the mandible as the open-closing movement and the protrusio are, it is useful to evaluate the basic kinematic principles and reduce them to simple technical constructions. Both the open-closing movement and the protrusio could be reduced to 4-bar links, which were used to simulate the movements with help of a computer. Besides, the polodes and the curves of points in the muscular attachments could be constructed. The 2 entirely different 4-bar links have 3 things in common: The resting system - cranium, the moving system - mandibula, and 1 of the 2 arms connecting these 2 systems - the ligamentum laterale. As this ligament is taut during movements it can be considered a "guiding ligament" representing 1 of the 3 determining components of the mandibular movements. The other of the 2 arms has no anatomical equivalent; this arm, however, is "replaced" by the 2 other determining components of the mandibular movements: the joint and the muscles. The curves, which the Caput mandibulae describes, are practically identical for the open-closing movement and the protrusio despite of the different 4-bar links and these curves exactly correspond to the Discus articularis, taut by the upper part of the M. pterygoideus lateralis. The muscles do not only just move the mandibula, but they are also the component, which can choose between the different mandibular movements. By means of the curves, which points in the muscular attachments describe, the function of the masticatory muscles could be analyzed exactly.  相似文献   

15.
Several different models of the linker histone (LH)–nucleosome complex have been proposed, but none of them has unambiguously revealed the position and binding sites of the LH on the nucleosome. Using Brownian dynamics-based docking together with normal mode analysis of the nucleosome to account for the flexibility of two flanking 10 bp long linker DNAs (L-DNA), we identified binding modes of the H5-LH globular domain (GH5) to the nucleosome. For a wide range of nucleosomal conformations with the L-DNA ends less than 65 Å apart, one dominant binding mode was identified for GH5 and found to be consistent with fluorescence recovery after photobleaching (FRAP) experiments. GH5 binds asymmetrically with respect to the nucleosomal dyad axis, fitting between the nucleosomal DNA and one of the L-DNAs. For greater distances between L-DNA ends, docking of GH5 to the L-DNA that is more restrained and less open becomes favored. These results suggest a selection mechanism by which GH5 preferentially binds one of the L-DNAs and thereby affects DNA dynamics and accessibility and contributes to formation of a particular chromatin fiber structure. The two binding modes identified would, respectively, favor a tight zigzag chromatin structure or a loose solenoid chromatin fiber.  相似文献   

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Interpreting channel behavior in patches requires an understanding of patch structure and dynamics, especially in studies of mechanosensitive channels. High resolution optical studies show that patch formation occurs via blebbing that disrupts normal membrane structure and redistributes in situ components including ion channels. There is a 1-2 μm region of the seal below the patch where proteins are excluded and this may consist of extracted lipids that form the gigaseal. Patch domes often have complex geometries with inhomogeneous stresses due to the membrane-glass adhesion energy (Ea), cytoskeletal forces, and possible lipid subdomains. The resting tension in the patch dome ranges from 1-4 mN/m, a significant fraction of the lytic tension of a bilayer (∼10 mN/m). Thus, all patch experiments are conducted under substantial, and uneven, resting tension that may alter the kinetics of many channels. Ea seems dominated by van der Waals attraction overlaid with a normally repulsive Coulombic force. High ionic strength pipette saline increased Ea and, surprisingly, increased cytoskeletal rigidity in cell-attached patches. Low pH pipette saline also increased Ea and reduced the seal selectivity for cations, presumably by neutralizing the membrane surface charge. The seal is a negatively charged, cation selective, space with a resistance of ∼7 gigohm/μm in 100 mM KCl, and the high resistivity of the space may result from the presence of high viscosity glycoproteins. Patches creep up the pipette over time with voltage independent and voltage dependent components. Voltage-independent creep is expected from the capillary attraction of Ea and the flow of fresh lipids from the cell. Voltage-dependent creep seems to arise from electroosmosis in the seal. Neutralization of negative charges on the seal membrane with low pH decreased the creep rate and reversed the direction of creep at positive pipette potentials.  相似文献   

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Objective

To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area.

Methods

Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied.

Results

Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm2).

Conclusions

Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.  相似文献   

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