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1.
香溪河河流连续统特征研究   总被引:29,自引:3,他引:29  
以香溪河附石藻类密度、藻类叶绿素a浓度、Shannon-Wiener多样性指数及生态系统初级生产力随河流级别的变化为例探索该河流的连续统特征。结果表明,附石藻类密度、藻类叶绿素a浓度和Shannon-Wiener多样性指数总体上都有随着河流级别增加而增加的趋势,但在1~3级河段之间这种趋势并不明显,甚至出现了逆转。河流初级生产力也有随河流级别增加而增加的趋势,并在第4级河流达到最大,随后有所下降。在全水系范围内河流初级生产力(P)与群落呼吸(R)比值P/R均大于1,说明香溪河是一条以自养生产为主的河流。所研究的特征并不完全与连续统概念的预测相一致,表明河流已经受到了一定程度的人为干扰。  相似文献   

2.
北京白河与温榆河浮游动物调查   总被引:2,自引:0,他引:2  
2004~2006年对北京地区白河和温榆河浮游生物群落进行调查.结果显示:白河浮游动物137种,隶属于78个属,其中原生动物最多,共计73种,其次是轮虫55种,枝角类7种,桡足类2种;温榆河浮游动物135种,隶属于83个属,其中原生动物共计65种,轮虫类53种,枝角类13种,桡足类4种.两河浮游动物种类组成大部分相同,以原生动物为主,但两河大型浮游动物的种类组成差别较大.据两条河流浮游动物的生态状况和凋查结果综合分析,白河的水质较好,多数站点水体清洁,只有少数站点水体达轻度污染,温榆河水质较差,大多数站点水体属轻度污染,个别站点属中度污染.  相似文献   

3.
《BMJ (Clinical research ed.)》1907,2(2447):1553-1554
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4.
《Plains anthropologist》2013,58(50):290-298
Abstract

Twenty-four Knife River F I int quarries have been newly discovered in Dunn County, North Dakota. Five were previously known in Mercer County. The flint occurs as pebbles, cobbles, and boulders in alluvial, slope-wash, and colluvial lag deposits of Pleistocene age. The flint in these deposits was originally derived from a silicified lignite bed in the Golden Valley Formation of Eocene age and possibly also from other lignite-bearing formations. The flint has a characteristic petrography and can be readily distinguished from all other commonly used rock types in North Dakota and adjacent areas.  相似文献   

5.
The temporal crustacean-zooplankton variation in the mid-Po River (Italy) was analyzed from November 1974 through November 1982. Samples were collected at three stations at monthly intervals.Separate taxon-by-taxon multiple regression analyses (MLTRG) were carried out with zooplankton taxa as the criterion variable and river depth, river discharge and water temperature as the predictor variables. Moina brachiata and Eucyclops serrulatus were correlated with water temperature, Cyclops vicinus inversely correlated with temperature, Eudiaptomus padanus, C. vicinus and Daphniidae with river discharge; Copepodites inversely correlated with river depth.MLTRG showed that water temperature and river discharge account for about 15% of total zooplankton variation.Factorial analysis of variance (ANOVA) was carried out on residuals calculated from MLTRG. Among-years and among-months variation were significant for all the examined taxa. Significant years × months interactions indicated that seasonal variations were also different in different years.ANOVA stressed that there were still unexplained significant residuals in years and months variations.Weekly and daily samples collected in Summer 1979 were submitted to MLTRG and ANOVA as above. Among-week variations were significant for all the examined taxa, whereas among-days were significant for Daphiidae and M. brachiata (Cladocera), and not significant for any of the other taxa. Caution is recommended in interpreting the results of river zooplankton studies. Differences between species responses warn us not to pool species into larger taxa. Temporal variation changes from year to year, so long-time series are necessary to clarify the most important trends of river zooplankton.  相似文献   

6.
Indigenous people of northern Australia make extensive use of wild resources as a source of food, in their art and craft, and for medicinal purposes. These resources are part of a socially and culturally significant landscape. Using data collected from household surveys across two catchments in northern Australia, the Daly River, Northern Territory (NT) and the Fitzroy River, Western Australia (WA), we describe indigenous aquatic resource use patterns. The former is a perennial system with extensive vegetated wetlands that can remain inundated for 4?C5?months, while the latter can cease to flow during the winter dry season (May?COctober) and its floods usually last for weeks. Subsistence strategies depend on seasonal availability of a wide array of aquatic species and are attuned to the life histories and movement patterns of key species, such as Long-necked Turtle (Chelodina rugosa) and Magpie Goose (Anseranas semipalmata). Indigenous households harvested resources from different habitats. Our results show a clear progression from use of the main river channel shortly after the wet season to use of billabongs late in the dry season in the Daly River, and a constant reliance on the main river channel and tributaries in the Fitzroy River. Difference in the main species utilised appears strongly related to habitat use, with four of the five most commonly harvested in the Daly catchment being non-fish species associated with billabong habitats. Commonly harvested species from the Fitzroy catchment included small bodied species used as bait and two popular food species, Black Bream (Hephaestus jenkinsi) and Catfish (Neoarius spp.). Results suggest that indigenous subsistence strategies are vulnerable to changes in the natural systems that provide the ??ecosystem goods,?? particularly annual inundation of floodplains that drives productivity and provides habitat for some key species. Water resource developments, such as river regulation and increased abstraction for irrigated agriculture, could adversely affect a highly valued customary component of the indigenous economies of tropical Australia.  相似文献   

7.
This paper critically reviews developments in the conceptualization and elaboration of the River Ecosystem Health (REH) concept. Analysis of literature shows there is still no consistent meaning of the central concept Ecosystem Health, resulting in models (i.e. elaborations) that have unclear and insufficient conceptual grounds. Furthermore, a diverse terminology is associated with describing REH, resulting in confusion with other concepts. However, if the concept is to have merit and longevity in the field of river research and management, unambiguous definition of the conceptual meaning and operational domain are required. Therefore a redefinition is proposed, based on identified characteristics of health and derived from considering semantic and conceptual definitions. Based on this definition, REH has merit in a broader context of river system health that considers societal functioning next to ecological functioning. Assessment of health needs integration of measures of multiple, complementary attributes and analysis in a synthesized way. An assessment framework is proposed that assesses REH top-down as well as bottom up by combining indicators of system stress responses (i.e. condition) with indicators identifying the causative stress (i.e. stressor). The scope of REH is covered by using indicators of system activity, metabolism (vigour), resilience, structure and interactions between system components (organization). The variety of stress effects that the system may endure are covered by using biotic, chemical as well as physical stressors. Besides having a unique meaning, the REH metaphor has added value to river management by being able to mobilize scientists, practitioners and publics and seeing relationships at the level of values. It places humans at the centre of the river ecosystem, while seeking to ensure the durability of the ecosystem of which they are an integral part. Optimization of the indicator set, development of aggregation and classification methodologies, and implementation of the concept within differing international frames are considered main aims for future research.  相似文献   

8.
The Upper Mississippi River is characterized by a series of locks and dams, shallow impoundments, and thousands of river channelization structures that facilitate commercial navigation between Minneapolis, Minnesota, and Cairo, Illinois. Agriculture and urban development over the past 200 years have degraded water quality and increased the rate of sediment and nutrient delivery to surface waters. River enhancement has become an important management tool employed to address causes and effects of surface water degradation and river modification in the Upper Mississippi River Basin. We report information on individual river enhancement projects and contrast project densities, goals, activities, monitoring, and cost between commercially non‐navigated and navigated rivers (Non‐navigated and Navigated Rivers, respectively). The total number of river enhancement projects collected during this effort was 62,108. Cost of all projects reporting spending between 1972 and 2006 was about US$1.6 billion. Water quality management was the most cited project goal within the basin. Other important goals in Navigated Rivers included in‐stream habitat improvement and flow modification. Most projects collected for Non‐navigated Rivers and their watersheds originated from the U.S. Department of Agriculture (USDA). The U.S. Army Corps of Engineers and the USDA were important sources for projects in Navigated Rivers. Collaborative efforts between agencies that implement projects in Non‐navigated and Navigated Rivers may be needed to more effectively address river impairment. However, the current state of data sources tracking river enhancement projects deters efficient and broad‐scale integration.  相似文献   

9.
<正>其实,不仅是黄河首曲地区,整个三江源地区除高山冰雪覆盖外,有很多大面积湿地,海拔高,温度低。从生态系统来看,三江源地区包括黄河首曲是世界上最高的湿地系统,有丰富的高原生物多样性。对地球的生物多样性以及下游河流的水涵养都有很大的意义。我们的母亲河黄河与长江都是在高原湿地上发育的。  相似文献   

10.
11.
The objective of this study is to optimize the river monitoring network in Taizihe River, Northeast China. The situation of the network and water characteristics were studied in this work. During this study, water samples were collected once a month during January 2009 - December 2010 from seventeen sites. Futhermore, the 16 monitoring indexes were analyzed in the field and laboratory. The pH value of surface water sample was found to be in the range of 6.83 to 9.31, and the average concentrations of NH4+-N, chemical oxygen demand (COD), volatile phenol and total phosphorus (TP) were found decreasing significantly. The water quality of the river has been improved from 2009 to 2010. Through the calculation of the data availability and the correlation between adjacent sections, it was found that the present monitoring network was inefficient as well as the optimization was indispensable. In order to improve the situation, the matter element analysis and gravity distance were applied in the optimization of river monitoring network, which were proved to be a useful method to optimize river quality monitoring network. The amount of monitoring sections were cut from 17 to 13 for the monitoring network was more cost-effective after being optimized. The results of this study could be used in developing effective management strategies to improve the environmental quality of Taizihe River. Also, the results show that the proposed model can be effectively used for the optimal design of monitoring networks in river systems.  相似文献   

12.
汉江支流堵河鱼类群落结构及多样性   总被引:1,自引:0,他引:1  
基于堵河2018年6月-2019年5月渔获物,分析了鱼类群落组成及变化、优势种以及群落多样性时空分布特征,讨论了外界环境扰动作用对鱼类群落结构和生物多样性的影响.结果 表明:调查期间共采集鱼类38种,分属4目8科,其中鲤形目鱼类最多(26种),占总种数的68.4%.群落优势种为鳙(Aristichthys nobili...  相似文献   

13.
基于Budyko假设的洮河与大夏河径流变化归因识别   总被引:1,自引:0,他引:1  
杨林  赵广举  穆兴民  田鹏  高鹏  孙文义  张丽梅 《生态学报》2021,41(21):8421-8429
受气候变化和人类活动的影响,世界许多河流水文过程发生了显著的变化。研究河川径流变化特征及其原因对流域水资源管理和规划有十分重要的意义。以黄河上游支流洮河、大夏河为研究对象,采用Mann-Kendall趋势检验法、突变分析等方法探究河川径流的趋势变化、阶段特征,并采用Budyko水热耦合平衡方程定量评估径流变化影响因素的贡献率。研究发现洮河与大夏河流域年径流深均呈显著减少趋势,减少速率为:-1.85 mm/a、-1.36 mm/a (P≤0.01)。通过突变检验可将洮河的径流序列分为基准期1961-1987年,剧烈人类活动期1988-2017年,而大夏河的基准期为1961-1985年,人类活动期1986-2017年。洮河、大夏河流域下垫面变化对径流变化的贡献率超过60%,降雨次之,潜在蒸散发最弱,约贡献10%。流域下垫面改变是引起研究区河川径流变化的主要因素。  相似文献   

14.
River networks as biodiversity hotlines   总被引:1,自引:0,他引:1  
For several years, measures to insure healthy river functions and to protect biodiversity have focused on management at the scale of drainage basins. Indeed, rivers bear witness to the health of their drainage basins, which justifies integrated basin management. However, this vision should not mask two other aspects of the protection of aquatic and riparian biodiversity as well as services provided by rivers. First, although largely depending on the ecological properties of the surrounding terrestrial environment, rivers are ecological systems by themselves, characterized by their linearity: they are organized in connected networks, complex and ever changing, open to the sea. Second, the structure and functions of river networks respond to manipulations of their hydrology, and are particularly vulnerable to climatic variations. Whatever the scale considered, river networks represent "hotlines" for sharing water between ecological and societal systems, as well as for preserving both systems in the face of global change. River hotlines are characterized by spatial as well as temporal legacies: every human impact to a river network may be transmitted far downstream from its point of origin, and may produce effects only after a more or less prolonged latency period. Here, I review some of the current issues of river ecology in light of the linear character of river networks.  相似文献   

15.
This paper presents the results of haemagglutination-inhibition tests carried out on sera from 441 persons, 1,080 cattle and 335 birds in the Kimberley area. Two Alphaviruses (group A) (Ross River and Sindbis) and one Flavivirus (Murray Valley Encephalitis) were used for the preparation of haemagglutinins in the haemagglutination-inhibition tests. The tests showed a high percentage of antibody of Murray Valley Encephalitis in humans, birds and cattle, with an obvious focus of infection in the study site when cattle sera from different geographic areas were compared. These results are discussed in relation to the evolution and ecology of arboviruses in the Ord River area.  相似文献   

16.
The Anacostia River severs Washington, D.C. Military waste, urban runoff, and former farmland dirty the water, but people who live along its shores cherish the river and fight to make it clean. Political ecology, stressing the power relations, inequalities, connections, and contradictions that join natural and social processes over time, enlarges historical and anthropological theory in Washington. In this article I explore the experiences and perspectives of people who have lived along the Anacostia River over the last 10,000 years. Linked transformations in environmental and social processes repeatedly created unsettled, contradictory, and unjust relations between people and the natural and built environment. The pollution of the Anacostia River reflects colonialism and conquest: nationalism, militarism, empire; racism, inequality, and urban renewal. I begin with the British conquest, then turn to four successive moments in state formation: the founding of the capital, the invention of a strong central government, urban renewal in the capital core, and the contemporary development of the waterfront. The use values of people who live along the river conflict with the exchange values that have dominated the city's history. The city's environmental justice movement has emerged from these use values and today confronts a massive redevelopment plan that exploits and undermines the movement, [political ecology, environmental justice, urban history, race, and poverty]  相似文献   

17.
In samples of the Tra Ly River in the Red River mouth (Northern Vietnam), 46 species of free-living nematodes have been found, five of which are new to science. The species dominant in abundance were Ptycholaimellus adocius Dashchenko et Belogurov, 1984; Dichrocuadora affinis Gagarin et Nguyen Vu Thanh, 2011; and Tripyloides minor sp.n. The species composition of nematodes is listed and the new species Tripyloides minor sp. n. is described and illustrated. The nematode described and illustrated by Riemann (1970) from watercourses of Colombia as Tripyloides amazonicus (Gerlach, 1957) is recognized as a valid species (Tripyloides riemanni nom.n).  相似文献   

18.
19.
T Sato  K Kato  Y Ose  H Nagase  T Ishikawa 《Mutation research》1985,157(2-3):135-143
Mutagenic activity was observed in sediments of the Suimon River bed with and without S9 mix. The direct-acting mutagens in the sediment were investigated. The sediment was extracted with methanol and fractionated on a Silica gel column. The benzene fraction from the Silica gel column exhibited mutagenic activity without S9 mix in strain TA98, while it failed to show mutagenic activity in nitroreductase-deficient strain TA98NR. This observation led to the suspicion that nitro compounds were the direct-acting mutagens of these samples. The benzene fraction was treated by heptafluorobutyric anhydride (HFBA) and investigated with gas chromatography equipped with an electron capture detector (GC-ECD). 2-Nitrofluorene, 4,4'-dinitrobiphenyl, 2,7-dinitrofluorene and 1-nitropyrene were detected and measured quantitatively. The mutagenic activity of a mixture of these compounds was compared with that of the original fraction and the direct-acting mutagenicity of Suimon River sediment can be explained by these nitroarenes, especially 1-nitropyrene.  相似文献   

20.
Summary

An account is given of the 5 lichens, 76 bryophytes, 40 angiosperms and the ‘sewage-fungus’ community recorded from a survey of the River Tweed, Scotland, together with historical and environmental data. For most of its length the river water is relatively soft and low in key nutrients, although phosphate levels in the past were probably higher due to the effluents from wool mills. The presence or absence of each macrophyte was recorded for successive 0.5 km lengths of the river, and histograms are included which summarise the distribution of individual species. In addition, a subjective estimate of the relative abundance within each length was made for each species, and some of these data have been included in an ordination table. Some comparison is also made with data from the literature on rivers in North-east England.  相似文献   

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