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1.
2003年7月至2004年4月，每季度对武汉市南湖大型底栖动物进行定量和定性的采样分析，共发现大型底栖动 物30种；优势种为霍甫水丝蚓和刺铗长足摇蚊，均呈聚集分布；大型底栖动物的年均密度和生物量分别为4437 ind/m~2和 17．79 g/m~2，其密度和生物量春季最高，Shannon-Wiener 多样性指数和 Margalef 多样性指数的年均值分别为1．515和 1．123．比较分析了南湖大型底栖动物组成的历史变化，对水环境进行了生物学评价，并提出了南湖大型底栖动物合理利 用的建议． 相似文献
2.
水文报道1987年河南封丘曹岗湖底栖动物的调查结果。该湖底栖动物主要由寡毛类8种, 水生昆虫47种和腹足类2种组成, 其中克拉泊水丝蚓和刺铗粗腹摇蚊群为优势种类, 平均密度为2087个/m2, 生物量为4.8690g/m2, 并与长江中游浅水湖泊中的底栖动物作了比较, 对某些环境因素与底栖动物种类组成、数量分布的关系也作了扼要的分析。 相似文献
3.
湖北省三道河水库底栖动物的初步研究 总被引：4，自引：2，他引：2
2007年8月至2008年4月,在湖北省三道河水库6个采样点调查底栖动物,共采集到底栖动物17种,其中水生昆虫11种,均为摇蚊科;寡毛类6种,均为颤蚓科,春季优势种为前突摇蚊,夏季优势种为小摇蚊、流水长跗摇蚊和前突摇蚊,秋、冬季优势种为霍甫水丝蚓,底柄动物种类数、密度和生物量随季节变化明显,种类数夏季＞冬季＞秋季＞春季,密度和生物量春季＞冬季＞秋季＞夏季,周年密度和生物量分别为366.42±102.93ind/m2和0.5649±0.1779g/m2,属贫营养型水库,现存量自坝前向库尾逐步递增,Shannon-Wiener指数、Margalef丰富度指数和Pielou均匀度指数均在夏季最高,秋季最低,4次调查中寡毛类密度均未超过1 000ind./m2,水质属轻度污染. 相似文献
4.
丹江口水库大型底栖动物群落结构及其水质生物学评价 总被引：11，自引：1，他引：10
2007年7月至2008年5月,按季度对丹江口水库4个区域(丹江库区、汉江库区、取水口、五青入库区)14个采样点进行大型底栖动物调查.共采集到底栖动物61种,主要由寡毛类(颤蚓科、仙女虫科)和摇蚊科组成.其中,寡毛类密度在全年中占优势地位,占底栖动物总密度的90%以上;生物量的优势种则主要为软体动物.空间分布上,底栖动物密度以汉江库区最高(大坝前:33792ind./m~2),丹江库区次之,取水口和五青入库区的密度相对较低,且五青入库区偶尔出现0密度的样品;生物量则由于丹江库区和取水口经常有软体动物出现而导致该区域内生物量相对较高.季节变化上,密度分布为夏季春季秋季冬季;生物量也呈现出类似的分布,但秋季和冬季差别较小.采用Shannon-Wiener多样性指数、Goodnight-Whitley生物指数、Wright生物指数及Carlander生物量法对丹江口水库水质进行评价,比较而言,Goodnight-Whitley指数不适宜用于丹江口水库的水质评价;而综合利用其它三种方法进行评价的结果表明:取水口为轻污染状态,丹江库区为轻-中污染,汉江库区为中-重污染;五青入库区由于水深太浅,底栖动物生境易受外界影响导致群落波动较大,因此不宜采用底栖动物作为评价指标. 相似文献
5.
江苏省水库底栖动物调查及其综合评价 总被引：11，自引：0，他引：11
于1998年5月-1999年5月对江苏省48座大中型水库底栖动物进行了调查．鉴定的底栖动物计75属种，优势种类为尾鳃蚓属（Branichiura）、水丝蚓属(Limnodrilus）、管水蚓属（Aulodrilus)、长足摇蚊属（Pelopia)、隐摇蚊（Cryptochironomus）等5属．底栖动物密度为288．4ind．／m^2，变动范围43．2-928．2ind．／m^2；生物量为8．753g／m^2，变动范围0．235—61．884g／m^2．北部、中部、南部水库各类底栖动物的季节变化呈现较大的差异．用Goodnight ＆ Whitley生物指数和Wright寡毛类密度法评价水库水质，除少数水库有轻度污染外，水质状况总体良好．用能量估算法估算水库底栖动物的平均渔产潜力为5．8kg/hm^2。 相似文献
6.
湖北浮桥河水库底栖动物的群落结构及生物多样性 总被引：6，自引：3，他引：6
1997年 4月至 1998年 1月 ,在浮桥河水库 14个采样点调查底栖动物 ,共获 4 7种 .其优势种类为霍甫水丝蚓 (Limnodrilushoffmeisteri)、中国长足摇蚊 (Tanypuschinensis)、前突摇蚊属 (Procladiussp .)和摇蚊属 (Chironomussp .) .水库底栖动物的Shannon指数和Margalef指数偏低 ,上游的指数值最高 .从种类相似性来看 ,底栖动物的季节变化不明显 ;在水平分布上 ,上游与库汊的种类相似性最低 ,库汊与下游的种类相似性最高 .浮桥河水库底栖动物的平均密度为5 2 9.1ind/m2 ,平均生物量为 35 34.1mg/m2 ,均以水生昆虫占优 ,其时空变化主要受水生昆虫控制 .能量估算法估算出浮桥河水库底栖动物的渔产潜力为 1.5× 10 4 kg/a . 相似文献
7.
保安湖是江汉湖群的一个典型浅水湖泊。近几十年来，随着经济的快速发展，保安湖面临多重人类压力影响，富营养化问题日趋严重。历史上曾开展过数次的保安湖底栖动物调查，但有关群落结构的长期变化及其驱动机制改变的认知仍为空白。本研究基于30余年（1986 2019）的多次调查数据，探索保安湖底栖动物的群落演变规律及其群落构建机制。研究共记录保安湖底栖动物5门10纲25目49科110属170种（历史记录154种，现场调查51种）。总物种数由1992年的107种降为2019年的51种；平均密度由1992年的433 ind．/m2增加到2019年的2177.6 ind．/m2；平均生物量由2001年的160.6 g/m2降低为2019年的26.7 g/m2。优势种在1987年有寡毛类、水生昆虫和软体动物多个类群，其后逐步演变为现阶段少数几种耐污的寡毛类和摇蚊类，如霍甫水丝蚓（Limnodrilus hoffmeisteri）、中国长足摇蚊（Tanypus chinensis）、红裸须摇蚊（Propsilocerus akamusi）等，而多年生大型软体动物衰退明显。PERMANOVA和SIMPER分析结... 相似文献
8.
珠江三角洲是我国主要的水产养殖区域之一.为了解珠江三角洲鱼类养殖池塘底栖动物群落结构,进而评价养殖水体水质状况,于2016年7-8月对6种养殖模式30口池塘底栖动物及其环境因子进行调查.结果表明:1)共采集底栖动物18种,隶属于3门14属,其中寡毛类和水生昆虫均为7种,软体动物为4种.优势种为克拉泊水丝蚓(Limnodrilus claparedeianus)、水丝蚓属一种(Limnodrilus sp.)和摇蚊属一种(Chironomus sp.)等耐污种类.2)6种养殖模式池塘底栖动物平均种类数无显著差异,但其密度和生物量却存在显著差异,杂交鳢Y(杂交鳢幼鱼)和杂交鳢C(杂交鳢成鱼)养殖池塘均显著高于其他4种养殖模式池塘.3)皮尔逊相关分析结果表明,影响珠江三角洲池塘底栖动物密度和生物量的主要因素是总氮(TN)和总磷(TP).两个主要分类群中,寡毛类密度和生物量仅与TN浓度呈显著正相关,而摇蚊幼虫却与TN和TP浓度均呈显著正相关.4)采用Shannon-Wiener多样性指数、Margalef多样性指数和Biotic Index生物指数对6种养殖模式30口池塘水质进行评价,结果表明Shannon-Wiener多样性指数不宜应用于珠江三角洲池塘的水质评价,Margalef多样性指数和Biotic Index生物指数的评价结果均表明杂交鳢Y、杂交鳢C以及草鱼池塘全部处于重度污染,而大口黑鲈S(投喂饲料)、大口黑鲈S+B(投喂饲料+冰鲜鱼类)和罗非鱼池塘大部分处于重度污染,少数处于中度污染. 相似文献
9.
太平湖水库的底栖动物 总被引：5，自引：3，他引：5
研究了太平湖水库底栖动物群落组成（１９９２－１９９３年）定量样品出现２６种（属），主要是寡毛类和摇蚊科幼虫，软体动物只有１种，现存量有明显的季节差异，本次调查结果与１９８５－１９８６年资料比较，种类数减少，现存量显著增加，生物量由０．５６２ｇ／ｍ＾２增加到３．９０ｇ／ｍ＾３生物多样性指数偏低，底栖动物的参数与环境因素进行了相关分析，寡毛类的密度和生物量与总氮，总磷正相关，水生昆虫的密度和生理量与水 相似文献
10.
浙江千岛湖深水区大型底栖动物时空变化格局 总被引：12，自引：4，他引：8
2007-2008年对浙江千岛湖深水区底栖动物群落进行了研究.共调查到8种底栖动物,其中寡毛类7种,线形动物门1种.群落类型不存在季节差异,优势种为霍甫水丝蚓和正颤蚓.群落年均密度和生物量分别为594.6ind./m~2和0.54g/m~2.双因素方差分析表明,密度和生物量无季节变化,但存在显著的空间差异,两者均是上游中游下游.密度和生物量与水深、透明度显著负相关,前者与水柱混合水样的TN和TP、与底部局部水样的TP显著正相关,后者与水柱混合水样的TP显著正相关.逐步回归分析表明,水深是密度和生物量的唯一最优解释因子,随水深增加密度和生物量均呈指数式下降. 相似文献
11.
The Mill Run watershed is a structurally-controlled synclinal basin on the eastern limb of the Massanutten Mountain complex of northwestern Virginia. Bedrock contacts are obscured by coarse sandstone debris from exposures near basin divides. Colluvium blankets more than half the basin, masking geomorphic surfaces, affecting vegetation patterns, and contributing to the convexity of the alluvial, terrace, pediment and erosion surfaces. Examination of the bedrock geology, geomorphology, soils and vegetation shows distinct distributional correspondences. Vegetation is strongly interdependent with geomorphology, bedrock geology, and soils. On convex colluvial slopes, mixed hardwood forests are most common. In concave coves and deep gorges, mixed hardwoods are replaced by conifers. In thin colluvium, in poorly developed soils, and on blockfields, chestnut oak is singularly prevalent. Conifers dominate shaley bedrock areas. Soils and surficial sediments have a major effect on near-surface hydrology. During wet seasons, cemented horizons in the subsurface cause temporary saturation in the superjacent horizons; lateral movement of soil-water effectively eliminates a vertical component of ground-water recharge. Vegetation is strongly dependent on water availability and thus reflects the distribution of subsurface barriers and sediment-soil fades changes. 相似文献
12.
Drop calorimetry measurements between 900 and 1850 K are reported for amorphous anorthite, andesine, wollastonite, diopside, cordierite and pyrope. The isobaric heat capacities of the glassy and liquid phases of these materials, and the enthalpies of fusion of the minerals have been derived. The calorimetric entropies of fusion of these substances and of other oxide minerals are generally consistent with the calculated volume changes on melting and with the observed pressure dependences of the melting points. The thermodynamics of mixing of liquid plagioclases have been examined, and it is concluded that their enthalpies of mixing are markedly different from the values derived directly from solution calorimetry measurements at 985 K. 相似文献
13.
Michael O. Garcia Diane Hanano Ashton Flinders Dominique Weis Garrett Ito Mark D. Kurz 《Bulletin of Volcanology》2012,74(6):1445-1463
The size, shape, and magmatic history of the most recently discovered shield volcano in the Hawaiian Islands, Mahukona, have been controversial. Mahukona corresponds to what was thought to be a gap in the paired sequence (Loa and Kea trends) of younger Hawaiian volcanoes (<4?Ma). Here, we present the results of marine expeditions to Mahukona where new bathymetry, sidescan sonar, gravity data, and lava samples were collected to address these controversies. Modeling of bathymetric and gravity data indicate that Mahukona is one of the smallest Hawaiian volcanoes (～6,000?km3) and that its magmatic system was not focused in a long-lived central reservoir like most other Hawaiian volcanoes. This lack of a long-lived magmatic reservoir is reflected by the absence of a central residual gravity high and the random distribution of cones on Mahukona Volcano. Our reconstructed subsidence history for Mahukona suggests it grew to at least ～270?m below sea level but probably did not form an island. New 40Ar–39Ar plateau ages range from 350 to 654?ka providing temporal constraints for Mahukona’s post-shield and shield stages of volcanism, which ended prematurely. Mahukona post-shield lavas have high 3He/4He ratios (16–21?Ra), which have not been observed in post-shield lavas from other Hawaiian volcanoes. Lava compositions range widely at Mahukona, including Pb isotopic values that straddle the boundary between Kea and Loa sequences of volcanoes. The compositional diversity of Mahukona lavas may be related to its relatively small size (less extensive melting) and the absence of a central magma reservoir where magmas would have been homogenized. 相似文献
14.
Dynamics of dissolved major (Na,K, Ca,Mg, and Si) and trace (Al,Fe, Mn,Zn, Cu,and Cr) elements along the lower Orinoco River 
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下载免费PDF全文 Abrahan Mora Jürgen Mahlknecht Juan Carlos Baquero Alain Laraque Juan A. Alfonso Daniel Pisapia Laura Balza 《水文研究》2017,31(3):597-611
This study addresses the changes in dissolved major and trace element concentrations along the Orinoco River, including the mixing zone between the Orinoco and Apure Rivers. Water samples from the Apure and Orinoco Rivers were collected monthly in four sectors over a period of 15 months. Auxiliary parameters (pH, dissolved oxygen, conductivity, and temperature), total suspended sediments, dissolved organic carbon (DOC), and major (Na, K, Ca, Mg, and Si) and trace (Al, Fe, Mn, Zn, Cu, and Cr) element concentrations were measured in all sectors. The relative contribution of both rivers after the Apure–Orinoco confluence was determined using Ca as a tracer. Moreover, a mixing model was developed to determine whether dissolved species exhibit a conservative behavior during mixing. The results indicate that DOC is removed from waters during the Apure–Orinoco mixing, probably due to absorption of DOC on mineral phases supplied by the Apure River. Dissolved Na, Ca, and Mg behave conservatively during the mixing processes, and their concentrations are controlled by a dilution process. The anomaly in the temporal pattern of K in the Orinoco is caused by the input of biogenic K originating from the Apure River during the high‐water stage. The loss of dissolved Si during the low‐water stage can be explained by the uptake of Si by diatoms. Dissolved Mn, Zn, Al, and Fe showed a non‐conservative behavior during the Apure–Orinoco mixing. The removal of Mn and Zn from the dissolved phase can be explained by the formation of Mn‐oxyhydroxides and the scavenging of Zn onto Mn oxides. Dissolved Fe is controlled by redox processes, although the removals of Fe and Al due to the preferential adsorption of large organometallic complexes by mineral surfaces after the Apure–Orinoco confluence can affect the mobility of both elements during transport. The conservative behavior shown by Cu and Cr can be related to the tendency of both elements to be complexed with small organic colloids, which are not preferentially adsorbed by clays. 相似文献
15.
Geology and isotopic composition of helium,neon, xenon and metallogenic age of the Jinding and Baiyangping ore deposits,northwest Yunnan,China 总被引：23，自引：0，他引：23
TheJindingoredeposit,locatedinthenorthwestYunnanProvince,isthelargestPb-Zndeposit(Pb Zn>15Mt1),averagingZn=6.08%andPb/Zn=1/4.7)inChinaatpresent.Toitsnorth,alargeCu-Co-AgdeposithasbeenfoundatBaiyangpingrecently1).TheJindingPb-Zndepositishostedinsandstonesa… 相似文献
16.
Abu Sayeed Shafiuddin Ahmed Mohammad Belal Hossain Saad Mohammad Omar Faruque Babu Moshiur Rahman Jun Sun Mohammad Shafiqul Islam Sarker 《国际泥沙研究》2022,37(1):83-96
Sediment samples from the Gomti River basin were investigated to determine and evaluate trace metal concentrations,their biological effect,and potential ecological and human health risks for adults and children.The mean concentrations of trace metals were organized in the descending order of mercury(Hg)(0.08 mg/kg)>chromium(Cr)(0.06 mg/kg)>lead(Pb)(0.05 mg/kg)>arsenic(As)(0.02 mg/kg)>cadmium(Cd)(0.01 mg/kg).The current study illustrated that metals were attributed to the area from natural sources and different anthropogenic sources especially from industries.However,the concentration levels were lower than the sediment quality guidelines(SQGs)based on the effect-range classifications of threshold effect concentration(TEC)and probable effect concentration(PEC).Therefore,the concentration of the elements showed no adverse biological effects on aquatic organisms.The evaluated potential ecological risk index also revealed the low toxicity to the aquatic environment.Moreover,the applied sediment quality indices,geo-accumulation index(Igeo),contamination factor(CF),and contamination severity index(CSI)suggested that the contamination levels of the elements were in the acceptable range,and the contamination had not notably impacted on the sediment quality.The risk index(HI)concerning age groups was significantly less than the threshold limit of 1 indicating that the contamination had no non-carcinogenic risk effect.The total carcinogenic risk(TCR)was less than a risk value of 1×104.Hence,the current study suggests that immediate remediation is not required due to an absence of alarming conditions in the study area.Proper monitoring of the attribution of the metal elements should be done for the betterment of human and environmental health。 相似文献
17.
Facets of uncertainty: epistemic uncertainty,non-stationarity,likelihood, hypothesis testing,and communication 总被引：1，自引：1，他引：0
Keith Beven 《水文科学杂志》2016,61(9):1652-1665
ABSTRACTThis paper presents a discussion of some of the issues associated with the multiple sources of uncertainty and non-stationarity in the analysis and modelling of hydrological systems. Different forms of aleatory, epistemic, semantic, and ontological uncertainty are defined. The potential for epistemic uncertainties to induce disinformation in calibration data and arbitrary non-stationarities in model error characteristics, and surprises in predicting the future, are discussed in the context of other forms of non-stationarity. It is suggested that a condition tree is used to be explicit about the assumptions that underlie any assessment of uncertainty. This also provides an audit trail for providing evidence to decision makers.
Editor D. Koutsoyiannis; Associate editor S. Weijs 相似文献
18.
In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization. 相似文献
19.
M. J. Defant S. Sherman R. C. Maury H. Bellon J. de Boer J. Davidson P. Kepezhinskas 《Journal of Volcanology and Geothermal Research》2001,107(1-3)
Saba is the northernmost volcano along the Lesser Antilles island-arc chain. The Lesser Antilles arc results from the west-northwest subduction of the Atlantic lithosphere beneath the Caribbean Plate. Sediment thickness along the trench decreases northward away from sediment sources on the continent of South America. We focused our attention on Saba precisely because it is the furthest away from documented geochemical effects in the southern arc volcanics of the large sediment thicknesses — normally attributed to both source or upper level contamination (i.e. assimilation).Field mapping, petrology, mineralogy, K–Ar dating, and geochemical analyses (major and trace element) indicate a complex history of magma petrogenesis including crystal fractionation, magma mixing, and, surprisingly, crustal assimilation. This is the first time assimilation has been documented in the northern section of the Lesser Antilles arc. Magma mixing shows up in the field as banded pumice and petrographically and mineralogically as complex zoning in phenocrysts (such as reverse zoning in plagioclase), disequilibrium mineral assemblages (e.g. quartz and olivine), and disequilibrium between minerals and whole-rock compositions (e.g. forsterite content of olivine). Mass-balance modeling of major and trace elements support our contention that crystal fractionation (including amphibole) played an important role in magma evolution. However, various geochemical trends can only be explained by assimilation-fractional crystallization based on the fact that the trends of various trace elements and trace-element ratios vary with increasing silica. Finally, we could find no evidence of sediment source contamination in the most mafic rocks. It may exist but is overprinted by the later assimilation effects. 相似文献
20.
Sun, climate, hunger, and mass migration 总被引：9，自引：1，他引：8
Kenneth J. Hsu 《中国科学D辑(英文版)》1998,41(5):449-472
Paleoclimatic studies indicate four epochs of global cooling during the last 4 000 years, i. e. during the few centuries before
and after 2000 BC, 800 BC, 400 AD, and 1 600 AD; the quasiperiodicity corresponds to cyclic variation of solar activity. Global
temperature changes influenced regional precipitation patterns: Northern Europe was wetter while the middle- and low-latitude
lands were more arid during colder epochs. Both sets of cold climatical conditions were unfavorable for agricultural production.
Historical records show that large demographic movements in history took place because of crop failures and mass starvation,
rather than escaping from war zones. The “wandering” of the Germanic tribes during the first two or three centuries of the
Christian Era is one example. Whereas the accelerated release of carbon dioxide from the burning of fossil fuels is ultimately
to cause global warming, historical evidence indicates, however, that global warming has been on the whole a blessing to mankind.
Global cooling, on the other hand, has curtailed agricultural production and has led to famines and mass migrations of people.
Perhaps the most important task at the present is not so much computer-modelling of greenhouse effect on global climate, but
water-management and agricultural researches to insure food-supply for an everincreasing world population. 相似文献