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1.
嘉陵江南充段硅藻群落结构及水环境分析   总被引:4,自引:1,他引:3  
为了揭示嘉陵江流经南充A段5县(市)受到的污染及水质状况,按枯水期、平水期和丰水期采集研究15个采样点的硅藻样品,分析其群落结构的物种组成、细胞密度、多样性指数和均匀度指数等,并结合化学指标对水质状况进行评价。结果表明:(1)嘉陵江南充段共有硅藻136种(含变种和变型);细胞密度介于4500--39000ind/L之间,总平均18213ind/L;(2)硅藻物种数、细胞密度、均匀度指数及多样性指数等呈现出显著季节性和水平分布上的差异;(3)嘉陵江南充“段水质总体上属于β-中污水体,具有一定的自净能力。其中,阆中水质最好,属清洁水体;南部、仪陇和蓬安水质有所下降,介于β-中污与清洁水体之间;南充水质较差,属α-中污水体。  相似文献   

2.
嘉陵江下游硅藻群落结构及物种多样性研究   总被引:9,自引:0,他引:9  
于2006年11月,2007年2月、5月和8月,分别采集嘉陵江下游8个采样点藻类样品,分析其硅藻群落结构及物种多样性,并利用物种多样性指数及硅藻商等对水质进行了生物学评价。结果表明:(1)共发现89种硅藻,硅藻细胞密度变幅为0.57×104—4.51×104ind/L,总平均2.31×104ind/L;多样性指数值变幅为0.72—3.12,总平均2.20;均匀度指数值变幅为0.15—0.52,总平均0.36;硅藻商变幅为0.66—9.48,总平均3.24。(2)硅藻群落结构呈现出季节和水平分布上的变化。在季节变化上,物种丰富度、细胞密度及多样性指数等以温度较低的春(5月)、秋(11月)两季最高,而以夏季(8月)最低。在水平分布上,从上游到下游,硅藻群落结构呈现出物种丰富度、多样性指数值逐渐减小,而细胞密度和硅藻商逐渐增加的趋势。(3)嘉陵江下游水质总体为β-中污水体。其中位于城市上游的云门、沙溪、温塘峡、井口水质较好,为微污或β-中污水体,而位于城区及下游的合川、毛背沱、磁器口和朝天门水质较差,为α-中污或污染水体。  相似文献   

3.
为了研究溶洞硅藻的群落结构及水质状况,于2014年4月、6月、9月和12月份别采集在毕节市七星关区层台镇玉龙村溶洞3个样点的硅藻样品,分析其物种组成、密度、多样性和均匀度指数等。结果显示:研究期内共鉴定出硅藻256种,隶属2纲5目11科25属,硅藻密度在0.5×103—4.7×103个·L-1之间,平均密度为2.8×103个·L-1。溶洞硅藻Shannon-Wiener多样性指数平均数值为2.7266,Margalef多样性指数平均数值为7.3868,Pielou均匀度指数平均数值等于0.8623。得出的结论是溶洞的4月和6月水质清洁,9月份轻度污染,12月份污染严重,营养结构属于贫营养。  相似文献   

4.
贵州高原三板溪水库浮游植物群落动态与环境因子的关系   总被引:1,自引:0,他引:1  
为探究贵州高原氮限制型大型深水水库浮游植物群落结构与环境因子的关系,分别于2012年11月(枯水期)、2013年4月(平水期)、8月(丰水期)对三板溪水库上、中、下游浮游植物和环境因子进行采样调查,共检出浮游植物6门87属,主要由绿藻、硅藻和蓝藻构成。浮游植物丰度在枯水期、平水期、丰水期分别为0.064×104~1.17×104、8.21×104~422.47×104和9.08×104~2903.33×104cells·L-1,其中枯水期和丰水期时加池丰度最高,南加丰度最低,平水期则为大坝最高、南加最低。枯水期、平水期、丰水期分别以颗粒直链藻(Melosira granulata)、钝脆杆藻(Fragilaria capucina)和具缘微囊藻(Microcystis marginata)为优势种。浮游植物集中分布于水体表层0~10 m的范围内,并随水深的增加丰度逐渐降低;三板溪水库总磷平均浓度为0.403 mg·L-1,枯水期为0.281~1.139 mg·L-1、平水期为0.394~0.639 mg·L-1、丰水期为0.054~0.736 mg·L-1,总氮平均浓度为1.38mg·L-1。氮磷比(3.7∶1)低于浮游植物生长的最佳氮磷比7∶1,表现出三板溪水库的氮限制型,与大多数淡水水体氮磷营养结构不一致。RDA分析与Pearson相关分析结果表明,水温为影响三板溪水库浮游植物群落动态的关键环境因子、氮磷比为重要的环境因子,氮磷营养盐主要通过促进硅藻及抑制蓝藻来影响浮游植物群落动态。  相似文献   

5.
三峡水库蓄水前后浮游植物调查及水环境初步分析   总被引:45,自引:13,他引:32       下载免费PDF全文
比较了三峡水库蓄水前后湖北库区干流江段及其主要支流的藻类生态特征及水质状况,结果显示,蓄水前(2002年12月至2003年6月)和蓄水后(2003年6月至2004年5月)三峡湖北库区江段藻类的群落结构和细胞密度存在明显差异。蓄水前共鉴定藻类7门66属79种,硅藻、绿藻、蓝藻分别占34.6%,38.5%和10.3%,其余藻类合计16.6%。蓄水后,藻类的总种类数增至151种,硅藻、绿藻、蓝藻所占比例依次为23.8%,55.0%和9.9%,其余藻类合计11.3%。藻类的细胞密度,蓄水前,干流平均272.6×104ind/L,支流1042×104ind/L;蓄水后,干流和支流的平均细胞密度分别高达384.8×104ind/L和2006.7×104ind/L,较蓄水前增加41.2%和92.6%,数据说明,三峡成库过程对湖北库区水生态系统中的藻类群落结构产生了影响,尤以对支流中的影响更为明显。作者通过分析蓄水后库区水质下降的原因及其负面影响,提出了相应的防治措施与建议。  相似文献   

6.
嘉陵江浮游生物群落结构研究   总被引:2,自引:0,他引:2  
为揭示嘉陵江梯级水库浮游生物群落结构特征,按枯水期和丰水期对嘉陵江12个梯级水库24个样点进行浮游生物的野外采集,分析其群落结构的物种组成,并采用Shannon-wiener指数、Margalef指数和Pielou均匀度指数进行分析.结果表明:嘉陵江四川段浮游植物共8门42科95属171种,浮游动物的组成共有4纲9目21科30属62种;浮游动物优势种类有21种.浮游生物评价结果表明梯级库区水质处于中度污染状态.  相似文献   

7.
鹤地水库浮游生物与富营养化特征分析   总被引:5,自引:0,他引:5  
林桂花  韩博平 《生态科学》2002,21(3):208-212
于2000年丰水期和枯水期调查分析了鹤地水库的营养状态及浮游生物特征.结果表明鹤地水库营养盐含量很高,综合营养状态指数评价为中-富营养化水平.浮游植物丰水期和枯水期的细胞密度分别为1 950.5~3 509.7×104 cells@L-1和130.5~231.3×104 cells@L-1,蓝藻中的微囊藻和席藻数量占细胞总数的83%以上.在丰水期和枯水期,浮游植物的群落结构均为蓝藻-绿藻-硅藻型,优势种为微囊藻和席藻.次优势种由丰水期蓝藻中的粘球藻,颤藻,绿藻中的衣藻,和硅藻中的颗粒直链藻等转变为枯水期的蓝藻门的水华束丝藻和硅藻门的颗粒直链藻等富营养化指示种.鹤地水库的浮游动物种类不多,但数量很高.丰水期的无节幼体和桡足幼体数量很多,但从优势种类来说,轮虫以曲腿龟甲轮虫,纵长异尾轮虫,剪形臂尾轮虫为主,枝角类的优势种为长额象鼻蚤;枯水期时无节幼体的数量最多,桡足幼体数量急剧下降,优势种类则转变为枝角类的长额象鼻蚤和桡足类的广布中剑水蚤.两个水期浮游动物的优势种类均是以耐污种和广布性种类为主.  相似文献   

8.
滇池入湖河流大清河河口段浮游藻类格局研究   总被引:4,自引:0,他引:4  
2006年7月至2007年12月对大清河3个样点的浮游藻类组成及密度、浮游叶绿素α浓度等指标进行逐月监测.共观察到浮游藻类65个分类单元,计53个属.所有样点的平均藻类密度是1.23×108ind·L-1,最高密度为1.39×109ind·L-1,最低密度为3.21×105ind·L-1.铜绿微囊藻(Microcystis aeruginosa)为绝对优势种,监测期间其平均相对丰度为92.23%.随着离湖距离的增加,浮游藻类总密度、铜绿微囊藻的百分含量明显降低,而香农-威纳(Shannon-Wiener)、辛普森(Simpson 1/Dominance)多样性指数和均匀度(Evenness)则呈现升高趋势.同时,样点2、3的铜绿微囊藻百分含量与滇池的极为相似,而样点1则距离滇池较远,其铜绿微囊藻的百分含量及生物多样性指数方面均不同于样点2、3,说明滇池水的倒灌已显著影响到样点2、3的藻类组成.通过比较各样点间的群落相似性指数发现:样点1、3间的相似性指数显著低于样点1、2和样点2、3间的相似性指数.样点2、3问的相似性指数除2007年4、5及7月外,均超过60%.通过对样点1、2和3的浮游藻类群落在工程运行前后进行"非度量多维标度"(NMS)分析,发现示范工程运行后的1年内还未对大清河监测河段水生生物群落的恢复有显著作用.  相似文献   

9.
大辽河水系夏季浮游植物群落结构特征及水质评价   总被引:6,自引:0,他引:6  
作为建立中国水环境生态学基准的基础性工作,于2010年7月,按照相关规范的要求,对大辽河水系浮游植物群落结构和水质状况进行了调查.结果表明:调查期间大辽河水系共检出5门124种或变种,其中以绿藻和硅藻为主,分别占43.55%和31.45%;总细胞密度在2.05×105~1.46×107个·L-1,平均6.35×106个·L-1,绿藻和硅藻占优势;主要优势种是硅藻的颗粒直链藻极狭变种(Melosira granulata var.angustissima);共检出污染指示种44种,其中β-中污带指示种居多,有36种,占所有指示种的81.81%;Shannon多样性指数为1.43 ~2.68,Margalef指数为1.00~1.78,Pielou均匀度指数为0.52 ~0.83;综合水体中浮游植物的密度、优势种类、指示种、生物多样性指数评价表明,大辽河水系处于富营养化状态、中等程度污染水平.  相似文献   

10.
亚热带大型水库——新丰江水库的浮游生物群落特征   总被引:8,自引:0,他引:8  
于2000年丰水期和枯水期,调查了新丰江水库的浮游生物群落结构,新丰江水库处于贫营养状态,浮游生物密度和生物量均较低。浮游植物34种,丰水期以蓝、绿藻为主,分别占总数量的31.7%和36.8%,蓝藻、绿藻细胞微小,chl.a量未占优势;枯水期硅藻为优势种群,占63.9%,浮游生物22种,丰水期轮虫为主,占65.3%,枯水期桡足类占81%,丰水期动物密度较高,但丰水期以轮虫如螺形龟甲轮虫为主,枯水期以无节幼体,桡足幼体及广布中剑水蚤居多,因此枯水期生物量高于丰水期。  相似文献   

11.
福建九龙江北溪浮游植物群落分布特征及其影响因子   总被引:4,自引:0,他引:4  
分别于2011年枯水期(2月)、丰水期(5月)和平水期(10月),系统调查研究了福建九龙江北溪浮游植物群落组成、丰度的分布特征及其与环境因子的关系.共鉴定浮游植物107种,隶属于7门64属.不同水文期浮游植物主要优势种类不同,枯水期为马索隐藻和梅尼小环藻,丰水期为四尾栅藻和四角十字藻,平水期则演替为微小平裂藻.不同水文期浮游植物丰度变化明显,其平均值依次为枯水期(154.77×104 cells·L-1)>平水期(76.40×104 cells·L-1)>丰水期(45.40×104 cells·L-1).相关分析表明,枯水期和平水期浮游植物丰度与铵态氮(NH4+-N)呈显著正相关,丰水期浮游植物丰度与温度呈极显著正相关.典范对应分析(CCA)表明,水体温度是影响该水域浮游植物分布格局的重要因子,溶解态活性磷浓度也对浮游植物的分布有较大的影响.CCA排序图较好显示了浮游植物物种分布和环境因子之间的关系.  相似文献   

12.
San Pedro River's wetlands sustain trophic nets in the fluvial system, due to the high habitat availability, and space and temporal variations. In order to describe the relationship between environmental parameters and ichthyofauna, this study evaluated fish assemblages composition, distribution, abundance, density, biomass, richness species, diversity and equitability in the wetlands. Sampling considered three different sites and climatic seasons (dry, rainy and cold fronts). The physical and chemical parameters considered were dissolved oxygen, temperature, pH, water transparency and the depth. Fishes were caught with a shrimp net, after six minutes towings and were identified afterwards. A total of 1 049 organisms of 25 fish species were caught, two of which were exotic species: Oreochromis niloticus and Parachromis managuense. A total of 23 species were found at site I (with the highest density 0.23 ind./m2), 17 at site II (0.23 ind./m2) and 14 at site III (0.12 ind./m2). The dry season had the highest species number with 21 species, followed by the rainy season with 17 species, and the cold season with five species. Similarly, the highest biomass (8.30 g/m2) was found in dry season, followed by the rainy (2.16 g/m2) and the cold seasons (0.03 g/m2). Considering seasons, highest density was found during the dry (0.436 ind./m2), followed by the rainy (0.213 ind./m2) and the cold (0.023 ind./m2) seasons. The dominant density species during the study period, according to the quadrants graphic of Olmstead-Tukey were: Petenia splendida, Vieja heterospila, Vieja synspila, Dorosoma petenense and Astyanax aeneus. There were significant differences in the species richness among sites. Temperature, depth and transparency showed differences among the seasons. The canonical correspondence analysis indicated that fish distribution was governed by environmental parameters during all seasons. In terms of fish abundance and composition, environmental parameters play an important role showing spatial and temporal differences in the ecosystem, this could be explained with the fact that most of young fishes have a movement behavior to the wetlands, searching refuge and feed during the dry season. Considering the diversity indexes variation, it may be concluded that San Pedro River's wetlands correspond to a system where the ichthyofauna composition fluctuates spatial and seasonally.  相似文献   

13.
Here we assessed the efficacy of performing field surveys during both dry and rainy seasons to estimate species richness and composition of phyllostomid bats in 12 sites of the Brazilian Atlantic Forest. Our goal was to elucidate two opposite scenarios. If bat species compositions differ between the dry and rainy seasons, then field surveys in both seasons will be considered complementary for estimating local bat assemblages. In contrast, if bat species compositions in the dry season are a nested subset of the species present in the rainy season, then field surveys in both seasons will be considered redundant. Our results showed that field surveys performed only during the rainy season exhibited the same efficacy in recording bat species as field surveys considering both dry and rainy seasons combined. Consequently, the rare species sampled in the rainy season contributed to the uniqueness of communities in terms of species composition. Considering that time, funding, and the number of field personnel available for work are important factors when determining the sampling effort in highly biodiverse regions like the tropics, our results can be useful in establishing protocols for research projects with limited resources aiming to create a comprehensive list of species.  相似文献   

14.
Seasonality is known to influence ant activity in many tropical rain forests in the world such as South America and Africa. We surveyed ant fauna in the leaf litter in the locality of Minko'o. The work aimed to evaluate the effect of seasonal variation on the diversity and composition of litter ants. Ants were sampled from November 2015 to June 2017, using four sampling methods: visual capture, bait, pitfall trap and extraction. Species richness, Shannon diversity index and analysis of similarities were used to characterise diversity of ant communities between seasons. We collected 306 ant species, shared out between 56 genera and 11 subfamilies. Subfamilies Myrmicinae, Ponerinae, Dolichoderinae, Formicinae, Dorylinae, Cerapachyinae and Pseudomyrmecinae occurred in all the seasons. Species richness was highest in major dry season with 243 species followed by minor rainy season with 188, major rainy season with 177 species and finally minor dry season that recorded the lowest with 155 species. Kruskal–Wallis test showed that ant species richness did not differ between seasons (p > 0.05). Species diversity index indicated that diversity was the highest during minor dry season (H′ = 4.24), followed by the major dry season (H′ = 4.23), minor rainy season (H′ = 4.21) and lowest during major rainy season (H′ = 4.06). Eight most frequents ants have been recorded: Axinidris sp.1, Camponotus flavomarginatus, Monomorium guineense, Myrmicaria opaciventris, Odontomachus troglodytes, Carebara perpusilla, Paltothyreus tarsatus and Pheidole megacephala. Assessment of the seasonal effect on diversity reveals that dry season is richer and more diverse than rainy season and the season significantly influence the diversity of litter ants.  相似文献   

15.
Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataforma Deltana" section (0.007 +/- 0.022 ind/m2 in dry season and 0.014 +/- 0.06 ind/m2 in rainy season) and in the CFI project the densities in "Golfo de Paria" section were 0.705 +/- 0.829 ind/m2 in rainy season and 1.027 +/- 1.107 ind/m2 in dry season. The most frequent size range was 3.1-4.6cm. The highest biomass was found in "Golfo de Paria" section (7.581 +/- 0.018 mg/m2 in dry season and 0.005 +/- 6.542 x 10(-06) mg/m2 in rainy season for 2004-2005 and 3.979 +/- 4.024 mg/m2 in dry season; and 3.117 +/- 3.137 mg/m2 in rainy season for 2006). A linear relationship was found between the sea star size and its weight but no relationship was observed between its size and the depth where it was collected. Mollusks are dominant in the sea star diet (47.4% in abundance). The diet in any of the sections, seasons or between projects or size class was heterogeneous, using multivariate ordinations (MDS) and SIMPER analysis and there was no difference in the prey number or food elements that a sea star can eat. Although A. marginatus has been described as a predator, in this study were also inferred scavenger and detritivorous habits.  相似文献   

16.
为了探讨西双版纳热带植物园引种植物主要定植区近地层的光合有效辐射特征及其变化规律,利用2008—2009年不同季节的小气候观测资料,分析了西双版纳热带植物园引种植物主要定植区近地层的光合有效辐射的季节和日变化特征。结果表明:西双版纳热带植物园区域的光合有效辐射具有明显的日变化和季节差异,雨季最强,旷地的光合有效辐射日总量可达406.6mol·m-2·d-1,雾凉季最弱,旷地光合有效辐射日总量为236.0mol·m-2·d-1;由于受高大树木遮蔽的影响,在沟谷林、龙脑香林和树木园的光合有效辐射数值较低;受太阳高度角变化和林冠林隙的影响,在雨季近地层光合有效辐射会出现突跃现象。各引种植物定植区近地层的光合有效辐射的数值也不同,存在地域差异和季节差异。在具有高大树木、遮蔽较大的定植区,近地层光合有效辐射的数值较小;而遮蔽较小的定植区,情况则反之,近地层光合有效辐射的季节差异与旷地相似,雨季较大,雾凉季较小。在具有高大树木、遮蔽较大的定植区,近地层光合有效辐射与旷地的比值较小,不足旷地的10%,其中在具有多层多种森林群落结构的沟谷林,其最小比值(雾凉季)仅为1.6%;而遮蔽较小的定植区比值较大(>55%)在干热季其数...  相似文献   

17.
In many tropical landscapes, agroforestry systems are the last forested ecosystems, providing shade, having higher humidity, mitigating potential droughts, and possessing more species than any other crop system. Here, we tested the hypothesis that higher levels of shade and associated humidity in agroforestry enhance coffee ant richness more during the dry than rainy season, comparing ant richness in 22 plots of three coffee agroforestry types in coastal Ecuador: simple-shade agroforests (intensively managed with low tree species diversity), complex-shade agroforests (extensively managed with intermediate tree species diversity) and abandoned coffee agroforests (abandoned for 10-15 yr and resembling secondary forests). Seasonality affected responses of ant richness but not composition to agroforestry management, in that most species were observed in abandoned coffee agroforests in the dry season. In the rainy season, however, most species were found in simple-shade agroforests, and complex agroforestry being intermediate. Foraging coffee ants species composition did not change differently according to agroforestry type and season. Results show that shade appears to be most important in the dry seasons, while a mosaic of different land-use types may provide adequate environmental conditions to ant species, maximizing landscape-wide richness throughout the year.  相似文献   

18.
研究分析刘家峡水库浮游植物群落结构的变化, 探讨西北地区河道型水库环境因素对浮游植物群落结构的影响, 为刘家峡水库增殖渔业提供科学依据。2020年3—10月, 在刘家峡水库设置11个采样点, 每月对浮游植物进行定性和定量采集, 同时采集水样监测总氮、总磷和高锰酸盐指数等水环境指标, 分析水质变化规律, 及浮游植物的优势种、多样性和群落结构的季节变化特征。结果表明: 刘家峡水库共检测到浮游植物7门35属63种, 其中硅藻门种类最多, 共17属40种; 其次为绿藻门8属12种; 蓝藻门4属4种, 裸藻门1属2种, 黄藻门2属2种, 甲藻门2属2种, 金藻门1属1种。浮游植物密度在(3.17—59.09)×104个/L, 平均密度为13.54×104个/L。浮游植物生物量在0.0370—0.5004 mg/L, 平均生物量为0.2137 mg/L。浮游植物密度和生物量均有在4、5月份上升和6月份骤然下降的趋势, 最高值均出现在5月份。多样性指数H′值在1.16—2.43, 平均值为1.84; 丰富度指数D值在1.22—1.57, 平均值为1.42; 均匀度指数J值在0.23—0.51, 平均值为0.38。丰富度指数D值变化趋势与均匀度指数J值刚好相反。RDA分析显示, 对浮游植物影响最强的环境因子是总氮和透明度, 其次为溶解氧和水温。综合浮游植物和水质指标评价刘家峡水库处于Ⅰ或Ⅱ类水, 是极贫营养至贫营养类型。研究可为刘家峡水库水生态保护和渔业资源的可持续利用提供科学依据。  相似文献   

19.
Questions: How does the seed bank respond to different types of tree‐fall gaps and seasonal variations? How does the soil seed bank influence recovery of the standing vegetation in the mature forest and tree‐fall gaps? Location: 1800 — 2020 m a.s.l., Quercus‐Pinus forest, Baja California Sur, Mexico. Methods: Seed size, species composition and germination were estimated under different environmental conditions during dry and rainy seasons: a mature forest plot and gaps created by dead standing trees, snapped‐of f trees and uprooted trees. The soil seed bank was investigated using direct propagule emergence under laboratory conditions, from soil cores obtained during both seasons. Results: 21 species, 20 genera and 14 families constitute the seed bank of this forest community. Fabaceae, Asteraceae, Euphorbiaceae and Lamiaceae were the most frequently represented families in the seed bank. Floristic composition and species richness varied according to the different modes of tree death. Species composition of seed banks and standing vegetation had very low similarity coefficients and were statistically different. Seed bank sizes varied between 164 and 362 ind.m‐2 in the mature forest plot for the dry and rainy seasons, respectively, while soil seed bank sizes for gaps ranged between 23–208 ind.m‐2 forthe dry season and between 81–282 ind.m‐2 for the rainy season. Conclusions: Seed bank sizes and germination response were always higher in the rainy season under all the environmental conditions analysed. Results suggest that timing responses to gap formation of the soil seed bank could be more delayed in this temperate forest than expected.  相似文献   

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