蚂蚁河大型底栖无脊椎动物及其与环境响应关系研究

本文通过典型对应分析(CCA)和相关分析研究了大型底栖动物群落结构和主要环境因素之间的相关性,并通过生物多样性指数(如Shannon-Wiener指数)评估了不同河段对物种多样性的影响。研究表明,蚂蚁河中的大型底栖动物分布主要影响环境因子有水温、溶解氧和底质层中沙泥含量,与下游相比,蚂蚁河中上游的底栖动物物种多样性更高,平均生物密度更低。     

白洋淀底栖动物群落影响因子研究

基于2016年春、夏、秋3季的调查采样,采用典范对应分析(canonical correspondence analysis,CCA)研究底栖动物群落结构和分布对水环境因子和底泥环境因子的响应,识别影响底栖动物群落分布的关键环境因子。CCA结果显示,水环境因子中透明度、叶绿素a、水深、水温、溶解氧、氨氮、硝氮和氧化还原电位是影响底栖动物分布的主要因子;底泥环境因子中底质中值粒径、沉水植物生物量和氨氮含量是影响底栖群落分布的主要因子。优势物种摇蚊科和颤蚓科对高污染物浓度环境适应性更好。水体中氮、磷对底栖动物影响显著,而底泥中氮、磷的影响较小,可以通过氮磷的吸附转移降低水体污染对底栖动物的胁迫。     

昆承湖大型底栖动物时空分布及对环境修复的指示性

2015年对常熟市昆承湖的大型底栖动物进行了时空分布调查,开展了水质生物学评价与环境影响因子分析,并基于底栖动物分布特征对昆承湖2006—2012年环境修复工程效果进行初步评估。结果表明:4次调查共采集底栖动物12科22种,优势物种多为耐污型;底栖动物年均密度为38.3 ind/m~2,各季节密度分布存在差异,但均以摇蚊幼虫类密度占优,其次为寡毛类和软体动物,底栖动物年均生物量为24.54 g/m~2,主要为软体动物所贡献;底栖动物Shannon-Wiener多样性指数值(H')、Margalef多样性指数值(D)、Pielou均匀度指数值(J)和BI指数值表明,昆承湖总体处于中度污染状态;不同湖区因污染程度等环境因素不同,底栖动物物种、密度与生物量分布存在差异,典范对应分析表明水体DO、浊度、TN、TP等水质因子以及底泥TN、总有机物等是影响底栖动物分布的主要环境因子;昆承湖实施封闭湖泊口门、深度清淤等环境修复措施后,水质总体得到改善,但湖泊水深增大、基底形态单一以及水生植物分布少等因素也影响了湖泊底栖动物密度与种群分布。     

梯级水库对南渡江干流底栖动物丰枯水期沿程变化的影响

为探讨梯级水库影响下河流底栖动物种群在河流丰枯水期的沿程变化规律,通过对丰水期(8月)和枯水期(1月)采样处理和计量鉴定,对我国大型热带河流——海南南渡江干流的底栖动物的生物量、丰度、多样性、均匀度在丰枯水期的沿程变化进行了分析。结果表明:丰枯水期共检测出底栖动物2门4纲22种,各物种丰度在0～236个/m~2之间,生物量在0.27～31.5g/m~2之间;底栖动物种群结构沿程变化受梯级水库建设影响较大;丰、枯水量变化对底栖动物群落影响显著,受枯水期水库蓄水大幅度改变水流连通性影响,枯水期底栖动物种类沿程变化幅度大于丰水期;与温带河流不同,南渡江干流大多数底栖动物种类在冬季仍能较好繁殖,枯水期底栖动物丰度和生物量均大于丰水期。     

大纵湖大型底栖生物群落结构及水质生物学评价

大纵湖位于长江、淮河两大水系交融的里下河地区洼地中心地带,是江苏省级规划保护的重点湖泊之一。近20 a来,在人类活动影响下,大纵湖生态环境受到了严重挑战。底栖动物是水生态系统中的重要组成部分,在能量流动和物质循环中起着承上启下的作用。于2015～2016年对大纵湖底栖动物群落分布特征进行了监测分析。结果表明:在调查期间,大纵湖共采集出底栖动物10种(属),其中寡毛类、摇蚊幼虫、软体动物及其它底栖动物平均密度分别为132.27,100.52,82.02,5.29 ind./m~2,平均生物量分别为1.52,0.61,168.74,0.02 g/m~2。底栖动物密度与生物量均呈现出时空分布不均匀的特征。大纵湖底栖动物优势种主要为苏氏尾鳃蚓、霍甫水丝蚓、中国长足摇蚊和环棱螺。基于调查结果,选用4种不同的生物指数(BPI生物学指数、Shannon-wiener指数、Goodnight生物学、Wright指数)对大纵湖进行水质生物评价,结果表明大纵湖目前处于轻度-中度污染阶段。     

西南水电站建成后底栖动物与环境因子的灰关联分析

底栖动物作为河流生态系统的组成部分,在物质与能量转换中发挥着重要的作用,水库的修建对底栖动物的影响日益受到关注。本文通过收集水电站建成后的底栖动物及其环境因子的数据,采用灰关联方法确定底栖动物的关键环境制约因子,计算分析得到总磷与底栖动物关联度最高,关联度0．6828。通过有效控制关键环境因子,促进底栖动物群落多样性的维持,对于维系河流生态系统的健康具有重要的现实意义。     

漓江大型底栖无脊椎动物及其与水环境的关系

为研究漓江上游水库为下游河道枯季航运补水所造成的水生态影响,对漓江大型底栖无脊椎动物空间分布特性与相应的水环境因子进行调查,并采用Shannon-Wiener指数、Simpson指数、均匀度、丰富度指数分析物种多样性。结果表明:纹石蚕、黑龙江短沟蜷为上、中游优势种;纹石蚕、黑龙江短沟蜷、河蚬为下游优势种;纹石蚕、黑龙江短沟蜷为整个漓江水系的优势种。Shannon-Wiener指数、Simpson指数、均匀度、大型底栖无脊椎动物的平均密度和平均动物量均呈现出下游大于中游、中游大于上游的趋势;而物种丰富度指数呈现出下游小于中游、中游小于上游的趋势。大型底栖无脊椎动物和环境因子的典范对应分析表明:温度、电导率、盐度、浊度、水深、总磷、化学需氧量为影响大型底栖无脊椎动物群落结构和分布的主要环境因子。     

黄河流域干旱区湖泊冰封期浮游植物群落结构特征及影响因子研究

为研究黄河流域上游干旱地区湖泊冰封期浮游植物群落结构及影响因子,选取干旱区典型湖泊——乌梁素海、奈伦湖为研究对象,于2019年3月冰封期进行采样调查,分析冰封期湖泊营养状态特征与浮游植物物种组成、数量及多样性指数,利用冗余分析(RDA)揭示浮游植物物种与环境因子影响关系,并运用方差分解分析主要环境因子的影响程度。结果表明,冰封期水体浮游植物共6门21属29种,其中硅藻12属16种,占据全部物种的55.2%;不同采样点浮游植物数量、生物量变化范围为3.2×10~4～1.4×10~5cells/L和0.047～0.328 mg/L,主要优势种以尖针杆藻(Synedra acus)、美丽星杆藻(Asterionella formosa)、双头辐节藻(Stauroneis anceps)等硅藻为主;不同浮游植物多样性指数H′范围0.70～1.74,介于中度污染,表明研究湖泊浮游植物多样性相对较差;不同采样点位之间浮游植物群落相似性主要处于Ⅱ、Ⅲ等级,即极不相似和轻度相似,表明各采样点之间浮游植物群落结构具有较为明显的差异。RDA分析结果表明,影响浮游植物物种分布的主要环境因子水温、总氮和硝酸盐;方差分解分析进一步显示,营养因子(总氮和硝酸盐)单独对优势种物种分布解释量达到33.66%,理化因子(水温)单独对优势种物种分布解释量达到13.24%。     

渭河流域水生态系统健康评价

渭河系黄河最大支流,渭河流域河流水生态系统健康与黄河高质量发展息息相关。2011—2013年在渭河流域进行了4次野外采样调查,共布设采样点77个,采集鱼类、底栖动物、着生藻类和水环境因子等信息,分析了渭河流域水生态系统特征,并采用生物完整性指数法对渭河流域水生态系统健康进行了评价。渭河流域共采集到鱼类51种,底栖动物116种,着生藻类248种,影响渭河流域鱼类群落结构的环境因子为海拔,影响底栖动物群落结构的环境因子为河宽、电导率和硬度,影响着生藻类群落结构的环境因子为河宽。水生态系统健康评价结果表明:底栖动物和着生藻类健康状况优于鱼类,超过80%的采样点处于一般以上健康水平;3种生物水生态系统健康评价结果整体趋势相同,渭河干流上游和右岸支流、泾河源头以及北洛河中游支流健康状况较好,渭河中游和下游地区、泾河大部分区域以及北洛河上游健康状况较差。     

漓江大型底栖动物空间分布及水力驱动因子

大型底栖动物群落结构及其分布是评价河流生态健康的重要指标。基于典型水文年丰、枯两季调查,分析了漓江流域中、下游典型河段底栖动物群落结构空间分布格局、摄食类群及其与水力要素的响应关系。结果表明:①典型河段群落结构中腹足纲个体占优,优势物种为中华圆田螺和短沟蜷;丰水期底栖动物密度为829 ind/m²,枯水期为264 ind/m²;②摄食类群中刮食者占优势,且滤食者、收集者和捕食者枯水期的相对丰度高于丰水期,刮食者枯水期的相对丰度低于丰水期,摄食类群中游的相对丰度大于下游;③典型河段生物多样性呈现空间异质性,且中游明显低于下游;④流速、底部剪切力及底质粒径是影响漓江底栖生物枯水期分布的主要因素,水深和层流层厚度则是影响丰水期分布的主要因素,分选系数、层流层厚度是底栖生物多样性最主要的影响因素。研究成果可为变化水力条件下漓江水生态修复提供支持。     

扬州境内湖泊浮游植物群落结构与环境因子的关系

2013年5月—2014年5月对扬州境内3个湖泊(高邮湖、邵伯湖和宝应湖)的浮游植物群落组成与水环境因子进行监测,运用相关系数法和典范对应分析(CCA)法分析了浮游植物群落结构与环境因子之间的关系。结果表明:3个湖泊的群落组成均主要以硅藻、绿藻为主要优势种群,群落结构的季节变化趋势较为相似;水温、N、P是影响3个湖泊浮游植物数量的主要环境因子;CCA分析结果表明,水温和TN是影响高邮湖浮游植物群落分布的主要环境因子,NH⁺₄-N、TP和pH是影响邵伯湖浮游植物群落分布的主要环境因子,COD_Mn、NH⁺₄-N和TP是影响宝应湖浮游植物群落分布的主要环境因子。     

Spatial distribution of diatom assemblages in the surface sediments of Selin Co,central Tibetan Plateau,China, and the controlling factors

Currently there are few studies on modern diatom ecology in large lakes on the Tibetan Plateau. To illustrate spatial patterns of diatom communities and study the correlation with environmental variables, 143 surface sediments were sampled from the largest lake (Selin Co) on the central Tibetan Plateau. A total of 143 diatom species belonging to 30 genera were identified, most of which were halophilic and basophilic species. Our results show that diatom communities exhibit a distinct spatial pattern in different environments including fluvial rivers, the inlet of Selin Co, the small lake region and the large lake region of Selin Co. Based on a depth-constrained cluster analysis, the diatom taxa were divided into three different communities: the shallow sedimentary zone (0–12 m), middle sedimentary zone (12–22 m) and deep sedimentary zone (22–48 m). The dominant species were Cocconeis placentula, Nitzschia hungarica and Anomoeoneis costata respectively. Through Canonical correspondence analysis, it was indicated that the spatial distribution of the diatom assemblages was mainly influenced by water depth, grain size and temperature, with water depth being the dominant factor. WA-PLS and WA regression models were used to establish a diatom-depth transfer function (r²_boot = 0.73, RMSEP = 0.19; r²_boot = 0.76, RMSEP = 0.19), further demonstrating the correlation between the diatom community and water depth. Our results defined the spatial distributions and controlling factors of diatom assemblages from the different environments.     

Imbalance of plankton community metabolism in eutrophic Lake Taihu, China

Studies suggest that oligotrophic lakes are net heterotrophic and act as net sources of CO₂, whereas eutrophic lakes are net autotrophic and act as net CO₂ sinks. Data on plankton community metabolism in Lake Taihu contradict this hypothesis. Here, the ratios of depth integrated gross primary production (GPP) to plankton community respiration (PCR) were less than one on 75% of the study sampling dates, indicating that this system was net heterotrophic. Partial pressure estimated for CO₂ also indicated that the lake was a net source of CO₂. Net heterotrophic conditions here may be related to limitation of phytoplankton photosynthesis by the poor underwater light climate (due to elevated suspended solids (SS) and nutrients originating in the catchment) and the preferential enhancement of respiration by high water temperatures. GPP and PCR were significantly correlated (PCR = 1.22GPP + 0.46, r² = 0.80) indicating a partial dependence of heterotrophs on algal derived carbon. The slope of the regression line relating PCR to GPP was more similar to slopes found in rivers than in lakes, likely due to the large nutrient and SS load to the lake.     

Community dynamics and function of algae and bacteria during winter in central European great lakes

Abundant phytoplankton and bacteria were identified by microscopy and high-throughput 16S rRNA tag Illumina sequencing of samples from water- and ice phases collected during winter at two central European Great Lakes, Balaton and Fertő (Neusiedlersee). Bacterial reads at all sites were dominated (>85%) by Bacteroidetes and Proteobacteria. Amongst phototrophs, microscopy and 16S sequencing revealed that both phytoplankton and cyanobacteria were represented, with a median of 1500 cyanobacterial sequence reads amongst 13 samples analyzed. The sequence analysis compared replicate Balaton and Fertő ice and water samples with an outgroup from three Hungarian soda lakes. In particular, both water and ice from Fertő contained high contributions from cyanobacteria. Two percent of total reads identified to the level of family in water at Fertő were dominated by a single operational taxonomic unit (OTU) of a cyanobacterium within the Rivulariaceae, which was largely absent from ice. Conversely, ice samples from both lakes yielded an abundant OTU assigned to a Flavobacterium sp. known to be associated with freshwater ice. Principal Coordinates Analysis (PCoA) revealed that the ice communities from all sites were similar to one another, and that the water communities did not cluster together. Fluorescence emission spectra obtained at 77 K confirmed the presence of intact cyanobacteria in Fertő water and ice. Photosynthetic characterization of phototrophs resident in water and ice analyzed by assay of acid-stable photosynthetic H¹⁴CO₃^– incorporation showed that communities from both phases were photosynthetically active, thus adding to growing recognition of ice-covered lakes as viable habitat for phototrophs.     

Investigation of Aksehir and Eber Lakes (SW Turkey) Coastline Change with Multitemporal Satellite Images

Detection and analyses of coastline changes are an important task in environmental monitoring. Several factors such as geology, hydrology, climate impact, environmental problems etc. play an important role in this change. The main objective of this study is to determine coastline change in the Aksehir and Eber lakes (SW, Turkey) by using different remote sensing methods on the multitemporal satellite images. In present study, Landsat MSS (1975), Landsat TM (1987), Landsat ETM+ (2000) and ASTER (2006–2008) satellite images were used. In order to explain reasons of coastline change, geological, hydrogeological and hydrological investigations were carried out. Also, surface area and volume calculations were performed with the aid of bathymetric map which was digitized by using the Arc GIS 9 version software program. The obtained data show that precipitation, evaporation and surface flow are effective in the Aksehir and Eber coastline change. The Eber Lake was evaluated with level measurements due to aquatic plants covered surface of the lake. The coastline change of the Eber Lake is related to hydraulic factors. The Aksehir Lake volume and surface area have decreased 1.11 km³ and 257.95 km², respectively from 1975 to 2006 years. Furthermore, the Lake Akşehir was dried up completely in 2008.     

Towards better water security in North China

Water shortages and related environmental degradation in North China are major issues facing the country. As runoff from the mountainous parts of the region steadily decrease and water resources become overcommitted, serious water and environmental problems have resulted. These include drying-up of rivers, decline in groundwater levels, degradation of lakes and wetlands, and water pollution. Thus, 4000,km of the lower reaches of the Hai River – some 40% of its length – has experienced zero flows and, as result, parts of this river have become an ephemeral stream. The area of wetland within the Basin has decreased from 10,000,km² at the beginning of 1950s to 1,000km² at present. Over-extraction of groundwater occurs beneath 70% of the North China Plain, with the total groundwater over-extraction estimated at 90,billion m³. Thus, problems of water shortage and related environmental issues in North China have become the most significant limiting factors affecting sustainable development in this important region of China. This paper addresses the water security issues facing North China in the 21st Century using the Hai River basin as an example. We describe hydrologic cycles under changing environments, water-saving agriculture, assessment of water resource security, and efforts towards achieving integrated catchment management.     

Spatial and temporal variations of dissolved CO2, CH4 and N2O in Lakes Edward and George (East Africa)

We report dissolved CO₂, CH₄ and N₂O concentrations in two large East African lakes, Edward (surface area 2,325 km², average depth of 37 m) and George (surface area 273 km², average depth of 2 m). Lake George showed modest seasonal and spatial variations, and lower partial pressure of CO₂ (pCO₂) (26 ± 16 ppm, mean ± standard deviation), CH₄ (234 ± 208 nmol/L) and N₂O saturation levels (%N₂O) (80 ± 9 %) than Lake Edward (404 ± 145 ppm, 357 ± 483 nmol/L, 139 ± 222 %). Surface waters in both lakes were over-saturated in CH₄, and Lake George was under-saturated in CO₂ while Lake Edward was slightly over-saturated in CO₂. This difference was related to higher phytoplankton biomass in Lake George than Lake Edward, with average chlorophyll-a concentrations of 177 ± 125 and 18 ± 25 µg/L, respectively. Permanent high cyanobacterial biomass in Lake George led to uniform dissolved CO₂, CH₄ and N₂O concentrations. In surface waters of Lake Edward, spatial variations of pCO₂, CH₄ and N₂O were related to bottom depth, and locally (in particular in Katwe Bay) also related to the inputs of water from Lake George via the Kazinga Channel, a 40-km natural channel connecting the lakes. Short-term mixing events related to storms increased CO₂, CH₄ and N₂O content in surface waters, in particular for CH₄ and N₂O. This indicates that mixing events in response to storms can create ‘hot moments’ for CH₄ and N₂O emissions to the atmosphere in tropical lakes, given the weaker vertical density gradients compared to higher latitude systems.     

沉积物-水界面中可交换态氮对不同菹草密度的响应

为了认清沉水植物对富营养化浅水湖泊沉积物-水界面可可交换态氮的影响,通过模拟试验,利用连续流动注射分析仪测定了NO-3-N、NH3-N等指标,并结合其他环境指标,研究了沉积物-水界面中TN、NO-3-N、NH3-N对不同菹草量(0 g、150 g、300 g)的响应。结果表明,菹草的存在增加了间隙水氧化还原电位(Eh),降低了p H,且菹草量越大,间隙水中Eh、p H值变化越明显;利用单因素方差分析,得出300 g菹草组与对照组的间隙水TN质量浓度有显著差异(P0.05);菹草量越大,间隙水中TN、NO-3-N和NH3-N以及表层沉积物中固定态铵、有机氮、NH3-N和NO-3-N的去除效果越好。     

Thermal habitat characteristics for warmwater fishes in coastal embayments of Lake Ontario

Along 40 km of the Lake Ontario shoreline near Toronto, Ontario, small coastal embayments (4.38-848 × 10³ m²) have been constructed or modified by lake-infilling to restore warmwater fish habitat. We describe how the thermal regimes of these embayments differ from those of small inland lakes, how embayment bathymetry alters the degree of exchange with Lake Ontario, and predict how embayment thermal regimes affect warmwater fish growth. The accumulated growing-degree days, calculated from a 14 °C baseline (∑ GDD₁₄), of seven South-Central Ontario inland lakes and an embayment disconnected from Lake Ontario ranged from 844 to 1157 GDD. Compared to the inland lakes and disconnected embayment, the coastal embayments connected to Lake Ontario achieved fewer ∑ GDD₁₄ and had a greater range, 390-1047, reflecting differences in their degree of exchange with and the cooling effect of Lake Ontario. The thermal regime of coastal embayments differs most from inland lakes during May-late-July. During early summer, mean embayment depth explains over 50% of the variability in ∑ GDD₁₄, with deeper embayments cooling more from lake exchange than shallow embayments. After mid-summer, the cooling embayments are warmed by exchanges with Lake Ontario. This late-summer warming is insufficient to compensate for the cooling effect of the Lake earlier in the summer. Bioenergetic simulations of bluegill, Lepomis macrochirus, growth indicate that most of these embayments are too cool for adequate summer growth of YOY sunfish. Nevertheless, small coastal embayments that are shallow with suitable controls on exchange with the Lake can provide acceptable warmwater fish habitat.     

基于遥感的1973-2015年武汉市湖泊水域面积动态监测与分析研究

近年来,武汉市城市内涝频发,湖泊的减少被认为是导致其发生的重要原因。然而目前尚未有一个统一、科学的数据来表示整个武汉市湖泊的历史变迁。为了掌握近几十年武汉市湖泊的时空变化规律,基于多源遥感数据,采用归一化差异水体指数（NDWI）和面向对象分割结合的水体提取算法,对1973-2015年武汉市的湖泊分布进行了提取,并结合武汉市气象资料和统计年鉴对引起其变化的影响因素进行了分析。结果如下：（1）1973年,武汉市辖区内的湖泊水域面积为1170.84 km²,2015年为856.27 km²,42年间减少了314.57 km²,剧烈减少时期发生在1973-2005年,2005年以后,基本趋于稳定。（2）1973年武汉市中心城区湖泊水域面积为148.90 km²,1973年到1996年,湖泊水域面积基本趋于稳定,而在1996年之后,武汉市中心城区湖泊水域面积开始剧烈减少,2010年之后,武汉市中心城区的湖泊水域面积基本趋于稳定;2015年,武汉市中心城区湖泊水域面积为99.94km²,相对于1973年,减少了48.96 km²。（3）1973年到2015年,武汉市年降水量呈现略增加的趋势,年平均气温则有一定的增加趋势;而在1990年之后,武汉市人口的增加、城镇的快速发展及房地产开发导致了大量的湖泊被侵占;气候变化和人类活动共同导致了武汉市的湖泊水域面积减少,其中人类活动是其变化的主要因素。