大伙房水库3种邻苯二甲酸酯分布特征与风险评价

大伙房水库作为辽宁省重要饮用水源地,库区水质安全具有举足轻重的作用。本研究对不同季节大伙房水库库区及主要入库河流中3种主要邻苯二甲酸酯(PAEs)的空间分布及季节变化特征进行了分析,并利用风险暴露模型对库区水体PAEs的风险特征进行了评估。结果表明,大伙房水库库区及入库河流流域中的PAEs含量均处于较低水平,在空间分布上库区中PAEs分布呈自东向西先增大后减小的趋势,在季节上具有夏季春季秋季的变化特点;主要入库河流中PAEs浓度呈自河流上游至下游逐渐增高的趋势,秋季河流水体中PAEs含量最少。在PAEs组分上,邻苯二甲酸二正丁酯(DBP)在所有采样点均有检出,DBP和邻苯二甲酸二异辛酯(DEHP)具有一定的同源性且与水中总氮、总磷浓度呈负相关。风险暴露模型结果表明,大伙房水库中DBP的非致癌风险指数均远小于1,不会对人体产生健康危害。     

三峡水库坝前水域浮游植物群落时空动态研究

于20122013 年对三峡水库坝前水域浮游植物组成、优势种、密度、生物量及多样性进行了周年季度调查, 共鉴定浮游植物151 种属, 其中绿藻门71 种, 硅藻门47 种, 蓝藻门20 种, 隐藻门和甲藻门各4 种,裸藻门和金藻门各2 种, 黄藻门1 种。浮游植物优势种的季节更替明显, 夏季和秋季优势种类为硅藻和绿藻,冬季为硅藻、蓝藻和绿藻, 春季为绿藻、硅藻和隐藻。浮游植物年均密度和生物量分别为3.95106 ind./L 和4.078 mg/L, 空间差异表现为支流和库湾远高于干流, 季节动态表现为夏季最高, 春季和冬季次之, 秋季最低。三峡水库坝前水域浮游植物多样性指数偏低, 水体污染类型属于-中污染。研究为客观了解三峡水库坝前水域浮游植物群落的空间分布与季节变化特征提供一定的参考依据。       

香溪河库湾枝角类的种类组成及垂直分布

枝角类在水库生态系统的物质循环和能量流动过程中具有重要的作用, 有关水库枝角类的研究在水库水生生物研究中历来备受重视。枝角类在深水水体中具有垂直分布的特性, 生物和非生物因素影响着包括枝角类在内的浮游动物垂直分布及垂直分布的时空变化。香溪河河口至兴山峡口段在2003 年6 月三峡水库蓄水后被没,形成香溪河库湾。因受干流库区的水体顶托, 库湾水体流速缓, 更新时间长, 容易产生富营养化现象, 香溪河库湾2004 年春季就有藻类异常繁殖现象发生。       

三峡水库神农溪库湾水体季节性分层特性

三峡水库蓄水后,较大程度改变了支流库湾原有河流生态环境。本研究对神农溪库湾2016年水温、溶解氧、叶绿素等指标垂直分层结构和季节演替规律进行分析。结果表明:神农溪库湾表层水温全年变化在10.6～32.4℃,库湾水体水温层化结构受水动力条件影响较大;春季受干流表层倒灌异重流影响水温呈"阶梯"型分布,夏季受干流中层倒灌异重流影响水温呈"双混斜"型分布,秋冬季受底层倒灌异重流影响水温呈"半U"型分布;水温分层结构对溶解氧和叶绿素垂直剖面变化有一定的影响,春夏季节水体溶解氧出现显著的分层现象,春季溶解氧分布受叶绿素a影响显著,夏季受水温影响显著。本研究将为分析三峡水库支流神农溪库湾生境条件变化提供数据支撑,为库区水环境管理与水资源利用提供科学依据。     

北京河流底栖硅藻沿城乡梯度带空间分布及其季节变化

研究了北京市区沿城乡梯度带河流底栖硅藻的空间分布及其季节变化特征。通过在2014年的春季、夏季和秋季在山区对照溪流、城市上游河道和城市下游河道3个样区,共23个样点进行了底栖硅藻样品采集。分析表明,主要优势种的空间差异明显。在对照溪流,主要优势种为极小曲丝藻(Achnanthidium minutissimum);在城市上游河道,主要优势种分别为短文假十字脆杆藻(Pseudostaurosira brevistriata)和连结十字脆杆藻腹面变种(Staurosira construens var.venter);在城市下游河道,主要优势种为谷皮菱形藻(Nitzschia palea)。然而,3个样区内的主要优势种相对丰度季节变化较小(P0.05)。其中,A.minutissimum及P.brevistriata的季节变化特征均为春季秋季夏季,而S.construens var.venter及N.palea的季节变化特征均为春季夏季秋季。结果发现,北京市城乡梯度带的河流硅藻种类组成差异较大,但主要优势属种季节变化相对较小,表明硅藻种类能较好地反映城乡梯度带的河流环境变化状况,可用于北京市河流水质生物监测。     

毛竹光合作用对环境因子的季节响应

采用Li-6400测定毛竹光合作用对光照强度、CO2浓度、温度和湿度等环境因子响应的季节变化,结果表明:毛竹最大净光合速率、光补偿点、光饱和点、光合量子效率的年均值分别为7.30、19.15、1075mmol.m-2.s-1,0.032;最大净光合速率夏季>秋季>冬季>春季;春季的光补偿点最高,夏季次之,而秋季和冬季均较小;光饱和点与光合量子效率的季节变化均为秋季>夏季>冬季>春季。毛竹CO2补偿点、CO2饱和点、羧化效率的年均值分别为73.52、1500μmol.mol-1,0.033。CO2补偿点春季>冬季>秋季>夏季;CO2饱和点春季>秋季>夏季>冬季;羧化效率夏季>秋季>冬季>春季。毛竹光合最适温度均在20～30℃,光合最适温度在春、秋季与实验前3天最高气温的平均值十分接近,而夏、冬季与测定前10天的最高气温平均值较为接近,光合最适温度在春、秋两季相当,夏季稍高,冬季最低。光合最适湿度为40%～65%,季节变化趋势:秋季>夏季>冬季>春季。总体而言,毛竹光合作用对环境因子的季节响应与环境因子的季节变化、叶片的生理活性密切相关。     

内蒙古乌兰察布地区鸟类群落结构及季节变化

为了解内蒙古自治区乌兰察布地区的鸟类群落结构季节变化及其影响因素,于2012年10月至2013年12月,采用固定半径样点法和样带法对该地区6种生境类型的鸟类进行调查。共记录到鸟类17目45科153种,其中夏候鸟76种,旅鸟38种,留鸟34种,冬候鸟5种。春、夏、秋季均以夏候鸟为主,冬季则留鸟占优势。非雀形目鸟类所占比例明显高于雀形目。鸟类多样性指数为春季秋季夏季冬季,均匀性指数为春季夏季秋季冬季;聚类分析表明,春季和秋季鸟类群落结构最为相似。不同季节各生境鸟类群落结构亦存在差异,春、夏、秋季的湿地鸟类群落多样性均最高,而农田和居民区的鸟类群落较为相似。栖息地类型、食物资源及候鸟迁徙是该地区鸟类群落结构季节变化的主要影响因素。     

丹江口水库淅川库区大气氮湿沉降特征

大气氮沉降是除河流输入外水库水体重要的外源氮输入途径。以丹江口水库淅川库区为研究区,于2018年11月至2019年10月在库区周边设置了6个采样点,采集并分析了库区大气氮湿沉降样品,探讨氮湿沉降的时空分布特征以及对水库水体外源氮输入的贡献。研究结果表明,研究区大气氮湿沉降量为24.21 kg hm^-2 a^-1,其中氨氮占比（47.45％）为最大,有机氮占比（36.34％）次之,硝氮占比（16.21％）最小。硝氮湿沉降量在空间上表现出显著差异性。氨氮、有机氮湿沉降量的季节差异显著,氨氮是以夏季最高,秋季次之,冬季最低,而有机氮是以秋季最高,夏季次之,冬季最低。氨氮、硝氮、有机氮湿沉降量之间存在显著相关性,氨氮、有机氮湿沉降量与降水量之间存在显著相关性。总氮、氨氮湿沉降量分别为1321.98 t/a和627.34 t/a,分别占河流总氮、氨氮入库量的10.82％、34.85％。研究结果可为探索有针对性的库区水体氮污染控制途径提供重要理论基础。     

三峡水库坝前段蓄水前后枝角类的周年变化

三峡水库蓄水前后,作者从2002年6月至2004年7月按月在坝前段(茅坪—归州)采集枝角类,研究蓄水前后枝角类的变化,结果显示蓄水前该江段水流急不适合枝角类栖息,仅在水流相对较缓的岸边采集到2种;蓄水后水环境较适宜枝角类生活,周年内共采集到20种,并存在着明显的季节变化和水平分布上的差异,文中对其原因进行了分析讨论。       

永定河流域大型底栖动物功能摄食类群时空分布及生态评价

2017年春季(4月)、夏季(7月)、秋季(11月)对永定河流域23个样点的大型底栖动物、水环境和水文因子进行了野外调查,分析了永定河流域大型底栖动物功能摄食类群的群落组成与时空分布特征及其对河流生境变化的响应情况。永定河流域3个季节共采集到大型底栖动物78种,隶属3门6纲39科,其中,春季52种、夏季50种、秋季53种,功能摄食类群以收集者占绝对优势,其次为捕食者,刮食者、滤食者、撕食者所占比例极低。3个季节优势种均属于收集者类群,春季优势种为直突摇蚊属、流水长跗摇蚊属、环足摇蚊属,夏季优势种为雕翅摇蚊属,秋季优势种为多足摇蚊属、摇蚊属、直突摇蚊属。冗余分析结果表明: 水温、流速、盐度以及总磷是影响春季大型底栖动物功能摄食类群的主要影响因子;总磷、溶解氧、电导率以及流量是夏季大型底栖动物功能摄食类群的主要影响因子;总磷和溶解氧是影响秋季大型底栖动物功能摄食类群的主要影响因子;总磷在春、夏、秋季均与收集者类群表现出正相关性,表明永定河流域大型底栖动物功能摄食类群受到了水质污染的影响。基于功能摄食类群参数的评价表明:1)物质循环方面,妫水河初级生产力显著高于其他区域,秋季大于其他季节;洋河次级生产力和分解能力显著高于其他区域,春季大于其他季节,但洋河自养/异养作用显著低于其他区域,春季小于其他季节;2)纵向输入能力方面,桑干河显著高于其他区域,秋季大于其他季节;3)沿岸物质的输入方面,妫水河显著高于其他区域,夏季大于其他季节。     

三峡水库蓄水后长江上游鱼类群聚沿河流-水库梯度的空间格局

研究对2005—2012年长江上游合江、木洞、万州和秭归江段的鱼类群聚结构进行了调查, 以分析三峡水库蓄水后长江上游鱼类群聚沿河流-水库梯度的空间格局。结果显示, 在三峡蓄水后, 在合江至秭归江段累计采集到土著鱼类368706尾, 合计132种, 隶属于17科, 其中鲤科鱼类为优势类群。沿河流-水库纵向梯度, 土著鱼类物种数下降而外来鱼类物种数增加。对应分析表明, 合江至秭归江段的鱼类群聚呈现出明显分化: 库区以上河段鱼类组成以流水性鱼类为主, 库区鱼类则以静水缓流型为主。指示物种分析进一步指出, 河流区鱼类以犁头鳅(Lepturichthys fimbriata)、红唇薄鳅(Leptobotia rubrilabris)、圆口铜鱼(Coreius guichenoti)、圆筒吻(Rhinogobio cylindricus)等22种鱼类为指示物种, 其功能群特征表现为偏好流水生境、生活史为均衡主义及食性为昆虫食性; 库区鱼类以宽口光唇鱼(Acrossocheilus monticolus)、宽鳍鱲(Zacco platypus)、鳊(Parabramis pekinensis)、鳙(Aristichthys nobilis)等16种鱼类为指示物种, 其功能群特征表现为偏好静水生境、食性为草食性或浮游食性。以上研究表明, 三峡水库蓄水导致的水环境变化是影响长江上游鱼类纵向格局的主要驱动力。建议相关管理部门根据不同河段鱼类群聚特征制定不同的渔业管理措施, 如保护土著鱼类资源、控制外来入侵鱼类。     

Species richness of crustacean zooplankton and trophic structure of brackish lagoons in contrasting climate zones: north temperate Denmark and Mediterranean Catalonia (Spain)

We sought to identify environmental factors influencing crustacean zooplankton species richness in brackish lagoons and to elucidate whether crustacean zooplankton species richness and trophic structure of brackish lagoons differ among two regions with contrasting temperatures. We sampled 35 and 42 brackish lagoons (salinity ranging from 0.3 to 55‰) in Mediterranean Catalonia (NE Spain) and northern-temperate Denmark, respectively. No significant differences were found in total crustacean zooplankton species richness or cladoceran richness between the climatic regions. Calanoid richness was higher in Denmark than in Catalonia, while cyclopoid richness was higher in Catalonia. Salinity was the most important variable associated with zooplankton species richness in both regions, richness of total zooplankton species, cladocerans and cyclopoids being negatively related with salinity. In both regions, a shift occurred from dominance of large filter feeding cladoceran species at low salinities to copepods and small cladoceran species at higher salinities. Cladoceran richness increased with increasing total phosphorus, but was not influenced by total nitrogen or chlorophyll-a. Trophic structure in Mediterranean brackish lagoons showed a more pronounced seasonal variation than in north temperate brackish lagoons. Our results imply that the indirect effects of climate warming, such as changes in salinity and hydrology, will have a larger impact on brackish lagoon ecosystems than the increase in temperature per se.     

Species Richness and Distribution of Copepods and Cladocerans and their Relation to Hydroperiod and Other Environmental Variables in Doñana, South-west Spain

Twenty-five sites located in five wetland zones within Doñana, south-west Spain were studied for copepod and cladoceran species richness and composition in relation to habitat characteristics from January to March 2004. The γ-diversity of copepods and cladocerans combined varied between wetland zones, which differed significantly in conductivity, surface area and abundance of vegetation. However, there were no significant differences between zones in local species richness of either copepods or cladocerans or the two combined. Species richness was significantly higher in sites with intermediate hydroperiods (duration between 3 and 5 months) than in sites with shorter or longer hydroperiods. CCA analyses performed separately for copepods and cladocerans extracted conductivity, surface area, and vegetation cover as the main factors structuring species composition of both groups. Ours is one of the first studies of zooplankton in the natural marshes of the Doñana World Heritage Site, and we recorded five species new to the Doñana area.     

Rehabilitation of shallow lakes: time to adjust expectations?

We investigated the relative importance of flood defenses and other environmental variables for the cladoceran and copepod communities in floodplain water bodies in Southeastern Norway. The water bodies covered gradients of size, distance to the river and water chemistry, and half of them were located behind flood defenses. The effects of environmental variables on the communities were analyzed using redundancy analysis. The set of environmental variables accounted for more of the explained variation in the cladoceran community than in the copepod community. Water quality was much more important than flooding-related variables for both communities. Although cladoceran species richness was slightly higher in water bodies outside flood defenses, total nitrogen, total organic carbon (TOC), and water body area were the most important factors for the cladocerans. Macrophyte coverage was the most important variable for both species richness and community structure of copepods. Although our results show that water quality and spatial/structural variables are more important than flood defenses in structuring the communities, the effect of TOC on the cladoceran community could likely be mediated through effects of flood defense on TOC. Prospects for a continued anthropogenic pressure on river floodplains raise concern for the future of these unique ecosystems.     

The effect of different fish communities on the cladoceran plankton assemblages of the Kis-Balaton Reservoir,Hungary

In 1995 the authors studied the effect of differentfish communities on the structure of the cladoceranplankton in a shallow hypertrophic lake. After a fishkill of 1991, different fish communities developedin the Kazetta and the outer area of the Kis-Balatonreservoir. In the outer area of the reservoir, thedensities of plankton feeding fish species wereconsiderably higher than in the Kazetta. Thesedifferences induced changes in the structure anddynamics of the cladoceran plankton. The biomass ofsmall-bodied cladocerans (mainly Bosmina longispina)was higher and the biomass of the large-bodiedcladocerans (D. hyalina, D. magna) was lower in thewestern and eastern part of Kis-Balaton reservoir thanin the Kazetta. A peak in cladoceran biomass in theKis-Balaton reservoir was observed during the summer,close or during a bloom of filamentous cyanobacteria,whereas in the Kazetta a peak was observed during thespring, before the bloom of cyanobacteria. The adultfemales of D. hyalina were larger and produced moreeggs in the Kazetta than in the outer area of thereservoir.     

三峡库区河流生境质量评价

三峡水库建成蓄水后,库区流水生境的大幅度减少及垂直落差最高可达30 m的消落带的形成,使库区支流生境发生了剧烈变化,因此对库区河流生境质量评价十分必要。基于水文情势、河流形态和河岸带生境3个方面18个指标的河流生境评价指标体系,对三峡库区36条重要支流254个样点河段进行河流生境质量评价。结果表明,4.72%的样点河流生境质量处于优等,30.31%为良好等级,49.61%为一般等级,15.35%为较差等级,没有最差等级的样点。对于表征河流生境状况的水文情势、河流形态和河岸带生境3个类别,254个河段总体上河岸带生境状况最好,其次为水文情势,河流形态最差。从总体上来看,三峡库区支流生境质量是自然环境和人类活动相互作用的结果,其中河岸带植被状况、消落带宽度、人为干扰、河床底质状况、水文情势自然性等为主要的驱动因子。     

Seasonal dynamics and composition of cladoceran and copepod assemblages in ponds of a Hungarian cutaway peatland

Seasonal dynamics of cladoceran and copepod zooplankton were studied over a one‐year period in five permanent ponds of a cutaway peatland, situated in the Danube−Tisza Interfluve, Central Hungary. 17 cladoceran, 11 cyclopoid copepod and 6 harpacticoid copepod species were identified and most of them were typical of small lowland ponds. Nevertheless, some taxa like Cyclops insignis, Ceriodaphnia setosa and Macrocyclops distinctus are considered to be rare in Hungary. The microcrustacean assemblages exhibited apparent seasonal succession with typical seasonal species. There appears to be at least two main successional patterns in the five ponds. After general cyclopoid copepod dominance in winter (Cyclops strenuus and Cyclops insignis), at sites with higher proportion of open water and submerged vegetation, spring was characterized by the dominance of the large cladoceran Daphnia curvirostris, which declined during summer, when microcrustacean assemblages composed mainly of smaller, littoral cladocerans. At these sites, species richness and diversity reached their maximum in autumn. In the case of duckweed covered ponds, succession led to less diverse autumn assemblages with fewer species, dominated by Simocephalus exspinosus. Our results draw the attention to the importance of long‐term investigations and the often neglected winter sampling in the accurate evaluation of species richness (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Patterns in the Distribution of Cladocerans (Crustacea: Branchiopoda) in Lakes Across a North–south Transect in Alaska, USA

The remains of cladocerans were examined from the surface sediments of 51 freshwater sites along a north–south transect spanning Alaska. We identified 27 cladoceran taxa from the sediments, consisting primarily of littoral chydorid species. Variations in cladoceran assemblages were related to measured physical and chemical variables using multivariate techniques. Redundancy analysis (RDA) indicated that lake depth, total phosphorus (TP), and altitude all had a significant influence in determining the composition of cladoceran assemblages. Cladoceran communities in tundra and forest-tundra lakes, which were relatively shallow and nutrient-poor, had relatively low abundances of pelagic Cladocera, and were primarily composed of several littoral chydorid species. Among pelagic cladoceran species, there was a distinct shift in dominance from the Bosminidae in lakes in the southern boreal forest region to Daphniidae in lakes in the northern boreal forest. Daphnia dominated lakes had significantly higher total phosphorus, specific conductivity, and calcium concentrations than lakes dominated by Eubosmina. Overall, the relative importance of physical and chemical factors in structuring cladocerans is similar to other previously studied regions, and suggests the Cladocera may be useful as ecological and paleoenvironmental indicators in this region.     

三峡水库蓄水后期香溪河库湾浮游甲壳动物群落结构

为了解三峡水库蓄水后期香溪河库湾浮游甲壳动物群落结构及其时空变化, 于2015年1月至2017年12月对香溪河库湾浮游甲壳动物进行了逐月采样分析。共鉴定出浮游甲壳动物23种, 其中枝角类10种, 桡足类13种。出现频率较高的物种均为长江流域常见种, 生物量和密度峰值分别出现在5月和6月, 在1月和2月则未能采集到标本, 生物量和密度在年际间差异显著, 但群落组成差异不显著, 群落季节变化规律表现为春季-夏季以蚤状溞(Daphnia pulex)和僧帽溞(Daphnia cucullata)大型枝角类占优势, 秋季以简弧象鼻溞(Bosmina coregoni)小型种占优势。库中生物多样性指数高于库首和库尾, 库首和库尾生物多样性指数差异不明显, 生物多样性在季节上同样具有一定差异。CCA分析表明水温、叶绿素浓度和水深是解释浮游甲壳动物群落变化重要因素。我们的研究结果表明尽管香溪河库湾营养盐、水温、浮游甲壳动物生物量和密度均未达到稳定状态, 但群落组成在年际间无显著性差异, 浮游甲壳动物物种丰富度也高于蓄水初期, 生物多样性指数存在一定的时空差异, 适当程度的干扰有利于维持浮游甲壳动物较高的生物多样性。