The occurrence of vulnerable seagrass species Halophila beccarii Ascherson, 1871 from restored mangrove of Koduvally Estuary,south‐west coast of India

The ocean turf grass, Halophila beccarii Ascherson, 1871 was recorded for the first time in the intertidal region of the restored mangrove ecosystem of the Koduvally Estuary on the south‐west coast of India. It was found co‐existing in the shallow muddy area of the mangroves, dominated by mangrove trees of Rhizophora mucronata and Sonneratia alba, and macroalgae, Ulva sp., Enteromorpha sp. and Chaetomorpha sp. The meadow is sparsely scattered with shoots near the mangroves, with a mean density of 720 shoots/m². Details regarding the morphology and hydrographic conditions are described. The occurrence of H. beccarii in the Koduvally estuary is an encouraging sign of improved ecosystem health through mangrove restoration. The development of seagrass meadow in the estuary will improve the sediment stability and water quality. A further comprehensive study on the spatiotemporal variation of this species in the estuary is also recommended for conservation and management of this vulnerable seagrass species.     

Assessment of physico‐chemical properties of water and phytoplankton bloom formation in a eutrophic pond using multivariate analysis

An investigation of the water chemistry and phytoplankton bloom formation characteristics of a seasonal earthen pond located in the Alappuzha District, Kerala (India) was carried out during November 2011 to May 2012. Twelve important physico‐chemical parameters (temperature, Secchi disc transparency, pH, electrical conductivity EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia‐nitrogen, nitrite‐nitrogen, nitrate‐nitrogen, total phosphorus (TP), dissolved iron and chlorophyll a related to phytoplankton growth in the pond were the focus of the present study. Chlorophyll a was used as a measure of phytoplankton biomass. The pond developed subsurface phytoplankton blooms of Chlorella vulgaris, Aphanothece sp., Leptosira sp., Lepocinclis globulus and Lepocinclis fusiformis. Visible scums of Lepocinclis globulus and Euglena proxima was also observed during March 2012. Principal component analysis was performed to understand the biochemical processes in the pond ecosystem leading to the Euglena spp. bloom.     

渤海湾浮游细菌分布特征及环境影响因素

于2011年5月、2012年5月和2012年11月分别对渤海湾33个站位表层水体中的浮游细菌及环境因子进行了调查,探讨渤海湾浮游细菌生态分布特征及其与环境影响因子的关系。结果表明:在渤海湾表层水体中,2011年5月的海洋浮游细菌丰度为(2. 51~28. 39)×108L-1,2012年5月的浮游细菌丰度为(2. 62~87. 26)×108L-1,2012年11月浮游细菌丰度为(2. 18~18. 15)×108L-1;浮游细菌数量在空间上都是近岸站位高于远岸站位; 2011年5月和2012年5月,浮游细菌生长所需有机碳分别来源于浮游植物胞外分泌的溶解有机碳和陆源输入有机碳,浮游细菌与氨氮都有极显著相关性关系,与磷酸盐均呈显著负相关关系; 2012年11月,浮游细菌除了与亚硝酸盐氮、水温呈正相关外,与其他环境因子都呈负相关关系。     

鹤壁矿区奥陶系灰岩地下水水文地球化学特征及反向模拟

为探讨采矿活动对岩溶地下水水质的影响,以鹤壁矿区奥陶系灰岩地下水为研究对象,基于不同时期岩溶地下水水化学资料,采用Piper图结合离子组合比例分析法,分析矿区岩溶地下水主要组分的物质来源和水岩相互作用过程,并借助PHREEQC软件对其进行了反向水文地球化学模拟。结果表明:研究区岩溶水水化学类型主要为HCO_3-Ca·Mg型、HCO_3·SO_4-Ca·Mg型和SO_4·HCO_3-Ca·Mg型。主要水岩作用为碳酸盐岩、石膏和岩盐的溶解与阳离子交替吸附作用。煤矿区的岩溶水水质受采煤活动影响,水中SO_4~(2-)、Cl~-与TDS的含量较高,且采矿活动对水质的影响随时间增强。     

Bioecology of macrobenthic communities in the microtidal monsoonal Kodungallur–Azhikode Estuary,southwest coast of India

A comprehensive study of the macrobenthic communities in the Kodungallur–Azhikode Estuary (KAE) was conducted during 2009–2011 period. A total of 18,846 organisms were collected, with 60% being malacostracans, followed by polychaetes (20%), molluscs (9%) and ‘others’ group (11%). A total of 79 species in 71 genera belonging to 49 families were identified, with 33 spp. being polychaetes, 26 spp. being malacostracans, 11 spp. being molluscs and 9 spp. being in the ‘others’ group. A single species of opportunistic amphipod (Americorophium triaeonyx) comprised more than 62.05% of the total numerical abundance of macrobenthos. The other dominant species were Obelia bidentata, Arcuatula senhousia, Cirolana fluviatilis, Prionospio cirrifera and Capitella sp. Canonical correspondence analysis (CCA) results indicated environmental parameters such as water column salinity, turbidity, sediment Eh, substratum type, chlorophyll‐a concentration, depth and organic matter in sediment were the significant factors influencing the distribution of macrobenthic species in the KAE. The present study provides baseline information for future KAE benthic studies.     

郑州市城区及郊县地下水主要污染组分及成因

明确不同地区地下水污染的组分和成因,可为针对性的制定地下水资源管理制度、改善水质提供保障。由于城区和郊县经济发展水平和地下水资源开发利用模式差别较大,水污染程度和污染组分可能存在较大差异。以郑州市的金水区和巩义为例,运用主成分分析法对两者地下水污染状况进行评价。结果表明:巩义市地下水主要污染组分以硝酸盐等有机污染物为主,金水区以硫酸盐、氨氮等有机污染物为主。造成这种现象的主要原因是巩义市工矿企业、农田较多,金水区农田、工矿企业较少而生活污水排放比重较大。根据两个地区不同的地下水污染状况和成因,就地下水资源保护和管理提出针对性的建议。     

改进的主成分分析法在白洋淀水质评价中的应用

针对数据标准化信息丢失以及主成分中各系数相近造成的涵义不明确,对主成分分析法进行了改进,很好地实现了降维的效果.将其应用于河北省白洋淀水质综合分析,结果表明:在各观测断面中普遍存在富营养化现象,氨氮、总磷是水质的主要污染指标.通过对各断面的水质进行综合评比,得出各站点的污染程度排序,为白洋淀区域治理提供理论指导.     

阿克苏地区水资源承载力变化及驱动力生态脆弱性分析

以塔里木河源流区阿克苏地区为研究对象,分析区域水资源承载力变化及引起变化的驱动力因素。采用主成分分析法分析了2004-2014年水资源承载力水平,提取了社会经济和生态2个系统的主成分,并进一步选取生态脆弱性作为生态评估指标,采用模糊层次分析对驱动力生态环境的动态变化进行了分析。结果表明:自2004年到2014年,阿克苏地区的水资源承载力总体呈下降趋势,承载F值从-2.99增加到4.69,人口与GDP、生态用水率是承载力变化的主要驱动因素;生态系统的脆弱度整体呈上升态势,生态脆弱性由Ⅰ级的轻度脆弱区上升至Ⅲ级强度区,其中森林覆盖率和垦殖率影响因子为分别0.29和0.12,通过调整可降低生态破坏程度以增加水资源的可持续性。     

我国不同区域用水结构变化及其驱动因素分析

以江西、湖北,山东、江苏,以及贵州、西藏等6省(自治区)为例,采用信息熵和主成分分析方法,从经济社会、水文气象、农业及用水4方面选取了13个因子,揭示了我国中、东、西部地区1999-2014年间用水结构变化特征及各主导因素的影响机制,分析了最严格水资源管理制度实施于用水结构产生的效果。结果表明:(1)近16年来,东部地区的山东省总用水量持续下降,用水结构信息熵值上升降趋势明显,处于较高水平;西部地区的西藏自治区总用水量增加显著,用水结构信息熵值处于较低水平,其余地区总用水量总体保持平稳,生产用水量占总用水量的平均比重为91%;(2)最严格水资源管理制度实施以来,各省生产用水量逐渐减少,用水结构的信息熵值表现为不同程度的上升趋势;(3)影响各地区用水结构变化的主要驱动因子依次为各产业产值和人口、地区水资源禀赋和总耗水量。     

宁夏全区及5市水循环健康状况分析

针对水环境及水资源基础条件变化下的水循环健康问题,以宁夏全区及其所辖5个地级市为研究对象,收集2010-2018年的相关基础数据资料,结合当地区域水资源实际状况,筛选出15个评价指标,利用主成分分析法对宁夏及5市水循环健康状况进行评价分析。结果表明：宁夏全区及5市的水循环健康状况均呈现整体上升的趋势,但由于各地区在经济发展及水环境治理政策之间的差异,因此在影响因素方面存在明显的地区差异性。银川市水循环健康状况主要受农业用水量和污水处理的影响,石嘴山市的主要影响因素是当地水资源量及污水处理能力,吴忠市主要取决于当地的生态投资及排水管道建设,固原市主要受当地水资源总量限制,中卫市的主要影响因素是农业用水量和绿化率。     

水化学成分聚类法分析干旱区地下水补给

以巴丹吉林沙漠及邻区为例,基于距离空间基本原理,对水样化学成分进行了离散性、主成分和相关性分析,指导样品数据采集和化验。计算结果表明,祁连山冰川融水自身化学成分在该地区聚类最高,多次聚合说明祁连山冰川融水是该地区地下水补给源。由聚类图推测:祁连山冰川融水通过地下首先经过诺尔图,然后到达古日乃和拐子湖;古日乃和拐子湖地下水某些样品聚合距离大,可能是由黑河水渗入引起的,少量黑河水可通过古日乃渗入拐子湖引起地下水成分变化;没有迹象显示黑河水补给巴丹吉林沙漠(以诺尔图为代表)地下水。     

Assessing water-quality data: The relationship between the water quality amelioration of Lake Balaton and the construction of its mitigation wetland

Lakes are sensitive to environmental changes and anthropogenic effects; and Lake Balaton, the largest shallow freshwater lake in Central Europe, is no exception. To protect the lake (primarily Keszthely Bay) against elevated nutrient loads, the Kis–Balaton Water Protection System (KBWPS) was constructed as a mitigation wetland at the mouth of the River Zala, the largest tributary of the lake. This research demonstrates the effect of the KBWPS on Keszthely Bay's oligotrophication processes. The concentration values of KBWPS and Keszthely Bay's measured parameters and their stochastic relations were analyzed by applying cluster- discriminant analysis, Wilks' lambda statistics, confirmatory principal component- (PCA), and input–output analyses to 19 parameters from 14 monitoring stations. First, the sampling sites were clustered for each year, showing that when the runoff in the system was low, Keszthely Bay behaved as a separate entity, while in the years with high runoff it rather displayed a similarity to the wetland area of the KBWPS. Secondly, PCA showed that, from the perspective of stochastic relations, changes in the background processes of Keszthely Bay were observed only after the settling of the KBWPS; and that the runoff in the examined years did not have any significant influence on it. Furthermore, the eutrophication processes moved upstream from Keszthely Bay to the hypertrophic area of KBWPS. This study confirms that the effects of the KBWPS – together with other load reduction measures – had a beneficial effect on the oligotrophication of Lake Balaton.     

Stratification,diel and seasonal energy transfers in Malilangwe Reservoir in the south‐eastern lowveld of Zimbabwe

This study provides a 9‐month record of Malilangwe Reservoir stratification and diel and seasonal energy transfers between February and October 2011. The reservoir was not strongly stratified during the hot‐wet season (February and March), exhibiting low dissolved oxygen concentrations of <2 mg DO L^?1 in the bottom layers (<6 m depth). During the cool‐dry season, when both the air temperature and solar radiation input decreased, the water temperatures in the epilimnion and across the thermocline decreased, and the water column was very weakly stratified. In this state, the reservoir could easily be mixed, even by light winds, resulting in overturning, thereby giving the bottom water an opportunity to become aerated, as observed during the cool‐dry season. The stability was greatest when the water level was high (during midday), while it was considerably lower during the predawn hours. The calculated annual Birgean heat budget for the reservoir was 110 MJ m^?2 year^?1 for February to October 2011. The diurnal Birgean heat budget was consistently associated with heat loss over a 24 hour period in all seasons, mostly between 0400 and 1000 h. Spearman's correlation suggests that the DO was significantly correlated with stability for the three study months (February r = 0.69, P < 0.05; June r = ?0.76, P < 0.001; October r = 0.96, P < 0.001). The results of this study suggests that warming temperatures (warmer months or seasons) will result in high Birgean heat budgets, which could potentially trigger some important changes in plankton population dynamics in small reservoir, with severe water quality implications. The nutrient concentrations varied throughout the seasons.     

黄河流域水-能源-粮食安全系统的耦合协调发展研究

为探究黄河流域水-能源-粮食安全系统协调发展对推动流域人地关系协调、高质量发展的意义,以黄河流域水-能源-粮食安全系统为核心,构建流域水-能源-粮食安全系统综合指数,采用主成分分析法计算各指标权重,利用耦合协调度模型对2007-2017年黄河流域水-能源-粮食安全系统耦合协调度进行测算,并对2018-2027年流域耦合...     

潭江水质时空变化特征及其驱动因子

为掌握潭江水质的变化特征,采用Mann-Kendall趋势检验以及水质综合污染指数等方法分析了潭江干流2001-2019年的水质年际变化特征,利用主成分分析方法识别了影响潭江水质变化的主导水质参数,通过相关性模型分析了影响水质变化的主要驱动因子.结果 表明:潭江上游的水质最好但有一定的恶化趋势,下游的水质次之且无明显的...     

干旱区梭梭茎干液流特性及对土壤水分的响应

研究荒漠植物耗水特征及其与土壤水分的关系,分析维持荒漠植物生长的潜在水源,对提高干旱区用水效率,保证荒漠生态环境的安全具有重要意义。以新疆干旱区荒漠植被梭梭为研究对象,采用热扩散法研究其茎干液流特性,采用中子仪测定和烘干法相结合的方法测定土壤含水率,并分析了茎干液流与土壤水分的响应关系。结果表明:梭梭的茎干液流密度呈明显昼夜变化,日间液流密度明显高于夜间,且随着胸径的增大,日间液流密度减小;土壤含水率随土层深度的增加呈倒"S"型分布,5~8月土壤含水率逐渐减小,中间土层含水率随时间推移减小幅度显著;随着土壤含水率的降低,夜间液流密度基本保持不变,但日间液流密度的峰值明显减小。分析结果可为提高干旱区用水效率,保证西部生态环境的安全提供理论支撑。     

长江三源浮游植物群落特征差异与环境因子关系

长江源地处青藏高原腹地,水体环境特殊,关于源区间浮游植物特征差异及环境作用因子尚不清晰。对比了2012—2016年长江三源浮游植物特征,并采用主成分分析(PCA)、典范对应分析(CCA)揭示了浮游植物特征与13种环境因子间的关系。结果表明:隐藻门仅在南源当曲被发现,长江南源样点的浮游植物平均种类数最多,为18种,长江北源最少,为9种;北源的浮游植物平均密度最大,为37.70×10⁴ ind/L,南源平均密度最小,为28.90×10⁴ ind/L;长江南源的浮游植物平均生物多样性指数最高,达到3.04,北源平均生物多样性指数最低,为1.84;长江源区总体上浮游植物密度较低,水体处于贫营养状态。各源环境因子PCA结果显示:第一轴主要成分(71.23%)可解释为总氮、电导率,主要代表了河流营养物特征;第二轴主要成分(28.77%)可解释为海拔、床沙中值粒径、水温、含沙量和化学需氧量,主要代表河流生境状况。物种和主要环境因子CCA结果表明蓝藻门种类数与总氮、隐藻门种类数与海拔和床沙中值粒径,绿藻门种类数与海拔、化学需氧量和床沙中值粒径均呈明显的正响应关系,隐藻门和绿藻门种类数和含沙量、水温呈明显的负响应关系。     

Secondary seed dispersal in hydro‐fluctuation belts and its influence on the soil seed bank

The completion of the Three Gorges project altered the water level fluctuations from “summer submersion and winter exposure” to “summer exposure and winter submersion.” The reverse seasonal flooding has dramatically changed both the time and duration of exposure and submergence of reservoir banks. Secondary seed dispersal by water is the primary method of dispersal in hydro‐fluctuation belts. This study conducted field sampling and germination experiments to evaluate the effects of reverse seasonal flooding on species composition, diversity, and density of the secondary seed dispersal system and the soil seed bank, and their changes with elevation, in the Xiangzi River. The results indicate that that the secondary seed dispersal system and soil seed bank were associated with 42 and 50 plant species, respectively, and their average seed densities were 1,876.27 and 7,322.18 seeds/m², respectively. The quantity of seeds from secondary seed dispersal accounted for 20.40% of the soil seed bank. The species life‐form composition of both consisted mainly of annual and perennial grasses. Among these grasses, the dominant species in the secondary seed dispersal system were Cynodon dactylon and Paspalum distichum, whereas the dominant species in the soil seed bank were Solanum nigrum and Rumex dentatus. Due to the effects of reverse seasonal water level fluctuations, the species composition and quantity of the soil seed bank and secondary seed dispersal system largely exhibited similar spatial distribution characteristics, but some differences were observed. The species quantity, species diversity index, and seed density in the soil seed bank were the highest in the middle section of the hydro‐fluctuation belt, followed by the top section and then the bottom section. Conversely, the species quantity, species diversity index, and seed density in the secondary seed dispersal system were highest at the top section, followed by the middle section and then the bottom section.     

Comparison of Taxon‐Specific and Taxon‐Generic Risk Screening Tools to Identify Potentially Invasive Non‐native Fishes in the River Neretva Catchment (Bosnia and Herzegovina and Croatia)

The Freshwater Fish Invasiveness Screening Kit (FISK) v2 and Aquatic Species Invasiveness Screening Kit (AS‐ISK) risk identification screening tools were used to assess the invasiveness potential of 24 non‐native (NNS) freshwater fish species in the River Neretva catchment (Bosnia and Herzegovina and Croatia), a risk assessment (RA) area that is an important Mediterranean hotspot for fish endemism. The two assessors assigned similar scores for the invasiveness potential of the NN fishes, and both screening tools successfully distinguished invasive from non‐invasive species. Mean calibrated threshold scores were 10.25 for FISK and 10.00 for AS‐ISK, with the latter increasing to 12.62 when questions that assess the likely impact of predicted future climate conditions on the RA were taken into consideration. These relatively low threshold values are characteristic of areas with an elevated number of translocated species and suggest that NN fishes pose a considerable threat to native species and ecosystems. FISK ranked 50.0–62.6% of the species as being of ‘high risk’ compared with 58.4–59.3% using AS‐ISK. The highest scores (‘very high risk’) were attributed to gibel carp Carassius gibelio (Bloch, 1782) and pikeperch Sander lucioperca (Linnaeus, 1758). The generic screening tool for aquatic species (AS‐ISK) provided similar risk rankings to its predecessor, FISK, as regards invasiveness potential. For this reason, it is likely to be an effective tool for evaluating the potential invasion risk of NNS freshwater fishes for other RA areas in the Balkans. Copyright © 2017 John Wiley & Sons, Ltd.     

基于主成分-聚类分析的南水北调中线干渠水质时空分异规律

作为京、津、冀、豫4省市重要水源,南水北调中线工程水质安全对于工程的稳定运行和优化管理十分重要。为掌握总干渠的水质状况和时空分异规律,对南水北调中线干渠25个断面的9个水质指标变化情况进行分析,运用主成分分析和聚类分析相结合的方法,识别主干渠主要水质指标成分,甄别各断面水质变化相似性特征,并开展水质评价与分区,为中线水质保护和管理提供决策参考和优化建议。研究结果表明,主成分分析将9项水质指标降维到4项,前4个主成分能够解释80.23%的原始环境信息,重点关注中线工程耗氧程度和酸化趋势。聚类分析将中线总干渠划分为4类水质管理区段,通过比较各段水质指标差异,识别出各分类渠段关键性水质指标,针对渠段特性进行水质时空分异规律分析。研究成果可为中线水质保护和管理提供理论依据。