Temporal trends in phosphorus and lacustrine productivity in Lake Simcoe inferred from lake sediment

The historical phosphorus record and lake productivity of Lake Simcoe (southern Ontario, Canada) was reconstructed based on sediment cores collected throughout the lake. Sediment phosphorus concentrations have increased in all basins, in particular since the 1970s, with most changes occurring in the non-apatite (organic and inorganic) phosphorus fractions. Similarly, sediment organic carbon and nitrogen concentrations have increased significantly, molecular C:N and C:P ratios have decreased and δ¹³C_org and δ¹⁵N have increased. These data suggest that autochthonous primary production has increased over the last four decades. The apparent contradiction with modeling efforts is reconciled if we consider that bioavailable phosphorus has made up an increasing proportion of the total phosphorus load over the last several decades. This study suggests that the forms of P delivered to Lake Simcoe must be considered for the development of a sound management plan.     

Influence of Nutrients in Water and Sediments on the Spatial Distributions of Benthos in Lake Simcoe

The shoreline and sublittoral areas of Lake Simcoe were surveyed in October 2005 as part of a baseline inventory of current conditions, and as part of an exploratory analysis to determine if there were threshold nutrient levels above which nutrients were a major controlling factor in the distributions (abundances) of benthic organisms. Along the shore environment, there was no generalized relationship between nutrients and indices of benthic community composition below water-borne total phosphorus concentrations of ∼ 0.05 mg/L, indicating that other factors were more important at those lower levels of phosphorus. Benthic community composition did not vary with water quality in the sublittoral zone, but did vary with sediment quality (total Kjeldahl nitrogen, total phosphorus). The benthic community had higher relative abundances of caddisflies and mayflies at sublittoral stations with TKN levels at or near the provincial low-effect level of 550 mg/kg, and had higher relative abundances of more tolerant taxa such as worms, amphipods, and snails at locations with TKN levels in excess of the provincial severe-effect level of 4,800 mg/kg. The relationship between composition and TKN in sediments was not obvious below concentrations of ∼ 300 mg/kg, indicating that other factors were more important at those levels of TKN. This study was the first to document an inland (non-Great Lake) colonization by the exotic amphipod Echinogammarus ischnus. This species was found along most of the shoreline with the exception of shorelines within Cook's Bay, along Sibbald Point Provincial Park and at the far end of Kempenfelt Bay. Where found, E. ischnus were generally numerically dominant members of the benthic community.     

Evidence for internal phosphorus loading,hypoxia and effects on phytoplankton in partially polymictic Lake Simcoe,Ontario

Hypoxia and cyanobacterial blooms were extensive in Lake Simcoe during the 1980s and are still a problem to a lesser degree despite extensive nutrient load reduction from the catchment basin. The continuing signs of productivity indicate a potential internal phosphorus (P) source. Internal P load, as a redox-dependent release from bottom sediments, is hard to determine in a large, relatively shallow and partially unstratified lake such as Lake Simcoe. Of the lake's three major basins, only Kempenfelt Bay stratifies long enough to develop hypoxia in the stagnant summer hypolimnion. The following indications of sediment P release are available from historic data: 1) hypolimnetic hypoxia still occurs in Kempenfelt Bay although the hypoxic factor (number of days that an area equal to the bay's surface area is overlain by water of ≤ 2 mg/L dissolved oxygen, DO) has decreased substantially and significantly from 15.8 d/yr (1980–1994) to 4.0 d/yr (1995–2011); 2) hypoxic factors for other lake sections and at different DO levels also indicate widespread hypoxia; 3) concentrations of redox dependent metals, Fe and Mn, increase with depth; and 4) euphotic zone P and chlorophyll concentrations increase and water clarity decreases during fall turnover. Cyanobacterial blooms appear to occur in response to internal load as supported by occasional cyanobacteria counts. These indicators provide evidence that internal loading is likely occurring and affecting the water quality in Lake Simcoe. We expect that further monitoring, specific for internal load, will corroborate these results.     

东平湖水质现状与可持续旅游开发

根据2008年水质监测,东平湖水质趋于恶化,水体富营养化已达中富-富营养化水平。针对日益兴盛的旅游业对东平湖水环境产生的不利影响,分析了东平湖旅游开发存在的问题,并提出旅游开发与水环境保护并举、充分发挥政府的主导作用、提高湖区人民和游客的环境保护意识、建立可持续生态旅游系统等建议。     

Quantification of internal phosphorus load in large,partially polymictic and mesotrophic Lake Simcoe,Ontario

Hypoxia and cyanobacteria still occur occasionally in large, mesotrophic Lake Simcoe, and total phosphorus (TP) concentration has remained relatively constant despite external nutrient load reduction. This may indicate a potential internal P source. Internal load as redox-dependent P release from bottom sediments is hard to determine in such a relatively shallow and mostly mixed lake. This study represents the first attempt to quantify internal P loading over many years for the three main sections of Lake Simcoe. Internal load was determined (a) as in situ estimate based on TP increases between July and October and (b) as gross estimate from the product of experimentally determined P release rates and hypoxic extent of sediment surfaces in space and time. Hypoxic extent was quantified (1) as the hypoxic factor determined from dissolved oxygen profiles below the level of 3.5 mg/L, and (2) as active sediment area release factor (AA) modeled from summer euphotic TP concentration, which is especially useful in the mixed sections. Annual internal load for the whole lake was determined as a near constant 62.2 metric tonnes/yr (86 mg/m²/yr) for 1980–2011 using the gross estimates of the AA approach and 88 t/yr before and 53 t/yr after external load abatement and zebra mussel invasion using in situ estimates. Means of in situ and AA-based estimates for 2000–2011 are in close agreement except for polymictic Cook's Bay. These estimates are 45 to 89% of external load, which suggests that internal loading is an important source of P in Lake Simcoe.     

洞庭湖水位变化对水质影响分析

长江中下游江湖关系的剧烈演变引起了洞庭湖水位的相应变化,并带来了显著的生态环境效应。为了揭示洞庭湖水位变化与水质变化的内在联系和特征,根据洞庭湖区典型水文站1995年-2010年历史水位与水质观测资料,从年内季节和年际时间尺度上,对洞庭湖水位变动情况及其对水质的影响进行了分析。结果表明,所选的洞庭湖区的典型水文站15年来水位总体呈现下降的趋势;在年际变化上,水质指标TN、高锰酸盐指数随着水位的降低而升高;年内季节变化上,TN含量表现出枯水期>平水期>丰水期的特征,而TP含量表现出相反的特性,随着丰水期水位的升高而含量也相对升高。总体上,洞庭湖水位变化与水质状况表现出较强的相关性。     

新疆博斯腾湖二维水质数学模型研究

博斯腾湖流域经济总产值占全州经济总量的80%以上,是巴州工农业生产的重要聚集区域。然而,随着流域社会经济的快速发展,流域污染物的产生量、入湖量和污水排放量日益增加,点源污染和面源污染逐年加剧,博斯腾湖已由淡水湖泊演变为微咸湖。因此,建立二维水质数学模型,分析矿化度变化规律,为博斯腾湖的环境管理及环境保护规划等提供科学依据。     

晋阳湖夏季浮游生物调查及水质分析

2009年5-9月,对晋阳湖的浮游生物及水质进行了调查,结果表明:晋阳湖共有浮游植物47种,浮游植物生物量为100.63 mg/L,浮游动物30种,生物量0.304 mg/L,水质类型为SCⅡa型。晋阳湖处于富营养化状态。     

太湖出入湖水质评价

１９８７年沿太湖历年巡测线进行了４次水文、水质同步监测，共有１３９条河道参加评价，有水文，水质监测项目３８个，评价中水质采用五级水标准，选用ｐＨ值等１８项指标和为评价参数，评价结果表明，入太湖水质污染主要以有机污染为主，出湖污染主要在江苏湖东段，占总量的６０％，因此，保护好太湖水质必须控制和减少入湖污染物量，加强污染源治理，限制污染行业发展。     

Three-dimensional Water Quality and SAV Modeling of a Large Shallow Lake

This study presents the Lake Okeechobee Environment Model (LOEM), a three-dimensional (3D) hydrodynamic, sediment, water quality, and submerged aquatic vegetation (SAV) model of Lake Okeechobee, Florida. The LOEM is developed under the framework of the EFDC model (Hamrick 1992). Lake Okeechobee is the largest subtropical lake in North America (1,730 km²), it is very shallow (mean depth 2.7 m), and it includes a littoral habitat that makes up 20% of its area. The LOEM is calibrated, verified, and validated to 3 years of water quality and SAV data. The water quality results are consistent with observed data from 25 locations in the lake. The model is capable of reproducing key water quality characteristics of the lake without having to resort to extensive, site-specific parameter manipulations. The SAV model is calibrated using measured SAV data in the lake. The SAV model is capable of representing the spatial and temporal variations of SAV variations in the lake well. The LOEM is applied to study water quality and SAV processes in the lake. The model results are consistent with observed data indicating that algal growth in the lake is primarily nitrogen limited in the summer and nitrogen and light co-limited in the winter. Lower water elevation generally leads to larger SAV area. SAV can have positive impact on the lake water quality by reducing algae concentration. The calibrated, verified, and validated LOEM model serves as a useful tool to support lake management.     

太湖自动监测站水质分析及影响评价

近年来,太湖流域的水污染问题受到极大的关注,水量水质监测站在监控和改善太湖流域的水环境中起着举足轻重的作用。介绍了太湖流域水质自动监测站的建设情况,分析了2008年引江济太期间常熟等5个自动监测站的监测数据,并对监测站的重要性进行详细的分析和评价。由监测数据得知,5个自动监测站水质总体上有所改善。为进一步改善太湖流域的水质,建议加大监测站的建设和优化力度,加强监测站之间和监测站与水量控制单位的联动性。     

阿哈水库模糊综合评价及污染防治措施

以贵阳市阿哈水库为研究对象,根据阿哈水库水质检测资料,用模糊综合评价法对水库的水质进行了评价。由水质评价结果可以得出,阿哈水库满足国家饮用水标准,但已受到一定程度的污染。对水库水质污染因素进行了分析,并结合实际提出了具体的防治措施,为水库的污染治理和防治提出了科学依据。     

农业面源污染对湖泊水质影响的初步分析

我国是一个多湖泊的国家，湖泊水质直接影响我国整体水质状况。目前，许多湖泊严重污染，湖泊周边地区成为典型的“水质型缺水”地区。调查资料显示，农业面源污染成为主要污染源之一。通过分析典型湖泊的污染成因，提出了防治污染的具体措施。     

地表雨水径流对上海海港新城滴水湖水质的影响分析

滴水湖是一个面积约4．5km^2的人工湖,位于上海海港新城的市中心。降雨期间,城市地表径流经过规划的网状水系汇入到滴水湖,经过与湖沟通的海闸排到东海。根据远景规划,滴水湖的水质需要满足城市娱乐和景观用水要求。因此,维持滴水湖良好的水质显得尤为重要。耦合一个简单的城市降雨一径流模型,CE-QUAL-W2水质模型被用来模拟远景年滴水湖的水质。模拟了3个不同年降雨概率的典型年。即2003（90％）、2004（50％）和2002（10％）年。模拟的污染指标主要有溶解氧（DO）、藻类、生化需氧量（BOD5）、总磷（TP）、氨氮（NH3-N）和总氮（TN）。结果显示,在3个典型年里滴水湖的综合水质能够维持在地表水Ⅲ～Ⅳ类。比较而言,在90％降雨保证率年,滴水湖的水质最好,因为地表径流最小以至携带的地面污染负荷最少。从各污染指标的日平均值来看,在各个典型年里DO优于Ⅲ类,因此远景年的水质对湖中的鱼类等生物几乎没有负面影响。     

洞庭湖区供水安全问题

随着气候变化和人类水土资源开发活动影响的深入,洞庭湖区面临着严重的供水安全问题。现结合供水安全的含义,从水量、水质变化以及供水设施等方面,分析洞庭湖区水量的变化以及水质状况演变趋势,并从科学调水用水、水源保护、法规制度的制定等3方面提出了相应的对策与措施,为科学的解决本地区的供水安全问题提供依据,以期能够引起人们对洞庭湖区供水安全方面问题的重视。     

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.     

季节性Kendall检验在白洋淀水质趋势分析中的应用研究

详细介绍了季节性Kendall检验方法的原理和数学模型，并以白洋淀为实例，对其2000-2004年的水质变化趋势进行分析，从趋势分析结果可以看出，白洋淀以有机物污染最为严重，且污染物主要来源于府河沿岸和淀周边。     

Analysis of Storm Water Runoff Impact on Water Quality of Dishui Lake in New Harbour Town, Shanghai

1 IntroductionThe Shanghai Municipality Government is planning a har-bour town,on the coast southeast of Shanghai , will be one ofprospective . The city centre of the new harbour town will be amixedland-use catchment with residential ,commercial ,and e-du…     

江苏省太湖地区水质自动监测系统的研发和实现

水质自动监测和GSM通信是当前水文自动化建设中一个重要的发展内容之一，采用多参数水质检测仪和GSM短信息通信方式研制的水质、水情自动监测预警系统，可实时监测苏南大运河、太湖及相关水域的水质。