The Effect of Zooplankton on Microalgae Blooming and Water Eutrophication

Data of field experiments conducted in a eutrophic water body were used to assess the effect of zooplankton on microalgae blooming. The experiment was based on the use of mesocosms to isolate the components of zooplankton and ichthyofauna ecosystems. The population Daphnia longispina is shown to reduce the population of cyanobacteria Anabaenaflos-aquae by a factor of 350 as compared with the water body, thus allowing the phase of highly-transparent water to extend to the mid-summer. D. Longispina can reduce the population of Microcystis aeruginosa, which is associated with the second period of the transparent-water phase. The filtration activity of zooplankton is shown to be able to recover the quality of eutrophic water bodies.     

Water Blooming in the Reservoir with Long-Term Discharge Regulation

Water Resources - The factors of phytoplankton development in the stratified Mozhaisk Reservoir are analyzed on the basis of long-term observations and model calculations. To analyze the...     

Suppression of Alga Blooming by Zooplankton Filter Feeders in Small Water Bodies

The study is focused on the ability of filterers–phytophages Daphnia longispina O.F. Mueller to suppress blooming in shallow-water bodies in Moscow oblast. The effect of phytoplankton development on the composition of daphnia populations is studied. With the predominance of small-cell (<40 μm in length) green, yellow-green, and euglena algae in the phytoplankton and, accordingly, in the nutrient budget of daphnia, the biomass of D. longispina (12 mg/L) is 1.5–6.0 times greater than that in the water bodies where the phytoplankton shows the predominance of Aphanizomenon flexuosum Komárek et Ková?ik (filamentous cyanobacteria) and Volvox polychlamys Korshikov (cenobial green algae). The mean fertility of the reproducing organisms of D. longispina (the number of eggs per female reached 11) was also higher in the former case.     

净化湖泊水体氮污染的固定化硝化-反硝化菌研究

依据太湖水体氮污染的特点,设计应用低温辐射技术引导玻璃态单体丙烯酸羟乙脂－２－Ｈｙｄｒｏｘｙｅｔｈｙｌ ａｃｒｙｌａｔｅ（ＨＥＡ）与聚乙二醇二甲基丙烯酸酯Ｐｏｌｙｅｔｈｙｌｅｎｅ ｇｌｙｃｏｌ ｄｉｍｅｔｈａｃｒｙｌａｔｅ（１４Ｇ）制备高分子载体,并使用增殖细胞技术固定化硝化－反硝化菌净化湖水。研究结果表明,富营养化湖水经过固定化硝化－反硝化菌ＳＢＲ工艺净化后,总氮下降７０％,氨氮下降８４％,ＣＯ     

Suppression of Phytoplankton Blooming in Water Bodies with the Use of Filtering Zooplankton in Flow-Through Ecosystems

Water Resources - The study has been focused on the population composition dynamics and trophic relationships of Simocephalus vetulus (O.F. Müller, 1776) in the absence of the food stress of...     

Methods for Counting Water Bacteria – Comparison and Significance

A comparison is made between the results of bacteriological investigations into the total of 501 samples from 4 brooks, 2 rivers, 5 reservoirs and 2 wastewater treatment facilities by means of the following methods: Cultures on plates with various media, direct counting and counting of microcolonies. Linear regressions exist between the logarithms of the numbers of germs or bacteria of cultures on plates or direct counts, the ratio of the number of bacteria to the number of germs decreasing with an increasing number of bacteria. In case of equal numbers of bacteria, stagnant waters contain fewer germs than flowing waters.     

Effect of Biochar and Hyper-Thermal Inoculum Addition on Polycyclic Aromatic Hydrocarbon-Degrading Bacteria during Composting

The effects of biochar and hyper-thermal inoculum on polycyclic aromatic hydrocarbon-degrading bacterial communities (PAHBC) during the livestock manure composting are studied here. The experiment is performed on composting of livestock manure and wheat straw amended with biochar and hyper-thermal inoculum. Physicochemical properties, enzyme activity, polycyclic aromatic hydrocarbons (PAHs), and microbial activities are monitored and the comprehensive assessment is analyzed during the composting process. The results show that the dominant phyla Firmicutes, Proteobacteria, and Actinomycetes that are potential PAH-degrading bacterial community hosts are enriched. Meanwhile, the addition of biochar and hyper-thermal inoculum enhances the abundance of PAHBC. Therefore, the biostimulation of biochar and hyper-thermal inoculum could affect the frequency and composition of PAHBC.     

滇池东北岸生态修复区的环境效应--Ⅰ.抑藻效应

研究了滇池东北沿岸带生态修复区抑制蓝藻水华的功能,对比监测了修复区内外水体中chl.a浓度,通过原位围隔试验研究了修复区内聚集藻类的降解过程,测定了水生植被的遮光率及其对藻类光合作用的影响。结果显示,修复区具有捕获富集和分解消除漂浮性蓝藻的作用,同时能通过水生植物的遮荫作用抑制藻类光合作用。在蓝藻水华暴发期(7-10月)修复区内蓝藻大量聚集,chl.a最高浓度达到修复区外的29倍;聚集在修复区内的藻类在微生物作用下迅速降解,chl.a降解过程符合一级反应动力学方程,反应系数为k=0.2173(时间单位为天);修复区内挺水植被的遮光率可以达到90％以上,能降低植被区内水体中藻类光合作用强度60％左右。     

Effect of Well Disinfection on Arsenic in Ground Water

Domestic water wells are routinely subjected to in situ chemical disinfection treatments to control nuisance or pathogenic bacteria. Most treatments are chlorine based and presumably cause strongly oxidizing conditions in the wellbore. Water resource managers in Wisconsin were concerned that such treatments might facilitate release of arsenic from sulfide minerals disseminated within a confined sandstone aquifer. To test this hypothesis, a well was subjected to four disinfection treatments over 9 months time. The first treatment consisted of routine pumping of the well without chemical disinfection; three subsequent treatments included chlorine disinfection and pumping. Pretreatment arsenic concentrations in well water ranged from 7.4 to 18 μg/L. Elevated arsenic concentrations up to 57 μg/L in the chemical treatment solutions purged from the well are attributed to the disintegration or dissolution of biofilms or scale. Following each of the four treatments, arsenic concentrations decreased to less than 10 μg/L during a period of pumping. Arsenic concentrations generally returned to pretreatment levels under stagnant, nonpumping conditions imposed following each treatment. Populations of iron-oxidizing, heterotrophic, and sulfate-reducing bacteria decreased following chemical treatments but were never fully eradicated from the well. Strongly oxidizing conditions were induced by the chlorine-based disinfections, but the treatments did not result in sustained increases in well water arsenic. Results suggest that disruption of biofilm and mineral deposits in the well and the water distribution system in tandem with chlorine disinfection can improve water quality in this setting.     

秋冬季环境下固定化氮循环细菌净化湖泊水体氮污染动态模拟

本文依据太湖秋冬季水体氮污染的特点,应用辐射增殖氮循环细胞进行了净化湖水氮污染的动态模拟实验,研究结果表明,富营养化湖水经固定化氮循环净化后,总氮下降７２．４％,氨氮下降８５．６％,出水水质得到明显改善,固定化氮循环细茵在冬季低温（７℃）条件下仍保持了较高的降氮能力,总氮和氨氮去除率分别为５５．６％,５８．９％,降氮效果与湖水滞留时间有关,探讨了固定化氮循环细茵的降氮机理。     

The Effect of Sampling Frequency on Ground Water Quality Characterization

There is an implicit relationship between the frequency of sampling and the value of information obtained. This relationship is briefly explored by a study of nitrates in aquifers of the Quaternary age and fluorides and sulfates in aquifers of the Cambro-Ordovician age in Iowa. The ambient distribution of these chemicals, in general, is positively skewed with a significant number of observations in the lower end of the feasible range. It is shown that a much broader perspective of the distribution of these chemicals in ground water can be obtained by studying a whole spectrum of parameters (quantiles) ranging from the minimum to the maximum, rather than just the mean or the median alone. Simple random samples of varying sizes drawn from the available data base revealed that many parameters of location, such as the quantiles, of nitrates, fluorides, and sulfates in selected aquifers can be estimated closely by samples of sizes 50, 100 and 250. Results based on such hindsight warrant further investigation of the behavior of sampling distributions of a set of high priority chemicals in different hydrogeological environments.     

抽水对地下水位、汞、氡的影响——以古城试验为例

介绍了在内蒙古古城进行的同层抽水对水位、水温(地热)、气氡、气汞、水氡与水汞影响的观测试验及其结果。结果表明,抽水对井水位影响最大,影响距离可达近1 km;对水温影响较为明显;对气氡、气汞的影响不明显;水氡与水汞的动态可能有一定影响,但影响幅度不大。     

不同岩性下水对断层摩擦性状影响的实验研究

利用双轴伺服控制加载装置, 在干燥和饱和水(浸在水中)条件下, 开展了砂岩、 大理岩和花岗岩的摩擦实验。 对比干湿条件下断层摩擦应力和声发射的演化特征, 讨论水对断层滑动性状的影响。 研究表明, 低正应力条件下, 砂岩和大理岩标本表现为稳滑, 而花岗岩则表现为粘滑; 岩体矿物成分、 孔隙率和以及滑动面的状况共同影响断层摩擦的稳定性; 干湿条件下摩擦强度的变化为水对断层滑动面和围岩抗剪强度影响的综合效应; 砂岩含有硬度较小的矿物, 初始粘结力低, 孔隙率高, 水对滑动面和围岩都起到弱化的作用; 方解石硬度和摩擦特性控制了大理岩的摩擦性状, 而标本含有穿晶和晶内微破裂增强了水对大理岩摩擦强度的弱化作用; 花岗岩组成矿物的硬度大且胶结紧密, 初始粘结力大, 孔隙率低, 因此摩擦性状对含水量的变化响应较小。 不同岩性的摩擦稳定性在干湿条件下均存在差异, 不同岩性断层摩擦性状对含水量的变化响应不同, 因此研究水库诱发地震时要考虑断层的岩性特征。     

The Effect of Three Drilling Fluids on Ground Water Sample Chemistry

Three monitoring wells were installed in borings that were constructed using water-based drilling fluids containing either (1) guar bean, (2) guar bean with breakdown additive, or (3) bentonite. These fluids were selected to observe their effect on the chemistry of subsequent water samples collected from the wells. The wells were installed to depths of 66 feet, 100.5 feet and 103 feet, respectively, in fine-to-medium sand and gravel outwash deposits near Antigo, Wisconsin. Drilling fluids were necessary to maintain an open borehole during well construction through strata containing cobbles and boulders.
The bentonite and guar drilling fluids caused temporarily elevated concentrations of chemical oxygen demand (COD) in ground water samples collected from the monitoring wells. Using standard development, purging and sampling procedures, elevated COD concentrations persisted for about 50 days for the well bored with the guar-with-additive fluid, 140 days for the bentonite well and 320 days for the guar well. Unfiltered ground water samples for all wells had greater concentrations of COD than samples filtered through a 0.45 micron filter. Sulfate concentrations also decreased with time in the guar-with-additive well and bentonite well, but not in the guar well.
The elevated COD concentrations are attributed to the large concentrations of oxidizable carbon present in the guar bean drilling fluid and in the organic polymers present in the bentonite drilling fluid. Well development and purging procedures, including borehole flushing, surging, bailing and/or chemically induced viscosity breakdown of the guar mud decreased the time before background conditions were achieved. Future research should evaluate the physical and geochemical interaction of different drilling fluid compositions with a variety of geologic matrices and drilling, well development and well purging techniques.     

天津两井水位同震效应分析

从不同的方位对天津地区两口地震观测专用井记录到的国外7级、国内6级以上的地震进行分析。两口井所处的地理位置、地质结构、井深及其含水层岩性不同,对同一地震的表现形式也不尽相同。通过对比分析,得到井水位对地震的响应特点及几点认识：观测井孔一般对远场大震记录比较灵敏,而对近震及地方震反映不灵敏;井孔水位仪记录的水位波幅与震级、震中距有关;井孔同震效应的能力和井孔对固体潮的反映能力不一致。