Contribution of biological processes to self-purification of water with respect to petroleum hydrocarbon associated with No. 0 diesel in Changjiang Estuary and Jiaozhou Bay, China

Mesocosms in 25-m³ ethylene vinyl acetate or 4-m³ polyethylene bags were performed at two sites in China: Changjiang Estuary in spring–summer 1998, and Jiaozhou Bay in autumn 1999 and spring–summer 2000. The experiments were designed to show the contributions of physical, physicochemical and biological processes to self-purification of water with respect to the water-soluble fraction (WSF) of petroleum hydrocarbon associated with No.0 diesel (PHAD). Over the experimental periods, the WSF-PHAD concentration in water declined significantly. A kinetic model for WAS-PHAD distribution in multiphase environments – in this case water (W), suspended sediment (SS), phytoplankton (PPT), zooplankton (ZPT) and atmosphere (ATM) – was developed to estimate the contributions of the various processes. In the model, the key processes responsible for self-purification include (1) physical transport by volatilization from W to ATM; (2) biological transformation through biodegradation; (3) biological transfer involving bioconcentration by PPT and ZPT; and (4) physicochemical transfer through sorption by SS. Model parameters were determined from the mesocosm experiments and parallel laboratory experiments, or taken from the literature. It indicated that volatilization plays an important role in short-term self-purification especially regarding alkanes with relatively low molecular weight, accounting for 82.9±2.5%. After the volatilization stops, bioconcentration by PPT contributes greatly to long-term self-purification especially regarding alkanes of higher molecular weight and polycyclic aromatic hydrocarbons (PHAs), accounting for 0.7 – 17.8% with an average of 7.8±7.3%. The bioconcentration is dominated by biomass of PPT as well as the WSF-PHAD concentration. However, the biodegradation process makes the greatest contribution to both the short- and long-term self-purification, affecting alkanes of both lower and higher molecular weight as well as PHAs. The results suggest that it is necessary to take into account the biological processes of biodegradation and bioconcentration in estimating the self-purification of water with respect to oil pollutants.     

Distribution of pathogenic enterobacteria in the water of open reservoirs]

Investigations carried out indicated that the main source of microbial contamination of open reservoirs were effluents often drained without any purification and disinfection. Salmonellae were isolated in 10.6 +/- 0.88% of the water samples examined in the Southern regions of the country. Isolation of pathogenic enterobacteria from the water of open reservoirs was seasonal, with the maximal percentage in winter and in spring, this being connected with delay of self-purification processes in the cold seasons of the year. Serovars isolated from water and patients proved to be identical. There was no direct correlation between the coli index and the isolation of pathogenic enterobacteria.     

海洋着色菌YL28对含沉积物的海水养殖水体氮污染去除效应的研究

用含有沉积物的氮化物污染实际水体作为测定体系,通过测定水体无机三态氮、总氮、COD、pH以及沉积物总氮、COD和对4种代谢酶活性的动力学过程的监测,评价了一株不产氧光合细菌——海洋着色菌(Marichromatium gracile)YL28对海水实际养殖水体脱氮效应。结果表明:水体本身具有一定的自净作用;与对照组相比,YL28组水体氨氮、亚硝氮、硝氮、沉积物总氮和COD的残留率明显降低(P0.05),在6~10d内水体COD明显升高,水体总氮和pH未见显著差异。处理过程中,在特定的时间范围内,转化酶、蛋白酶、脲酶和脱氢酶活性明显升高(P0.05),与沉积物总氮和COD去除规律相吻合。由此可见,添加YL28对污染海水养殖水体中无机三态氮、沉积物有机氮化物和有机碳化物具有明显的去除作用,本研究为海水养殖微生态水质修复剂的开发和应用奠定基础。     

Comparison of different methods of water quality evaluation by means of oligochaetes

Using as examples water bodies in different geographical zones (Lake Ladoga, the River Sukhona, shallow-water ponds of the North Caucasus) the known methods of water quality evaluation by means of oligochaetes are considered. There is no unique universal method of pollution bioindication in. this way. In water bodies of all types the mass development of oligochaetes and the reduction of their species diversity are indications of. (1) large quantities of organic matter; (2) favourable oxygen regime; (3) absence or insignificant quantity of heavy metal solids, petroleum substances and agricultural chemicals; (4) intensive self-purification of the water body.     

过水性湖泊自净能力的动态变化

通过对过水性湖泊骆马湖1991—2003年出、入湖口附近主要水质指标监测资料的分析,研究了湖泊湿地自净能力的变化情况。结果表明:1991—2003年,各采样点水质指标无显著变化,但出、入湖口水质差异显著,表明骆马湖目前尚有较强的自净能力;各采样点间主要水质指标的变异系数逐渐减小,表明湖泊对水体总氮、溶解氧、挥发酚、非离子氨、砷等主要富营养化物质和污染物的净化能力不断减小,湿地生态系统的自净能力显著下降。总氮、溶解氧及部分外源污染物指标在不同采样点间的变异系数可作为湿地生态系统自净能力与健康状况的重要参考指标。     

养殖水质原位自净微生物诱导及复合应用

本文采用原位诱导有益微生物（污水菌、芽胞杆菌、硝化菌和副球菌等）,复合添加外源的有益微生物（金藻、栅藻、硅藻、芽胞杆菌、光合菌、酵母菌和EM（effective microorganisms）菌等）,在养殖水体中建立稳定的有益微生物复合菌群,使水体中亚硝酸氮和氨氮清除率分别可达100%和99%。并进一步利用这些菌群在小红鲫鱼（red crucian carp）和南美白对虾（Penaeus vannamei）养殖中进行原位水质净化应用。在小红鲫鱼养殖水质原位自净中,无需清污和换水,就可长期维持水环境完全稳定,连续养殖50 d以上,水中未检测出亚硝酸氮,氨氮低于0.2 mg/L,稳定在优质安全的养殖环境;在南美白对虾养殖中,投菌后初期水体亚硝酸氮较快下降,第10 d后氨氮浓度也降至养殖安全范围内,形成稳定安全的养殖水质环境。实验效果显著,表明微生物菌群原位水质自净技术具有推广应用前景。     

微生态制剂对刺参幼参在封闭式循环养殖系统中的应用研究

目的对循环水养殖系统水质指标和刺参幼参的生长代谢进行分析。方法在水温（16±1）℃的循环养殖系统中投喂不同的微生态制剂。结果30d实验结果表明：循环养殖系统具有一定自净能力,微生态制剂能够显著延长循环养殖系统的自净周期。其中“EM菌剂”在控制溶解氧含量等方面具有优势。结论复合微生态制剂“海微净水剂”和“hEM菌剂”在降解氨氮、亚硝酸盐、磷酸盐和化学耗氧量等方面效果较单一微生态制剂“EM菌剂”效果好,并且刺参的生理活动也较强。此外“NEM菌剂”能够显著提高刺参幼参的生长速度。     

Are bacteriophages significant for the self-purification of surface water?

Summary As early as 1926 the present author has claimed that in the self-purification of water (under experimental conditions realized in the laboratory) bacteriophages take no part, at least not an easily discernable one. The investigations ofSchuurman on the significance of typhoid phages in the self-purification of the water in the Tjiliwoeng river induced the author to attack the problem once more from the experimental side. The results of these recent investigations allow of no other conclusion than that under circumstances and conditions as have been fully described, bacteriophages do not act on the self-purification of water. It might be conceived, that the high temperature of the Tjiliwoeng river and its high content of colloidal clay allow the phage to play a certain part, although the results of the author's experiments make this hardly probable. At all events such an influence is neither proved nor made probable by the results ofSchuurman's experiments with the untreated Tjiliwoeng water, because of his failing to exclude the action of the protozoa.     

Can we use the Shiga-bacteriophage as indicator for a faecal pollution of water?

Summary and conclusions In an important percentage of stools of healthy persons Shiga bacteriophage occurs.The Shiga bacteriophage occurs during some lapse of time in water which has been polluted by human faeces. The Shiga bacteriophage could be ascertained in water by means of the enrichment method ofNyberg.The Shiga bacteriophage method for indicating the pollution of strongly polluted water is as sensitive or sometimes less so than the methods ofEijkman and ofClemesha.For the examination of water in several stages of purification in water works the Shiga bacteriophage method is as sensitive or even more so than the other methods.The Shiga bacteriophage does not act strongly in the self-purification of polluted water.The Shiga bacteriophage may be used as indicator for a faecal pollution of water and this method may be applied along with the other bacteriological methods in water control. It may be advantageous to study more closely its limits and its benefits in the practice of water control     

玛纳斯河流域水资源可持续利用评价方法

水资源短缺是制约玛纳斯河流域水资源可持续发展的"瓶颈"因素,对流域水资源可持续发展水平进行综合评价对其国民经济可持续发展至关重要。从水资源、社会、经济、生态环境四个子系统出发,采用了熵值法和投影寻踪理论相结合的评价模型,对流域水资源可持续利用水平进行评价,并将两种方法的评价结果进行加权求和,得出流域水资源可持续利用变化趋势。评价结果表明,该模型方法可靠,分析结果合理,评价结果可以为水资源可持续开发利用提供科学依据,是评价水资源可持续利用水平的一种有效新方法。最后,提出了促进流域水资源可持续利用的建议,为实现水资源可持续开发利用提供借鉴和参考。     

Influence of inhibitors of cytoskeleton proteins on water exchange of wheat roots under the after-action of water stress

The dynamics of water molecular state and transport in winter wheat (Triticum aestivum L.) of roots different resistance cultivars was studied by a biophysical method, Nuclear Magnetic Resonance (NMR), and a physiological method, Water-Holding Capacity (WHC). The effective coefficient of water self-diffusion (D(eff)), spin-spin relaxation times (T(2)) and WHC were measured after structural modification of cytoskeleton by colchicine and cytochalasin B after the action of water stress. New information about molecular mechanisms of water state and water transport regulation determined by the influence of dynamic cytoskeleton structure has been obtained. This is very important for the development of a fundamental theory of water exchange in plants, and for the ways of its optimization under conditions of environmental stress.     

干旱区包气带土壤水分运移能量关系及驱动力研究评述

包气带土壤能量和水分平衡及其驱动因子是维系地下水-土壤-植物-大气连续体(GSPAC)系统中水分运移发生的关键因素。在降水稀少、水资源短缺的干旱地区,开展包气带土壤水分形态、运移过程与能量的耦合规律研究对揭示区域水资源形成和转化机理具有极其重要的现实意义。文章总结了土壤水分运移理论研究进展,探讨了水分参与水文循环过程及干旱环境下土壤水分可能表现形态及其降雨入渗、再分布、渗漏、蒸发、毛管水上升等过程驱动机制,评述了包气带土壤水分与能量过程在不同空间尺度上生态水分效应。在一个非饱和土壤系统中,水分运移受包气带结构,土壤物理特征,植物根系和土壤生化环境的综合控制,物质和能量平衡改变是驱动水分循环的源动力,而土壤环境变化是导致水分运移形态的发生变化根本原因。因此,在气候变化背景下,研究干旱区土壤与大气界面以及包气带与饱和带界面水、汽、热耦合转化形式与能量驱动过程,能够提升我们对包气带土壤水分运移规律机理的深入理解,丰富对区域气候和水文变化认知。为干旱区生态植被恢复建设和水资源精细化管理提供理论向导。     

Research progress on water uptake through foliage

Leaf is one of the most sensitive organs that response to atmospheric environment changes. In arid region, especially under water stress conditions, water from foliar uptake is one of the main water subsidy sources, which plays an important role in plant survival, growth and ecosystem sustainable development. Foliar water uptake attracts more attention in physiological and ecological research all over the world. This essay summarized the main measurement methods of foliar water uptake at home and abroad in detail: vessel control method, stable isotope technology and heat ratio method. And analyzed the significance of foliar water uptake from physiological and ecological aspects; and discussed the influence factors of foliar water uptake from water condition perspective, water absorption and leaf structure aspects. The following aspects should be paid more attention in future researches: (1) measure the amount of foliar water uptake by using stable isotope technology and heat ratio method; (2) the relationship among foliar uptake of fog, dew, rain and water vapor in arid region; (3) the foliar uptake amount and rate should be simulated by models; (4) the mechanisms of foliar water uptake should be researched; (5) study foliar water uptake of different plants at ecosystem scale.     

Research progress on water uptake through foliage

Leaf is one of the most sensitive organs that response to atmospheric environment changes. In arid region, especially under water stress conditions, water from foliar uptake is one of the main water subsidy sources, which plays an important role in plant survival, growth and ecosystem sustainable development. Foliar water uptake attracts more attention in physiological and ecological research all over the world. This essay summarized the main measurement methods of foliar water uptake at home and abroad in detail: vessel control method, stable isotope technology and heat ratio method. And analyzed the significance of foliar water uptake from physiological and ecological aspects; and discussed the influence factors of foliar water uptake from water condition perspective, water absorption and leaf structure aspects. The following aspects should be paid more attention in future researches: (1) measure the amount of foliar water uptake by using stable isotope technology and heat ratio method; (2) the relationship among foliar uptake of fog, dew, rain and water vapor in arid region; (3) the foliar uptake amount and rate should be simulated by models; (4) the mechanisms of foliar water uptake should be researched; (5) study foliar water uptake of different plants at ecosystem scale.     

基于氮磷比解析太湖苕溪水体营养现状及应对策略

生态化学计量学是评价水体营养状态的重要手段,利用其氮磷比指标探讨了我国太湖主要入湖河流苕溪的营养状态。野外监测结果显示,苕溪水体氮素超标严重,磷素污染轻度,硝酸盐、颗粒态磷为氮磷的主要赋存形态,且氮磷浓度呈现相似的季节变化规律,表明苕溪主要受农业面源污染影响。氮磷比分析表明,苕溪水体春、秋季处于磷素限制状态,夏季适合藻类生长,冬季低温条件下不利于藻类的大量繁殖;苕溪生物量增长受磷素限制,线性拟合亦显示其氮磷比主要受磷素波动的调控;苕溪干流大面积暴发蓝藻水华的风险较部分支流及死水区低,苕溪水入湖后,特别是夏季其暴发风险将显著提高。针对苕溪水体的富营养化现状,提出若干条水质改善应对策略。     

水生态文明城市建设对城市水生态承载力的影响——以武汉市为例

城市水生态承载力能较好反映水资源-水环境-水生态-经济社会复合系统间多要素互馈关系,水生态文明城市建设对城市水生态系统具有多方面影响,对城市水生态承载力在水生态文明城市建设前后的变化进行定量研究具有重要意义。以城市"社会-经济-自然"复合生态理论为指导,充分考虑人类活动与城市水生态系统的响应关系,基于DPSIR框架构建城市水生态承载力评价指标体系,以水生态文明建设试点城市武汉市为例,综合运用熵权法、TOPSIS和障碍度诊断模型等方法,分析2008-2019年武汉市水生态承载力的变化趋势和影响因素。结果表明,水生态文明城市试点建设期间（2015-2017年）的水生态承载力平均水平（0.552）明显高于建设前（0.361）和建设后（0.438）,建设成果主要体现在压力和影响指标的改善以及响应指标的大幅度提升上。阻碍武汉市水生态承载力提升的主要指标为生态环境状况指数、建成区绿化覆盖率、农田灌溉亩均用水量、酸雨量和饮用水源地水质达标率。根据评价结果提出水城共生共荣发展模式、引导产业结构转型等提升武汉市水生态承载力的建议。     

Applications of the compensating pressure theory of water transport

Some predictions of the recently proposed theory of long-distance water transport in plants (the Compensating Pressure Theory) have been verified experimentally in sunflower leaves. The xylem sap cavitates early in the day under quite small water stress, and the compensating pressure P (applied as the tissue pressure of turgid cells) pushes water into embolized vessels, refilling them during active transpiration. The water potential, as measured by the pressure chamber or psychrometer, is not a measure of the pressure in the xylem, but (as predicted by the theory) a measure of the compensating pressure P. As transpiration increases, P is increased to provide more rapid embolism repair. In many leaf petioles this increase in P is achieved by the hydrolysis of starch in the starch sheath to soluble sugars. At night P falls as starch is reformed. A hypothesis is proposed to explain these observations by pressure-driven reverse osmosis of water from the ground parenchyma of the petiole. Similar processes occur in roots and are manifested as root pressure. The theory requires a pump to transfer water from the soil into the root xylem. A mechanism is proposed by which this pump may function, in which the endodermis acts as a one-way valve and a pressure-confining barrier. Rays and xylem parenchyma of wood act like the xylem parenchyma of petioles and roots to repair embolisms in trees. The postulated root pump permits a re-appraisal of the work done by evaporation during transpiration, leading to the proposal that in tall trees there is no hydrostatic gradient to be overcome in lifting water. Some published observations are re-interpreted in terms of the theory: doubt is cast on the validity of measurements of hydraulic conductance of wood; vulnerability curves are found not to measure the cavitation threshold of water in the xylem, but the osmotic pressure of the xylem parenchyma; if measures of xylem pressure and of hydraulic conductance are both suspect, the accepted view of the hydraulic architecture of trees needs drastic revision; observations that xylem feeding insects feed faster as the water potential becomes more negative are in accord with the theory; tyloses, which have been shown to form in vessels especially vulnerable to cavitation, are seen as necessary for the maintenance of P, and to conserve the supplementary refilling water. Far from being a metastable system on the edge of disaster, the water transport system of the xylem is ultrastable: robust and self-sustaining in response to many kinds of stress.