基于非线性系统理论的水-碳耦合模型

针对现存水-碳耦合模型中存在机理复杂、结构不平衡、不确定性较大、资料需求难以满足等问题,根据非线性水文循环模拟理论的"从复杂现象中,寻找简单规律"的理念,基于非线性水文循环理论构建具有一定物理机理和精度的水-碳耦合模拟方法。采用American-Flux的Duke站点和白洋淀上游的崇陵试验流域小区的试验数据,在点尺度和小区尺度对构建模型的精度加以验证,结果显示,基于非线性理论的耦合模型能够更加合理和准确的模拟水文循环中蒸散发量和土壤含水量的变化过程;最后采用该模型估算了温室气体排放量对水文循环要素的影响,在二氧化碳浓度加倍情景下,试验小区径流深增加0.5%;平均土壤含水量增加1.2%;蒸散发量减少4.9%。综合表明,构建模型达到了采用简单方法解决复杂问题的效果。

城市水系统关联模型研究

为了理清城市水系统中多因素间的复杂关系,对系统解决城市水问题提供帮助,基于水系统理论与城市水系统模拟相关研究,提出了城市水系统中水-经济社会-生态环境各因素之间相互作用和反馈的关联模型理论框架,建立了城市水系统演变过程中由针对经济发展的正反馈回路和针对可持续性的负反馈回路共同控制的新模式,构建了模拟城市水-经济社会-生态环境内在联系的城市水系统关联模型。以武汉市为例,应用建立的城市水系统关联模型,采用2001—2017年的历史统计数据,建立了武汉市城市水-经济社会-生态环境各要素之间互馈作用的模拟模型,预测了武汉市的城市发展轨迹,并与武汉市2030年的远期规划进行比较,验证了模型的有效性,表明城市水系统模型能够揭示城市水-经济社会-生态环境多要素的耦合驱动机制,体现了节水技术与绿色发展相关政策两大因子导向下的生态环境、经济社会协同发展的良好预期。

Effects of seawater acidification on the early development of sea urchin Glyptocidaris crenularis

In this study, we evaluated the effects of CO_2-induced seawater acidification on fertilization, embryogenesis and early larval development in the sea urchin Glyptocidaris crenularis, that inhabits subtidal coastal areas in northern China. The range in seawater p H used in experiments was based on the projections of the Intergovernmental Panel on Climate Change(IPCC), to the year 2100. A natural seawater treatment(p H_(nbs) =7.98±0.03) and three laboratory-controlled acidified treatments(OA_1, ΔpH_(nbs) =-0.3 units; OA_2, ΔpH_(nbs) =-0.4 units; OA_3, ΔpH_(nbs) =-0.5 units) were used in experiments. Results show that:(1) there was a negative effect of seawater acidification on fertilization and on the percentage of abnormal fertilized eggs;(2) the size of early cleavage stage embryos decreased in a dose-dependent manner with decreasing p H;(3) both the hatching rate of blastulae and the survival rate of four-armed pluteus larvae decreased as pH declined;(4) larval abnormalities including asymmetrical development, changes in the length of skeletal elements, and corroded spicules were observed in all seawater acidified-treatments compared with the control. These data indicate that seawater acidification has a negative impact on the early development of G. crenularis, and supports the hypothesis that the response of echinoderms to ocean acidification(OA) varies among species. Further research is required to clarify the specific cellular mechanisms involved.

Development and evaluation of specific PCR primers targeting the ribosomal DNA-internal transcribed spacer(ITS)region of peritrich ciliates in environmental samples

Peritrich ciliates are highly diverse and can be important bacterial grazers in aquatic ecosystems. Morphological identifi cations of peritrich species and assemblages in the environment are time-consuming and expertise-demanding. In this study, two peritrich-specifi c PCR primers were newly designed to amplify a fragment including the internal transcribed spacer(ITS) region of ribosomal rDNA from environmental samples. The primers showed high specifi city in silico, and in tests with peritrich isolates and environmental DNA. Application of these primers in clone library construction and sequencing yielded exclusively sequences of peritrichs for water and sediment samples. We also found the ITS1, ITS2, ITS, D1 region of 28 S rDNA, and ITS+D1 region co-varied with, and generally more variable than, the V9 region of 18 S rDNA in peritrichs. The newly designed specifi c primers thus provide additional tools to study the molecular diversity, community composition, and phylogeography of these ecologically important protists in dif ferent systems.

A novel male-associated marker for sex identification in Ussuri catfish Pseudobagrus ussuriensis

The Ussuri catfish Pseudobagrus ussuriensis is a promising aquaculture fish with sexual dimorphism that males grow 2–3 times faster than females. Therefore, all-male breeding could increase production of this fish, and sex-linked markers would be useful during the breeding process. In this study, a male-associated marker named PuGT54 was isolated in P. ussuriensis from a previously constructed microsatellite library. A total of 185 P. ussuriensis individuals containing 95 females and 90 males were used to test the usage of this maker. And results showed that sexes of all individuals were successfully identified, indicating the high reliability and accuracy of this marker for sex identifi cation. Furthermore, the male-specifi c fragment amplifi ed by this maker was cloned and sequenced, which was 118 base pairs in length. As homologous genes of this fragment was not found through BLASTn, detailed information of the male-specifi c fragment is unknown presently. Nevertheless, this marker would be helpful in conservation, breeding and ecological study of P. ussuriensis.

Prediction of the maximum water inflow in Pingdingshan No.8 mine based on grey system theory

In order to prevent and control the water inflow of mines, this paper built a new initial GM（1, 1） model to torecast the maximum water inflow according to the principle of new information. The effect of the new initial GM（1, 1） model is not ideal by the concrete example. Then according to the principle of making the sum of the squares of the difference between the calculated sequences and the original sequences, an optimized GM（1, I） model was established. The result shows that this method is a new prediction method which can predict the maximum water inflow accurately. It not only conforms to the guide- line of prevention primarily, but also provides reference standards to managers on making prevention measures.

Leak Detection in Water Distribution Systems Using Bayesian Theory and Fisher’s Law

A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of parameter values was quantified by probability density function and updated by Bayesian theory. Values of the parameters were estimated based on Fisher’s law. The amount of leaks was estimated by back propagation neural network. Based on flow characteristics in water distribution systems, the location of leaks can be estimated. The effectiveness of the proposed method was illustrated by simulated leak data of node pressure head and flow rate of pipelines in a test pipe network, and the leaks were spotted accurately and renovated on time.

Risk analysis for a cascade reservoir system using the brittle risk entropy method

The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.