武汉市一组复合氧化塘藻类与某些生态因子的相关性研究

报道了从1988年3月至1989年12月对武汉市墨水湖地区一组复合氧化塘中藻类总细胞数(ACN)、叶绿素a(chl·a)与水温、透明度、总氮(TN)、总磷(TP)、总溶解磷(TDP)、溶解磷(DP)、非溶解磷即总磷与总溶解磷之差值(TP-TDP)等的相关性及ACN与chl·a的相关性的研究结果,并讨论了这些相互关系对氧化塘处理效果、氧化塘水质变化的指示意义.     

Changes in Soil Properties of Abandoned Shrimp Ponds in Southern Thailand

Chemical soil properties between active shrimp ponds andabandoned ones on the Bangkok soil series were compared,at Ranote District, Songkhla Province in southern Thailand.Soil samples were collected at depth intervals of 0–10, 10–20, 20–30, 30–40 and 40–50 cm from pond bottoms at the same ponds used in a former study conducted in 1994, fora total of 6 ponds with 3 sampling sites for each pond. Theseponds were active during the previous study in 1994, abandonedin 1996 and investigated by this study in 1999. All the samples were analyzed for exchangeable Ca, Mg, K and Na electrical conductivity (EC), organic matter, S, P and pH, and statistically compared with the analytical results of theprevious study. An increase in amounts of Ca, Mg, K, Na and EC in the abandoned ponds as compared with the active ones by1.3–3.4, 1.4–2.1, 7.0–30.0, 1.2–6.3 and 1.3–10.9 timesrespectively was observed. That more of these elements weregained than lost each time the seawater was introduced intothe ponds, is explained by the Element Input/Output Consideration as proposed herein. Furthermore, a decreasein organic matter, S and P was also observed in the abandonedpond soils, and attributed to the absence of shrimp food and shrimp excreta following the cessation of shrimp raising activities. An unexpected decline in the soil pH of the abandoned ponds was found as well. Aerobic decomposition of organic matter during the absence of shrimp raising activitiescaused by soil microorganisms triggering SO₂ and H₂SO₄ formation probably played a more significantrole than the increase in the amounts of the basic elements (Ca, Mg, K, and Na) eventually reducing soil pH in the abandoned ponds. The significant depletion of the amounts of organic matter in the abandoned pond soils also supports this observation.     

Phosphorus removal by the multipond system sediments receiving agricultural drainage in a headstream watershed

Wetland systems in headstream watersheds are important to control the nonpoint source pollutant phosphorus. Experiments were conducted using intact sediment-water columns obtained from the multipond system in Liuchahe watershed of Chaohu Lake to determine its capacity to retain P. It was found that pond sediments had strong P retention ability. For the Hill pond, Village pond and Rice pond, their retention coefficient(A) were 288.3, 279.2 and 260.8 L/m^2, respectively. The equilibrium P concentration(EPCw) were 0.016, 0.028 and 0.018 mg/L, respectively. The Hill pond indicated the highest P retention ability. P retained in the pond sediments indicated high stable degree. P removal from the overlying water column into the pond sediments followed a first-order kinetic model. Under the experimental hydrological conditions, the retention time had a positive correlation with the P loading. The multipond system could provide enough retention time to retain P in drainage runoffs. At the P levels evaluated, the sediments of the multipond system are effective sinks to retain P from nonpoint source runoffs.     

斑节对虾Penaeus monodon养成期间池水CODMn和BOD5的变化及其相互关系

研究了有益微生物制剂调控下,斑节对虾生长周期内,池水中CODMn和BOD5的变化规律.结果表明,CODMn和BOD5的动态变化大致分为3个阶段：前期在低浓度下缓慢增长,中期由较低浓度向较高浓度快速增长,后期在较高浓度波动,回归分析结果显示二者呈显著的线性正相关关系（P〈 0.01）.在养殖后期,未投放微生物的对照池中CODMn和BOD5浓度比投放微生物的试验池中有所增高,分别增高约9 %和21 %.     

小型养殖塘水体中CH4、CO2和N2O浓度的时空变化特征及影响因素

养殖塘作为重要的温室气体排放源,水体中温室气体浓度的变化不仅是准确量化温室气体排放量的基础,还是明确其影响因素的重要依据.基于顶空平衡-气相色谱仪法对长三角一处典型的小型养殖塘水体中CH₄、CO₂和N₂ O浓度的时空变化特征以及影响因素进行了分析.结果表明,除春季外,在水温影响下,CH₄和N₂ O浓度在午间或午后出现高值;受水温和水生植物光合作用影响,CO₂浓度的高值出现在晨间光合作用较弱的时候.养殖塘水体中CH₄和CO₂浓度呈现秋季最高、冬季最低的季节变化特征,c（CH₄）在秋季和冬季的均值分别为176.34 nmol·L^-1和32.75 nmol·L^-1,主要受气温、水温和溶解氧（DO）影响;c（CO₂）秋季和冬季的均值分别为134.37 μmol·L^-1和23.10 μmol·L^-1,主要受水生植物光合作用和pH影响;c（N₂ O）在夏季最高,冬季最低,均值分别为97.05 nmol·L^-1和19.41 nmol·L^-1,主要受气温和水温影响.在空间上,垂直方向上,夏季养殖塘c（CH₄）随水深的加深而降低,表层与底层、中间层的浓度差值为71.28 nmol·L^-1和42.80 nmol·L^-1,秋季随水深的加深而升高,底层与表层的浓度差值为163.94 nmol·L^-1.c（CO₂）在夏季和秋季都表现为随着水深的加深而升高,其底层与表层的浓度差值分别为18.69 μmol·L^-1和29.90 μmol·L^-1.N₂ O浓度在垂直方向上无明显变化规律.水平方向上,夏季饲料及春季鸡粪投放的区域会出现CH₄、CO₂和N₂ O浓度的高值,春季和夏季CH₄浓度约为其他区域的1.34~1.98倍和1.95~2.42倍,春季N₂ O浓度和夏季CO₂浓度约为其他区域的1.13~1.26倍和1.39~1.74倍.     

不同溃坝条件下尾矿库溃坝试验与灾害影响研究*

为探究不同溃坝条件下尾砂流的演进规律与灾害影响,提高应对尾矿库溃坝灾害的防灾减灾能力。以四川某尾矿库为研究背景,采用模型试验与数值模拟相结合的方法,研究不同溃坝条件下溃坝砂流的演进和沉积规律,并预估溃坝灾害影响。研究结果表明:溃坝方式对溃坝砂流的演进过程、尾砂的沉积分布情况与致灾程度有显著影响;与漫顶溃坝相比,瞬时溃坝砂流的淹没范围更广、破坏性更强;砂流在流动过程中存在水-砂分层流动与沉淀的动态变化过程,其淹没面积大于尾砂的沉积面积;试验与数值模拟结果的一致性较高,采用两者相结合的方法研究溃坝砂流流动规律及灾害影响具有一定的可靠性。     

Hydrologic Impact Assessment of Land Cover Change and Stormwater Management Using the Hydrologic Footprint Residence

Urbanization impacts the stormwater regime through increased runoff volumes and velocities. Detention ponds and low impact development (LID) strategies may be implemented to control stormwater runoff. Typically, mitigation strategies are designed to maintain postdevelopment peak flows at predevelopment levels for a set of design storms. Peak flow does not capture the extent of changes to the hydrologic flow regime, and the hydrologic footprint residence (HFR) was developed to calculate the area and duration of inundated land during a storm. This study couples a cellular automata land cover change model with a hydrologic and hydraulic framework to generate spatial projections of future development on the fringe of a rapidly urbanizing metropolitan area. The hydrologic flow regime is characterized for existing and projected land cover patterns under detention pond and LID‐based control, using the HFR and peak flow values. Results demonstrate that for less intense and frequent rainfall events, LID solutions are better with respect to HFR; for larger storms, detention pond strategies perform better with respect to HFR and peak flow.     

水生植物微生物强化系统对日本沼虾养殖水体的生物净化

通过在池塘水体中栽种以轮叶黑藻(Hydrilla verticillata)为主的水生植物,并添加活菌含量>108 g-1的复合微生物制剂,构建了水生植物-微生物强化系统,研究该系统对日本沼虾(Macrobrachium nipponense)养殖水体的生物净化效果。结果表明,试验40 d时,所添加的1.0 mg.L-1活性微生物可充分依赖水体中水生植物的巨大表面积而形成固定化的生物膜,使得植物区及相邻水体中细菌和真菌数量提高25%～69%,强化水体的净化功能。水生植物-微生物强化系统可通过相互的协同作用,提高对氮、磷和有机物等的利用能力,在促进自身生长的同时,可大幅降低水体中NH4+-N、NO2--N、NO3--N、TP、PO43--P含量,抑制TN、高锰酸盐指数的快速升高,提高水体中溶解氧,竞争藻类生长的资源,使得水体中藻类的丰度有所下降,pH也趋于稳定。研究表明,水生植物-微生物强化系统是一种良好的日本沼虾养殖水体生物净化系统,当水体中添加的微生物质量浓度为1.0 mg.L-1时,适宜的水生植物覆盖率为40%。     

Road Facilitation of Trematode Infections in Snails of Northern Alaska

Abstract:  Road disturbances can influence wildlife health by spreading disease agents and hosts or by generating environmental conditions that sustain these agent and host populations. I evaluated field patterns of trematode infections in snails inhabiting ponds at varying distances from the Dalton Highway, a wilderness road that intersects northern Alaska. I also assessed the relationships between trematode infections and snail densities and six environmental variables: calcium concentration, aquatic vegetative cover, canopy cover, temperature, pond size, and community structure. Presence of trematode infections and snail density were negatively correlated with distance from the highway. Of the pond characteristics measured, only calcium concentration and vegetation density declined with distance from road. However, neither variable was positively associated with snail density or trematode presence. One potential explanation for observed patterns is that vehicles, road maintenance, or vertebrate vectors attracted to the highway facilitate colonization of snails or trematodes. Emerging disease threats to biological diversity in northern ecosystems highlight the importance of understanding how roads affect disease transmission.     

有色金属尾矿库土地复垦与环境治理效益估算研究进展

有色金属矿山选矿形成的尾矿库是潜在的高风险重金属污染源,闭库后应及时进行土地复垦与环境治理.有色金属尾矿库的综合整治效果如何,可以通过合理的效益估算来分析,有效的效益估算往往涉及多学科领域的专业知识.在归纳总结国内外有色金属尾矿库复垦治理效益相关研究的基础上,系统地阐述了复垦治理经济效益、社会效益和生态环境效益的概念、内容及其估算方法.对已有有色金属尾矿库复垦治理效益估算的研究表明:尾矿库复垦的直接经济效益较小,主要是估算复垦区内植物的经济收益以及采用收益还原法估算复垦土地的增值收益;社会效益主要是采用价值法和替代法针对增加就业和社会保障进行估算,较少关注复垦治理对社会其他方面的贡献;生态环境效益估算方法主要包括污染损失率法、生态服务价值法及环境价值法等,但与复垦治理技术措施结合较少,效益估算对复垦治理措施优化的作用较弱.总体来看,有色金属尾矿库复垦治理效益估算的内容涵盖不够全面,尚未形成适合重度重金属污染尾矿库特点的效益估算体系,效益估算准确性较低.因此,合理确定尾矿库复垦治理效益估算的内容、完善效益估算方法及其数学模型、合理确定模型参数,是有色金属闭库尾矿库土地复垦与环境治理效益估算进一步研究的重点内容.有效的效益估算可为优化有色金属尾矿库复垦治理措施、寻求最佳复垦治理模式及确定复垦治理的资金投入提供依据.