Microdistribution of macroinvertebrates in a temporary pond of Central Italy: Taxonomic and functional analyses

Spatial distribution of physical and chemical variables and macroinvertebrate composition, structure and functional aspects were investigated in five microhabitats available (Ranunculus acquatilis+Ranunculus sardous, Spirogyra sp., Juncus effusus, and unvegetated littoral sediments and central sediments) in a temporary pond near Rome during spring 2004. The central sediments were found to differ greatly from the other substrates. They were characterized by higher nutrient contents (total P, total N), organic matter and organic C, and silt and clay in the sediments, and lower dissolved oxygen content and lower pH in the water. Species richness and densities of total macrofauna showed the lowest values in central sediments and the highest ones in submerged macrophytes (Ranunculus spp.) and emergent vegetation (Juncus effusus). Oligochaeta Tubificidae, some Nematoda (Dorylaimus spp.), and Chironomidae Tanypodinae (Procladius sp. and Psectrotanypus varius) and Chironominae (Chironomus plumosus group) characterized the central sediments, whereas Ephemeroptera and most of the Odonata and Coleoptera species were commonly found in submerged macrophyte beds. Some species of Coleoptera and Hemiptera (Hygrobia hermanni, Helochares lividus, Berosus signaticollis and Gerris maculatus) were mainly found in the algal substratum, and some Nematoda species (Tobrilus spp. and Aporcelaimellus obtusicaudatus), Oligochaeta Enchytraeidae, young larvae of Sympetrum and Diptera Ceratopogonidae in littoral sediments. Juncus effusus appeared to be mainly colonized by Chironomidae Orthocladiinae (Psectrocladius sordidellus group and Corynoneura scutellata) and Tanytarsini (Paratanytarsus sp.). Central sediments also favoured high abundances of collector-gatherers, burrowers and drought resistant forms with passive dispersal, whereas Ranunculus spp. hosted mainly scrapers, shredders, swimmers+divers and active dispersal forms without any resistant stages to desiccation. Juncus plants were mostly colonized by collector-filterers and by organisms capable of both active dispersal and surviving desiccation. Littoral sediments and algae showed similar functional organization and intermediate features between central sediments and submerged macrophyte beds. All these results demonstrate that microhabitat characteristics play a crucial role in selecting macroinvertebrate taxa according to their environmental requirement, feeding mechanism, movement and resistance to drought. Moreover, our study confirms the role of submerged and emergent vegetation in maintaining high biodiversity and suggests that all microhabitats should be considered to provide both an exhaustive collection of species for pond management and conservation and basic insights into the functioning of pond communities.     

Experimental evaluation of design methods for in-site detention ponds

In this study,the detention rate of detention pond was defined to include both reduction and delay of peak flow.Flood routing experiments,with various combinations of inflow hydrographs and outlet devices in an in-site detention pond,were performed to examine the effectiveness of two analysis methods,namely the simplified method and the hydrological routing method;and to compare the detention rate of two types of outlet,namely the rectangular sharp-crested weir and the rectangular orifice.Comparison between...     

碳酸盐型盐湖卤水的模拟太阳池结晶试验

在碳酸盐型盐湖提锂工艺中, 太阳池是一个重要组成部分, 目的是储存太阳能能量以结晶析出碳酸锂。文章利用加热方法首次在实验室条件下进行模拟太阳池结晶试验, 试验的蒸发量随着温度的升高而加大, 但蒸发量的不同对析盐结晶影响不大。在不同时间段模拟试验中, 24 h时间段的Mg2+析盐浓度较Li+大, 且随着时间的延长逐渐降低, 而Li+则相反;Mg2+析出速率随着时间的增加而逐渐降低, 而Li+析出速率基 本保持一致。在不同温度模拟试验中, 卤水主要组分总析出率与温度的升高呈正相关, 卤水中CO32?和Li+的浓度降低速度大于其他组分, CO32?和Li+的析出率远大于其他组分, 析出主要矿物鉴定结果均为扎布耶石     

Field investigation of a dry detention pond with underground detention storage

Abstract

A dry pond is an urban drainage component designed to temporarily store stormwater runoff and to encourage infiltration of surface water to the subsurface layer. This paper investigates field measurement of a dry pond at Taiping Health Clinic, Perak, Malaysia that has been functioning well for five years. The pond has a surface area of 195 m², maximum depth of 32 cm, and a storage capacity of 31.88 m³. The study focused on the infiltration functionality of the constructed dry pond and the results show that it has an average infiltration rate of 125 mm/h and dries up in 330 min after being filled to a depth of 31 mm. A public-domain hydrological model was then employed to simulate hydrographs of ponding and draining, the results of which matched observations with 86–98% accuracy. These results can lead to better understanding of the system and allow duplication of such a drainage design elsewhere.

Editor D. Koutsoyiannis

Citation Lai, S.H. and Mah, D.Y.S., 2012. Field investigation of a dry detention pond with underground detention storage. Hydrological Sciences Journal, 57 (6), 1249–1255.     

Antibiotic resistance of bacteria isolated from shrimp hatcheries and cultural ponds on Donghai Island, China

The resistance of bacteria to 12 different antibiotics was investigated in shrimp farms on Donghai Island, China. Antibiotic-resistant bacteria were found to be widespread in shrimp farms, indicating a high environmental risk. Further, significant differences were found in bacterial strains among farms (ANOVA, p < 0.05), showing resistance to antibiotics such as ampicillin, trimethoprim, compound sinomi, tetracycline, chloramphenicol and cefazolin. No significant differences in antibiotic resistance were found among 6 hatcheries evaluated in this study (ANOVA, p > 0.05), between exalted and traditional shrimp ponds (ANOVA, p > 0.05), and between cultural ponds and corresponding control water source sites (T-test, p > 0.05). In cultural ponds, no significant difference in bacterial resistance to antibiotics was found between water and sediment (T-test, p > 0.05), and antibiotic resistance of bacteria from water showed a significant positive correlation with that from sediment (p < 0.05). Therefore, our study indicates that bacterial multiple antibiotic resistance (MAR) is more widespread in shrimp hatcheries than ponds.     

关于磷石膏尾矿库安全专篇的研究

磷石膏尾矿库是以磷石膏渣堆积起来形成的尾矿库,其安全问题一直是磷化工企业及安全生产管理部门非常关心的问题。根据《尾矿库安全监督管理规定》,尾矿库工程在设计阶段应该编写安全专篇,需要对尾矿库及尾矿坝稳定性、尾矿库防洪能力及排洪设施和安全观测设施的可靠性进行充分论证。3个方面的内容紧密联系,其是否安全可靠决定着尾矿库是否安全运行。针对磷石膏尾矿库的安全专篇问题,分析了专篇中的关键技术内容,对防洪计算、稳定性计算和安全监测分析等方面的本质问题进行了探讨,并将这三者作为一个系统进行分析总结。通过对湖北某磷石膏尾矿工程安全专篇的编写与分析,对具体的技术方法给出了说明。目前尾矿库工程安全问题受到了广泛的关注,其结果提供了比较完整的具体经验,采用的方法和得出的结论对相关工程可以起一定的借鉴作用。     

Basal‐topographic control of stationary ponds on a continuously moving landslide

The Slumgullion landslide in the San Juan Mountains of southwestern Colorado has been moving for at least the last few hundred years and has multiple ponds on its surface. We have studied eight ponds during 30 trips to the landslide between July 1998 and July 2007. During each trip, we have made observations on the variability in pond locations and water levels, taken ground‐based photographs to document pond water with respect to moving landslide material and vegetation, conducted Global Positioning System surveys of the elevations of water levels and mapped pond sediments on the landslide surface. Additionally, we have used stereo aerial photographs taken in October 1939, October 1940 and July 2000 to measure topographic profiles of the eight pond locations, as well as a longitudinal profile along the approximate centerline of the landslide, to examine topographic changes over a 60‐ to 61‐year period of time. Results from field observations, analyses of photographs, mapping and measurements indicate that all pond locations have remained spatially stationary for 60–300 years while landslide material moves through these locations. Water levels during the observation period were sensitive to changes in the local, spring‐fed, stream network, and to periodic filling of pond locations by sediment from floods, hyperconcentrated flows, mud flows and debris flows. For pond locations to remain stationary, the locations must mimic depressions along the basal surface of the landslide. The existence of such depressions indicates that the topography of the basal landslide surface is irregular. These results suggest that, for translational landslides that have moved distances larger than the dimensions of the largest basal topographic irregularities (about 200 m at Slumgullion), landslide surface morphology can be used as a guide to the morphology of the basal slip surface. Because basal slip surface morphology can affect landslide stability, kinematic models and stability analyses of translational landslides should attempt to incorporate irregular basal surface topography. Additional implications for moving landslides where basal topography controls surface morphology include the following: dateable sediments or organic material from basal layers of stationary ponds will yield ages that are younger than the date of landslide initiation, and it is probable that other landslide surface features such as faults, streams, springs and sinks are also controlled by basal topography. The longitudinal topographic profile indicated that the upper part of the Slumgullion landslide was depleted at a mean vertical lowering rate of 5.6 cm/yr between 1939 and 2000, while the toe advanced at an average rate of 1.5 m/yr during the same period. Therefore, during this 61‐year period, neither the depletion of material at the head of the landslide nor continued growth of the landslide toe has decreased the overall movement rate of the landslide. Continued depletion of the upper part of the landslide, and growth of the toe, should eventually result in stabilization of the landslide. Published in 2008 by John Wiley & Sons, Ltd.     

乐清湾水环境特征及富营养化成因分析

根据2002-2003年乐清湾海域春、夏、秋、冬4个航次的调查资料,分析了乐清湾海域水化学要素在不同季节的分布和变化特征,探讨了陆源污水、海水养殖自身污染与富营养化的关系.结果表明,乐清湾水域DIN和DIP浓度全年平均分别为0.630mg/dm^3和0.039mg/dm^3秋、冬季几乎100%测站属劣四类水质,春、夏季近90%超过四类水质标准.水体营养状态指数（E）值各季平均在4～9,呈严重富营养化状态.研究指出沿岸工农业废水、生活污水的排放及水产养殖业的无序、无度发展是造成该水域严重富营养化的三个主要原因.认为目前乐清湾水质已不能满足该海域功能区划提出的要求,必须进行综合整治.     

基于ASTER影像的近海水产养殖信息自动提取方法

水产养殖地已经成为海洋环境监测的热点目标之一。采用具有高光谱分辨率和较高空间分辨率(15m)的ASTER遥感影像,以九龙江河口地区为研究示范区,进行近海水产养殖信息的自动提取方法研究。结果表明,利用ASTER影像的光谱信息和水产养殖地的纹理结构信息,可以实现近海水产养殖地的自动提取。先利用监督分类方法提取混淆有其他水体的水产养殖信息,采用邻域分析来增强水产养殖地的空间纹理信息。通过综合监督分类和水产养殖地空间纹理增强的结果,在专家决策分类器中建立决策规则,进行水产养殖地的自动提取,提取的精度达93%。     

沉水植物氧化塘对污水厂尾水深度净化效果与机制的小试研究

室外采用玻璃缸装置研究了抚仙湖常见的9种沉水植物氧化塘对澄江县污水厂尾水营养盐的去除效果及机制.结果表明:氧化塘中沉水植物的光合作用导致水体较高的DO和pH值,从而提高氧化塘总氮和总磷的去除率,但沉水植物叶片的腐烂分解则提高了水体氮磷的含量.沉水植物氧化塘对总氮和总磷的去除率分别介于19.44%-64.71%和28.13%-98.33%.沉水植物的直接吸收对总氮和总磷量去除的贡献比较低,占氧化塘总氮和总磷量的0.26%-1.54%和0.47%-1.77%.沉水植物氧化塘内DO、pH变化,促进了氮的降解及氧化还原分解,使其对氮的去除占氧化塘总氮量的30.71%-65.25%,而磷的去除则主要通过化学沉淀及基质吸附,占氧化塘总磷量的73.37%-93.34%.最终,选出蓖齿眼子菜、苦草、黑藻、金鱼藻和光叶眼子菜对氧化塘中氮磷具有较高的去除率.