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

Marcello Bazzanti  Cristina Coccia  Maria Giuseppina Dowgiallo 《Limnologica》2010,40(4):291-299

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.  相似文献   

Experimental evaluation of design methods for in-site detention ponds     

Yao-Ming HONG 《国际泥沙研究》2010,25(1):52-63

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...  相似文献   

碳酸盐型盐湖卤水的模拟太阳池结晶试验   总被引：1，自引：0，他引：1  

唐力君  郑绵平  刘建华 《地球学报》2009,30(2):249-255

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  相似文献   

Field investigation of a dry detention pond with underground detention storage     

Sai Hin Lai  Darrien Yau Seng Mah 《水文科学杂志》2013,58(6):1249-1255

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.  相似文献   

Antibiotic resistance of bacteria isolated from shrimp hatcheries and cultural ponds on Donghai Island, China   总被引：1，自引：0，他引：1  

Zhang YB  Li Y  Sun XL 《Marine pollution bulletin》2011,62(11):2299-2307

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.  相似文献   

关于磷石膏尾矿库安全专篇的研究     

王涛  李杨  周勇  吕庆  刘大炜 《岩土力学》2011,32(Z2):407-412

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。  相似文献   

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

Jeffrey A. Coe  Jonathan P. McKenna  Jonathan W. Godt  Rex L. Baum 《地球表面变化过程与地形》2009,34(2):264-279

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.  相似文献   

Water levels in Lake Ontario 4230–2000 years B.P.: evidence from Grenadier Pond,Toronto, Canada     

Francine M. G. McCarthy  John H. McAndrews 《Journal of Paleolimnology》1988,1(2):99-113

Lake Ontario water levels have been rising for the past 11 500 years due to differential isostatic rebound of the St. Lawrence outlet. Small scale fluctuations in water level superimposed on this general trend have received little study, with the exception of the Nipissing Flood.The transgression of a Grenadier Pond was studied from cores along a transect from the bar that separates the pond from Lake Ontario to the marsh on the north shore. Radiocarbon dates of the transition from swamp peat to pond marl in five cores provide estimates of the rate of water level rise since 4230 years B.P. These estimates are supported by changes in sediment type and in abundance of pollen and seeds of aquatic plants. There were three short intervals of accelerated water level rise in Grenadier Pond, around 4200, 3000, and 2000 years B.P., when water levels rose up to 2 m instantaneously, within the resolution of radiocarbon dating. Sedimentological and paleobotanical data suggest that Grenadier Pond was an open embayment of Lake Ontario until 1970–1850 years B.P., when it was isolated by the bar, and therefore sediments deposited prior to this time reflect water levels in Lake Ontario.Short term departure of up to 2 m from the average rate of water level rise over the past 4000 years, as observed in the record at Grenadier Pond, is of the same range as historically observed departures from the mean lake stage of Lake Ontario. This implies that a threshold discharge exists above which broadening of the outflow channel occurs to accommodate further increase in discharge with little rise in lake level. The intervals of accelerated water level rise in Lake Ontario broadly coincide with periods of cool, wet climate, suggesting that increased moisture may have caused the short term fluctuations in water level.This is the second of a series of papers to be published by this journal that was presented in the paleolimnology sessions organized by R. B. Davis and H. Löffler for the XIIth Congress of the International Union for Quaternary Research (INQUA), which took place in Ottawa, Canada in August 1987. Drs. Davis and Löffler are serving as guest editors of this series.  相似文献   

基于图像处理技术的养殖池集污特性研究   总被引：2，自引：0，他引：2  

张慧  吴常文  江丹丹  赵乐  桂福坤 《海洋与湖沼》2016,47(2):374-379

本文针对养殖池的集污试验,研究了用于量化分析污物聚集面积的图像处理技术,并将其用于方形圆切角养殖池在边侧管式射流方式下的集污特性研究。图像处理技术包括图像预处理、图像增强、图像分割、轮廓提取四个步骤,成功获得了污物的量化分布面积。在养殖池集污特性研究方面,本文研究了射流流速为24cm/s条件下,不同射流角(射流方向与池壁夹角)对污物聚集效果的影响。结果表明,方形圆切角养殖池存在一个最优的射流角度,本文研究条件下,最优角度约为40°。本文研究结果,可为养殖池水力驱动优化布置提供参考。  相似文献   

对虾病毒病与化学需氧量相关关系研究   总被引：19，自引：0，他引：19  

马建新  刘爱英  宋爱芹 《海洋科学》2002,26(3):68-71

通过对虾池内主要环境因子与对虾病毒病相关关系的研究,发现虾池内化学需氧量（COD）太高是诱发对虾病毒病暴发流行的主要环境因子之一。利用多级S型净化池可以大幅度消除水体中的COD,有效预防对虾病毒病的暴发流行。  相似文献