Spatial analysis of water quality and its suitability in farming giant freshwater prawn (Macrobrachium rosenbergii) in Negeri Sembilan region,Peninsular Malaysia     

Benjamin Ezekiel Bwadi  Firuza Begham Mustafa  Mohammad Lokman Ali  Subha Bhassu 《Singapore journal of tropical geography》2019,40(1):71-91

Finding potential sites for resilient prawn production in the tropical environment that also prevents wastage of natural resources is not an easy task. The purpose of this study is to evaluate water quality suitability for prawn farming in Negeri Sembilan of Peninsular Malaysia based on Geographic Information System (GIS). To achieve this goal, numerous criteria including sources of water, water temperature, water pH, sources of pollution, salinity, soil texture and availability of phytoplankton criteria were considered for the modelling process. Analytic Hierarchy Process (AHP) technique was performed to standardize the criteria and the weighting process. The weighted overlay of indicators and results were accomplished by applying the Multi‐Criteria Decision Analysis (MCDA) method in GIS. It was indicated that the Negeri Sembilan area has potential for prawn farming. The results showed that about 25 per cent (163 056.93 ha) of the area was most suitable for prawn farming, about 58 per cent (384 656.88 ha) was considered moderately suitable, while 18 per cent (117 633.49 ha) was regarded as least suitable. The study concluded that the multi‐criteria decision analysis of water quality for prawn farming is vital for regional economic planning in the Negeri Sembilan area and also significant when establishing a model for aquaculture development.  相似文献   

Environmental determinants of species turnover of aquatic Heteroptera in freshwater ecosystems of the Western Ghats,India     

《Limnologica》2020

Partitioning beta diversity into its two components of spatial turnover and nestedness is a more robust method for checking spatial variability in biological communities than calculating the total beta diversity alone. The relative contribution of spatial turnover and nestedness has been used to test the effects of climatic, environmental, spatial and temporal variables on community composition. In this study, we tested the effects of environmental factors and microhabitat features on total beta diversity and its spatial turnover and nestedness components using a comprehensive dataset of aquatic Heteroptera collected from four types of permanent freshwater habitats (i.e. streams, ponds, rock tanks and reservoirs) in the Western Ghats of India. We observed that communities in all four types of habitats were predominantly shaped by dissimilarity caused due to spatial turnover (>85 %). Each type of habitat showed the presence of one or more species uniquely associated with it, which might contribute to the turnover between communities. The abiotic environment (climatic factors, topological factors, soil characteristics and microhabitat features) as well as assemblage structure differed significantly between habitat types. Communities in each type of habitat were affected by different environmental factors, such as precipitation and temperature patterns for streams, altitude and rocky substrate for rock tanks, and soil characteristics and the presence of aquatic macrophytes for ponds and reservoirs. Assemblages observed in the four types of permanent habitats are thus compositionally distinct due to species replacements between local communities, which in turn are strongly influenced by environmental variables. Similar to previous studies, our results show that spatial turnover largely measures the same phenomenon as total beta diversity on a regional scale.  相似文献   

Estimating groundwater recharge for a freshwater lens in an arid region: Formative and stability assessment     

Mosaed S. Alrashidi  Ryan T. Bailey 《水文研究》2020,34(4):1063-1080

The formation of subsurface freshwater lenses on top of brackish groundwater is a fascinating hydrologic phenomenon that creates groundwater supplies of great potential value in arid regions. Information on the recharge quantity and mechanism of these lenses is both scarce and uncertain. This study examines the formation and macroscale stability of the Rawdatain freshwater lens in Kuwait, for which significant pre-development data are available. The Rawdatain is a large (150 million m³) subsurface freshwater lens overlying brackish groundwater compared to the other freshwater lenses in the Arabian Peninsula. In this study, a three-dimensional (3D) density-dependent groundwater flow model is tested against the following data targets to estimate long-term diffuse and focused groundwater recharge: (i) groundwater head, (ii) total dissolved solids (TDS) groundwater concentration, (iii) volume and vertical thickness of stored groundwater of three different water quality TDS ranges (0–700, 700–1000 and 1000–2000 mg/L) and (iv) geometrical shape features of the lens along cross-sections. To better represent the spatial variation in TDS, six different recharge zones were assigned to allocate diffuse and focused recharge conditions. Twelve recharge rate scenarios, encompassing a wide range of feasible long-term average annual recharge values (200,000–5,000,000 m³/year), were tested against the multiple targets and compared with the groundwater age of the Rawdatain lens. Based on comparison with data targets, the long-term average annual recharge is estimated to be 500,000 m³/year. Scenarios of reduced recharge, which may occur due to changes in land-use or climate, demonstrate the extremely slow response of the lens, which is in agreement with the slow development and formation of the lens (>2,000 years). Within a 100-year time frame, a 50% reduction in annual recharge reduces the lens volumes by 21, 17 and 9% for the three water quality categories, respectively. This study demonstrates the stability of freshwater lenses in arid regions and also provides methodology for similar focused rainfall recharge freshwater lenses.  相似文献   

基于投入产出理论的水资源研究进展及水资源管理展望     

杨洋  效存德  王晓明  刘世伟 《冰川冻土》2021,43(1):214-224

近年来,气候变化背景下的水资源问题得到日益增加的关注,其研究从水资源短缺、供需平衡等内容转向适应可持续发展的综合研究。基于投入产出理论的水资源研究,从系统循环的角度分析资源的流动性和持续性,能够揭示水资源-经济社会复合系统中各要素的内在数量关系,提出面向可持续发展的水资源价值观和方法论。首先,从模型拓展和实际应用两条主线梳理了国内外基于投入产出理论的水资源相关研究。在模型方面,概括了投入占用产出模型、水资源投入产出模型和区域间投入产出模型的发展和适用性,对比分析了不同区域间投入产出模型的优缺点。在应用方面,分别从不同时空尺度、驱动力因素等方面对虚拟水、水足迹和水资源优化配置三个热点内容进行了整理,并指出：基于投入产出理论的水资源研究基本建立在价值型模型的基础上;区域间投入产出模型已成为分析区域间经济结构、资源流动等环境问题的重要工具。其次,讨论了投入产出模型在冰冻圈水资源管理中的应用,提出基于服务角度的水资源管理模式。最后,展望了投入产出理论在水资源研究中的应用,以期能够为决策者提供额外的信息以便更好的管理水资源。  相似文献   

Quantitative analysis of the feedback induced by the freshwater flux in the tropical Pacific using CMIP5     

Hai Zhi  Rong-Hua Zhang  Pengfei Lin  Lanning Wang 《大气科学进展》2015,32(10):1341-1353

Freshwater flux (FWF) directly affects sea surface salinity (SSS) and hence modulates sea surface temperature (SST) in the tropical Pacific. This paper quantifies a positive correlation between FWF and SST using observations and simulations of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) to analyze the interannual variability in the tropical Pacific. Comparisons among the displacements of FWF, SSS and SST interannual variabilities illustrate that a large FWF variability is located in the west-central equatorial Pacific, covarying with a large SSS variability, whereas a large SST variability is located in the eastern equatorial Pacific. Most CMIP5 models can reproduce the fact that FWF leads to positive feedback to SST through an SSS anomaly as observed. However, the difference in each model's performance results from different simulation capabilities of the CMIP5 models in the magnitudes and positions of the interannual variabilities, including the mixed layer depth and the buoyancy flux in the equatorial Pacific. SSS anomalies simulated from the CMIP5 multi-model are sensitive to FWF interannual anomalies, which can lead to differences in feedback to interannual SST variabilities. The relationships among the FWF, SSS and SST interannual variabilities can be derived using linear quantitative measures from observations and the CMIP5 multi-model simulations. A 1 mm d-1 FWF anomaly corresponds to an SSS anomaly of nearly 0.12 psu in the western tropical Pacific and a 0.11°C SST anomaly in the eastern tropical Pacific.  相似文献   

双壳类分子生物标志物对海水重金属的响应评述   总被引：1，自引：0，他引：1  

孟范平  高鹰  赵顺顺  付海防  肖静 《中国海洋大学学报(自然科学版)》2011,41(5):100-109

海洋双壳类动物的组织和器官对微量重金属具有高富集能力,诱导机体内的某些分子生物标志物(molecular biomarkers,MBMs)发生变化,可用于指示海水中的重金属污染水平。近10年来,许多学者在双壳类MBMs对海水重金属的响应规律方面进行了研究,其中,金属硫蛋白(MTs)、热激蛋白70(HSP70)、抗氧化防御系统等受到了较多的关注。本文在介绍这些MBMs结构和功能的基础上,重点评述了各种MBMs对海水重金属的响应特征,并提出了影响双壳类MBMs应用于海水重金属监测的因素及进一步研究的方向。  相似文献   

Associated terrestrial and marine fossils in the late-glacial Presumpscot Formation, southern Maine, USA, and the marine reservoir effect on radiocarbon ages   总被引：1，自引：0，他引：1  

Woodrow B. Thompson  Carol B. Griggs  Norton G. Miller  Robert E. Nelson  Thomas K. Weddle  Taylor M. Kilian   《Quaternary Research》2011,75(3):552-565

Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907 ± 31 to 11,650 ± 50 ¹⁴C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520 + 95/−20 cal yr BP. Ages of shells juxtaposed with the logs are 12,850 ± 65 ¹⁴C yr BP (Mytilus edulis) and 12,800 ± 55 ¹⁴C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000 yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England.  相似文献   

中国各季节气候对热盐环流减弱的不同响应     

程军  刘征宇  张福颖  郭品文  杨洋 《南京气象学院学报》2011,34(6):653-661

使用CCSM3（community climate system model version 3）模式的＂淡水扰动试验＂结果,对热盐环流强度减弱后中国区域冬、夏气候的不同响应特征进行了研究。结果表明：CCSM3可较为准确地再现中国附近区域表面气温及降水量的量值和分布形态。当热盐环流年平均强度减弱约80%之后,中国区域冬、夏季的表面气温与降水量显著降低,但冬、夏季的降低幅度与空间分布形态存在显著的差异。冬季的降温幅度较大且分布较为一致,平均降温幅度可达2.2℃,最大的降温幅度可达4℃;夏季的降温幅度相对较小且南北差异较大,平均降温幅度为1.3℃,最大的降温幅度为3℃。冬、夏季降水量的降低幅度都在6%左右,但其成因及其分布形态都存在显著差异。  相似文献   

二叠纪-三叠纪之交双壳类的灭绝与复苏过程          下载免费PDF全文

黄云飞  童金南  向烨  肖传桃  宋海军  田力  宋婷  楚道亮 《地球科学》2015,40(2):334-345

为了建立早-中三叠世双壳类的残存-复苏模式及深入探讨双壳类迟缓复苏的原因,对全球范围内该时期双壳类属的 时限分布进行了统计.总体来看,3个亚纲(Pteriomorphia、Palaeotaxodont和Heteroconchia亚纲)和5种生活方式(外栖活动 类、外栖固着类、半内栖类、内栖浅掘穴类和内栖深掘穴类)的双壳类均展示出了一致的规律,属级分异度直到中三叠世Anisian 期才恢复到晚二叠世末生物大灭绝之前的水平.二叠纪残存类型在早-中三叠世双壳类中所占的比例逐步降低,从占过 渡层的77.3%降低到了中三叠世Anisian期的33.7%,指示双壳类的缓慢复苏过程.而在整个早三叠世的漫长复苏期中,双壳 类仅遭受背景灭绝,表明双壳类的迟缓复苏受限于长时期的高压环境,随着海洋环境的逐步好转,才逐渐出现新的类型.   相似文献   

舟山北部海域海底第四系淡水资源赋存潜力   总被引：1，自引：1，他引：0  

张志忠  邹亮  周良勇 《海洋学报》2018,40(3):50-61

为了解东海舟山北部海域海底第四系淡水资源赋存情况，本文在系统分析舟山北部海域地质钻孔和单道地震资料基础上，分析了研究海域海底第四纪地层结构与沉积环境，阐述了研究海域海底松散沉积物分布规律，探讨了上海陆地地区早更新世中、晚期和早期古河道在研究海域的延伸和分布状况，分析了研究海域海底第四系含水层赋存状况。研究海域第四系可供开发利用的主要含水层为早更新世中、晚期的第四承压含水层（Ⅳ）和早更新世早期的第五承压含水层（Ⅴ）；第四承压含水层古河道分布区富水性最佳，含水层顶部发育厚层黏性土隔水层区域赋存淡水资源的可能性很大，含水层开发利用潜力可分为开发前景良好A区、开发前景较好B区和开发前景一般C区3类；第五承压含水层在古河道分布区富水性强，具有很好的淡水赋存潜力和良好的开发利用前景。  相似文献