盐度对芦苇(Phragmites australis)表流湿地除氮效果的影响     

蔡舰  白承荣  巴图那生  娜仁格日乐  高光 《湖泊科学》2017,29(6):1350-1358

利用芦苇湿地去除农业污水中的氮是博斯腾湖流域控制富营养化的重要手段.但是,污水中的盐分往往会抑制芦苇(Phragmites australis)湿地的除氮效果.为了探索不同盐度对芦苇湿地脱氮效果的影响和机制,研究4个不同的盐度梯度(淡水、2‰、5‰和10‰)对芦苇表流湿地中氮去除的影响,测定不同盐度下湿地表层(0~10.0 cm)和下层土壤(10.0~20.0 cm)中硝化、反硝化作用强度的变化.结果表明,盐度上升显著降低了湿地氮的去除率,但是不同离子形态的氮变化趋势并不一致.5‰和10‰盐度下的芦苇湿地中总氮、铵态氮去除率分别下降了9.03%、31.80%和23.10%、39.20%,亚硝态氮累积率分别上升了190%、690%,而硝态氮并未发生明显变化.相对于参与反硝化作用的菌群,盐度对参与硝化作用菌群的抑制作用更强是产生此现象的主要原因.除此之外,盐度升高导致植物根系泌氧减少也是土壤中的硝化作用强度降低的重要原因之一.  相似文献   

干旱区内陆河流域荒漠河岸林群落生态过程与水文机制研究   总被引：15，自引：11，他引：4  

李卫红  郝兴明  覃新闻  陈亚宁  黄湘   《中国沙漠》2008,28(6):1113-1117

干旱区内陆河流域生态水文过程研究已成为当今地理学、生态学研究的焦点,是开展生态恢复研究的重要内容。塔里木河下游断流河道的生态恢复是以沿自然河道生态输水为主要形式的,因此,有必要加深对塔里木河下游荒漠河岸林群落生态过程与水文机制的认识。在对塔里木河下游荒漠河岸林植被生态退化及其退化原因分析的基础上,综述了塔里木河下游典型植物生态水位的研究进展,阐述了植物适宜生态水位、胁迫地下水位和临界地下水位研究的阶段性成果,并进一步展望了未来研究的焦点问题。指出了群落生态水位、植被群落与土壤水分、盐分异质性的关系,提出植物水分利用机制是群落生态过程与水文机制研究的核心问题。  相似文献   

Development and application of a remote sensing-based salinity prediction model for a large estuarine lake in the US Gulf of Mexico coast   总被引：1，自引：0，他引：1  

Fugui Wang  Y. Jun Xu 《Journal of Hydrology》2008,360(1-4):184-194

Salinity in estuaries is highly variable due to river discharge, tidal motion, and winds. Information on the spatial and temporal changes in salinity can provide important ecological indications, but accurate monitoring of the space–time variability for a large estuary is often costly and time-consuming. This study applied remote sensing techniques to develop a salinity prediction model for Lake Pontchartrain, a large estuarine lake located in the Northern Gulf of Mexico, USA. “Ground truth” salinity was measured along two transects across the lake and near the shoreline. Water-leaving reflectance from the measurement locations was extracted from Landsat Thematic Mapper (TM) images pre-processed through “banding” noise reduction and radiometrical correction approaches. Ordinary least square and ridge regression methods were performed to identify model parameters and to determine relationships between salinity and reflectance. Salinity in the lake on eight dates was predicted with the developed model. Difference in salinity level and patterns, and impacts of Hurricanes Katrina and Rita on salinity were assessed with ANOVA and Fuzzy Similarity methods. The results showed that the model achieved a high power in prediction of the lake salinity (R² = 0.89 and RMSE of validation = 0.27). Reflectance from TM bands 1, 2, and 4 was positively correlated to salinity levels and explained 1.9%, 20.3%, and 10.2% variance in salinity levels. Reflectance from bands 3 and 5 was negatively correlated to salinity and explained 34.1% and 31.2% variance. Under normal circumstances without the impacts of hurricanes, the lake salinity presented two patterns with average salinity level of 5.5 ppt. After Katrina’s landfall, the average was significantly increased by 1.1 ppt and the spatial patterns were altered. The pattern on 30 August 2005 was the most dissimilar one as compared to the two normal patterns, and then followed by the patterns on 9 and 25 October, and 7 September 2005. This study demonstrated that satellite remote sensing techniques can be applied to monitor salinity in coastal environments, and that freshwater discharge not only affects salinity levels and patterns under normal conditions but also is crucial for the return of salinity patterns to normal conditions after hurricane disturbance.  相似文献   

Determination of Salinity in Fluid Inclusions with Laser Raman Spectroscopy Technique   总被引：2，自引：0，他引：2  

Seyed Javad Moghaddasi 《中国地质大学学报(英文版)》2000,11(4)

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A spatio-chemical survey of hydrogeothermal springs in Lake Elementaita, Kenya     

Francis Mwaura 《International Journal of Salt Lake Research》1999,8(2):127-138

The hydrochemistry of three areas of geothermal activity in the Lake Elementaita basin were surveyed. The results indicated warm temperatures between 30–40°C, high alkalinity (1,200 mg CaCO₃/l) and specific conductance (4,300–8,100 μS/cm). pH was above 9 with a high concentration of carbonates, chlorides and sulphates. Apart from playing a significant role in the lake chemistry, lacustrine springs provide a significant source of water supply, particularly during the dry season. However, there is a serious lack of scientific information on the hydrogeology and hydrochemistry of the thermal springs.  相似文献   

计算混合液电阻率的一种有效方法   总被引：6，自引：0，他引：6  

邹长春  尉中良  潘令枝 《物探化探计算技术》1999,21(3):216-219

实验结果表明,采用并联电阻模型计算混合液电阻率有时会带来较大的误差。本文抛开此模型,根据溶液电阻率、矿化度以及温度三者之间的关系,提出了一种计算混合液电阻率的新方法,并对其应用作了简单介绍。  相似文献   

台湾浅滩南部边缘海域1997年8月温盐度的多周日变化   总被引：2，自引：0，他引：2  

张学斌  胡建宇  张彩云  陈照章  林奋强  梁洪星  洪建胜 《台湾海峡》2000,19(1):89-94

通过对１９９７年８月台湾浅滩南部边缘两站位多周日（分别为７２和６０ｈ）实测数据的分析,对温、盐的多周日变化及其形成机制进行了探讨。认为：表层温度主要由当地的太阳辐照度和表层流况所决定,表层的盐度主要由表层流况决定,表层的温、盐变化的周日重复发较差;由于台湾浅滩南部海区存在着陆架／陆锋面而测站恰好处于锋面中,在潮汐的调制下该锋面做横向摆动,从而导致不同物理性搏击的水体交替占领测站,导致各层次产生温、  相似文献   

Refined Modeling of Water Temperature and Salinity in Coastal Areas   总被引：3，自引：3，他引：0  

SHEN Yongming 《中国海洋工程》2000,14(4):447-458

The prediction of water temperature and salinity in coastal areas is one of the essential tasksin water quality control and management.This paper takes a refined forecasting model of water tempera-ture and salinity in coastal areas as a basic target.Based on the Navier-Stokes equation and κ-ε turbu-lence model,taking the characteristics of coastal areas into account,a refined model for water temperatureand salinity in coastal areas has been developed to simulate the seasonal variations of water temperatureand salinity fields in the Hakata Bay,Japan.The model takes into account the effects of a variety ofhydrodynamic and meteorological factors on water temperature and salinity.It predicts daily fluctuationsin water temperature and salinity at different depths throughout the year.The model has been calibratedwell against the data set of historical water temperature and salinity observations in the Hakata Bay,Japan.  相似文献   

焉耆盆地土壤盐分剖面特征及其与土壤颗粒组成的关系   总被引：3，自引：0，他引：3  

杜金龙  靳孟贵  欧阳正平  刘延锋 《地球科学》2008,33(1):131-136

为查明焉耆盆地土壤盐分剖面特征及其影响因素, 进行土壤样本含盐量及颗粒组成测试, 利用Spearman等级相关分析两者关系.结果表明: 土壤盐分剖面分为3种类型——均布型、表聚型和振荡型, 均布型剖面含盐量最低且分布均匀, 表聚型剖面盐分表聚特征最明显(表聚系数4.20), 振荡型剖面含盐量高且变异程度大(变异系数82.4%); 土样类型中粉质壤土最多(占70.8%), 颗粒组成中粉粒平均含量最高(57.1%); 均布型剖面盐分与粘粒含量相关程度最高(相关系数0.560), 为极显著正相关; 振荡型剖面盐分与砂粒含量相关程度最高(相关系数-0.639), 呈极显著负相关; 表聚型剖面盐分与颗粒组成无明显关系.结合各类剖面分布区域可知, 在砂粒含量与盐分含量较低的非盐渍化地带, 土壤盐分分布主要受粘粒含量影响; 砂粒含量与盐分含量较高的盐渍化地带, 土壤盐分分布主要受砂粒含量影响.   相似文献   

Relationship between sea surface salinity and ocean circulation and climate change   总被引：2，自引：0，他引：2  

Yan DU  Yuhong ZHANG  Jiancheng SHI 《中国科学:地球科学(英文版)》2019,(5):771-782

Based on Argo sea surface salinity(SSS) and the related precipitation(P), evaporation(E), and sea surface height data sets, the climatological annual mean and low-frequency variability in SSS in the global ocean and their relationship with ocean circulation and climate change were analyzed. Meanwhile, together with previous studies, a brief retrospect and prospect of seawater salinity were given in this work. Freshwater flux(E-P) dominated the mean pattern of SSS, while the dynamics of ocean circulation modulated the spatial structure and low-frequency variability in SSS in most regions. Under global warming, the trend in SSS indicated the intensification of the global hydrological cycle, and featured a decreasing trend at low and high latitudes and an increasing trend in subtropical regions. In the most recent two decades, global warming has slowed down, which is called the"global warming hiatus". The trend in SSS during this phase, which was different to that under global warming, mainly indicated the response of the ocean surface to the decadal and multi-decadal variability in the climate system, referring to the intensification of the Walker Circulation. The significant contrast of SSS trends between the western Pacific and the southeastern Indian Ocean suggested the importance of oceanic dynamics in the cross-basin interaction in recent decades. Ocean Rossby waves and the Indonesian Throughflow contributed to the freshening trend in SSS in the southeastern Indian Ocean, while the increasing trend in the southeastern Pacific and the decreasing trend in the northern Atlantic implied a long-term linear trend under global warming. In the future, higher resolution SSS data observed by satellites, together with Argo observations, will help to extend our knowledge on the dynamics of mesoscale eddies, regional oceanography, and climate change.  相似文献