Nutrient flux in the Rhode River: Tidal transport of microorganisms in brackish marshes     

P. A. Rublee  S. M. Merkel  M. A. Faust 《Estuarine, Coastal and Shelf Science》1983,17(6):669-680

Concentrations of bacteria, chlorophyll a, and several dissolved organic compounds were determined during 11 tidal cycles throughout the year in a high and a low elevation marsh of a brackish tidal estuary. Mean bacterial concentrations were slightly higher in flooding (7·1 × 10⁶ cells ml⁻¹) than in ebbing waters (6·5 × 10⁶ cells ml⁻¹), and there were no differences between marshes. Mean chlorophyll a concentrations were 36·7 μg l⁻¹ in the low marsh and 20·4 μg l⁻¹ in the high marsh. Flux calculations, based on tidal records and measured concentrations, suggested a small net import of bacterial and algal biomass into both marshes. Over the course of individual tidal cycles, concentrations of all parameters were variable and not related to tidal stage. Heterotrophic activity measured by the uptake of ³H-thymidine, was found predominantly in the smallest particle size fractions (< 1·0 μm). Thymidine uptake was correlated with temperature (r = 0·48, P < 0·01), and bacterial productivity was estimated to be 7 to 42 μg Cl⁻¹ day⁻¹.  相似文献   

福建省滨海湿地持续利用研究   总被引：1，自引：0，他引：1  

陈加兵  郑达贤  黄发明 《台湾海峡》2006,25(1):83-88

本文从滨海湿地的概念入手，阐述了福建滨海湿地具有南北潮差不一、海平面高于黄海平均海平面、容易受到污染等特点，同时借助了GIS空间插值技术，提出了福建滨海湿地面积的测算方法；在此基础上，探讨了在福建沿海经济的高速发展、海洋大开发背景下，福建滨海湿地利用与保护存在的各种矛盾，并作了成因分析，最后针对滨海湿地各种矛盾提出了持续利用的对策．  相似文献   

胶州湾海岸湿地保护:社区参与原则、方法与程序     

张绪良  谷东起  李永科  毛卫华 《海洋湖沼通报》2007,(4):135-143

在对胶州湾海岸湿地进行分类、湿地退化现状研究基础上,认为相关政府部门应该采取建设海岸湿地自然保护区、海岸湿地公园,发展循环经济和严格管理海岸带和海域利用等胶州湾海岸湿地保护与合理利用措施。同时,社区参与也是推动胶州湾海岸湿地保护与合理利用的重要方面。提出了成立社区参与组织,调查社区对湿地资源利用的需求,推广合理利用湿地资源的社区参与项目,协调地方关系、扩大社区参与的范围和领域,开展湿地保护和合理利用的宣传教育等社区参与胶州湾海岸湿地保护的初步措施。  相似文献   

黄河上游玛曲湿地退化现状、成因及保护对策   总被引：8，自引：0，他引：8  

戚登臣  李广宇 《湿地科学》2007,5(4):341-347

位于黄河上游的玛曲湿地由于地处特殊的地理位置,具有特殊的生态功能,除了蓄水、涵养水源和维持生物多样性外,对调节黄河水量、泥沙量、小气候和维持区域生态平衡、社会经济的可持续发展具有重大意义。但近年来玛曲湿地大面积干涸和萎缩、湿地功能退化现象十分严重,这是自然因素与人为因素综合作用的结果。在对玛曲湿地退化因素深入分析与研究的基础上,提出了相应的保护对策。对于其保护,即要有制度的完善,又要有成熟的治理技术,制度应优先于技术;只有在制度不断完善、法制不断健全和人们思想观念逐渐提高的前提下,再采用先进的、可操作性强的、行之有效的治理技术,经过长期的治理与保护,玛曲持续多年的湿地退化问题才能从根本上得到解决。  相似文献   

湿地甲烷产生的测定方法及主要控制因子研究综述     

王维奇  曾从盛  仝川 《福建地理》2007,(2)

湿地甲烷排放是湿地甲烷产生、传输和氧化过程的综合作用的结果,其中,甲烷产生是甲烷排放的先决条件.本文对湿地甲烷产生的测定方法以及控制湿地甲烷产生的主要因子进行了综述.湿地甲烷产生的测定方法包括厌氧培养法和添加甲烷氧化抑制剂的方法,比较而言,运用厌氧培养法的研究成果较多,而且也较为成熟,对于培养土样的选择,鲜土与干土培养均有实例.许多因子控制着湿地甲烷的产生过程,包括温度、土壤水、pH值和底物等,其中,甲烷产生所需的底物因子最为重要。  相似文献   

Hydrogeomorphic types of glacially created kettle holes in North-East Germany     

Thomas Kalettka  Catrin Rudat 《Limnologica》2006,36(1):54-64

Kettle holes are glacially created, small, shallow, depressional wetlands collecting their water from internal or closed catchments in young moraine landscapes. Their water body is defined by having a maximum of 1 ha in extent. Mostly they undergo a wet-dry circle. In North-East Germany, kettle holes are widely spread, mostly on arable land. They are characterised by large differences in hydroperiod (HP), size, shape and edge steepness. They also have a high potential for both, geomorphic structural diversity and biological species diversity. However, kettle holes are subject to pollution, drainage and structural reduction that result from intensive land use practices.Although kettle holes in Germany are protected by law, protection strategies are not specific enough with respect to the variability of kettle holes, especially of HP. Therefore, the study objective was to characterise hydrogeomorphic (HGM) kettle hole types to create a basis for a decision support system with regard to the selection of the type dependent conservation and management measures.In three agricultural landscapes in North-East Germany, geomorphological and hydrological variables of 268 kettle holes (HP, shore overflow tendency, depth, area, form, shore width and slope) as well as those of their catchments (area, wetland to catchment area ratio, relief) were investigated from 1993 to 2003. By statistical analysis of datasets of 144 kettle holes, 10 HGM kettle hole types were defined. The basic types are “silted fen type” and “open-water type”. Basic subtypes of the latter type are “storage type”, “shore overflow type” and “puddle type”. Differences in spreading of kettle hole types in dependency on landscape relief were found.  相似文献   

Comparative studies on the dispersal of the Great Ramshorn (Planorbarius corneus L.): A modelling approach     

Fred Jopp   《Limnologica》2006,36(1):17-25

The Great Ramshorn (Planorbarius corneus L.) is a frequent inhabitat of central European wetlands and floodplains. The dispersal capacity of P. corneus, as a key factor to survival, was analysed using different computer model approaches: a general equation-based model and an individual-based model. Both models came to different conclusions on the maximum covered distances of P. corneus-individuals. The parametrisation of the models were based on detailed laboratory measurements and field experiments performed with specimen of the fen wetland system of Rhin-Havelluch (Brandenburg, North-East Germany). Based on the results of the statistical analysis, the dispersal behaviour could be depicted in the equation-based model as a random walk which implied a relatively regular resource utilisation in long-term simulations.Depicting the dispersal qualities of P. corneus with a highly resolved individual-based model showed distinct local aggregations clusters of the snail-individuals. As a consequence, the resource utilisation was less regularly in the long-term simulations for the individual-based model than it was in the equation-based model. Another characteristic of the individual-based representation was that in the case of several consecutive move steps and based on the autocorrelation of the data the P. corneus-individuals could use a wider area of space.The data from the empirical measurements of short-term dispersal observations of single individuals were integrated within the different model extrapolations. This made it possible to discuss the long-term consequences, like the large dispersal range of the individuals and the spatial distribution of the population in the plane, for the persistence of P. corneus in a real landscape.  相似文献   

Species diversity of the Okavango Delta, Botswana   总被引：4，自引：0，他引：4  

Lars Ramberg  Peter Hancock  Markus Lindholm  Thoralf Meyer  Susan Ringrose  Jan Sliva  Jo Van As  Cornelis Vander Post 《Aquatic Sciences - Research Across Boundaries》2006,68(3):310-337

  相似文献   

High Arctic wetlands: Their occurrence, hydrological characteristics and sustainability   总被引：1，自引：0，他引：1  

Ming-ko Woo  Kathy L. Young 《Journal of Hydrology》2006,320(3-4):432-450

High Arctic wetlands, though limited in occurrence, are an important ecological niche, providing the major vegetated areas in an arid and cold polar desert environment. These wetlands are often found as patches in the barren landscape. At a few locales which may be ice-wedge polygonal grounds, glacial terrain and zones of recent coastal uplift, wetland occurrence can become extensive, forming a mosaic that comprises patches of different wetland types. Reliable water supply during the thawed season is a deciding factor in wetland sustainability. The sources include meltwater from late-lying snowbanks, localized ground water discharge, streamflow, inundation by lakes and the sea, and for some ice-wedge wetlands, ground-ice melt. Different types of wetlands have their own characteristics, and peat accumulation or diatom depositions are common. The peat cover insulates the wetland from summer heating and encourages permafrost aggradation, with the feedback that a shallow frost table reduces the moisture storage capacity in a thinly thawed layer, which becomes easily saturated. All the wetlands studied have high calcium content since they are formed on carbonate terrain. Coastal wetlands have high salt concentration while snowmelt and ground-ice melt provides dilution. The sustainability of High Arctic wetlands is predicated upon water supply exceeding the losses to evaporation and lateral drainage. Disturbances due to natural causes such as climatic variations, geomorphic changes, or human-induced drainage, can reduce inundation opportunities or increase outflow. Then, the water table drops, the vegetation changes and the peat degrades, leading to the detriment of the wetlands.  相似文献   

洪泛作用下沼泽湿地化学元素空间分布结构研究   总被引：5，自引：0，他引：5  

王国平  刘景双  汤洁  翟正丽 《沉积学报》2003,21(4):688-694

以无尾河下游漫流区-洪泛沼泽湿地为研究对象，根据不同水力梯度洪泛作用淹水频率的差异，在距主河道不同距离处分层采集沉积物样品，对其中K、Na、Ca、Mg、Cu、Zn、Fe、Mn、Cr、Ni、Co、Pb、TOC、TN、pH空间变化规律进行分析探讨。结果显示，多数化学元素含量随距河道距离的增加和采样层深度的增加而降低。距离河流越远化学元素含量在垂直方向上的分布越均衡，变化的幅度减小。说明随着距主河道距离的增加，洪泛作用对沉积剖面中110cm以内各深度层次上的化学元素含量的影响在变小。对金属元素及部分理化参数的相关分析表明其间的相关性较显。  相似文献