Wetlands of recent Dutch embankments

Wetlands of new embankments are characterized with respect to soil and hydrological regime and the processes of desalination and vegetation succession. Soil- and height gradients, the lack of local drainage and the generally low nutrient content provide conditions for dynamic mesoseries (groundwatertable low in summer, saturated in winter) and locally for stable mesoseries (relatively high in summer, saturated in winter). Relations between vegetation and herbivores (gees, ducks, cattle) are discussed.     

Relationships between plant photosynthesis,radial oxygen loss and nutrient removal in constructed wetland microcosms

The objective of this study was to investigate the relationships between root radial oxygen loss (ROL), photosynthesis, and nutrient removal, based on the hypothesis that ROL is primarily an active process which is affected positively by photosynthesis, and is correlated positively with nutrient removal. Four common wetland plants were studied in small-scale monoculture wetlands. Higher ROL coincided with faster growth among the four monocultures. Significant correlation between ROL and photosynthetic rate existed in Cyperus flabelliformis wetland (P < 0.01). Both ROL and photosynthesis represented close correlations with nutrient removal rates in all four monocultures. Significant differences in ROL, photosynthetic rate, removal rates of NH₄⁺, and soluble reactive phosphorus (SRP) were found among the four species. ROL and photosynthetic rates showed single-peak daily and seasonal patterns, with maximum daily values around noon, and with maximum yearly values in summer or autumn for the four monocultures. The results suggest that the ROL of wetland plants is related to active physiological processes. Both ROL and photosynthetic rate are indices which can be used to identify wetland plants with a higher nutrient removal capacity.     

祁连山南麓高寒湿地生态系统呼吸季节、年际动态及影响因素

由于青藏高原高海拔、低温的特殊环境，使得生态系统呼吸(RE)对气候变化的响应极其敏感，然而对高寒湿地生态系统长时间尺度上的RE动态特征及驱动机制的研究相对薄弱。以青藏高原东北部高寒湿地为研究对象，分析了基于涡度相关系统观测的高寒湿地2004—2016年的CO₂通量排放动态及影响机制，对预测高寒湿地碳平衡对未来气候变化的响应具有重要意义。结果表明：高寒湿地在2004—2016年的月平均RE表现为单峰变化趋势，在8月达到峰值；年RE表现为逐年升高的趋势(P<0.05),年RE均值为(608.9±65.6) g C m^-2 a^-1;生长季RE约是非生长季RE的2.7倍，线性回归分析表明生长季RE(r~2=0.66,P=0.001)、非生长季RE(r~2=0.47,P=0.01)与全年RE呈极显著正相关。在月尺度上，分类回归树分析和线性回归分析表明土壤温度是月RE的最主要控制因素，暗示高寒湿地的土壤呼吸对整个生态系统的碳排放至关重要。在年际尺度上，生长季积温与生长季RE呈显著正相关(P<0.05),而生长季降水(PP...     

Systems ecological accounting for wastewater treatment engineering: Method,indicator and application

Wastewater treatment facility is vital for sustainable urban development. In the course of removing contaminants and discharging ready-for-reuse water, wastewater treatment consumes resources and triggers environmental emission during its lifetime. A comprehensive framework to analyze the embodied ecological elements as natural resources and environmental emissions of wastewater treatment is presented in this work. The systems method as a combination of process and input–output analyses is applied and a set of indicators are accordingly devised. Two representative ecological elements, i.e., greenhouse gases emissions and solar emergy of alternative wastewater treatment systems, i.e., a traditional activated sludge wastewater treatment plant and a constructed wetland have been taken into consideration. For each ecological element, five indicators have been calculated and compared to assess the impact on climate change and resources utilizing style of the case systems. The framework raised in this paper is fully supportive for optimal decision-making among different wastewater treatment technologies, and could be transplanted to be applied to systems ecological accounting for other production systems.     

A general review of tropical South American floodplains

High rainfall and its seasonal distribution cause periodic flooding of large areas in tropical South America. Floods result from lateral overflow of streams and rivers, or from sheet-flooding by rains as a consequence of poor drainage. Depending upon the size of the catchment area, flooding can occur with one peak (e.g., in the Amazon River and its large affluents) or in many peaks (e.g., in streams and small rivers).Vegetation cover of floodplains varies from different types of savannas and aquatic macrophyte communities to forests depending upon the hydrologic regime and local rainfall. Large differences exist in primary and secondary production due to large differences in nutrient levels in water and soils.An attempt is made to characterize the floodplains according to their hydrologic regimes, vegetation cover and nutrient status. The areal extent of different types of floodplains is estimated. The human impact is also evaluated.From a paper presented at the Third International Wetlands Conference, 19–23 September, 1988, University of Rennes, France.     

Transport of groundwater-borne phosphorus to Lake Bysjön,South Sweden

Lake Bysjön is a hypertrophic seepage lake, with groundwater as a main external source of phosphorus. Twelve groundwater samples from the vicinity of the lake were high in phosphate (0.4 to 11 mg l^–1, mean value 2.57 mg l^–1 PO₄-P), both within the riparian zone and in two shallow wells located upstreams the lake in the nearby village. Phosphorus sorption capacity of four sand samples measured with the Langmuir isotherm method was low (7.3 to 121,1 mg kg^–1 PO₄-P), with the lowest values found within the riparian zone. It is suggested that the phosphorus originates from garden fertilizers and other human sources, and that the low absorption capacity of the soils is caused by the leaching of calcium from the watershed, a process which started some 3000 years ago. Riparian zone itself has almost no retention capacity, and processes within it (e.g., redox-related) have only secondary importance for the transport of phosphorus to the lake.     

The Muni-Pomadze Ramsar site

The Coastal Wetlands Management Project (CWMP), funded by the Global Environment Facility and implemented by the Ghana Wildlife Department, seeks to preserve the ecological integrity of coastal lagoons that serve as important sites for migratory waterbirds. This report describes the geomorphology, hydrology, soils, water chemistry, and vegetation of the Muni-Pomadze Ramsar site. Muni lagoon is a saline, shallow water lagoon separated from the sea by a sand bar which may be breached occasionally. The bulk of the rainfall in the catchment evaporates or flows as surface runoff into three streams that empty into Muni lagoon. Open water in the lagoon varies seasonally from 100 ha in the dry season to over 1000 ha in the wet season. The natural flora of the site can be divided into four main types; flood plain (including mangrove and wetland vegetation), dune vegetation, riverine vegetation, and terrestrial vegetation on elevated ground. The latter consists of a combination of grasslands, thickets, and Eucalyptus plantations. Fifty-three percent of the site is classified as natural vegetation. An additional 32.5% is agricultural land and 12.6% is residential area for the 11 communities within the site. The main source of employment are farming or fishing. The area surrounding Muni lagoon is used extensively for bushmeat hunting and as the tribal hunting grounds of the Efutu people. Apart from the global importance of the Muni-Pomadze site for biodiversity, management of the site is further justified by its considerable potential for development as an income-generating and educational nature reserve with an eco-cultural theme, managed by the local communities in partnership with the governmental and non-governmental conservation agencies.     

Production and degradation of geosmin in a stratified lake with anaerobic hypolimnion (Schleinsee)

Abstract Depth profiles of geosmin concentrations were determined over the year in a stratified lake with anaerobic hypolimnion. Two independent sources of geosmin were observed. Most geosmin was produced under anaerobic conditions in the hypolimnion in the autumn. A much smaller source of geosmin production was actinomycetes in the epilimnion. With the onset of the autumnal circulation of the water body, rapid aerobic degradation of geosmin was observed.