4 research outputs found
Response of emergent macrophytes to hydrological changes in a shallow lake, with special reference to nutrient cycling
Seasonal denitrification potential in wetland sediments with organic matter from different plant species
Vegetation both physically and biochemically influences denitrification in wetlands. Litter from various plant species supplies various amounts and qualities of organic carbon to denitrifying bacteria, and may thus affect denitrification capacity. We explore whether there is seasonal variation in the denitrification potential in stands of Glyceria maxima, Phragmites australis, Typha latifolia, and Potamogeton pectinatus (the stands differed in terms of which species was predominant). Experiments and measurements investigated whether denitrification potential was related to organic matter and its availability to denitrifying bacteria, suitability for bacterial growth, and amount in the wetland. Availability of organic material, as measured in the slurries, was highest in the G. maxima and P. pectinatus samples, with the highest availability in May and August. However, when the samples were closer to wetland conditions, i.e., intact sediment cores containing litter and organic sediment, the denitrifying capacity was highest in the cores from G. maxima stands, but lowest in P. pectinatus cores. In addition, the denitrification potential of the intact cores was highest in November. Differences in denitrification capacity between the slurries and intact sediment cores, considering the organic material of the plant species and the seasonal pattern, were attributed to differences in the amount of plant litter generated
CATCH: decision support for stakeholders in catchment areas
Policy proposals for the management of water resources need to take into account two emerging themes: public involvement in the development of resource use policy and water management on a catchment level. The CATCH-model, a decision support system for catchment-based water management, builds on the use of ‘discourse and deliberation’ within stakeholder groups to define relevant socio-economic parameters and the relationships between these parameters. The sets of matrices that describe these parameters and their interrelation serve as the basis for evaluation of alternative management strategies and evaluation of specific measures for improving water quality
Influence of alternative states on nitrogen removal in experimental wetlands
Denitrification is the main process that remove nitrate from the water in wetlands. Plants can supply denitrifying bacteria with organic carbon and suitable attachment surfaces (Weisner et al. 1994). They also promote the development of anaerobic conditions through litter accumulation and decomposition, which would favour denitrification. The presence of plants has been shown to enhance nitrate removal in field studies (Bachand and Horne 2000). Toet et al. (2005) found a higher nitrogen removal in wetland compartments with emergent plants than with submersed plants. Results from microcosm studies have shown that the potential for denitrification is specific for different plant species (Bastviken et al. 2005). Wetlands may typically exist in alternative states, dominated by different kinds of vegetation. The purpose of this study was to investigate the effect of alternative state on nitrogen removal under controlled conditions in experimental wetlands