This paper considers certain elements relating to the ecological and economic importance of the aquatic macrophytes common in the Câmpia Română/Romanian Plain lakes, especially those species belonging to the genera Myriophyllum and Potamogeton, common in Bucharest’s urban lakes. At present, the macrophytes of the Bucharest lakes are collected by personnel of the Lakes, Parks and Leisure Administration of Bucharest by mechanised and manual methods, which are sun-dried and transported as waste and deposited in a landfill. Thus these macrophytes are merely generating costs through harvest, transport and storage, instead of being a direct revenue source for the City hall. This study presents a review of international literature in support of the economic potential as fertiliser for open field crop, orchard and garden crop application, as well as food for farm animals. The last portion of the paper argues the vital need for the preservation of macrophyte stands in the lacustrine habitat for green, sustainable and integrated management of the urban lakes used for leisure and fishing.
The aim of this study is to conclude the experiences of the maintenance practice of an artificial thermal lake. The first years (2015-2017) of the development of the lake were analysed and evaluated along the following questions: a) What kind of design processes and maintenance interventions are related to the process of fitting the lake into the landscape? b) How have the ecological conditions of the lake evolved in the past period (zonation, succession, plantation and colonization)? c) Which general experiences could be gained from the operation of this artificial thermal lake this far? The authors of the present study were already engaged in the planning process, participating in the preparation of four different design documentations. The planting design and the maintenance instructions were based on a physico-chemical monitoring, phytoplankton, zooplankton and macroinvertebrate sampling, and machrophyte assessment. The significant processes during the three years of the lake are presented by functional groups of biota, separately assessing the characteristics of the changes of macrophytes. In 2017 an individual macroinvertebrate assessment was done, moreover a fish die-off occurred in August 2017, which are mentioned separately as well. The data in total suggested that the water of the lake is highly hypertrophic, further machrophyte introduction can prevent the plant nutriments to be absorbed by algae. Partly the algal growth but also the unlucky coincidence of other factors (e.g. high water temperature, cold weather front, maintenance problems) led to the die-off of the spontaneously overpopulated fish stock in 2017.
One of the most important elements in the protection of water quality is buffer zones. In order to protect water quality, appropriate management of these areas is necessary. In the paper, changes in the land use in the buffer zone of 200 m width around lakes in the Mała Wełna catchment over 20 years were analysed. For the study eight lakes larger than 50 ha were chosen. Changes in the land use within the buffer zone were studied from 1980 to 2000, based on topographic maps in the scale 1:10 000. Results show both positive and negative aspects of land changes. An increase in forested areas and grasslands through tilled land were positive aspects of these changes. On the other hand, the enhancement of suburban development in these zones caused increased probability of water pollution from these areas. Calculations of potential nutrient loading from different types of land use in these zones indicated an enhancement of nutrient sources in the lakes within the 20-year study period. However, these changes are not significant in comparison to the nutrient loads contributed by the tributaries. Our study indicated that in the case of flow lakes, more important is an improvement in water quality in the tributaries and a reduction in nutrient sources in the catchment with the purpose of reducing the input of nutrients into the lake. Management of the buffer zone is one of the issues which have to be taken into consideration in lake protection after elimination of the major water pollutant sources.
Environmental pollution of lakes and rivers is considered as one of the most important environmental problems. Analysis of nutrient and trace element accumulation in sedimentary phases of lakes can reflect the overall regional pollution level, and the observed accumulation patterns of pollutants in sediment profiles can be used to reconstruct the history of anthropogenic impacts. As pollutants in sediments are associated with other substances, it is important not only to study total concentrations of pollutants, but also their speciation forms. The aim of this study was to describe phosphorus (including speciation forms) and trace element concentrations in sediment profiles of Lake Engure and to evaluate human impact on organic matter accumulation and properties in lake sediments. The concentrations of the studied elements in sediments of Lake Engure are at background levels, which is clearly evident when compared with metal concentrations in lake sediments in West European countries. The analysis of element concentration changes in sedimentary profiles provided information about trends in recent accumulation (within the last 100 years) and on the balance between natural and human-induced accumulation processes. Analysis of nutrient concentrations in sediments aided in identifying background values as targets for lake management activities.
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