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CNAA / Theses / 2004 / June /

Biogeochemistry of nitrogen and phosphorus in urban ecosystems (on the example of mun. Chisinau)

Author: Halil Ahmad
Degree:doctor of biology
Speciality: 03.00.16 - Ecology
Scientific adviser: Ion Dediu
doctor habilitat, professor, Institute of Ecology and Geografy of the ASM
Scientific consultant: Dumitru Drumea
Institution: National Institute of Ecology
Scientific council:


The thesis was presented on the 4 June, 2004
Approved by NCAA on the 14 October, 2004


Adobe PDF document0.28 Mb / in romanian


nutrients, biogenic loads, eutrophication, ecosistem, toxicity, sediments, soil, water ontogenez, population model, toxic efect, reproduction, migration


Regulation of the eutrophication process needs studying of the biogeochemical cycles, different ratios of nitrogen and phosphorus in water ecosystems and reaction of hydrobiontes on different ratios and concentrations of these elements.

Recent study presents results of analising of different components of urban on nitrogen and phosphorus, estimation of ratios between mineral and organic forms of these elements, estimantion of migration of nutrients with suprficial runoff from diffrent functional zones of the town, experiments on the evaluation of impact of different ratios and concentrations of nitrogen and phosphorus detected in main components of urban ecosystems on development of tested water organisms. The impact of different ratios of nitrogen and phosphorus is shown on such living functions of tested organisms. Optimal ratio of nitrogen and phosphorus was estimated by survaving of Gammarus Kishineffensis. Regulatory factor of water hydrobiontes in approaching ratio of nitrogen and phosphorus to the natural ones was shown.

Chronic tests experiments showed that every ratio of nitrogen and phosphorus (30:1, 15:1, 10:1) coresponds to the specific ontogenis resistens of tested organisms and depends on the concentration of toxicants, duration of experiments.

There was shown possibility of performing used methodology in estimation of different ratios of nutrients detected in components of environment in toxicological experiments on the population model of highest crustacee, which can be characterized with certain specific reaction on toxic load. That is why indicators of population could be used as indicators of the toxicity of solutions