Abstracts

Evolution of Species and Ecosystems: Theoretical Analysis and Computer-Assisted Modeling

Simple models of terrestrial ecosystems with a limited number of components are an efficient tool to study the laws of functioning of microbial populations and their communities in natural ecosystems under variable environmental conditions. Among other things is the increase of carbon dioxide in the atmosphere and limitation of plants’ growth by biogenic elements.

Main response types of ecosystems to changes in environmental conditions (change of СО2) have been demonstrated in a simple experimental system «plants – rhizospheric microorganisms – artificial soil”: 1) when a system is limited in terms of biogenic elements like nitrogen and phosphorus (this seems to be characteristic of most natural systems) response can hardly be expected; this has been proved by experiments conducted (Somova et.al.,1999); 2) when a system is not limited in terms of mineral nutrients если (this is characteristic of the agricultural crop) the response is quite realistic (up to 30-40% with double СО2 concentration in the atmosphere); 3) yet depending on the intensity and the mode of interaction of the producer with other components when assimilation of СО2 by the plants is total, carbon may not be bound by the plant biomass, but through enhanced respiration of microorganisms and plant roots be quickly returned into the atmospheric pool.

Mathematical model of interaction between plants and microorganisms with normal and elevated atmospheric СО2 and limitation by biogenic elements (nitrogen and phosphorus) yielded qualitative agreement of theoretical and experimental results.

Note. Abstracts are published in author's edition

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