Structure and functioning of the biota pool of marginal areas of soils of urbanozems

Korlyakov K. A., Markova L. M., Gashev S. N.

Soil areas bordering on artificial barriers were studied: curbs, concrete slabs, fences. Soil profiles with a height of 15-20 cm were cut near the artificial barrier and at a distance of 30 cm from it, which were the control. The aim of the work was to study the features of the composition and functioning of biota in the marginal areas and the continuum profile of the soil. A significant numerical prevalence of microbiota (bacteria, algae, fungi) has been established, which gives a more intense outbreak of numbers at the edges of the soil profile bordering the artificial separator. Bacteria in the marginal areas of the soil develop more intensively in the form of colonies and more abundant biofilm formation is noted. To an even greater extent, this pattern was observed in fungi: the growth rate of mycelium and the number of colonies from the edge prevailed over the soil areas in the middle several times and by one order of magnitude. The growth of algae on the fouling glasses cultivated in the marginal areas of soils was 2-3 days ahead of the growth of algae from the middle. In this period, the number of algae was higher from the edge of the soil, and in the middle – diversity. After 1-2 weeks, the reverse trend was observed, with the number of algae from the edge also dominating. In the course of bacterial growth, a similar pattern was observed – in the middle sections of the samples, the diversity of bacterial colonies increased, while the total number of colonies decreased. The samples from the middle of the soil were dominated by trichomal forms of algae, while on the edge – unicellular. The higher plants dominated in numbers in the middle, while on the edge of the artificially planted plants we gave more shoots. Chemical analysis of the marginal areas of the soil and from the middle of the soil profile showed that phosphates and nitrates dominate at the edge, which, apparently, provided more intensive growth of biota at the edge.

Keywords:algae, fungi, microorganisms, soil at borders, "edge effect", organomineral complex.