Peculiarity of the changes of nitrogen ammonium and nitrate forms content in moss turfs and in the soil under them depending on the local growth environmental conditions in the forest ecosystems

Bryophytes are a significant source of the Nitrogen in ecosystem, quickly absorbing nutrients from the atmosphere and soil, they accumulate them in the dead part of the moss turf and slowly release them as a result of its mineralization. Regulating temperature and moisture in both turf and soil, mosses provide stable and favorable habitat for microorganisms, particularly cyanobacterias, contributing to the fixation of N2 in nitrogen-limited forest ecosystems. Therefore, it is important to determine how the microenvironment, depending on ecological conditions, can change the cycle of nutrients in moss turfs. The purpose of the work was to determine of the nitrogen (ammonium and nitrate) mineral forms changes content in moss shoots of various life forms and under moss cover in order to find out the influence of the forest ecosystems environmental conditions on chemical reactions associated with fixation and exchange of the biophilic element as well as processes mineralization. The research objects were epigeic mosses with life form of loose turf – Atrichum undulatum (Hedw.) P. Beauv. and loose weft – Brachythecium rutabulum (Hedw.) Schimp. Moss samples were taken from experimental sites reserved and anthropogenically disturbed territories, which differed in water and temperature regime and light intensity. The Nessler’s reagent was applied to determine of the ammonium cations content in the mosses gametophyte and in the soil surface layer, amount of the nitrate-anions was determined according to V. I. Baranov and co-authors. It was established that the content of nitrogen ammonium and nitrate-anions in the mosses gametophyte depended on the stability of environmental conditions primarily water regime and the structural organization of turfs. In shoots with better water supply of the endohydric moss A. undulatum from old-growth beeches, the nitrogen ammonium content was 6,7 and 5,6 times higher, compared to the territory of the felling and recreation. The destruction processes of nitrogen-containing organic compounds (ammonification) and oxidation reactions of the reduced ammonium to nitrates (nitrification) took place more actively on reserved areas under more stable conditions of the edaphotope than in extreme conditions of anthropogenically transformed ecosystems.