Количественное распределение азотфиксирующих бактерий и их экология в районе филлофорного поля Зернова в Черном море

Abstract

1. Microzonality characterizes the quantitative distribution of Azotobacter and Clostridium in water. The bacterial number is influenced by wind troubles and by inflow of bottom waters. In distinction to fresh water reservoirs, Clostridium occurs in water less frequently and in lesser numbers than Azotobacter. 2. Azotobacter and Clostridium show microzonal distribution in grounds, in greater numbers than in water. For Clostridium life conditions in the grounds are more favourable than in water. 3. The phyllophora surface is abundant in bacteria which form micrecolonies, pseudozooglea or diffuse accumulations consisting of cells morphologically identical to Azotobacter species and resembling the cells of Rhizobium, Beijerinckia, Azotobacter, etc. Within the microzones they frequently have the appearance of pure cultures. The character of bacterial growth on phyllophora is similar under natural conditions, to that on artificial agar media. Clostridium occurs on phyllophora less frequently and in lesser numbers than Azotobacter. Water, grounds and thallom are inhabited by various oligonitrophils. Between the epiphytic bacteria and phyllophora here exist obviously metabiotic or symbiotic relationships. 4. Azotobacter and Clostridium strains isolated from water, ground and phyllophora thallom are able to fix nitrogen in the presence of a carbon source. 5. Nitrogen fixators and oligonitriophils of the phyllophora field can serve as a source of bound nitrogen and influence the biological productivity of this region of the Black sea.