Vertical structure of bacterial communities in peats of the Yakhroma river floodplain
The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole.
The Structure of Bacterial Complexes in the Protva River Floodplain
The synecological analysis of bacterial communities from the Protva River floodplain biogeocenosis showed that all of their horizons contain spirilla, which are typical hydrobionts, and pigmented coryneform bacteria associated with the herbaceous plants of the floodplain meadows. The alluvial meadow soils of the inundated regions of the floodplain differ from the unflooded regions of the floodplain in that they have a more diverse bacterial population that is continuously distributed over the soil profile.
Studies on the taxonomy of the Myxobacterales. I. Record of Canadian isolates and survey of methods.
One hundred and sixty-seven pure cultures have been isolated from among 338 myxobacteria obtained from Essex county (Ontario) soil samples by various methods. The fruiting body characteristics used in the characterization of the Myxobacterales have been found to be variable and unstable. However, the order may be considered to consist of two broad groups based on vegetative cell morphology and the formation of microcysts. A proposal is made to divide the genus Chondromyces into Stigmatella and Chondromyces and to assign the latter to the family Sorangiaceae. A number of biochemical tests have been found useful in identification and some are correlated with morphological features.The paper includes 42 color photographs as an aid for other investigators in the identification of the Myxobacterales.