Maximum Concentration Of Bacteria Research Articles

Подходы к моделированию микробиологической очистки сточных вод с помощью клеточных автоматов

The article discusses an approach to modeling microbiological wastewater treatment using simulation modeling by cellular automata. A model of the evolution of one type of microorganisms in a nutrient medium has been built and its research has been conducted by means of a numerical experiment. Non-colony-prone microorganisms and having the same scale in all dimensions were taken as model microorganisms. Nutrient medium is adopted single-component and having a uniform initial distribution. The influence of the size of the cellular automaton field and the characteristics of the division of bacteria on the parameters and behavior of the system was investigated. It was determined that, when using periodic boundary conditions, the scale of the field, when its size is more than 20×20 cells, does not affect the evolution of the system. The bacterial reproduction rate affects both the appearance of the concentration curves of bacteria and the nutrient component, as well as the internal parameters of the model, such as the average return of bacteria and the supply of nutrients accumulated by bacteria. The rate of decrease in the concentration of the nutrient increases until the maximum concentration of bacteria is reached, then there is an inflection point and then the decrease in the concentration of the nutrient medium is approximately exponential. The advantages/disadvantages of this approach and its applicability to specific phenomena and technological processes are given, which, in addition to microbiological water treatment, include the processes of biodegradation of toxic substances, industrial and food waste, the death of microorganisms upon contact with a toxic substance. The source code of the program that implements the simulator model is written in Python and is freely available.

An hypothesis describing the general temporal and spatial distribution of alfresco bacteria in the earth’s atmospheric surface layer

An hypothesis is presented that describes, in general terms, the temporal and spatial airborne bacterial distribution patterns in the mixed layer of the planetary atmosphere. It is hypothesized that the near coincidence of the solar radiation cycle and temporal atmospheric bacterial distribution patterns indicate that the bacterial distribution in the alfresco atmosphere is a function of the diurnal and annual solar cycles. A maximum concentration of bacteria is found in reference to the solar zenith as a standing wave in the rotating coordinate system of the moving earth. Conditions of weather, topography, source strength, and human activities (i.e. microbial air pollution-MAP) will modulate the cyclic patterns of atmospheric bacterial loadings.

Population dynamics of bacteria in Arctic sea ice

The dynamics of bacterial populations in annual sea ice were measured throughout the vernal bloom of ice algae near Resolute in the Canadian Arctic. The maximum concentration of bacteria was 6.0·10(11) cells·m(-2) (about 2.0·10(10) cells·l(-1)) and average cell volume was 0.473 μm(3) in the lower 4 cm of the ice sheet. On average, 37% of the bacteria were epiphytic and were most commonly attached (70%) to the dominant alga,Nitzschia frigida (58% of total algal numbers). Bacterial population dynamics appeared exponential, and specific growth rates were higher in the early season (0.058 day(-1)), when algal biomass was increasing, than in the later season (0.0247 day(-1)), when algal biomass was declining. The proportion of epiphytes and the average number of epiphytes per alga increased significantly (P<0.05) through the course of the algal bloom. The net production of bacteria was 67.1 mgC·m(-2) throughout the algal bloom period, of which 45.5 mgC·m(-2) occurred during the phase of declining algal biomass. Net algal production was 1942 mgC·m(-2). Sea ice bacteria (both arctic and antarctic) are more abundant than expected on the basis of relationships between bacterioplankton and chlorophyll concentrations in temperate waters, but ice bacteria biomass and net production are nonetheless small compared with the ice algal blooms that presumably support them.