Even though the relative contribution to the global warming potential from anthropogenically produced CO₂ and CH₄ is estimated at 49 and 17 percent, respectively, the generation of CH₄is of primary concern because it is not only increasing at a rate of 1.1 percent per year but it is also 32 times more effective in absorbing energy from the sun.
The primary source of methane is suspected to be biological in origin and, according to the 1990 report of the Japanese Intergovernmental Panel for Climate Change (IPCC), about 45 percent of the total methane emissions are produced not only in lake, marsh and coastal zone ecosystems but also rice paddy fields and the digestive systems of ruminant animals.
The objective of the present study was to elucidate the mechanisms of interaction between sulfate-reducing and methane-producing bacteria as sources of methane emission to the atmosphere. The experiments, carried out in cylindrical microcosms containing lagoon sediments covered by seawater of varying salinity, showed that the sulfate-reducing reaction was dominant in suppressing the methane fermentation reaction. Next, these competitive bacterial interactions where investigated as a function of both salinity and the organic and sulfur concentrations in the sediments. This was accomplished by covering the respective sediment samples with seawater, seawater diluted with deionized water and deionized water, each with and without the addition of glucose solution,(used to simulate organic loadings to brackish marsh ecosystems from wastewater effluents). The data showed that the amount of sulfide produced in the sediments followed a decreasing order: 100%, 50%, 25% and 0% seawater, respectively. In addition, it was established that this decreasing order, as a function of the dilution effect, also occurred for cations such as K⁺ and Na⁺.
The addition of glucose significantly enhanced the sulfide formation. Conversely, the decreasing sulfide production as a function of decreasing salinity coincided with an increase in the production of methane. These results suggested that, in brackish marsh ecosystems, the sulfate-reduction reaction is favored and appears to retard the methane fermentation reaction.

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Effect of salt on phages and host bacteria has not been investigated in relation to control of phages in industrial process.
We therefore investigated the effect of salt on phages and its host bacteria, using phages T1, T3, T4 and T5 and Escherichia coli B.
At 37°C, salt completely inhibited the growth of bacteria at 0.8 M. It did not affect the infectivity of phages. It considerably prevented the adsorption of phages onto bacteria. Salt completely inhibited the growth of phages at 0.6-0.9 M.
At 42°C, in the absence of salt, the growth of phage T1 was completely inhibited, whereas the growth of bacteria was the same as at 37°C. With phages T3, T4 and T5, this was not true.
At 42-43°C, with phages T3, T4 and T5, lower concentrations (0.2-0.3 M) of salt completely inhibited the phage growth.
The results suggest the possible use of salt for the control of phages in fermentation process.

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A numerical analysis was performed to determine the flow development and the mass transfer characteristics in laminar natural convection flows, arising due to the difference in concentration, between two fully submerged vertical parallel plates, for fluids having Schmidt numbers from 1 to 10³. A constant wall concentration was applied at one plate, while the other was a non-absorbent plate.
A forward-marching, implicit method with iteration was used to solve the nonlinear partialdifferential simultaneous equations. Numerical results were obtained for the variations of axial and transverse velocities, concentration, pressure, induced flow rate, and local and mean Sherwood numbers.
From the numerical results, dimensionless equations were derived for predicting the induced flow rate and the mean Schmidt number.

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