The Island of Martin Garcia lies at the confluence of the Uruguay and Paraná Rivers (upper Río de la Plata). This island is an outcrop of the crystalline basement. Due to basalt exploitation the island exhibits several ponds covered by carpets of free-floating macrophytes. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved ox...

By using 7 x 10(8) cells of Saccharomyces cerevisiae per ml with which 25 degrees Brix honey solutions were fermented to 9.5% (wt/vol; 12% vol/vol) ethanol in 2.5 to 3 h at 30 C, i.e., rapid fermentation, the death rate was found to be high, with only 2.1% of the yeast cells surviving at the end of 3 h under anaerobic conditions. As the dissolved oxygen in the medium was increased from 0 to 13 ...

We report an in-depth survey of next-generation DNA sequencing of ciliate diversity and community structure in two permanently ice-covered McMurdo Dry Valley lakes during the austral summer and autumn (November 2007 and March 2008). We tested hypotheses on the relationship between species richness and environmental conditions including environmental extremes, nutrient status, and day length. On...

Dissolved oxygen (DO) is considered as one of the most important aspect of aquaculture. It is needed by fish to respire and perform metabolic activities. Thus low levels of dissolved oxygen are often linked to fish kill incidents. On the other hand, optimum levels can result to good growth, thus result to high production yield. To increase pond production it is necessary to control dissolved ox...

Climate change is one of the key factors affecting the future quality and quantity of water in rivers and tidal estuaries. A coupled three-dimensional hydrodynamic and water quality model has been developed and applied to the Danshuei River estuarine system in northern Taiwan to predict the influences of climate change on water quality. The water quality model considers state variables includin...

The change of nonpoint source and freshwater discharge as a result of land use change might affect the water quality in a river. In the current study, a coupled three-dimensional hydrodynamic and water quality model was created and applied to the Danshuei River estuarine system and its adjacent coastal ocean. The hydrodynamic and water quality models were validated using observations of water s...

The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the per...

The effects of the duration of the floods on abiotic variables and attributes of species tolerant and intolerant to hypoxia (STH and SIH respectively) were evaluated in rivers and lakes of the upper Paraná River. Fish were sampled once a year, in six sampling stations, during the high water period from 2000 to 2003. There were overall reductions in dissolved oxygen levels and increases in trans...

Biological processes at a wastewater treatment plant are complex, multivariable, time varying and nonlinear. Moreover, interactions between the components are very strong. Control of dissolved oxygen is one of most important task at the plant. The level of dissolved oxygen in aerobic tanks has significant influence on behaviour and activity of microorganisms at the plant. Air for aerated tanks ...

Quantitative studies of the dissolved nitrogen in man have been previously made only for short periods of time, chiefly in determinations of cardiac output (Bornstein, 1919). Measurements of nitrogen absorption and elimination not only give an approximation of cardiac output, but also a’fford a representation of the absorption and elimination of all chemically inert gases, specifically the inha...