Search results
Results from the WOW.Com Content Network
The amount of dissolved oxygen is a measure of the biological activity of the water masses. Phytoplankton and macroalgae present in the water mass-produce oxygen by way of photosynthesis. Bacteria and eukaryotic organisms (zooplankton, fish) consume this oxygen through cellular respiration. The result of these two mechanisms determines the ...
The model describes how dissolved oxygen (DO) decreases in a river or stream along a certain distance by degradation of biochemical oxygen demand (BOD). The equation was derived by H. W. Streeter, a sanitary engineer, and Earle B. Phelps , a consultant for the U.S. Public Health Service , in 1925, based on field data from the Ohio River .
Dissolved oxygen levels required by various species in the Chesapeake Bay (US). In aquatic environments, oxygen saturation is a ratio of the concentration of "dissolved oxygen" (DO, O 2), to the maximum amount of oxygen that will dissolve in that water body, at the temperature and pressure which constitute stable equilibrium conditions.
Most aquatic habitats are occupied by fish or other animals requiring certain minimum dissolved oxygen concentrations to survive. Dissolved oxygen concentrations may be measured directly in wastewater, but the amount of oxygen potentially required by other chemicals in the wastewater is termed as oxygen demand. Dissolved or suspended oxidizable ...
In 1888, while still a doctoral student, Lajos Winkler discovered a much safer, and more precise, method of dissolved-oxygen analysis, which is still widely used today. [5] The Winkler method uses the dissolved oxygen to convert manganese(II) hydroxide into manganese(III) species, and then analyzing for the latter by titration .
Pacific Ocean sections of dissolved oxygen and apparent oxygen utilization. Data from the World Ocean Atlas 2009 . In freshwater or marine systems apparent oxygen utilization ( AOU ) is the difference between oxygen gas solubility (i.e. the concentration at saturation) and the measured oxygen concentration in water with the same physical and ...
Decreased levels of dissolved oxygen (DO) is a major contributor to poor water quality. Not only do fish and most other aquatic animals need oxygen, aerobic bacteria help decompose organic matter. When oxygen concentrations become low, anoxic conditions may develop which can decrease the ability of the water body to support life.
One of the most important features of chemostats is that microorganisms can be grown in a physiological steady state under constant environmental conditions. In this steady state, growth occurs at a constant specific growth rate and all culture parameters remain constant (culture volume, dissolved oxygen concentration, nutrient and product concentrations, pH, cell density, etc.).