Respirometer
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A respirometer is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and carbon dioxide. They allow investigation into how factors such as age or the effect of light affect the rate of respiration.
A simple respirometer designed to measure oxygen uptake or CO2 release consists of a sealed container with the living specimen together with a substance to absorb the carbon dioxide given off during respiration, such as soda lime pellets or cotton wads soaked with potassium hydroxide. The oxygen uptake is detected by displacement of manometric fluid in a thin glass U-tube connected to the container. When the organism takes in oxygen it gives off an equal volume of carbon dioxide. As this is absorbed by the soda lime, air is sucked in from the U-tube to keep the pressure constant, displacing the liquid. The rate of change gives a direct and reasonably accurate reading for the organism's rate of respiration.
As changes in temperature or pressure can also affect the displacement of the manometric fluid, a second respirometer identical to the first except with a dead specimen (or something with the same mass as the specimen in place of the organism) is sometimes set up. Subtracting the displacement of the second respirometer from the first allows for these factor's.
A 'Respirometer' is a commercially manufacutred system that measures the oxygen uptake rate of aerobic bacteria or the gas production of anaerobic bacteria in wastewater, soils, compost, and slurries. The AER-200 is an open source respirometer that measures the volume of oxygen released in the reaction vessel without the use of electorlytic chemicals. The Challenge Technology unit can provide rate as well as total uptake rates. A respirometer can be a bench top unit for laboratory studies and applications or an "on-line" unit that measures the uptake rate directly from the source, i.e. the treatment plant basin, at municipal and industrial treatment sites.
