History
The test was originally developed by Ludwig Wilhelm Winkler, in later literature referred to as Lajos Winkler, while working at Budapest University on his doctoral dissertation in 1888. 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, algae, fish) consume this oxygen through cellular respiration. The result of these two mechanisms determines the concentration of dissolved oxygen, which in turn indicates the production of biomass. The difference between the physical concentration of oxygen in the water (or the theoretical concentration if there were no living organisms) and the actual concentration of oxygen is called the biochemical demand in oxygen. The Winkler test is often controversial as it is not 100% accurate and the oxygen levels may fluctuate from test to test despite using the same constant sample.
Read more about this topic: Winkler Test For Dissolved Oxygen
Famous quotes containing the word history:
“If usually the “present age” is no very long time, still, at our pleasure, or in the service of some such unity of meaning as the history of civilization, or the study of geology, may suggest, we may conceive the present as extending over many centuries, or over a hundred thousand years.”
—Josiah Royce (1855–1916)
“The view of Jerusalem is the history of the world; it is more, it is the history of earth and of heaven.”
—Benjamin Disraeli (1804–1881)
“The principle office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–117)