Microbiology and Immunology

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Oxygen cycle in microorganisms

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the lake does not readily occur, the body of water can become

stagnant. In other words, the oxygen content of the water

becomes depleted and, without mixing, insufficient surface

level oxygen is available to replenish the supply. Fish life in

the water can suffer. Another example is the depletion of oxy-

gen from a lake by the explosive growth of algae. The algal

“bloom” can essentially make the water body incapable of

supporting life. Furthermore, if the algal species is a toxin pro-

ducer, the water can become hazardous to health. A final

example is the relationship between the oxygen cycle in

microorganisms and water pollution. Polluted water is typi-

cally enriched in nutrients that will support the rapid growth of

bacteria and other microbes. Their growth depletes the oxygen

in the water. In grossly polluted water, this depletion can be so

extensive that the water cannot support oxygen-dependent life.

Thus, the oxygen cycle in microorganisms, mainly bac-

teria, is very important in determining the quality of a water

body and so of the ability of the water to be a productive

source of life.

See also Carbon cycle in microorganisms; Composting,

microbiological aspects; Life, origin of; Nitrogen cycle in

microorganisms

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