They will avoid areas where DO levels are below 3 mg/L, but generally do not begin to suffer fatalities due to oxygen depletion until levels fall below 2 mg/L 22. The mean DO levels should remain near 5.5 mg/L for optimum growth and survival Â¹Â².n a stable body of water with no stratification, dissolved oxygen will remain at 100% air saturation. 100% air saturation means that the water is holding as many dissolved gas molecules as it can in equilibrium.
Lesson Summary. 1  Most protist diseases in humans are caused by protozoa. 2  Protozoa make humans sick when they become human parasites. 3  Trypanosoma protozoa cause Chagas disease and sleeping sickness. 4  Giardia protozoa cause giardiasis, and Plasmodium protozoa cause malaria.esson Summary. 1  Most protist diseases in humans are caused by protozoa. 2  Protozoa make humans sick when they become human parasites. 3  Trypanosoma protozoa cause Chagas disease and sleeping sickness. 4  Giardia protozoa cause giardiasis, and Plasmodium protozoa cause malaria.
Infectious diseases are caused by small microbes invisible to the eye. The microbes include bacteria, protozoans, fungi, yeast and virus. Of them bacteria and protozoans are the most common disease causing agents.Bacteria cause disease both in plants and animals.iseases caused by bacteria; Bacteria causes wide set of diseases by deranging the host physiology. courtesy:wikicommons. Most of the diseases caused by bacteria are life threatening and also damaging to the affected organ. Once infected the common symptoms like fever, weakness are observed by the host.