They will be able to describe the difference in water quality between streams at Crater of the Moon and near their school. The chemical tests of water quality the National Park Service uses to monitor Little Cottonwood Creek include measurements of water temperature, dissolved oxygen, and pH. These tests indicate a variety of things about the health of the stream environment. Aquatic organisms have adapted to survive within a certain range of water temperatures. Very high or low temperatures may exceed the tolerance limit for some aquatic life. Because warm water holds less oxygen than cool water, increasing temperature can negatively affect the whole aquatic ecosystem.
Temperature also affects aquatic life's sensitivity to toxic wastes, parasites and disease.
Fish become more vulnerable because they are in a weakened condition from lack of dissolved oxygen, or under stress from higher water temperature. Dissolved Oxygen Dissolved oxygen is essential for the maintenance of healthy lakes and rivers, since most aquatic plants and animals need a certain level of dissolved oxygen for survival. Waters with consistently high dissolved oxygen are healthy and stable aquatic ecosystems, capable of supporting many different kinds of organisms. Much of the dissolved oxygen in water comes from the atmosphere. Waves on still water and tumbling water on fast-moving rivers mix atmospheric oxygen into the water.