How does a low level of dissolved oxygen affect the ecosystem in the water?
If the level of dissolved oxygen drops for any length of time, fish that need large amounts of oxygen, such as trout and bass, go elsewhere if they can. Carp, catfish, worms, and fly larvae (the immature, worm-like stage in a fly’s life cycle) can handle low oxygen levels, so they thrive. The ecosystem begins to include more organisms that can live with little or no oxygen. If the level of dissolved oxygen continues to drop, even the carp and catfish end up gasping for oxygen. The water is on its way to becoming a dead zone. In the following two experiments, you will use a kit to measure the level of dissolved oxygen in water under several conditions. In one experiment, you will determine how the level changes as the amount of decaying matter in the water changes. In the second experiment, you will…
