Final answer:
Pollution can lead to low oxygen levels in aquatic ecosystems through eutrophication. Excessive nutrients promote the growth of algae and other plants, leading to an overabundance of organic matter. As the plants die and decompose, bacteria consume oxygen, resulting in low oxygen levels in the water.
Step-by-step explanation:
Pollution can lead to low oxygen levels in aquatic ecosystems through eutrophication. Eutrophication occurs when excessive nutrients, such as nitrogen and phosphorus, enter a body of water. These nutrients promote the growth of algae and other aquatic plants, leading to an overabundance of organic matter. As the plants die and decompose, bacteria consume oxygen during the process, causing low oxygen levels in the water.
For example, if a nearby factory releases untreated sewage into a river, the sewage may contain high levels of nutrients. When these nutrients enter the river, they can cause excessive algal growth. As the algae die, bacteria break them down, consuming large amounts of oxygen in the process. This can lead to low oxygen levels, known as hypoxia, which can harm aquatic organisms.
Learn more about pollution's impact on oxygen levels in aquatic ecosystems through eutrophication