Final answer:
Elodea increases O2 through photosynthesis, can lower nutrient levels to prevent algal blooms, and provides a habitat that supports algae and phytoplankton growth.
Step-by-step explanation:
The roles of elodea in an aquatic chamber or ecosystem include several ecological functions. First, as a type of aquatic plant, elodea helps to increase the O2 concentration in water through the process of photosynthesis, which is critical for the survival of aquatic organisms. Second, by competing for nutrients, it can help to lower the nutrient levels in the water, potentially reducing the risk of algal blooms that can lead to hypoxic conditions. Third, since plants like elodea provide a habitat and food source, they can increase the amount of algae and phytoplankton by creating a more habitable environment for these primary producers, which are vital to the food web.