What are the niches of algae, duckweed, salvinia, and elodea?
These are all examples of aquatic plants. They carry out the process of photosynthesis and are a food source for first level consumers (herbivores).
An easy way to think of niche is that this is the job performed by an organism in the environment where it lives.
Plants carry out the process of photosynthesis. This process allows plants to use the energy from sunlight and convert water and carbon dioxide into carbon containing molecules like carbohydrates (sugar).
Here is video of a lab testing the impact of carbon dioxide levels on the rate of photosynthesis in elodea plants.
These plants are used as a food source by many herbivores. Some examples of organisms that eat duckweed are; ducks, geese, turtles, fish, beavers and musksrats.
Hope this helps!