Plants/Algae
Both plants and algae are primary producers, deriving energy from the sun through photosynthesis to form the base of the food web in the ocean. There are many species of alga that live among the reefs of Hawaiian Islands Humpback Whale National Marine Sanctuary, including red, green, and brown algae as well as some seagrasses. These undersea plants and algae produce oxygen during photosynthesis, provide habitat for marine animals, and are a food source for numerous species. Some species even produce calcified structures that actually aid in reef building.