Good question! Sunlight can penetrate the ocean to a depth of about 600 feet. This is called the “euphotic zone.” Ninety percent of ocean life lives here, including ALL the ocean plants. Below that, there isn’t enough sunlight for photosynthesis, so plants can’t grow. The animals that live down that deep are some of the most unusual on Earth. There are the ones who “glow in the dark,” for instance. And of course, they cannot be vegetarians – no plants!
Answer provided by Dr. Universe