What Do Turtles Eat?

Adult Green Turtles are herbivorous. They almost-exclusively feed on various species of seagrasses and seaweed. While mature green turtles are entirely herbivorous, juveniles are known to eat a variety of marine invertebrates. Their diet of plant matter grows larger as they age, until as mature adults they become complete herbivores.
As large and well-protected animals, adult green turtles have few enemies and even fewer predators. Only human beings and the larger sharks are known to feed on the sea turtle. Tiger sharks are known predators of adult green turtles. Juvenile turtles and recently emerged hatchlings have significantly more predators, including sharks, crabs, small mammals and shorebirds.

Turtle Weed Algae - Species of the Reef

The unsung hero of the reef are the algaes. They provide food for the many herbivores on the reef providing the foundation of most marine food chains. In todays' world one of their most important roles is turning carbon dioxide into oxygen and food. As you can see, protecting the reef helps protect our oxygen supplies.
Large algae may also provide homes for a wide variety of small organisms. The algae above is known as turtle weed and is found on the Great Barrier Reef. It can be found from 5 m to about 20 metres deep. Turtle weed is popular in home aquariums also, playing its' part in the removal of nitrates and converting CO2 to oxygen.