Why are coral reefs important to ocean life? Coral reefs take carbon dioxide out of the water and secrete it into their skeletons. Corals provide an important cleaning function by filtering debris from the water. Corals are an important link in the benthic food chain. Coral reefs provide food, shelter, and breeding grounds for thousands of marine organisms. Coral reefs grow upward to near sea level, providing shallow zones for benthic organisms.