As you move up to the food chain, the energy will decrease. This explains that the more the consumers, the lesser the energy that the last consumer will get from the sunlight. This is because each energy will decrease as it passes by the consumers because each consumers takes a portion of the full energy from the sun.
The climate change impacts a coral in many different ways. But the main reason that could happen is if the climate were a coral lives is too cold and it begans to die. Corals have feelings toi, when they get a sense that they are going to die they try to leave but if they can't they will just die.