What made the specific reef we were exploring so intriguing was that its existence seemed to defy many beliefs about coral reefs. Although corals were not plants, sunlight was usually essential to their survival. They needed it to power the zooxanthellae, the microscopic algae that live inside them and make up most of their food. This is why most corals grow in shallow, clearer water. The Amazon Reef, on the other hand, was located in deep, turbid waters that were a mix of fresh and salt water.
