Tropical oceans are known as the deserts of the sea. And yet this unlikely environment is the very place where the rich and fertile coral reef grows. Dutch researcher Jasper de Goeij investigated how caves in the coral reef ensure the reef’s continued existence. Although sponges in these coral caves take up a lot of dissolved organic material, they scarcely grow. However, they do discard a lot of cells that in turn provide food for the organisms on the reef...

Caves in coral reefs are the largest and least well known part of the reef. (Credit: iStockphoto/Charles Humphries)