This intimate portrait of algae (red) living within the tentacles of its host, a sea anemone (green outline), shows the mutually beneficial connection between plant and animal. The algae use energy from sunlight to make sugars from carbon dioxide and water and give up to 90 percent of this sugar to their host, in this case the anemone.
The relationship is important for productive and diverse ecosystems in coral reefs. The breakdown of their dynamic can result in the collapse of entire reef ecosystems. Understanding the cell biology that occurs throughout the relationship may offer clues to maintaining coral reef health.