Describe the role of zooxanthellae in coral health.

Zooxanthellae are microscopic algae that live in symbiosis with coral polyps, playing a crucial role in coral health. Their primary function involves photosynthesis; by converting sunlight into energy, they produce carbohydrates that serve as an essential nutrient source for corals. This symbiotic relationship is vital because it allows corals to thrive in nutrient-poor marine environments, as the energy provided by zooxanthellae supports coral growth, reproduction, and the production of calcium carbonate, which forms the coral's skeleton. Without zooxanthellae, corals would struggle to obtain the necessary energy to maintain their complex structures and ecosystems, potentially leading to coral bleaching and diminished health. Thus, the role of zooxanthellae in providing energy through photosynthesis is fundamental to the vitality and resilience of coral reefs.