What is occurring during coral bleaching?

• A. Corals reproduce rapidly
• B. Corals regenerate their tissues
• C. Corals expel symbiotic algae due to elevated ocean temperatures
• D. Corals grow larger due to increased nutrient availability

Answer: (C)

During coral bleaching, corals expel the symbiotic algae known as zooxanthellae due to elevated ocean temperatures. These algae live within coral tissues and provide essential nutrients through photosynthesis, contributing to the vibrant colors of corals and helping them thrive. When water temperatures rise, which can result from climate change or other environmental stressors, corals become stressed and expel these algae. This loss can lead to the corals appearing white or "bleached," and without the algae, the corals are deprived of a crucial food source. As a result, prolonged bleaching can lead to coral starvation, decreased growth rates, and increased vulnerability to disease, ultimately threatening coral reef ecosystems.