Final answer:
A primary requirement for coral reef development is sunlight due to the mutualistic relationship between corals and photosynthetic algae. Corals thrive in shallow waters, forming structures essential for marine biodiversity and coastal protection, with significant economic importance from tourism.
Step-by-step explanation:
A primary requirement for coral reef development is the presence of sunlight, which is crucial because the corals form a mutualistic relationship with photosynthetic algae, known as zooxanthellae. These algae live inside the coral polyps and require sunlight to perform photosynthesis, thereby providing energy to the coral. Therefore, corals are usually found in shallow waters where sunlight can penetrate, typically not deeper than 20 meters. Coral reefs are also composed of calcium carbonate structures secreted by the corals, which accumulate over time to form the reef ecosystem. These reef structures provide essential habitats for diverse marine life and protect shorelines from erosion.
Coral reefs are not only important for the marine ecosystem but also have significant economic importance due to tourism and coastal protection. The threat of coral bleaching, a process where the coral loses the symbiotic algae and often leads to the death of the coral, highlights the sensitivity of coral reefs to environmental changes and the need for conservation efforts to protect these vital ecosystems.