Sedimentation from coastal development can cause significant damage to coral reefs by blocking sunlight and smothering the corals.

Coastal development often involves activities such as dredging, land reclamation, and construction, which can lead to increased sedimentation in the surrounding waters. This sediment can be carried by currents and deposited on nearby coral reefs. Coral reefs are delicate ecosystems that rely on clear, clean water for their survival. They need sunlight to enable the symbiotic algae, known as zooxanthellae, which live within their tissues to photosynthesise and produce food.

When sedimentation increases, it can block sunlight from reaching the corals, thereby reducing the amount of light available for photosynthesis. This can lead to a reduction in the energy available for the corals, which can in turn affect their growth and reproduction. In severe cases, it can lead to coral bleaching, a condition where corals expel the zooxanthellae and turn white. Without the zooxanthellae, the corals can starve and die.

Furthermore, sedimentation can physically smother corals. When sediment settles on the coral, it can clog the polyps, which are the tiny, soft-bodied organisms that make up the coral. This can prevent the polyps from feeding and can cause them to suffocate. Over time, this can lead to the death of the coral colony.

In addition, sedimentation can also affect the other organisms that live within the coral reef ecosystem. For example, it can reduce the availability of food for filter-feeding organisms, and it can affect the survival of coral larvae, which need to settle on clean surfaces to grow.

Overall, sedimentation from coastal development can have a significant impact on coral reefs, affecting their health, survival, and the biodiversity they support. It is therefore crucial to manage coastal development in a way that minimises sedimentation and its impacts on these valuable ecosystems.