Coral Acclimatization to Disturbance

Abstract

Offshore reefs (Similan Islands, Thailand) and near-shore reefs (Cahuita, Costa Rica and Hainan, China) under disturbance are investigated. Coral reefs along the west sides of the Similan Islands are naturally affected by Large Amplitude Internal Waves (LAIW), while reefs on the east sides are only impacted to a lower extend. LAIW frequently introduce cold, oxygen depleted, CO2- and nutrient-rich deep water into the reefs which strongly impacts the metabolism of corals. On the other hand, the near-shore reefs under investigation are exposed to anthropogenic impacts. A decrease in live coral cover and biodiversity in the reefs of Costa Rica, and an initiating phase shift from a coral to an algae dominated reefs in Hainan indicate the serious disturbance to these ecosystems. Increasing anthropogenic pressure will inevitably lead to their collapse. In contrast to the pulsed disturbances by LAIW, the chronic land based disturbances are permanently increasing and therefore an acute risk.