Assessment of coral reef resilience patterns in response to local stressors and climate change at Gorgona Island, Colombia

Abstract

Scleractinian corals are steno-tolerant due to their preference for warm, clear, shallow, and fully saline waters. However, it can also exist outside this range, inhabiting extreme ambient conditions. It has been proposed that at extreme environments, corals can adapt to climate change. The Eastern Tropical Pacific region is recognized as an extreme environment for coral reef development. The largest coral reefs in the Colombian Pacific occur at Gorgona Island, and these reefs have shown remarkable recovery from past El Niño events, and they have not experienced significant bleaching in recent warming events. To provide insights into the resilience capacity of coral reefs on Gorgona Island, this research aims to identify the physiological mechanisms in Pocillopora corals when they face local and global stressors. Through laboratory and field experiments, coupled with environmental monitoring, some traits in the corals were identified that aided in explaining the resilience of pocilloporid reefs. The first study in this research assessed the effect of deoxygenation (a global stressor) on Pocillopora capitata and the coral reefs of Gorgona Island. The second study evaluated the physiological changes that occur in Pocillopora when they face cool temperatures and hypoxia, conditions that occur during upwelling events (a regional stressor). The last study evaluated the resistance and resilience capacity of Pocillopora damicornis to local stressors (low salinity and sediments) using a reciprocal transplant experiment between two neighboring reefs, that differ in their distance from shore.