การตอบสนองของปะการังต่อการเพิ่มขึ้นของอุณหภูมิและแสง

Abstract

Coral bleaching events in global and regional scales have seriously affected on coral mortality and their ability to recover. There is spatial variability in bleaching response in Thai’s water reefs based on their thermal history or environmental conditions. In cellular scale, coral and its zooxanthellae would be able to adapt or resist to environmental conditions such as higher sea surface temperature and light. The aim of this study was to investigate the effects of elevated temperature and light on photosynthesis and growth of zooxanthellae from different environmental conditions and Study the trend of coral recovery when exposed to light stress and increased temperature of Pocillopora acuta. Coral nubbins from different environmental condition, Maiton Island and Panwa Cape, Phuket, Thailand were collected and exposed to two experimental sets: increasing of temperature and light response experiment and limiting of temperature experiment. The results showed that synergistic effects of stress were observed on P. acuta from both sites decreased photosynthesis performance, loss of zooxanthellae association and reduction of chlorophyll concentration, especially HTAL, HTHL and 33ºC treatments. They were always elevated temperature which was the main factor affecting coral and minor factor was light. In addition, coral growth was gradually reduced, weakened, discolored and some corals nubbins were covered with algae, especially, coral nubbins from Maiton Island. However, coral nubbins from Panwa Cape showed an ability to recover when temperature was reduced. Therefore, we suggested that corals from Panwa Cape was more resistant than Maiton Island under same stressors leading to difference capacity to survive after coral bleaching event.