Vol. 37 No. 2, 1998

The Involvement of Calcium in Heat-induced Coral Bleaching

Shiao-Ping Huang^1,3, Ku-Lin Lin¹ and Lee-Shing Fang^1,2,*

¹Institute of Marine Resources, National Sun Yat-sen University, Kaohsiung, Taiwan 804
²National Museum of Marine Biology and Aquarium, Preparatory Office, Kaohsiung, Taiwan 800
³Department of Medical Technology, Foo-Yin Institute of Technology, Kaohsiung, Taiwan 831

Shiao-Ping Huang, Ku-Lin Lin and Lee-Shing Fang (1998) Coral bleaching is inducible by elevated sea water temperature. At the subcellular level the mechanism of bleaching is unclear. We investigated the relationship between intracellular calcium concentration and bleaching induced by elevated temperature. Intracellular calcium concentration rose in proportion to the duration of heat treatment. Bleaching was inhibited after applying the calcium chelator EGTA and the cation ionophore A23187 to deplete extra- and intracellular calcium concentrations. Further, heat-induced coral bleaching was inhibited when the ambient calcium concentration in sea water was reduced or depleted. The extent of bleaching was correlated with the calcium concentration of the sea water. These findings indicate that calcium plays a pivotal role in the subcellular mechanism of coral bleaching.

Key words: Coral bleaching, Calcium concentration, Exocytosis.

*Correspondence: -