• Corpus ID: 54974314

Adaptation / Exaptation in the host coral Favites complanata ( Ehrenberg , 1834 ; Scleractinia , Faviidae ) to increased Seawater Temperatures

@inproceedings{Strychar2009AdaptationE,
  title={Adaptation / Exaptation in the host coral Favites complanata ( Ehrenberg , 1834 ; Scleractinia , Faviidae ) to increased Seawater Temperatures},
  author={Kevin B. Strychar and Paul W Sammarco},
  year={2009}
}

• K. Strychar, P. Sammarco
• Published 2009
• Environmental Science

Recent evidence suggests that, as global climate changes and seawater temperatures rise, the primary cause of coral bleaching is zooxantheallar mortality indicated by cell apoptosis/necrosis. But are the coral hosts themselves sensitive to increasing temperatures, and, if so, to what degree? We exposed the coral Favites complanata (Ehrenberg, 1834) with their symbiotic zooxanthellae (Symbiodinium sp.) to experimental temperatures of 28 (control), 30, 32, and 34°C for 12h. We assessed coral and symbiont cells in situ for symptoms of apoptosis and necrosis using transmission electron microscopy (TEM). F. complanata host cells in situ exhibited little or no mortality from exposure to increased seawater temperatures, except at very high temperatures (34°C) for >12hrs. By contrast, we found high levels of apoptosis/necrosis in the zooxanthellae in situ under all experimentally elevated temperatures. These findings indicate that the host corals are adapted/exapted to seawater temperature increases. They also imply that the coral hosts do not suffer mortality from temperature stress but from loss of their symbionts – a process driving natural selection in Symbiodinium and most likely resulting in their rapid adaptation to a changing environment.