[Coral-List] abrupt cooling of corals during high tides

[jahangir vs]

Dear friends,
 
This summer, I observed a thermal phenomenon in the coral reef of Hengam Island, Persian Gulf (at 5-7 meters depth) which seems to be influential on coral thermal tolerances. These were abrupt decrease in water temperature up to 5 C only during big high tides (tidal height of more than 2.5) two times a day (semi-diurnal tidal regime). Usually these cooling periods, take about 3 hour (from 33.5 to 28.5 to 33.5 C). These abrupt changes did not happened in other seasons. Although diurnal changes in water temperature in shallow parts of coral reefs is common but yet i did not find any similar example of abrupt cooling resulted from high tides in the literature.
 
Please contact the list or my emails if you have any information about a similar phenomenon at your or other study sites.

Best Wishes,
Jahangir
 
Jahangir Vajed Samiei
MSc. of Marine Biology
Marine Biology Lab
Iranian National Institute for Oceanography (INIO)

website: http://www.inio.ac.ir/
Another e-mail: jvajedsamiei at inio.ac.ir
Cell phone: 00989192459404