[Coral-List] Culture conditions suitable for optimal growth of zooxanthellae

[SIVIWE ELVIS]

Dear colleagues

I would like to find advice and suggestion on the culture conditions suitable for optimal growth of zooxanthellae (zoox) and please kindly share if you have some experience on this. I have already started a culture of zoox isolated from both Pocillopora verrucosa and Anomastraea irregularis, which were collected from the wild, intertidal rocky pool and maintained in aquaria for a week before zoox were isolated (using media).

The culture condition is not my focus but the idea is to learn and understand better the morphological and physiological (pigments, photosynthesis, etc.) response of the zoox to heat stress associated with increasing temperature and light intensity. I am hoping I will also be able to know the threshold of these two stressors and if time allows, identify types or clades of zooxanthellae found the two corals species. A comparison may also be made to holobiont experiment, when zoox are inside coral polyp tissues in response to the same levels of stressors in the aquarium.

The culture conditions maintained include temperature (26 °C) and light using GrowLux® fluorescent tubes, closer to the culture flasks; use of orbital shaker for mixing culture within flasks. The main concern I have is my zoox cultures are taking too long to pick up growth and reach exponential growth phase though one can see little colour changes and tiny cells under microscope, and this is a third week introduced to F/2 medium, which I can see most researchers have successfully used; I even made a parallel zoox culture using BG11 medium in 500 mL Erlenmeyer flasks. Very nice-looking images were taken under microscope immediately after zoox were isolated from corals and I plan to start with experimental treatments once these cultures become denser, with cells doubling.

Any input or comments in this regard will be highly appreciated.

Thank you

Best regards

Siviwe Babane (MSc Marine Biology student)

University of KwaZulu Natal (UKZN)
College of Agriculture, Engineering and Science
School of Life Science
Biological Science Department
Westville, University road
Durban
4000