Acclimatisation through changes in zooxanthellae

Early on in life, most corals take up several kinds of zooxanthellae. Later, though, one type usually comes to dominate the tissues while the other types persist at very low densities. However, after a coral has bleached, some of the low density zooxanthella types - in particular the ones that have a higher bleaching tolerance threshold - are still healthy and may be able to increase their densities, a process called ‘symbiont shuffling’.

As a consequence of symbiont shuffling, the coral can undergo a change in its physiological tolerances, including its upper temperature tolerance limit.

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Bleaching tolerance and adaptation

March 17, 2008