What happens to species that can migrate, such as corals?
Corals have a hard time during the more intense events. In 1982/83 (a very strong event) many of the coral species of the Galapagos Islands were killed in large numbers. Fifteen years later in 1997/98 many of the previous survivors perished as well. Many coral species depend on a symbiotic relationship they have with algae-like species (called zooxanthellae) that live in the gastrodermal tissues of the corals and increase the availability of food. When the water warms too much, the zooxanthellae disappear; the white color of the coral skeleton ceases to be obscured by the darker zooxanthellae and the corals are said to “bleach”. If the waters remain warm for too long, the prolonged bleaching stresses the coral metabolism to the breaking point and they die. The good news is that corals are capable of re-establishing themselves in decimated areas, possibly after several years, by means of immigrating larvae from distant surviving populations.
