Sciences marines : recherche et développement

Abstrait

Global Warming and Human Pollution as the Major Causes of Coral Bleaching

Robyn Hannigan

Coral bleaching occurs while corals degrade or expel their dinoflagellate symbionts in reaction to environmental stressors inclusive of expanded sea floor temperature and elevated UV radiation[1]. Although corals can reacquire symbionts and recover in weeks to months, recovered corals may also grow slower and feature decreased fecundity in comparison to formerly unbleached corals, giving bleaching-resistant corals an ecological benefit after bleaching events. In extreme cases, bleaching may also arise on the scale of hundreds to thousands of kilometres and radically modify coral cover and composition with coral mortality from bleaching events approaching 100% in extreme cases. Branching corals inclusive of acroporid and pocilloporid corals are often more susceptible to bleaching and mortality than are massive corals, allowing the slowerdeveloping huge corals to be extra chronic on reefs after bouts of robust bleaching [2]. Bleaching occasions now no longer only lower live coral cover however additionally offer large areas for seaweed colonization, and these seaweeds can prevent corals from re-establishing if herbivores aren’t present in enough numbers to suppress seaweed colonization and growth. Additionally, large-scale bleaching and mortality of branching corals can suppress fish populations that are dependent on live coral for shelter and food.