Coral Triangle

node · earth · Western Pacific and eastern Indian Ocean

The tropical marine region spanning Indonesia, Malaysia, the Philippines, Papua New Guinea, Timor-Leste and the Solomon Islands, and the global centre of shallow-marine biodiversity. Its significance is quantitative and precise: a 2009 delineation found that 605 of the world's roughly 800 zooxanthellate coral species — about seventy-six per cent — occur within it, a concentration no other reef region approaches. The region is commonly given as roughly six million square kilometres. Why diversity peaks here rather than elsewhere is still argued: candidate explanations include the area's long geological persistence as shallow habitat through sea-level cycles, its position at the confluence of Pacific and Indian Ocean faunas, and the sheer number of islands generating and retaining local endemics. The Triangle matters to this Journey for a reason beyond biodiversity accounting. It is where the largest number of people depend directly on reef fisheries, and where reef loss is a food-security question before it is a conservation one.