Why Olive Ridley Turtles Travel Hundreds of Kilometres to One Spot in the Ocean |
Far out in the Bay of Bengal, to the east of Sri Lanka, the ocean rearranges itself every year.
The surface seems ordinary. But beneath it, cold, nutrient-rich waters rise, pushing upwards like a swelling dome. For a brief window between May and September, this patch of sea turns into one of the most active feeding zones in the Indian Ocean.
Scientists call it the Sri Lanka Dome.
And for Olive Ridley turtles, it has become a destination.
Recent satellite tracking has revealed that turtles nesting along India’s eastern coastline are not dispersing randomly into the ocean, as once believed. They are travelling with purpose, crossing hundreds of kilometres to gather in this single, food-rich zone.
The question is no longer where they go. It is why they all go here.
To understand the pull of the Sri Lanka Dome, scientists point to a powerful process: upwelling.
Think of it as an underwater fountain.
Winds and ocean currents interact in a way that lifts deep, cold water towards the surface. As it rises, it carries nutrients that have remained locked in the depths. When these nutrients meet sunlight, they trigger a surge in plankton — tiny organisms that form the base of the marine food chain.
This bloom sets off a cascade. Small fish arrive to feed, and what was once open water becomes a concentrated feeding ground.
The Sri Lanka Dome forms annually, usually beginning in May, strengthening through July and August, and fading by September.
As it intensifies, it draws in a wide range of marine life — fish,........