Photograph: © SAF
Excerpts;
Scientists have predicted that ocean temperatures will rise in the equatorial Pacific by the end of the century, wreaking havoc on coral reef ecosystems.
But a new study shows that climate change could cause ocean currents to operate in a surprising way and mitigate the warming near a handful of islands right on the equator. As a result these Pacific islands may become isolated refuges for corals and fish.
Here’s how it would happen, according to the study by Woods Hole Oceanographic Institution scientists Kristopher Karnauskas and Anne Cohen, published April 29 in the journal Nature Climate Change.
At the equator, trade winds push a surface current from east to west. About 100 to 200 meters below, a swift countercurrent develops, flowing in the opposite direction. This, the Equatorial Undercurrent (EUC), is cooler and rich in nutrients.
When it hits an island, like a rock in a river, water is deflected upward on the island’s western flank and around the islands. This well-known upwelling process brings cooler water and nutrients to the sunlit surface, creating localized areas where tiny marine plants and corals flourish…
Photo courtesy of: © Andrew Jalbert
