657 new islands discovered

Barrier islands are found along all continents except Antarctica and in all oceans, and they make up roughly 10 percent of the Earth's continental shorelines, it said.  The newly identified barrier islands didn't miraculously appear in the last decade. They've long existed but were overlooked or misclassified in past surveys, the Monitor quoted study team member Matthew L. Stutz of Meredith, as saying.

Scientists believed barrier islands couldn't exist in locations with seasonal tides of more than 13 feet.  Yet the new survey identifies the world's longest chain of barrier islands along a stretch of the equatorial coast of Brazil, where spring tides reach 23 feet, the Monitor noted.

The 54-island chain extends 571 km along the fringe of a mangrove forest south of the mouth of the Amazon river.  Past surveys didn't recognize it as a barrier island coast partly because older satellite images didn't show a clear separation between the islands and mangrove, says Stutz.

The findings illustrate the need for a new way to classify and study barrier islands, so that scientists can predict which of today's islands might be in danger of disappearing in the near future, the researchers say.

Unlike stationary landforms, barrier islands build up, erode, migrate and rebuild over time in response to waves, tides, and other physical processes in the open ocean environment. They help protect low-lying mainland coasts against erosion and storm damage, and can be important wildlife habitats.

The study was published in the March edition of the Journal of Coastal Research, according to the Monitor Tuesday.