Last Updated on Wednesday, 29 August 2012 06:52 Written by Administrator Wednesday, 29 August 2012 06:47

657 new islands found, according to an article in ScienceDaily 20 April 2011. Researchers from Duke University and Meredith College have carried out a global survey of coastline and identified a total of 2,149 barrier islands worldwide using satellite images, topographical maps and navigational charts. A previous survey in 2001 had identified 1,492 such islands. As described in ScienceDaily, “Barrier islands often form as chains of long, low, narrow offshore deposits of sand and sediment, running parallel to a coast but separated from it by bays, estuaries or lagoons. Unlike stationary landforms, barrier islands build up, erode, migrate and rebuild over time in response to waves, tides, currents and other physical processes in the open ocean environment”. The researchers do not claim all these extra islands appeared in the last 10 years, but that many may have been overlooked because they are in places where scientists believed they could not exist, such as where seasonal tides are greater than four metres.
The new survey found the world's longest chain of barrier islands on the equatorial coast of Brazil, where spring tides reach seven meters. Orrin Pilkey, Emeritus Professor of Geology at Duke University, explained: "This provides proof that barrier islands exist in every climate and in every tide-wave combination. We found that everywhere there is a flat piece of land next to the coast, a reasonable supply of sand, enough waves to move sand or sediment about, and a recent sea-level rise that caused a crooked shoreline, barrier islands exist".
Link: ScienceDaily