Barrier Island Facts

Barrier islands are all over the earth; sometimes they are so large that they have their own barrier islands. Long Island is one such example. While Long Island is technically not a barrier island by common description, the shores of Connecticut are well protected by that long island. Long Island's barrier islands run the length of it along the eastern shore, from New York City to the Hamptons.

From Miami Beach to the Carolinas

Miami Beach is on a barrier island, but on that island, the unique ecosystems that are normally found in this type of environment have been destroyed by overdevelopment. In their natural state, barrier islands host grasses and ground-nesting seabirds that find safety there due to lack of predators.

Further up the Atlantic Coast, in Georgia and the Carolinas, several pristine areas remain devoid of human populations; but on those that are inhabited, a constant battle against the elements rages on. Many houses have been built unwisely in the sand dunes, which are very sensitive, and every time a hurricane hits the area, massive destruction of property occurs.

Scientific surprises

To geologists, the formation of barrier islands is still somewhat of a mystery. It is not known for certain whether they were formed during the last glacial period 18,000 years ago when the glaciers melted and sea levels rose (the currently accepted theory) or if they were formed by wind and ocean currents that, over the ages, deposited sand along the shores that eventually built up.

Since the advent of satellite mapping, researchers at Duke University in North Carolina have spent considerable time going over images taken from space and have discovered that the old accepted figure of 1,492 barrier islands planet-wide was actually wrong by almost half that amount. The new total is 2,149. This figure was arrived at by comparing the high-resolution satellite photos to nautical charts and topographical maps.

A most surprising discovery was a chain of 54 islands near the mouth of the Amazon River in Brazil. This is a particularly sensitive area. It is virtually uninhabited by humans, having given life and shelter to a myriad of creatures and creating its own ecosystem. The recent destruction of large swaths of the Amazonian rainforest for cultivation is endangering this region with silt and fertilizer runoff. These islands, some just a few feet above sea level, are located to the north of the mouth of the Amazon. Because of prevailing currents, the large volumes of this water discharging into the Atlantic Ocean flow northward, possibly endangering the delicate ecological isolation now enjoyed.

World's biggest

Perhaps the biggest island to be called a barrier island is the Great Barrier Island off New Zealand's Hauraki Gulf north of Auckland. It is really an island of volcanic origin, 22 miles long and 12 miles wide, forming a natural barrier to the wild seas encountered outside of the bay.

The United States boasts of the longest barrier island of them all. Padre Island measures 113 miles in length, stretching from near the Mexican border north to Corpus Christi, Texas. The southern part of the island features the tourist destination town of South Padre Island, which is famous for its white sand beaches. The sand there is so finely ground that it almost resembles powder. It follows Long Island as the second largest island in the mainland United States, and the island of Hawaii is about twice as large in area.

Importance of barrier islands

Barrier islands often play the important role of protecting coastal wetlands. Many brackish water environments and systems such as marshes, estuaries and lagoons would not exist without barrier islands blocking storm swells that would destroy their delicate ecologies.

Barrier islands, no matter where in the world they are, create great sanctuaries for a diversity of flora and fauna, and great efforts are being made to preserve them for the sake of future generations.

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