Natural History of Long Island

L. Candela
A beautiful autumnal scene from the Bethpage Village Restoration.

Long Island was not always the small suburban area it is now. It took thousands of years to create the little island we live on today. Numerous natural events occurred to form the shape of Long Island, it's terrain, and it's environment. Long Island has a fragile ecosystem. If we don't care and protect our habitat, our waterways and lands will become very polluted.

Long Island was not always the separate piece of land it is today. Originally, it's base was part of Southern Connecticut, which slid under Long Island. The middle layer was formed during the age of the dinosaurs as a result of deposits left by ancient rivers. These deposits were sand, clay, and gravel. The top layer of Long Island was made by large sheets of ice called a glaciers. These glaciers were formed when snow fell but it was too cold to melt, which created blocks of ice. The first glacier came 60,000 years ago and was followed by another glacier 21,000 years ago.

The first glacier, which occurred 60,000 years ago, was the Wisconsian Glacier. It moved south across Canada and Northern America. It sharpened peaks of mountains, carried boulders, rocks, gravel, and soil in a frozen wall of ice hundreds of feet high. Large amounts of debris were deposited in mounds of hills stretching from Brooklyn to Montauk. This area is known as the Ronkonkoma Terminal Moraine. This glacier also created great rivers, making vast flatlands from the moraine to the Atlantic Ocean. This was the Hempstead Outwash Plain.

Temperature affected the creation of Long Island greatly. In the Northern Hemisphere warm and cold temperature gaps lasted tens of thousands of years. After the first movement of the glacier, it melted back. The sea level rose, most likely separating Long Island from the mainland.

About 40,000 years later, the climate cooled again. The glacier advanced to almost the same position, staying along the North Shore. When it began to melt, another moraine was deposited. This ridge runs from Brooklyn Heights to Orient Point. Because of the reappearance of the glacier, Long Island is not completely hilly like the North Shore nor completely flat like Mid-Island area. Instead Long Island is a combination of both surfaces.

The Wisconsian Glacier created many different land forms. Geologists think that ice projecting out of the wall of a glacier carved the deep indents of the North Shore, such as Oyster Bay and Cold Spring Harbor. The debris from this area was deposited on the peninsulas such as Great Neck and Manhasset Neck. The glacier also created lakes, gullies, and added boulders to Long Island. Lakes and ponds were made by huge amounts of glacial ice that later melted.

The way in which Long Island was formed resulted in two different terrains. The North Shore contains many bays, harbors, especially in the western section (separated from one another by wooded peninsulas called "necks"). Small, irregular hills with swamps and ponds fill the areas in between. On the other hand, the South Shore was a flat outwash plain, which is now made of mainly sand and gravel and gradually slopes to the sea. From Rockaway to Montauk Point is seventy five miles of sandbars and beaches with several inlets. The difference in the island's geography was a result of only the North Shore being covered with ice.

The Long Island Sound has a history too. Small islands were created to serve as a buffer between the mainland and ocean storms. These storms created salt water lagoons. The growth of salt marshes served as a breeding ground for vegetation and sea creatures. The barrier islands enriched the bay floors and shoreline and brought nutrients for the marine life. The shores of Long Island produced shell fish for early inhabitants.

Long Island Sound, a once productive place for life has many environmental problems. Most of the pollution that is deposited in the Sound comes from Long Island and Connecticut. As a result of pollution, much of the Long Island Sound has acquired a disease called hypoxia. Hypoxia is a lack of oxygen in the water. It occurs when too many nutrients, such as nitrogen in fertilizer and human waste, cause algae to bloom. This algae draws off all the oxygen from the water. Hypoxia, sewage spills, and overdevelopment along the shores result in closed beaches, massive fish kills, and decreasing marine life.

Long Island gets its water from underground reservoirs. It all begins when rain and snow seep into the soil and flow through layers of sand, gravel, and clay, called aquifers. These aquifers make up Long Island's underground reservoir. The ground water flows through the reservoir at speeds averaging one foot per day. Water at the top of the reservoir fills the island's rivers and streams. Some of the water flows down and outward taking from twenty five to one thousand years to pass beyond the reservoir and merge with the salt water that surrounds the water. The rest of the water that flows downward is the source of most of the island's drinking water. Thousands of wells tap the reservoir and pump more than four hundred million gallons per day.

Long Island underwent many natural events that made it what it is today. It took thousands of years to create the present habitat that people and animals occupy. It is still a beautiful place, but people need to pay attention to the needs of the environment.

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