Long Island Sound

Long Island Sound is a big area of water.

It sits between New York and Connecticut. It has salt water from the sea. It also has fresh water from rivers.

A long time ago, a giant ice sheet covered it. The ice made many islands and beaches. Now, many plants grow in the water. Green seaweed and tall grasses live there too. It is a busy place for sea life.

Long Island Sound is a large body of water.

It sits between Connecticut and Long Island. It is a tidal estuary. This means it mixes fresh water from rivers with salt water from the ocean.

Long ago, a giant ice sheet covered this area. This was part of the Late Wisconsin Glacier. The ice was very thick. As the ice moved, it scraped the land. It left behind piles of dirt and rocks called moraines. These moraines helped make the islands we see today. Before the ocean moved in, this area was a fresh water lake. We call this Lake Connecticut. About 8,000 years ago, the sea level rose. Salt water flowed into the basin. This changed the lake into a salty arm of the sea.

Many plants live in the water. Eelgrass grows in shallow, muddy areas. It looks like grass but is a different kind of plant. Its roots help hold the mud in place. This stops erosion, which is when soil washes away. Salt marshes also grow along the edges. These marshes are very busy places for sea life.

Long Island Sound is a large marine sound and tidal estuary.

It sits between the state of Connecticut to the north and Long Island in New York to the south. This body of water is a mix of fresh water and salt water. Fresh water flows in from many rivers, while salt water comes from the Atlantic Ocean. It stretches from the East River and the Throgs Neck Bridge in New York City to the Block Island Sound. This area is a very important part of the Intracoastal Waterway.

This place was shaped by giant ice sheets a long time ago. About 18,000 years ago, the Late Wisconsin Glacier covered this whole area. The ice was very thick in its middle and along its southern edge. As the ice moved, it scraped material off the land. It left behind piles of dirt and rocks called drift. These deposits created moraines, which are long ridges of land.

Some of these are the Ronkonkoma Moraine and the Harbor Hill Moraine. These ridges helped form the shape of Long Island.

Before the ocean arrived, the basin was a fresh water lake. We call this Lake Connecticut. Glacial meltwater from streams filled the basin with sand and gravel. This material is called outwash. About 8,000 years ago, the sea level rose. The water rose to about 20 meters below today's level. Then, salt water from the sea overflowed into the basin. This changed the fresh water lake into a salty, tidal arm of the sea.

Many different plants live in the Sound. Eelgrass grows in shallow, muddy areas. It looks like grass, but it is actually a different kind of plant. Its roots help hold the mud in place to stop erosion. Salt marshes are also very busy places. They produce three to seven tons of plants every acre each year. These marshes are full of salt marsh grasses. They help create many fish and shellfish in the water.

Many cities and towns live along the shores of the Sound. In Connecticut, cities include Stamford, Bridgeport, and New Haven. On the New York side, towns include Rye, Glen Cove, and Smithtown. The watershed, which is the land that drains into the Sound, is very large. It includes parts of New York, Connecticut, Rhode Island, Vermont, New Hampshire, and Massachusetts. As of the 2010 census, about 8.93 million people live in this watershed.

Long Island Sound is a marine sound and a tidal estuary of the Atlantic Ocean.

It is located primarily between the U.S. state of Connecticut to the north and Long Island in New York to the south. The water is a complex mix of freshwater and saltwater. Freshwater enters the sound through many different tributaries and rivers. Saltwater flows in from the Atlantic Ocean. This combination of waters makes the sound a productive environment. It stretches from the East River and the Throgs Neck Bridge in New York City all the way to the Block Island Sound.

The geography of the sound was shaped by massive ice sheets. About 18,000 years ago, the Late Wisconsin Glacier covered this entire region. This glacier was very thick in its interior and along its southern edge. As the ice moved, it scraped surface material from the New England landscape. The glacier then deposited this material, called drift, into the area. This process created several long ridges known as moraines. One major ridge is the Ronkonkoma Moraine, which stretches along southern Long Island. Another is the Harbor Hill Moraine, located along northern Long Island.

Smaller deposits also created recessional moraines along the Connecticut coast. These include the Norwalk area and the Madison-Old Saybrook area. These moraines are smaller and more discontinuous than the southern ones. Some islands, like the Captain Islands, are actually parts of a recessional moraine. Other areas, like the Thimble Islands, consist mostly of exposed bedrock with thin drift. The glacier also left sandy outwash deltas off the coast near Bridgeport and New Haven. These deltas were formed by meltwater streams carrying sand and gravel into the basin.

Before the ocean arrived, the basin was a freshwater body. It was likely formed by ancient stream flows. Glacial meltwater eventually filled the basin to create a lake called Lake Connecticut. This lake stayed freshwater until about 8,000 years ago. At that time, the sea level rose to about 20 meters below its current level. Eventually, seawater overflowed into the basin. This process transformed Lake Connecticut from a nontidal, freshwater lake into a tidal, saline arm of the sea. A ridge called the Mattatuck Sill sits on the west side of the basin. Its lowest point is about 10 meters below sea level.

The sound is home to many different types of plants and seaweeds. In the rocky intertidal zone, you can find brown seaweeds like Fucus and Ascophyllum. Some of these have air bladders to help them float toward sunlight. In the subtidal zone, which is below low tide, large kelp can grow. Some kelp specimens can reach a yard or two in length.

Tidal marshes are also very important. These marshes produce between three and seven tons of vegetation per acre every year. This growth comes mostly from salt marsh grasses. When this plant matter decomposes, it provides nutrients for fish and shellfish.

One very important plant is eelgrass, also called saltwater eelgrass. It is a vascular plant that looks like grass but is a different species. Eelgrass grows in protected bays and coves on muddy or sandy sediments. It grows best in shallow water because it needs sunlight. The roots of the eelgrass help stabilize the mud and trap moving sand. This helps prevent erosion along the shoreline. Eelgrass also provides a calm habitat for many invertebrates and food for waterfowl like brant geese. However, an outbreak of eelgrass wasting disease in the 1930s killed much of the population.

Many people live in the large watershed that drains into the sound. The watershed includes parts of New York, Connecticut, Rhode Island, Vermont, New Hampshire, and Massachusetts. As of the 2010 census, about 8.93 million people live in this area. Numerous rivers flow into the sound, such as the Connecticut River and the Housatonic River. Major cities like Stamford, Bridgeport, and New Haven sit along the Connecticut shore. On the New York side, towns include Rye, Glen Cove, and Smithtown. This large network of rivers and land makes the sound a vital part of the regional ecosystem.