Long Island Sound is a marine sound and tidal estuary of the Atlantic Ocean. It lies predominantly between the U.S. state of Connecticut to the north and Long Island in New York state to the south. From west to east, the sound stretches from the East River and the Throgs Neck Bridge in New York City, along the North Shore of Long Island, to Block Island Sound. The sound forms part of the Intracoastal Waterway.
A mix of freshwater from tributaries, and saltwater from the Atlantic Ocean, Long Island Sound is at its widest point and varies in depth from .
Shoreline cities
Major Connecticut cities on the sound include Stamford, Norwalk, Bridgeport, New Haven, and New London. Cities and towns on the New York side of the sound include Rye, Glen Cove, New Rochelle, North Hempstead, Oyster Bay, Smithtown, Port Jefferson, Brookhaven and Riverhead, Larchmont, Mamaroneck and portions of Queens and the Bronx in New York City.
Climate and geography The climate of Long Island Sound is warm temperate or Cfa in the Köppen climate classification. Summers are hot and humid often with convective showers and strong sunshine, while the cooler months feature cold temperatures and a mix of rain and occasional snow.
Glacial history
About 18,000 years ago, Connecticut, Long Island Sound, and much of Long Island were covered by a thick sheet of ice, part of the Late Wisconsin Glacier. About thick in its interior and about thick along its southern edge, it was the most recent of a series of glaciations that covered the area during the past 10 million years. Sea level at that time was about lower than today."Long Island Sound: An Atlas of Natural Resources", booklet"Prepared under the supervision of the Coastal Area Management Program" of the Connecticut Department of Environmental Protection, November 1977, "1. Glacial History" section, page 4
The continental ice sheet scraped off an average of of surface material from the New England landscape, then deposited the material (known as drift) from the Connecticut coast into the sound, creating what is now Long Island (the terminal moraine). When the ice sheet stopped advancing 18,000 years ago (as addition of snow at the origin was in equilibrium with the melting at the southern edge), a large amount of drift was deposited, known as the Ronkonkoma Moraine, which stretches along much of southern Long Island. Later, another period of equilibrium resulted in the Harbor Hill Moraine along most of northern Long Island. The next moraines (recessional moraines) to the north were created just on and off the Connecticut coast. These moraines, created by much smaller deposits (probably from equilibrium states that were much shorter in time) are discontinuous and much smaller than those to the south. The Connecticut coast moraines are in two groups: the Norwalk area and the Madison-Old Saybrook area. Sandy plains and beaches resulted from the erosion of moraines and redeposition in these areas, and to the east of each, where the drift cover is thinnest, exposed bedrock, creating rocky headlands, often with marshlands behind them.
The Captain Islands off Greenwich, Connecticut, along with the Norwalk Islands and Falkner Island off Guilford, Connecticut, are parts of a recessional moraine. Other islands, including the Thimble Islands, are for the most part exposed bedrock with a thin amount of drift, often not continuous. Other shoals and islands off the Connecticut coast are a mixture of these two extremes. The glacier also created several sandy outwash deltas off the coast, including one off Bridgeport, Connecticut, and another off New Haven, Connecticut. Fishers Island, New York, appears to be related to the Harbor Hill Moraine. To the east of the Thimble Islands, inland moraines along the Connecticut coast include the broken Madison Moraine and the Old Saybrook Moraine.
The Long Island Sound basin existed before the glaciers came. It probably had been formed by stream flows. A relatively thick cover of sand and gravel (termed outwash) was left in the basin from glacial meltwater streams. On the west, a ridge rising to about below the present sea level is called the Mattatuck Sill. Its lowest point is about below sea level. Glacial meltwater formed "Lake Connecticut", a freshwater lake in the basin, until about 8,000 years ago, when the sea level rose to about below today's level. Seawater then overflowed into the basin, transforming it from a nontidal, freshwater lake to a tidal, saline arm of the sea.
Rivers
Numerous rivers empty into the sound, including:
Connecticut Connecticut River - Old Saybrook Housatonic River - Stratford & Milford Mianus River - Greenwich Mill River (Quinnipiac River) - New Haven Mill River (Fairfield) - Fairfield Norwalk River - Norwalk Pequonnock River - Bridgeport Quinnipiac River - New Haven Rooster River/Ash Creek - Bridgeport & Fairfield Rippowam River - Stamford Saugatuck River - Westport Thames River (Connecticut) - Groton & New London West River (Connecticut) - West Haven
New York Byram River - Port Chester Hutchinson River-The Bronx Mamaroneck River - Mamaroneck Nissequogue River - Nissequogue & Ft Salonga
Rhode Island Pawcatuck River
Watershed demographics The whole watershed population is about 8.93 million as of the 2010 census. Due to extent of the Connecticut River, many riverside cities and towns are included in the Long Island Sound watershed. The largest towns and cities from south to north, west to east are:
New York Huntington Oyster Bay Smithtown Parts of these New York City boroughs: The Bronx Queens Brooklyn Port Chester Rye (city), New York
Connecticut Stamford Bridgeport New Haven New London Danbury Waterbury Norwich Willimantic Torrington Hartford
Rhode Island Westerly
Massachusetts Springfield Worcester Pittsfield
Vermont Brattleboro White River Jct.
New Hampshire Keene West Lebanon
Fauna and flora
Flora
Seaweed Seaweeds in the sound occur in greatest abundance in rocky areas between high tide and low tide as well as on rocks on the sea floor. Green seaweed populations fluctuate with the seasons. Monostroma, reproduces in the early spring and dies out by late summer. Grinnellia appears in August and disappears four to six weeks later."Long Island Sound: An Atlas of Natural Resources", booklet"Prepared under the supervision of the Coastal Area Management Program" of the "Connecticut Department of Environmental Protection", November 1977, "5. Vegetation" section, pp 17-21
In the rocky areas of the intertidal zone there are the seaweeds characterized by their brown tone, Fucus and Ascophyllum, some species of which have air bladders that allow them to float and receive direct sunlight even at high tide. Also present are Ectocarpus and red algae Polysiphonia, Neosiphonia, Porphyra and Chondrus (Irish moss).
In the marshy areas of the intertidal zone can be found Cladophora (mermaid's hair), Ulva (sea lettuce) and Codium.
In the subtidal zone (below low tide) are Palmaria palmata a red alga, along with two algae, Laminaria (kelp) and Chorda. Kelp can often be found washed up on the beach, and individual specimens are not uncommonly a yard or two long. Deeper in the subtidal zone are red algae such as Spermothamnion, Antithamnion and Callithamnion, which also often float freely.
In tidal pools can be found red or pink colored Phymatolithon, which can often encrust rocks and mollusk shells. Also present are green algae, including Ulothrix, Cladophora, and Ulva.
Plants found in tidal marshes Tidal marshes are some of the most productive biological systems in the world. Along the sound, they produce three to seven tons per acre per year of vegetation, largely in the form of salt marsh grasses. Much of this, enriched by decomposition, is flushed yearly into the estuary water where it directly contributes to the great finfish and shellfish production of the sound.
Salt marsh plants
Salt marshes host salt water cordgrass (Spartina alterniflora) along ditches and on the seaside edges of marshes where high tides daily inundate it. Salt meadow cordgrass (Spartina patens) and spikegrass (Distichlis spicata) grow in areas less frequently inundated by saltwater, typically closer to dry land. A short form of salt water cordgrass can sometimes be found in the depressions (pannes) in the higher areas where salt water collects and evaporates, leaving water even higher in salinity than seawater.
Other plants in the pannes are sea lavender, salt marsh aster, seaside gerardia, and some species of glasswort. Plants found near the border of the marsh with the upland include bayberry and groundsel-tree shrubs, switchgrass (growing where occasional storm tides reach), reeds and marsh elder.
Cattail marshes cattail marshes replace salt marshes in areas where the sound's salt water is more diluted with freshwater from rivers, including along the shores of the larger river estuaries such as the Connecticut River. Various types of grasses, including wild rice, and sedges, including bulrushes, are found here.
Eelgrass meadows Eelgrass - sometimes known as "Saltwater Eelgrass" in order to distinguish it from Freshwater Eelgrass, which is a different species (Vallisneria americana) - is typically found in protected bays, coves, and other areas of brackish water, but it also persists along areas of exposed shoreline along Long Island's north shore near Orient. Eelgrass is one of the few vascular plants found in the marine environment. Despite its name, it is actually not a species of underwater grass; instead, it is a plant that bears a physical resemblance to grass. It can tolerate a wide range of water salinity. It grows on muddy to sandy sediments (even among rocks), mostly below low tide, often forming large meadows. it grows best in shallow water because it is dependent upon sunlight, and the water of the Long island Sound can be very murky. Eelgrass roots help stabilize muddy sediments and can trap moving sand, helping prevent erosion. The leaves, which can range in size from less than 1 m to 2 m long, slow currents, providing calm environments for many species of mollusks and other invertebrates. Eelgrass is also an important food source for waterfowl, especially brant, a type of goose. During the 1930s, the Long Island Sound was struck by an outbreak of a mold infection known as "eelgrass wasting disease". As a result, most of the eelgrass that grew in the sound was killed off, and as an extension, populations of wildlife in the area that depended upon the eelgrass either as food or as a habitat went into a sharp decline. During the succeeding decades, areas along the Connecticut coast saw a slow gradual recovery of eelgrass populations. Unfortunately, the north shore of Long Island did not see much success, and efforts have been made to re-introduce eelgrass by planting it, especially in the eastern part of the Long Island Sound in the waters of Suffolk County. It is unlikely that the Long Island Sound will experience a complete recovery of its eelgrass population because there are still occasional outbreaks of eelgrass wasting disease within the sound.
Plants found on beaches and dunes Few undisturbed beach and dune systems exist on the Connecticut shore, the ones that do are located along the eastern portion of the coastline (east of the Connecticut River). Sea rocket and dune grass occur here, but not in abundance. Dune grass and plants that thrive on dunes are largely responsible for the creation and growth of the dunes. On the seaward side of dunes can be found Lathyrus japonicus (beach pea), Dusty Miller, and seaside goldenrod. Other beach plants are orache, beach clotbur, seaside spurge, and jimson weed. On the more protected landward side of dunes are beach plum, bayberry and beach rose. Rare species found on the landward side are beach knotweed and sand false heather.
Upland vegetation