This science unit will map out ways for the primary grade teacher in New Haven to make relevant to their students two distinctly different local geographical areas and the diversity of their indigenous wild life and geology. This unit will be designed to help small children make sense of the world around them and gain a perspective of their place in it.
Freshwater river habitats will be compared to saltwater coastal environments through the study of the wetlands of East Rock Park and the wetlands and coast of Lighthouse Point Park. We will focus in on comparisons between freshwater habitats, using the Mill River as an example, and salt water habitats, using Long Island Sound as a reference. We will compare how each unique aquatic environment provides habitats for very specific life forms. This unit will help make clear to a young mind the reasons for the differences and similarities between these two unique environments and will lay the foundation for further investigation into their own accessible surroundings.
Parks are critical open areas in our city, the city dweller’s primary contact point with the “natural” environment. As children and adults who live in the city are more removed from their natural surroundings by concrete and asphalt, a need for environmental education is more critical than ever. In our city of New Haven, I have selected two distinct parks to cover in this unit. Both parks are unique in their own flora, fauna, and geology. Both parks contain aquatic environments which support wild animals that depend upon the aquatic environments for survival. Aquatic environments may be freshwater, such as rivers, lakes, ponds, streams and freshwater marshes; or saltwater, such as oceans, estuaries, and saltwater marshes. Some aquatic animals such as fish or crabs, might live in the water. Others might live in the water some of the time and out of the water some of the time, such as frogs and salamanders. Some aquatic animals may find food, water, shelter, and space both in and out of the water, such as beaver or seals. Other animals like osprey, kingfisher, or seagulls are examples of wildlife that need to live near aquatic environments. All aquatic wildlife depends directly on aquatic habitats for survival. Water is one of the basic components of habitat for people and for wildlife. Water is essential for all life. Aquatic ecosystems and wildlife give humans early clear warning about the quality of the water environment upon which we all depend. For example, frogs, considered the “coal mine canaries” of the aquatic ecosystem, show signs early on of detrimental effects from human contaminants.
Waters from all of New HavenÍs streams, marsh creeks, and rivers drain into Long Island Sound which in turn drains into the Atlantic Ocean. The place where this fresh water drains into the salt water is called an estuary. Estuaries are semi-enclosed parts of the coastal ocean where sea water is diluted and mixed with fresh water coming from land. Our local rivers, harbors, and even Long Island Sound itself is all part of an estuarine system.
The word marsh has been defined as a treeless area of soft, wet land. To be a good marsh for wildlife it must be wet and it must have a varied balance of marsh plants that can support a population of small and larger animals which feed on the plants and on each other. Available food is not enough, the marsh must have a great variety of habitats in order to support a broad range of wildlife. It must have, deep water areas, shallow water areas, heavy vegetation on some of the shoreline, some bare areas on the shoreline, flooded grassy meadows, and dry grassy meadows. Marshy areas vary greatly. Some are permanent, some are temporary, some are freshwater, brakish water, or salt water, some are acidic, some are alkali, and they vary in size, depth, and in the forms of life they support. East Rock Park and Lighthouse Point have their own unique wetlands to study.
East Rock Park and Lighthouse Point Park both have a story to tell; it’s a record of what came before as well as what’s happening now. When you walk through the ranger station entrance to East Rock Park on the corner of Orange Street and Cold Spring Street and look up at the red sandstone around the base and up to the summit of East Rock along the traprock vertical ridges, think about the fact that these rocks are the result of molten material originating from below the earth’s crust moving up along cracks in the sandstone and solidifying into large sheets of black traprock otherwise known as dolerite. This happened approximately 170 million years ago. This traprock weathers to a brownish orange because of its iron content. Glacial activity created the final formations. Traprock resists erosion so hills were created. Streams of meltwater as the glacier receded were affected by the rise of the sea. This sent arms of rivers up beyond what is now North Haven. Sand and mud brought down by those rivers and peat formed in the salt marshes have since filled in those areas producing the flood plain through which the two rivers, the Mill and the Quinnipiac Rivers, wind their way towards New Haven Harbor and Long Island Sound. Beside the summit of East Rock are two other summits, Indian Head and Snake Rock, both formed by glacier activity. East Rock was quarried for its traprock for years. Many foundations of older New Haven homes were laid with East Rock traprock. The largest area quarried still visible is Corner Quarry, next to the Giant Steps leading to the summit.
College Woods, a level area near the Ranger Station, has gone through very few changes over the years. Many Indian artifacts found here have suggested this was the sight of a Quinnipiac village or camp sight long before the white settlers arrived in the New Haven area. Artifacts would include arrowheads, short bladed knives, and chisels. The Indians would use New Haven area rocks such as quartz, sandstone, and traprock to make these tools. They would also use rocks from other areas, west of the Hudson River, that flaked more easily such as jasper and black chert.
After years as a Quinnipiac hunting ground with the hills used as Indian lookouts, the white settlers arrived in this area. The Puritans attempted to establish a major commercial trading port. The area around the Mill River began to change rapidly. Grist Mills were built along the river and waterpowered by a low dam. In time Eli Whitney built his gun factory in 1798 on the Mill River below where the dam is today. It was here that Eli Whitney began the use of the interchangeable parts production process which became known as the American System of Manufacturing. Over the years much interest was given to making East Rock into a public park. Through generous donations of land from Yale College and individual families, East Rock Park went into operation in 1880 as a public park.
The Mill River is one of New Haven’s most beautiful rivers. It is dammed up to form Lake Whitney, a public water supply. The Lake lies in depressions created during the ice age about 10,000-15,000 years ago. The clear water coming out of the Whitney Lake supports fish and invertebrate. While the Quinnipiac tribe lived near the river, they harvested fish, crab, and shellfish from its waters. Fresh water springs ran from the base of East Rock. One hundred years ago the Mill River was a prime spot for swimming, boating, and fishing all the way down the river past Chapel Street . The park where the Mill River joins the Quinnipiac River was a popular sunbathing and swimming area. The Mill River was a tidal river healthy and abundant in wildlife.
Today the rich soil deposits of the river and its flooding and eroding action influence the plant growth in the low flood plain. There is a high water table preventing the deep penetration of root systems and secure anchorage of trees, thus many trees topple alongside the river. The black willow with its shallow, broad root system successfully thrives long the river banks. Other vegetation we find within the low flood plain of the Mill River are Pin Oak, Shrubs; such as Nannyberry and Silky Dogwood. The multiflora rose is a popular habitat and food source for nesting birds. Cattail marshes also provide cover for nesting and migrant birds. These marshes include water atruim, skunk cabbage, and swamps with woody shrubs. A very unusual fern grows in the shallow margins of the water. This unique plant is the water shamrock and looks like a floating four-leaf clover. The plants from Lake Whitney and Bantam Lake are the original stock from which all water shamrocks in the United States originate. Because the Mill River is a tidal river, there is an influx of salt water twice a day with the tidal changes. The seawater on the surface of the river tends to sink as lighter fresh water rises, and mixing takes place from the surface to the bottom of the river. This is known as tidal overmixing. The river water flows seaward on a shallow surface over an upstream movement of seawater. An unusual variety of vegetation grows within the confines of the fresh and salt water mix. We find a salt content in the river up to the footbridge crossing the Mill River. Here we begin to find cattails growing. These plants need less than 10% salt in the water source in order to survive. The plant material needs to be as hardy as the aquatic animal life that thrives in this fresh and salt water mix.
There is more life in a healthy wetland than there is in almost any other kind of habitat. A healthy wetland can support huge numbers of insects, fish, birds, and other animals. East Rock Park is on a major bird migration route bringing over 200 species of birds through, many of which are rarely seen elsewhere in the state. These birds converge on the wetlands on the way to their summer or winter homes to “refuel” on the rich food supply found in marshes. The spring migration of over twenty species of warblers through the park bring bird watchers from all over Connecticut. Throughout the winter, black ducks and pied-billed grebes winter on the river and woodpeckers, chickadees, brown creepers, and nuthatches, to name a few, live among the bare tree trunks.
Wetlands are vital nurseries for many species. Young fish, crab, and other creatures spend their earliest days in wetlands protected before moving out into the open waters. Wetlands also give protection to many endangered species. About 35 percent of all of the animals and plants listed as threatened or endangered in the U.S. either live in wetlands or depend on them in some way. Mammals, reptiles, and amphibians thrive in the flood plain marshes of the Mill River. Racoon, skunks, and oppossum live year round in the park. Muskrat, snakes, snapping turtles, and salamanders live in the river or along the river banks in the marshes. Red fox, bats,and flying squirrel are the more elusive residents of the park. The type of fish depend of the salinity of the water. Upriver where the water is fresh, sticklebacks, goldfish, carp, pumpkin seeds, banded killifish, and more recently, large mouthed bass thrive. Farther downstream towards the mouth of the river are found, among other species, mummichop which can stand the pollution and saltiness of the river.
Industrial waste, sewage, and thermal pollution has taken its toll on the Mill River. Just above State Street are old tide gates reaching across the river which have the enormous job of keeping polluted water from flowing upstream during the influx of high tide. There have been hundeds of acres of marsh land around the Mill River and New Haven Harbor that have been destroyed, drained and filled in for houses , roads, and other developments. Plans are in place to clean up the Mill River and to further protect this beautiful resource. Funding and time seem to be the continuing factors in actualizing these plans. Right now the city of New Haven is in the process of installing a sewage separation system in parts of the city. This will mean cleaner water in the surrounding rivers and in Long Island Sound. Heavy rains often force sewage to overflow into the Sound and into local rivers. With this new system fresh storm water will be routed into the Sound while human waste will be enclosed and routed to a sewage treatment plant.
East Rock Park
(figure available in print form)
To understand the geology of Lighthouse Point in relation to the rest of New Haven we have to go back about 250 million years. At that time there was a melding of continents, a collision which formed a single land mass. This collision closed an ancient ocean called Iapetos, sandwiched in a group of minicontinents called Avalonia and formed a supercontinent referred to by geologists as Pangaea from the Greek meaning “all-lands”. Connecticut is one area where these large continents were welded together. As this supercontinent started to pull apart separating North America , Europe, and Africa, the remnants of this welding stuck to the edges of these new continents. Much of Connecticut is the remnant of the welding of these continents. A small portion of Connecticut is what was once the small continents of Avalonia which were sandwiched during the collision. This portion reaches along the eastern shoreline of Connecticut westward and stops at Lighthouse Point. The geology we find at Lighthouse Point is very different from what we find elsewhere in New Haven. The granite formations at Lighthouse Point are much older than the basalt outcrops we find across Morris Cove at Nathan Hale Park or across New Haven Harbor to the volcanic rock west of New Haven. Since the rock we find is so different in type, age, and formation, the beaches and ecology we would find would also differ.
Lighthouse Point Park is now an 84 acre park which lies on the east side of New Haven harbor reaching out into Long Island Sound. Lighthouse Point was formed out of high temperatures and pressure and landscaped by glacier activity. The bedrock is billion year old granite. The Eastern Border Fault otherwise known as the Great Fault runs between Lighthouse point and the rest of New Haven. The point is flatland and saltmarsh which proves to be a natural draw for migrating birds following the coastline on the Atlantic flyway. A large area of the park in the northeast corner is designated as a bird sanctuary to give protection to these birds. While East Rock Park is known for its migrating warbler population, Lighthouse Point is just as well known for its coastal migrating hawk population. Throughout the fall, thousands of hawks of different varieties, falcons, osprey, and occasionally eagles can be sighted. An average count of twenty thousand raptors can be seen during the migration season. Thousands of songbirds migrate through Lighthouse Point during the fall also. Again the wetlands provide a place for them to rest and take advantage of the abundant food source before moving on.
Lighthouse Point has a variety of coastal communities that we can explore and learn about. These would include salt wetlands, rocky shoreline, and sandy beaches, all of which contain an intertidal zone, the area between the high-and low-tide lines. Tides and wave action are two of the most important factors which shape our coast. These two factors can also change a habitat dramatically every day. The tide rises and falls twice a day and during these times animals and plants who live within the intertidal zones need to withstand changes in temperature, moisture levels, and sometimes even salinity changes. Marine animals and plants have adapted in ways so as to survive these daily changes in their habitats.
Along the rocky shore we find animals and plants we would not see living at the sandy beach or the salt marsh. These marine organisms have found their own way of surviving the harsh action of waves against rocks and the rise and fall of the water. Animals and plant material either are anchored onto the rocks themselves such as barnacles, mussels, or seaweeds, or they hide in cracks such as crabs or seastars, or they bend with the waves as seaweeds do while floating on the waters surface while anchored to rocks. As the tide goes out, many animals, to avoid drying out, will pull their bodies into their shells and become inactive like the periwinkle. Others like crabs will lay under the protective moist layering of seaweed. As the tide goes out there are also left behind small pools of water in depressions and crevices in rocks. Many different animals and plants inhabit these pools during low tide including algae, anemones, hermit crabs, sea stars, and even tiny fish. They wait for the water level to rise again with the tide.
Life at the beach is very different. The beach proves to be a harsher habitat to live in for animals and plants. That is because what makes up a beach is always shifting and moving with the waves and the wind. Animals which live in this area cope with the conditions by usually burrowing into the sand, these would include clams, worms, sand dollars, and crabs. Much of what we find on top of the sand is material that has been washed ashore, seaweed which has become adrift and empty shells of animals which have been eaten.
Lighthouse Point contains areas of wetland or salt marsh which, like the wetland of the Mill River, provides nursery grounds for many animals and a home to crustaceans, fish, birds, reptiles and mammals. Salt marshes also provide a filtering system for pollutants and contaminants. They also trap nutrients and sediment which are slowly released into the water through decayed vegetation. Salt marshes are usually intersected by salt water creeks or tidal creeks which rise and fall with the tides. Lighthouse Point is intersected by Morris Creek. There was once a large expanse of wetlands in the Morris Creek area along the shoreline to East Haven. Through development this wetland has been broken up and reduced. Morris Creek has been rerouted many times due to the expansion of Tweed-New Haven Airport. These smaller marshes are not as effective as filtering and drainage systems. Sediment and nutrient rich silt brought through a marsh by creeks and rivers build up in the salt marsh and give marsh plants an ideal place to sprout and grow undisturbed. The most common plants in the salt marsh are grasses. The toughest, most productive grass is the spartina grasses. These grasses provide an abundant food source for the animals which make the marsh their home. The many plants we find in the salt marsh are dependent on the presence of salt water above the ground level at least some of the time. Salt marsh cordgrass which we find along tidal creeks and along the harbor edge is frequently flooded by saltwater. Where it is better drained, we find saltmeadow hay, spikegrass, sea lavendar, and glasswort. Farther inland within the marsh we find marsh elder and seaside goldenrod. The grass that marks the end of the salt marsh is called Phragmites. No saltwater reaches this point and dryland plants begin. Near the beach there is a grove of small gnarly trees which are persimmon trees. We usually find these thriving in a warmer climate. This grove is said to be the most northern grove of persimmon in the United States.
Lighthouse Point Park
(figure available in print form)
Salt marshes are vital to the ecology of the area supplying cover and homes to wild aquatic life and food for birds and mammals. It takes thousands of years for a salt marsh to form and very little time for a marsh to be destroyed. Since the early part of the century over fifty percent of the salt marshes in Connecticut have been destroyed through dredging, filling, waste disposal, industrial sites, housing developments, airports, and parking lots. At this time, most salt marshes are protected by law.
