Lake Ontario
Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York. The Canada–United States border spans the centre of the lake. On the Canadian side, the major cities are Kingston, Mississauga, Toronto, Hamilton, and St. Catharines. On the American side, the major cities are Rochester and Watertown.
The last in the Great Lakes chain, Lake Ontario serves as the outlet to the Atlantic Ocean via the Saint Lawrence River, comprising the western end of the Saint Lawrence Seaway. Its primary inlet is the Niagara River from Lake Erie. The Long Sault control dam, primarily along with the Moses-Saunders Power Dam regulates the water level of the lake.
The name Ontarí'io is most often translated from Huron as "beautiful lake", but other translations exist.
Geography
Lake Ontario is the easternmost of the Great Lakes and the smallest in surface area, although it exceeds Lake Erie in volume. It is the 13th-largest lake in the world. When its islands are included, the lake's shoreline is long. As the last lake in the Great Lakes' hydrologic chain, Lake Ontario has the lowest mean surface elevation of the lakes at above sea level; lower than its neighbor upstream. Its maximum length is, and its maximum width is. The lake's average depth is 47 fathoms 1 foot, with a maximum depth of 133 fathoms 4 feet in the Rochester Basin. The lake's primary source is the Niagara River, draining Lake Erie, with the Saint Lawrence River serving as the outlet. The drainage basin covers 24,720 square miles. As with all the Great Lakes, water levels change both within the year and among years. These water level fluctuations are an integral part of lake ecology and produce and maintain extensive wetlands. The lake also has an important freshwater fishery, although it has been negatively affected by factors including overfishing, water pollution and invasive species.Baymouth bars built by prevailing winds and currents have created a significant number of lagoons and sheltered harbors, mostly near Prince Edward County, Ontario, and the easternmost shores. Perhaps the best-known example is Toronto Bay, chosen as the site of the Upper Canada capital for its strategic harbor. Other prominent examples include Hamilton Harbour, Irondequoit Bay, Presqu'ile Bay, and Sodus Bay. The bars themselves are the sites of long beaches, such as Sandbanks Provincial Park and Sandy Island Beach State Park. These sand bars are often associated with large wetlands, which support large numbers of plant and animal species, as well as providing important rest areas for migratory birds. Presqu'ile, on the north shore of Lake Ontario, is particularly significant in this regard. One unique feature of the lake is the Z-shaped Bay of Quinte which separates Prince Edward County from the Ontario mainland, save for a isthmus near Trenton; this feature also supports many wetlands and aquatic plants, as well as associated fisheries.
Major rivers draining into Lake Ontario include the Niagara River, Don River, Humber River, Rouge River, Trent River, Cataraqui River, Genesee River, Oswego River, Black River, Little Salmon River, Credit River, Ganaraska River and the Salmon River.
The Welland Canal also drains into the lake.
Geology
The lake basin was carved out of soft, weak Silurian-age rocks by the Wisconsin ice sheet during the last ice age. The action of the ice occurred along the pre-glacial Ontarian River valley which had approximately the same orientation as today's basin. Material that was pushed southward by the ice sheet left landforms such as drumlins, kames, and moraines, both on the modern land surface and the lake bottom, reorganizing the region's entire drainage system. As the ice sheet retreated toward the north, it still dammed the St. Lawrence Valley outlet, so the lake surface was at a higher level. This stage is known as Lake Iroquois. During that time the lake drained through present-day Syracuse, New York, into the Mohawk River, thence to the Hudson River and the Atlantic. The shoreline created during this stage can be easily recognized by the beaches and wave-cut hills from the present shoreline.When the ice finally receded from the St. Lawrence valley, the outlet was below sea level, and for a short time, the lake became a bay of the Atlantic Ocean, in association with the Champlain Sea. Gradually the land rebounded from the release of the weight of about of ice that had been stacked on it. It is still rebounding about per century in the St. Lawrence area. Since the ice receded from the area last, the most rapid rebound still occurs there. This means the lake bed is gradually tilting southward, inundating the south shore and turning river valleys into bays. Both north and south shores experience shoreline erosion, but the tilting amplifies this effect on the south shore, causing loss to property owners.
Climate
The lake has a natural seiche rhythm of eleven minutes. The seiche effect normally is only about but can be greatly amplified by earth movement, winds, and atmospheric pressure changes. Because of its great depth, the lake as a whole does not completely freeze in winter, but an ice sheet covering between 10% and 90% of the lake area typically develops, depending on the severity of the winter. Ice sheets typically form along the shoreline and in slack water bays, where the lake is not as deep. During the winters of 1877 and 1878, the ice sheet coverage was up to 95–100% of the lake. During the War of 1812, the ice cover was stable enough the American naval commander stationed at Sackets Harbor feared a British attack from Kingston, over the ice. The lake has completely frozen over on five recorded occasions: in 1830, 1874, 1893, 1912, and 1934.When the cold winds of winter pass over the warmer water of the lake, they pick up moisture and drop it as lake-effect snow. Since the prevailing winter winds are from the northwest, the southern and southeastern shoreline of the lake is referred to as the snowbelt. In some winters, the area between Oswego and Pulaski may receive twenty or more feet of snowfall. Also impacted by lake-effect snow is the Tug Hill Plateau, an area of elevated land about east of Lake Ontario. The "Hill", as it is often referred to, typically receives more snow than any other region in the eastern United States. As a result, Tug Hill is a popular location for winter enthusiasts, such as snow-mobilers and cross-country skiers. Lake-effect snow often extends inland as far as Syracuse, with that city often recording the most winter snowfall accumulation of any large city in the United States. Other cities in the world receive more snow annually, such as Quebec City, which averages, and Sapporo, Japan, which receives each year and is often regarded as the snowiest city in the world.
Foggy conditions can be created by thermal contrasts and can be an impediment for recreational boaters. Lake breezes in spring tend to slow fruit bloom until the frost danger is past, and in the autumn delay the onset of fall frost, particularly on the south shore. Cool onshore winds also slow the early bloom of plants and flowers until later in the spring season, protecting them from possible frost damage. Such microclimatic effects have enabled tender fruit production in a continental climate, with the southwest shore supporting a major fruit-growing area. Apples, cherries, pears, plums, and peaches are grown in many commercial orchards around Rochester. Between Stoney Creek and Niagara-on-the-Lake on the Niagara Peninsula is a major fruit-growing and wine-making area. The wine-growing region extends over the international border into Niagara and Orleans counties in New York. Apple varieties that tolerate a more extreme climate are grown on the lake's north shore, around Cobourg.
Ecology
The Great Lakes watershed is a region of high biodiversity, and Lake Ontario is important for its diversity of birds, fish, reptiles, amphibians, and plants. Many of these special species are associated with shorelines, particularly sand dunes, lagoons, and wetlands. The importance of wetlands to the lake has been appreciated, and many of the larger wetlands have protected status. These wetlands are changing, partly because the natural water level fluctuations have been reduced. Many wetland plants are dependent upon low water levels to reproduce. When water levels are stabilized, the area and diversity of the marsh is reduced. This is particularly true of meadow marsh ; for example, in Eel Bay near Alexandria Bay, regulation of lake levels has resulted in large losses of wet meadow. Often this is accompanied by the invasion of cattails, which displace many of the native plant species and reduce plant diversity. Eutrophication may accelerate this process by providing nitrogen and phosphorus for the more rapid growth of competitively dominant plants. Similar effects are occurring on the north shore, in wetlands such as Presqu'ile, which have interdunal wetlands called pannes, with high plant diversity and many unusual plant species.Most of the forests around the lake are deciduous forests dominated by trees including maple, oak, beech, ash and basswood. These are classified as part of the Mixedwood Plains Ecozone by Environment Canada, or as the Eastern Great Lakes and Hudson Lowlands by the United States Environmental Protection Agency, or as the Great Lakes Ecoregion by The Nature Conservancy. Deforestation in the vicinity of the lake has had many negative impacts, including loss of forest birds, extinction of native salmon, and increased amounts of sediment flowing into the lake. In some areas, more than 90 percent of the forest cover has been removed and replaced by agriculture. Certain tree species, such as hemlock, have also been particularly depleted by past logging activity. Guidelines for restoration stress the importance of maintaining and restoring forest cover, particularly along streams and wetlands.
By the 1960s and 1970s, the increased pollution caused frequent algal blooms to occur in the summer. These blooms killed large numbers of fish, and left decomposing piles of filamentous algae and dead fish along the shores.