Lake Toba

Landsat photo of Sumatra surrounding Lake Toba

Lake Toba (Indonesian: Danau Toba) is a large lake, 100 km long and 30 km wide, in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about 900 m (3000 feet), stretching from 2.88° N 98.52° E to 2.35° N 99.1° E.

Geology

In 1949 the Dutch geologist Rein van Bemmelen reported that Lake Toba was surrounded by a layer of ignimbrite rocks, and that it was a large volcanic caldera. Later researchers found rhyolite ash similar to that in the ignimbrite around Toba (now called Young Toba Tuff to distinguish it from layers deposited in previous explosions) in Malaysia and India, 3000 km away. Oceanographers discovered Toba ash, with its characteristic chemical "fingerprint", on the floor of the eastern Indian Ocean and the Bay of Bengal.

The eruption

The Toba eruption (the Toba event) occurred at what is now Lake Toba about 71,500 ± 4000 years ago. It had an estimated Volcanic Explosivity Index of 8 (described as "mega-colossal"), making it possibly the largest explosive volcanic eruption within the last twenty-five million years. Bill Rose and Craig Chesner of Michigan Technological University deduced that the total amount of erupted material was about 2800 cubic km (670 cubic miles) — around 2000 km³ of ignimbrite that flowed over the ground and around 800 km³ that fell as ash, with the wind blowing most of it to the west. By contrast, the 1980 eruption of Mount St. Helens ejected around 1.2 cubic km of material, whilst the largest volcanic eruption in historic times, at Mount Tambora in 1815, emitted the equivalent of around 100 cubic kilometres of dense rock and created the "Year Without a Summer" as far away as North America.

The Toba eruption was the latest of a series of at least three caldera-forming eruptions which have occurred at the volcano. Earlier calderas were formed around 700,000 and 840,000 years ag

o.

To give an idea of its magnitude, consider that although the eruption took place in Indonesia, it deposited an ash layer approximately 15 cm (6 in) thick over the entire Indian subcontinent; at one site in central India, the Toba ash layer today is up to 6 m (20 feet) thick^[3] and parts of Malaysia were covered with 9 m of ashfall.^[4] In addition it has been calculated that 10¹⁰ metric tons of sulphuric acid was ejected into the atmosphere by the event, causing acid rain fallout.^[5]

The subsequent collapse formed a caldera that, after filling with water, created Lake Toba. The island in the center of the lake is formed by a resurgent dome.

Though the year can never be precisely determined, the season can: only the summer monsoon could have deposited Toba ashfall in the South China Sea, implying that the eruption took place sometime during the northern summer.^[6] The eruption lasted perhaps two weeks, but the ensuing "volcanic winter" resulted in a decrease in average global temperatures by 3 to 3.5 degrees Celsius for several years. Greenland ice cores record a pulse of starkly reduced levels of organic carbon sequestration. Very few plants or animals in southeast Asia would have

survived, and it is possible that the eruption caused a planet-wide die-off. There is some evidence, based on mitochondrial DNA, that the human race may have passed through a genetic bottleneck within this timeframe, reducing genetic diversity below what would be expected from the age of the species. According to the Toba catastrophe theory proposed by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign in 1998, human populations may have been reduced to only a few tens of thousands of individuals by the Toba eruption.

More recent activity

Smaller eruptions have occurred at Toba since. The small cone of Pusukbukit has formed on the southwestern margin of the caldera and lava domes. The most recent eruption may have been at Tandukbenua on the northwestern caldera edge, since

the present lack of vegetation could be due to an eruption within the last few hundred years.

Some parts of the caldera have experienced uplift due to partial refilling of the magma chamber, for example pushing Samosir Island and the Uluan Peninsula above the surface of the lake. The lake sediments on Samosir Island show that it has been uplifted by at least 450 metressince the cataclysmic eruption. Such uplifts are common in very large calderas, apparently due to the upward pressure of unerupted magma. Toba is probably the largest resurgent caldera on Earth. Large earthquakes have occurred in the vicinity of the volcano more recently, notably in 1987 along the southern shore of the lake at a depth of 11 km. Other earthquakes have occ

urred in the area in 1892, 1916, and 1920-1922.

Lake Toba lies near a fault line which runs along the centre of Sumatra called the Sumatra Fracture Zone.^[11] The volcanoes of Sumatra and Java are part of the Sunda Arc, a result of the northeasterly movement of the Indo-Australian Plate which is sliding under the eastward-moving Eurasian Plate. The subduction zone in this area is very active: the seabed near the west coast of Sumatra has had several major earthquakes since 1995, including the 9.3 2004 Indian Ocean Earthquake and the 8.7 2005 Sumatra earthquake, the epicenters of which were around 300 km from Toba.

People

Toba House

Most of the people who live around Lake Toba are ethnically Bataks. Traditional Batak houses are noted for their distinctive roofs (which curve upwards at each end, as a boat's hull does) and their colorful decor.

From Wikipedia

Danau Ontario

Seen from near Wolcott, New York

Lake Ontario, bounded on the north by the Canadian province of Ontario and on the south by Ontario's Niagara Peninsula and by New York State, USA, is one of the five Great Lakes of North America.

Name

The name of the lake is derived from ontarí:io, a Huron word meaning "great lake".^[2] The Canadian province of Ontario was later named after the lake.

Previous to its current name, the lake was identified in some maps under different names. In a map drawn in the Relation des Jésuites (1662-1663), the lake has the legend "Lac Ontario ou des Iroquois" and in smaller type "Ondiara". A French map produced in 1712 (currently in the Canadian Museum of Civilization), created by military engineer Jean-Baptiste de Couagne, identified Lake Ontario as "Lac Frontenac". Iroquois people called the lake "Skanadario."

Geography

Lake Ontario (43°30'N, 78°00'W) is the eastern-most and smallest in surface area (7,540 square miles, 19,529 km²) of the Great Lakes, although it exceeds Lake Erie in volume (393 cubic miles, 1639 km³). It is the 14th largest lake in the world and has a shoreline 712 miles (1146 km) long.

Lake Ontario has an elevation of 246 feet (75 m)above sea level. Its length is 193 miles (311 km), and its width is 53 miles (85 km). The average depth is 283 feet (86 m), with a maximum depth of 802 feet (244 m).

Its primary inlet is the Niagara River (from Lake Erie) and primary outlet is the St. Lawrence River. Other major rivers which flow into it include the Don River; Humber River; Trent River; the Cataraqui River; the Genesee River; the Oswego River; the Black River; and the Salmon River. Other notable geographic features include Hamilton Harbour, the Bay of Quinte, the Toronto Islands, and the Thousand Islands. The Bay of Quinte separates most of Prince Edward County from the north shore except for a 2 mile (3km) stretch of land connecting it to the mainland. The largest island on the lake is Wolfe Island located near Kingston at the St. Lawrence River entrance. It is accessible by ferry from both Canada and the U.S.

A portion of the Great Lakes Waterway passes through the lake, which is accessible from upstream by the Welland Canal and from downstream by the St. Lawrence Seaway. The Trent-Severn Waterway for pleasure boats connects Lake Ontario at the Bay of Quinte to Georgian Bay of Lake Huron passing through the inland Lake Simcoe. The Rideau Waterway, also for pleasure boats, connects Lake Ontario at Kingston to the Ottawa River at Ottawa. The Oswego Canal connects the lake at Oswego, NY to the New York State Canal System, with outlets to the Hudson River, Lake Erie, and Lake Champlain.

A large conurbation called the Golden Horseshoe (including major cities of Toronto and Hamilton, Ontario) is on the Canadian side at the western end of the lake. Other centres on the Canadian side with ports include St. Catharines, Oshawa, Cobourg and Kingston near the St. Lawrence River inlet. Close to 9 million people or over a quarter of Canada's population lives within the watershed of Lake Ontario.

The American shore of the lake is largely rural, with the exception of Rochester, New York and the much smaller port at Oswego, New York. The city of Syracuse is 40 miles (65 km) inland from the lakeshore and is connected to it by the New York State Canal System. Over 2 million people live in Lake Ontario's American watershed.

A high-speed passenger/vehicle ferry service across Lake Ontario between Toronto and Rochester was launched on June 17, 2004, using the vessel Spirit of Ontario I. The service was canceled on January 10, 2006.

On the south shore, breezes off the cool lake tend to retard fruit bloom until the spring frost danger is past, and the area has become a major fruit growing area, with apples, cherries, pears, plums, and peaches grown in many commercial orchards on both sides of Rochester. The Canadian part of the south shore, known as the Niagara Peninsula is also a major fruit-growing and wine-making area located between Stoney Creek and Niagara-on-the-Lake. Apple varieties that tolerate a more extreme climate are grown on the lake's north shore, around Cobourg.

From Wikipedia

Lake Huron

Lake Huron viewed from Arch Roc

Lake Huron, bounded on the west by the state of Michigan, USA, and on the east by the province of Ontario, Canada, is one of the five Great Lakes of North America. The name of the lake is derived from early French explorers who named it based on the Huron people inhabiting the region.

Geography

Lake Huron (45°00′N, 83°00′W) is the second-largest of the Great Lakes, with a surface area of 23,010 square miles (59,596 km²)—nearly the size of West Virginia, making it the third largest fresh water lake on earth (4th largest lake if the saline Caspian Sea is included). It contains a volume of 850 cubic miles (3,540 km³), and a shoreline length of 3,827 miles (6,157 km).

The surface of Lake Huron is 577 feet (176 m) above sea level. The lake's average depth is 195 feet (59 m), while the maximum depth is 750 feet (229 m). It has a length of 206 miles (332 km) and a breadth of 183 miles (245 km).

Major cities on Lake Huron include: Bay City, Michigan; Alpena, Michigan; Cheboygan, Michigan; St. Ignace, Michigan; Port Huron, Michigan; Goderich, Ontario; and Sarnia, Ontario.

A notable feature of the lake is Manitoulin Island, which separates the North Channel and Georgian Bay from Lake Huron's main body of water. It is the world's largest lake island.

Geology

Lake Huron is separated from Lake Michigan, which lies at the same level, and connects by the narrow Straits of Mackinac, making them geologically and hydrologically the same body of water (sometimes called Lake Michigan-Huron). Lake Superior is slightly higher than both. It drains into the St. Marys River at Sault Ste. Marie which then flows southward into Lake Huron. The water then flows south to the St. Clair River, at Port Huron, Michigan and Sarnia, Ontario.

The Great Lakes Waterway continues thence to Lake St. Clair; the Detroit River and Detroit, Michigan; into Lake Erie and thence--via Lake Ontario and the St. Lawrence River--to the Atlantic Ocean.

Like the other Great Lakes, it was formed by melting ice as the continental glaciers retreated.

History

Since its French discoverers knew nothing as yet of the other lakes, they called it La Mer Douce, the fresh-water sea. A Sanson map in 1656 refers to the lake as Karegnondi.

Lake Huron was generally labeled "Lac des Hurons" (Lake of the Huron Indians) on most early maps.

Ecology

Lake Huron has a lake retention time of 22 years.

Major industries that drain into Lake Huron include: iron and steel mills, automobile manufacturing, heavy machinery, paper mills, metalworking, and shipbuilding.

From Wikipedia

Lake Erie

Lake Erie (pronounced [ˈi.ɹi]) is the tenth largest lake on Earth^[2] and, of the five Great Lakes of North America, it is the fourth largest by surface area, the southernmost, shallowest, and smallest by volume.^[3][4] It is bounded on the north by the Canadian province of Ontario, on the south by the U.S. states of Ohio, Pennsylvania, and New York, and on the west by the state of Michigan. The lake is named after the Erie tribe of Native Americans who lived along its southern shore before being exterminated for aiding the Hurons, the enemy of the Iroquois League.^[3]

The lake creates a favorable environment for agricultural pursuits in the bordering areas of Ontario, Ohio, Pennsylvania, and New York. In addition, its waters are home to numerous fish species, making it a popular site for commercial fishing. However, since high levels of pollution were discovered in the 1960s and 1970s, there has been continued debate over the extent of commercial fishing and measures used to protect the lake.

Geography

Lake Erie (42°30'N, 81°00'W) has a mean elevation of 571 feet (174 m)^[1] above sea level. It has a surface area of 9,940 square miles (25,745 km²)^[1] with a length of 241 miles (388 km) and breadth of 57 miles (92 km) at its widest points.

It is the shallowest of the Great Lakes with an average depth of 62 feet (19 m) and with a maximum depth of 210 feet (64 m).^[1] The western section, comprising one-fourth of the area, is shallower with an average depth of 42 feet (13 m) and a maximum depth of 62 feet (19 m).

For comparison, Lake Superior has an average depth of 483 feet (147 m), a volume of 2,900 cubic miles (12,100 km³) and shoreline of 2,726 miles (4385 km).^{[citation needed]}

Lake Erie is primarily fed by the Detroit River (from Lake Huron and Lake St. Clair) and drains via the Niagara River and Niagara Falls into Lake Ontario. Navigation downstream is provided by the Welland Canal, part of the Saint Lawrence Seaway. Other major tributaries of Lake Erie include the Grand River, the River Raisin, the Huron River, the Maumee River, the Sandusky River and the Cuyahoga River.

he American states Ohio, Pennsylvania and New York are located to the south of Lake Erie; Michigan lies to the west, and the Canadian province of Ontario lies to the north. Point Pelee National Park, the southernmost point of the Canadian mainland, is located on a peninsula extending into the lake. Several islands are found in the western end of the lake; these belong to Ohio except for Pelee Island and 8 neighboring islands, which are part of Ontario.

The cities of Buffalo, New York; Erie, Pennsylvania; Toledo, Ohio; Port Stanley, Ontario; Monroe, Michigan; and Cleveland, Ohio are located on the shores of Lake Erie. It was the last of the Great Lakes discovered by the French explorers, who had followed rivers out of Lake Ontario and portaged into Lake Huron.

History

Native American

Before European contact, there were several tribes which lived along the shores of Lake Erie. The Erie tribe (from whom the lake takes its name) lived along the southern edge while the Neutrals (also known as Attawandaron) lived along the northern shore. Both tribes were conquered and exterminated during the Beaver Wars in 1655 by the Iroquois confederacy.

For many years after that war, the land around Lake Erie remained uninhabited and was used by the Iroquois as a hunting ground, until the waning of the their power around 1700. About that time, several other Native American tribes moved into the empty land, namely the Ottawa, Ojibwe, Wyandot, and Mingo tribes.

European Exploration and Settlement

In 1669, the Frenchman Louis Jolliet was the first documented European to sight Lake Erie, although there is speculation that Etienne Brule may have come across it in 1615. Lake Erie was the last of the Great Lakes to be explored by Europeans, since the Iroquois who occupied the Niagra river area were in conflict with the French, and they did not allow explorers or traders to pass through.

Recent History

Lake Erie infamously became very polluted in the 1960s and 1970s. Urban legend has described it as a dead lake, but both sport and commercial fishing have continued without interruption to the present day. Pollution in the lake did not get much attention until the great Cuyahoga River Fire in June of 1969. Pollution from Cleveland and other Ohio cities had so contaminated this tributary of Lake Erie with petrochemicals that it actually caught on fire. The fire embarrassed state officials and prompted the U.S. Congress to pass the Clean Water Act of 1972.

Ecology

Like the other Great Lakes, Erie produces lake effect snow when the first cold winds of winter pass over the warm waters, leading to Buffalo, New York being the eleventh snowiest place in the entire United States.^[5] The lake effect ends or its effect is reduced, however, when the lake freezes over. Being the shallowest of the Great Lakes, it is the most likely to freeze and frequently does.

The lake is also responsible for microclimates that are important to agriculture. Along its north shore is one of the richest areas of Canada's fruit and vegetable production, and along the southeastern shore in Ohio, Pennsylvania, and New York is an important grape growing region, as are the islands in the lake.

During the 1960s and 1970s, Lake Erie experienced changes in water quality associated with increasing levels of the nutrient phosphorus in the water and bottom sediments. The result was eutrophication of the system which resulted in major changes in productivity and algal blooms. The decomposition of algae led to extensive seasonal anoxic areas in the lake (the so-called dead zone), that were expanding rapidly in the early 1970s. The decomposing algal masses and associated fish kills fouled shorelines, contributing to the widespread impression of Lake Erie as a dead lake.

A 1972 agreement between Canada and the United States reduced the dumping and runoff of phosphorus into the lake significantly. A dead zone persists in the central Lake Erie basin during the late summer. The United States Environmental Protection Agency is currently studying this cyclic phenomenon.

Since the 1970s environmental regulation has led to a great increase in water quality and the return of economically important fish species such as walleye and other biological life.

However, the lake ecosystem is much changed from its original state, with a long list of invasive species well established. Common fish species such as rainbow smelt, alewife, white perch and common carp have all been introduced from outside the Great Lakes. Non-native sportfish such as rainbow trout and brown trout continue to be stocked for anglers to catch. Attempts to stock the lake with Coho Salmon were made, but failed, and that species is once again nearly absent from the lake. Recent invaders, zebra and quagga mussels have populated the entire Lake Erie ecosystem, altering energy flow through the food web away from the pelagic zone and into the benthic zone.

Other invasive species, such as the goby (recently arrived) and the grass carp (on the doorstep), have increased public debate about the risks of non-native invaders to Great Lakes ecosystems.

The effects of zebra mussels and gobies have been credited with the increased population and size of smallmouth bass in Lake Erie.

Lake Erie is home to one of the world's largest freshwater commercial fisheries. Once a mainstay of communities around the lake, commercial fishing is now predominantly based in Canadian communities, with a much smaller fishery, largely restricted to yellow perch, in Ohio. The Ontario fishery is one of the most intensively managed in the world. It was one of the first fisheries in the world managed on individual transferable quotas (ITQs) and features mandatory daily catch reporting and intensive auditing of the catch reporting system. Still, the commercial fishery is the target of critics who would like to see the lake managed for the exclusive benefit of sport fishing and the various industries serving the sport fishery.

Commercial landings are dominated by yellow perch and walleye, with substantial quantities of rainbow smelt and white bass also taken. Anglers target walleye and yellow perch, with some effort directed on rainbow trout. A variety of other species are taken in smaller quantities by both commercial and sport fleets.

Although management of the fishery is by consensus of all management agencies with an interest in the resource (the states of New York, Pennsylvania, Ohio and Michigan and the province of Ontario) under the mandate of the Great Lakes Fishery Commission, and driven by comprehensive fisheries assessment programs and sophisticated mathematical modeling systems, it remains the source of considerable recrimination, primarily from United States based angler and charter fishing groups with an historical antipathy to the commercial fishery. This conflict is complex, dating from the 1960s and changes in U.S. fisheries management that led to elimination of commercial fishing in most U.S. Great Lakes states. The process began in the state of Michigan, and its evolution is well documented in Szylvian (2004)^[10], using Lake Michigan as a case study. The underlying issues are universal, wherever sport and commercial fishing coexist, but their persistence in the Lake Erie context, one of the most intensively scrutinized and managed fisheries anywhere, suggests that these conflicts are cultural, not scientific, and therefore not resolvable by reference to ecological data. These debates are largely driven by social, political and economic issues, not ecology.

Geology

Lake Erie has a lake retention time of 2.6 years, which is the shortest of all the Great Lakes.

Like the rest of the Great Lakes, Erie's levels fluctuate with the season of the year, with the lowest levels in January and February, and the highest in June or July. Its average yearly levels also vary depending on long-term precipitation variations, with levels falling during droughts and rising during periods of extended above-average precipitation.

Lake Erie's short-term level changes are often subject to weather, since its shallowness and the southwest-to-northeast alignment of its longitudinal axis make it particularly prone to seiches, especially during high southwesterly winds, when the lake water tends to pile up at one end of the lake. This can lead to large storm surges, potentially causing damage onshore. During one storm in November 2003, the water level at Buffalo rose by 7 feet (2.1 m) with waves of 10-15 feet (3-4.5 m) on top of that, for a cumulative rise of as much as 22 feet (6.7 m). Meanwhile, Toledo at the western end of the lake will measure similar drops in water level. After the storm event, the water will slowly slosh back and forth, similar to the effect in a bath tub, until equilibrium is re-established.

Islands

Big Chicken Island

• Chick Island
• East Sister Island
• Gibraltar Island
• Green Island
• Gull Island
• Hen Island
• Johnson's Island
• Kelleys Island
• Little Chicken Island
• Lost Ballast Island
• Middle Island
• Middle Bass Island
• Middle Sister Island
• Mouse Island
• North Bass Island
• North Harbour Island
• Pelee Island
• Rattlesnake Island
• South Bass Island
• Starve Island
• Sugar Island
• Turtle Island
• West Sister Island

From Wikipedia

Danau Michigan

Danau Michigan ialah salah satu dari 5 Danau-danau Besar di Amerika Utara.

Memiliki wilayah permukaan 22.300 mil persegi (57750 km persegi). Panjangnya 307 mil dan luasnya 118 mil. Danau Michigan ialah danau terbesar ke-5 di dunia.

Dibatasi oleh negara bagian Amerika Serikat: Indiana, Illinois, Wisconsin, dan Michigan. Kota terbesar di Danau Michigan ialah Chicago.

From Wikipedia

Lake Superior

Lake Superior, Landsat photography

Lake Superior, bounded by Ontario, Canada and Minnesota, USA, to the north and Wisconsin and Michigan, USA, to the south, is the largest of North America's Great Lakes. It is the largest freshwater lake in the world by surface area and is the world's third-largest freshwater lake by volume.

Name

In the Ojibwe language, the lake is called "Gichigami" ("big water"), but it is better known as "Gitche Gumee" as recorded by Henry Wadsworth Longfellow in The Song of Hiawatha. Lake Superior is referred to as "Gitche Gumee" in the song The Wreck of the Edmund Fitzgerald, by Gordon Lightfoot.

The lake was named le lac supérieur, or "Upper Lake," in the seventeenth century by French explorers because it was located above Lake Huron.(Nute, 1946)

Hydrography

Lake Superior and the other Great Lakes

Lake Superior is the largest freshwater lake in the world by surface area. Lake Baikal in Russia is larger by volume, as is Lake Tanganyika (The Caspian Sea, while vastly larger than Lake Superior in both surface area and volume, is saline; though presently isolated, in the past, it has been repeatedly connected to, and isolated from, the Mediterranean via the Black Sea).

Lake Superior (48°00’N, 88°00’W) has a surface area of 31,820 square miles (82,414 km²)^[1]—which is larger than South Carolina. It has a maximum length of 350 miles (563 km) and maximum breadth of 160 miles (257 km). Its average depth is 483 feet (147 m) with a maximum depth of 1,333 feet (406 m).^[1] Lake Superior contains 2,900 cu mi (12,100 km³) of water. There is enough water in Lake Superior to cover the entire land mass of North and South America with a foot (30 cm) of water. The shoreline of the lake stretches 2,726 miles (4,385 km) (including islands). The lake's elevation is 600 feet (183 m)^[1] above sea level. American limnologist J. Val Klump was the first person to reach the lowest depth of Lake Superior on July 30, 1985 as part of a scientific expedition.

Annual storms on Lake Superior regularly record wave heights of over 20 feet (6 m).[1] Waves well over 30 feet (9 m) have been recorded.^[3]

Water levels, including diversions of water from the Hudson Bay watershed, are governed by the International Lake Superior Board of Control which was established in 1914 by the International Joint Commission.

Tributaries and outlet

The lake is fed by over 200 rivers. The largest include the Nipigon River, the St. Louis River, the Pigeon River, the Pic River, the White River, the Michipicoten River, the Brule River and the Kaministiquia River. Lake Superior drains into Lake Huron by the St. Marys River. The rapids on the river necessitate the Sault Locks (pronounced "soo"), a part of the Great Lakes Waterway, to move boats over the 25 foot (7.6 m) height difference from Lake Huron.

Geography

The largest island in Lake Superior is Isle Royale in the state of Michigan. Other large famous islands include Madeline Island in the state of Wisconsin and Michipicoten in the province of Ontario.

The larger towns on Lake Superior include: the twin ports of Duluth, Minnesota and Superior, Wisconsin; Thunder Bay, Ontario; Marquette, Michigan; and the two cities of Sault Ste. Marie, in Michigan and in Ontario. Duluth, at the western tip of Lake Superior, is the most inland point on the Saint Lawrence Seaway and the most inland port in the world.

Among the scenic places on the lake are: the Apostle Islands National Lakeshore; Isle Royale National Park; Pukaskwa National Park; Lake Superior Provincial Park; Grand Island National Recreation Area; Sleeping Giant (Ontario);and Pictured Rocks National Lakeshore.

Climate

Lake Superior's size creates a localized oceanic or maritime climate (more typically seen in locations like Nova Scotia) ^[4]. The water's slow reaction to temperature changes helps to moderate surrounding air temperatures in the summer and winter, and creates lake effect snow in colder months. The hills and mountains that border the lake form a bowl, which holds moisture and fog, particularly in the fall. The Lake Superior's surface temperature has warmed by 2.5 °C since 1979, which has been attributed to global warming.

Geology

Lake Superior's North Shore dates back to the beginnings of the earth. About 2.7 billion years ago, magma forcing its way to the surface created the intrusive granites of the Canadian Shield. These ancient granites can be seen on the North Shore today. It was in this period, the Penokean orogeny, that many valuable metals were deposited. The region surrounding the lake has proved to be rich in minerals. Copper, iron, silver, gold and nickel are or were the most frequently mined. Examples include the Hemlo gold mine near Marathon, copper at Point Mamainse, silver at Silver Islet, and uranium at Theano Point.

The mountains steadily eroded starting about 2.49 billion years ago, depositing layers of sediments which compacted and became limestone, dolostone, taconite, and the shale at Kakabeka Falls.

About 1.1 billion years ago, the continent was rifted, creating one of the deepest rifts in the world. The lake lies above this long-extinct Mesoproterozoic rift valley, the Midcontinent Rift, which explains its great depths. Magma was injected between layers of sedimentary rock, forming diabase sills. This hard diabase protects the layers of sedimentary rock below, forming the flat-topped mesas in the Thunder Bay area.

Lava erupted from the rift and formed the black basalt rock of Michipicoten Island, Black Bay Peninsula, and St. Ignace Island.

Around 1.6 million years ago, during the last Great Ice Age, ice covered the region at a thickness of 1.25 miles (2 km). The land contours familiar today were carved by the advance and retreat of the ice sheet. The retreat some 10,000 years ago, left gravel, sand, clay, and boulder deposits. Glacial meltwaters gathered in the Superior basin creating Lake Minong, a precursor to Lake Superior.^[6] Without the immense weight of the ice, the land rebounded, and a drainage outlet formed at Sault Ste. Marie, which would become known as St. Mary's River.

History

Pictographs at Lake Superior Provincial Park, Ontario

The first people came to the Lake Superior region 10,000 years ago after the retreat of the glaciers in the last Ice Age. They were known as the Plano, and they used stone-tipped spears to hunt caribou on the northwestern side of Lake Minong.

The next documented people were known as the Shield Archaic (c. 5000-500 B.C.). Evidence of this culture can be found at the eastern and western ends of the Canadian shore. They used bows and arrows, dugout canoes, fished, hunted, mined copper for tools and weapons, and established trading networks. They are believed to be the direct ancestors of the Ojibwe and Cree.^[7]

The Laurel people (c. 500 B.C. to A.D. 500) developed seine net fishing, evidence being found at rivers around Superior such as the Pic and Michipicoten.

Another culture known as the Terminal Woodland Indians (c. A.D. 900-1650) has been found. They were Algonkian people who hunted, fished and gathered berries. They used snow shoes, birch bark canoes and conical or domed lodges. At the mouth of the Michipicoten River, nine layers of encampments have been discovered. Most of the Pukaskwa Pits were likely made during this time.

The Anishinabe, also known as the Ojibwe or Chippewa, have inhabited the Lake Superior region for over five hundred years, and were preceded by the Dakota, Fox, Menominee, Nipigon, Noquet, and Gros Ventres. They called Lake Superior Anishnaabe Chi Gaming, or "the Ojibwe's Ocean". After the arrival of Europeans, the Anishinabe made themselves the middle-men between the French fur traders and other Native peoples. They soon became the dominant Indian nation in the region: they forced out the Sioux and Fox and won a victory against the Iroquois west of Sault Ste. Marie in 1662. By the mid-1700s, the Ojibwe occupied all of Lake Superior's shores.

In the 1700s, the fur trade in the region was booming, with the Hudson's Bay Company (HBC) having a virtual monopoly. In 1783, however, the North West Company (NWC) was formed to rival HBC. The NWC built forts on Lake Superior at Grand Portage, Nipigon, the Pic River, the Michipicoten River, and Sault Ste. Marie. But by 1821, with competition taking too great a toll on both, the companies merged under the Hudson's Bay Company name.

Many towns around the lake are either current or former mining areas, or engaged in processing or shipping. Today, tourism is another significant industry as the sparsely populated Lake Superior country, with its rugged shorelines and wilderness, attracts tourists and adventurers.

Shipping

Lake Superior has been an important link in the Great Lakes Waterway, providing a route for the transportation of iron ore and other mined and manufactured materials. Large cargo vessels called lake freighters, as well as smaller ocean-going freighters, transport these commodities across Lake Superior.

The SS Edmund Fitzgerald, a typical lake freighter which sank in 1975

Shipwrecks

The last major shipwreck on Lake Superior was that of SS Edmund Fitzgerald in 1975.

According to an old sailor's tale, Lake Superior never gives up her dead. This is due to the temperature of the water. Normally bacteria feeding off a sunken decaying body will generate gas inside the body, causing it to float to the surface after a few days. The water in Lake Superior, however, is cold enough year-round to inhibit bacterial growth, meaning bodies tend to sink and never surface.^[10] This is poetically alluded to in Gordon Lightfoot's famous ballad, The Wreck of the Edmund Fitzgerald.

Ecology

Although part of a single system, each of the Great Lakes is different. In volume, Lake Superior is the largest. It is also the deepest and coldest of the five. Superior could contain all the other Great Lakes and three more Lake Eries. Because of its size, Superior has a retention time of 191 years.

According to a study by professors at the University of Minnesota Duluth, Lake Superior has been warming faster than its surrounding climate. Summer surface temperatures in the lake have increased about 4.5 degrees Fahrenheit since 1979, compared with about a 2.7-degree increase in the surrounding average air temperature. The increase in the lake’s surface temperature is not only due to climate change but also due to the decreasing ice cover. Less winter ice cover allows more solar radiation to penetrate the lake and warm the water. If trends continue Lake Superior, which freezes over completely once every 20 years, could routinely be ice-free by 2040. These warmer temperatures can actually lead to more snow in the lake effect snow belts along the shores of the lake, especially in the Upper Peninsula of MIchigan.

From Wikipedia

Caspian Sea

The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea.^[2][3] It has a surface area of 371,000 square kilometers (143,244 sq mi) and a volume of 78,200 cubic kilometers (18,761 cu mi).^[4] It is an endorheic body of water and lies between the southern areas of the Russian Federation and northern Iran. It has a maximum depth of about 1025 meters (3,363 ft). It is called a sea because when the Romans first arrived there, they tasted the water and found it to be salty.^[5] It has a salinity of approximately 1.2%, about a third the salinity of most seawater.

Geography

The Caspian Sea is bordered by five countries:

• Kazakhstan, to the North & North East.
• Turkmenistan on the Southern half of the Eastern shore
• Iran has the southern shore with (Gilan, Mazandaran and Golestan provinces)
• Azerbaijan on the Southern part of the Western shore including its capital Baku.
• Russian Federation to the North West with (Dagestan, Kalmykia, Astrakhan Oblast),

Major natural features around the Caspian sea include:

• The Caspian Depression is north of the Caspian sea
• The central Asian steppes to the north eas t.
• The Caucasus mountains on the border between Russia and Azerbaijan.
• The Garabogazköl on the eastern sh ore.

The sea is connected to the Sea of Azov by the Man

ych Canal and the Volga-Don Canal.

Salinity

Depending on the inflow of fresh water from it

s effluents, the Caspian Sea is a fresh-water lake in its northern portions. It is more saline on the Iranian shore. The largely dried-up Garabogazköl embayment routinely exceeds oceanic salinity.

Cities near the Caspian Sea

Major cities by the Caspian Sea:

• Alyat, Azerbaijan
• Astara, Azerbaijan
• Avrora, Azerbaijan
• Baku, Azerbaijan
• Bank, Azerbaijan
• Buzovna, Azerbaijan
• Gobustan, Azerbaijan
• Kala, Azerbaijan
• Khudat, Azerbaijan
• Khachmaz, Azerbaijan
• Lankaran, Azerbaijan
• Massally, Azerbaijan
• Nabran, Azerbaijan
• Oil Rocks, Azerbaijan
• Syzan, Azerbaijan
• Sangachaly, Azerbaijan
• Sumqayit, Azerbaijan
• Primorisk, Azerbaijan
• Prishib, Azerbaijan
• Astara, Iran
• Babolsar, Iran

Map of the Caspian Sea, yellow sha ding in dicates Caspian drainage basin.

• Bandar Anzali, Iran
• Chaloos, Iran
• Noshahr, Iran
• Ramsar, Iran
• Rasht, Iran
• Sari, Iran
• Atyrau, Kazakhstan (formerly G uriev)
• Aqtau, Kazakhstan (formerly Shevchenko)
• Astrakhan, Russia
• Derbent, Russia
• Türkmenbaşy, Turkmenistan (formerly Krasnovodsk)
• Makhachkala, Russia

History

The Caspian Sea, viewed from Baku, Republic of Azerbaijan

The Caspian Sea is a remnant of the Tethys Sea, along with Black, and Aral seas. It became landlocked about 5.5 million years ago. Discoveries in the Huto cave near the town of Behshahr, Mazandaran (southern land of Caspian Sea) suggest human habitation of the area as early as 75,000 years ago.

In classical antiquity among Greeks and P

ersians it was called the Hyrcanian Ocean. In Persian antiquity, as well as in modern Iran, it is known as the Khazar or Mazandaran Sea. In Turkic speaking countries it is known as the Khazar Sea. Old Russian sources call it the Khvalyn (Khvalynian) Sea after the Khvalis, inhabitants of Khwarezmia. Ancient Arabic sources refer to Bahr-e-Qazvin — the Qazvin Sea.

The word Caspian is derived from th

e name of the Caspi, an ancient people that lived to the west of the sea in Transcaucasia.^[6] Strabo wrote that "to the country of the Albanians belongs also the territory called Caspiane, which was named after the Caspian tribe, as was also the sea; but the tribe has now disappeared".^[7] Moreover, the Caspian Gate, which is the name of a region in Tehran province of Iran, is another possible piece of evidence that they migrated to the south of the sea.

Historical cities by the sea include

• Hyrcania, ancient state in the north of Iran
• Tamisheh, (Mazandaran province of Iran)
• Anzali, (Gilan province of Iran)
• Atil, Khazaria
• Khazaran
• Baku, Azerbaijan
• Sumgait, Azerbaijan
• Astara, Iran, Azerbaijan

Fauna

An aerial view of the southern

Caspian coast as viewed from atop

the Alborz mountains in Mazandaran, Iran

The Caspian Sea holds great numbers of sturgeon, which yield eggs that are processed into caviar. In recent years overfishing has threatened the sturgeon population to the point that environmentalists advocate banning sturgeon fishing completely until the population recovers. However, prices for sturgeon caviar are so high that fisherman can afford to pay similarly high bribes to authorities to look the other way, making regulations in many locations ineffective.^{[citations needed]} Caviar harvesting further endangers the fish stocks, since it targets reproductive females.

The Caspian Seal (Phoca caspica, Pusa caspica in some sources) is endemic to the Caspian Sea, one of very few seal species living in inland waters (see also Baikal Seal).

The area has given its name to several species of birds, including the Caspian Gull and the Caspian Tern.

There are several species of fish endemic to the Caspian sea, including Kutum (also known as Caspian White Fish), Caspian Roach, Bream, and a species of salmon. Caspian Salmon is critically endangered

Oil

The area is rich in energy wealth. As well as recently discovered oil fields, large natural gas supplies are also in evidence, though further exploration is needed to define their full potential. Geopolitical jockeying is taking place amongst Caspian-bordering countries, especially in the light of Middle East instability and the subsequent recasting of many Western countries' energy policies. Another factor influencing this is the new US military deployment to the Central Asian region.

A key problem is the status of the Caspian Sea and the establishment of the water boundaries among the five countries bordering the Caspian. Russia, Azerbaijan and Kazakhstan signed an agreement in 2003 to divide the northern 64% of the sea among themselves, although the other two bordering countries, Iran and Turkmenistan, did not agree to this. This is likely to result in the three agreeing nations proceeding with oil development regardless; Iranian and Turkmen development is likely to stall.

At present, Azerbaijan and Kazakhstan have seen the biggest increase in oil production, an increase of 70% since 1992. Despite this, the region is still achieving less than potential output, with total regional production 1.6 million barrels (250,000 m³) per day, roughly equal to Brazil's production. This is expected to triple by 2010.

The oil in the Caspian basin is estimated to be worth over USD $12 trillion dollars.

International disputes

There are three major issues regulated by the Caspian Sea status: access to mineral resources (oil and natural gas), access for fishing and access to international waters (through Russia's Volga river and the canals connecting it to the Black Sea and Baltic Sea). Access to the Volga-river is particularly important for the landlocked states of Azerbaijan, Kazakhstan and Turkmenistan. This issue is of course sensitive to Russia, because this potential traffic will move through its territory (albeit onto the inland waterways). If a body of water is labeled as Sea then there would be some precedents and international treaties obliging the granting of access permits to foreign vessels. If a body of water is labeled merely as lake then there are no such obligations. Environmental issues are also somewhat connected to the status and borders issue. It should be mentioned that Russia got the bulk of the former Soviet Caspian military fleet (and also currently has the most powerful military presence in the Caspian Sea). Some assets were assigned to Azerbaijan. Kazakhstan and especially Turkmenistan got a very small share (because they lack major port cities).

• According to a treaty signed between the Persia (Iran) and the Russia, the Caspian Sea is technically a lake and it is to be divided into two sectors (Persian and Russian), but the resources (then mainly fish) would be commonly shared. The line between the two sectors was to be seen as an international border in a common lake (like Lake Albert). Also the Russian sector was sub-divided into administrative sectors of the four littoral republics.
• After the dissolution of the Soviet Union not all of the newly independent states assumed continuation of the old treaty. At first Russia and Iran announced that they would continue to adhere to the old treaty (but they don't have a common border any more, so this is practically impossible). Kazakhstan, Azerbaijan and Turkmenistan announced that they do not consider themselves parties to this treaty.
• Later followed some proposals for common agreement between all littoral states about the status of the sea.
  • Azerbaijan, Kazakhstan and Turkmenistan insisted that the sectors should be based on the median line, thus giving each state a share proportional to its Caspian coastline length. Also the sectors would form part of the sovereign territory of the particular state (thus making them international borders and also allowing each state to deal with all resources within its sector as it wishes unilaterally).
  • Iran insisted that the sectors should be such that each state gets a 1/5th share of the whole Caspian Sea. This was advantageous to Iran, because it has a proportionally smaller coastline.
  • Russia proposed a somewhat compromising solution: the seabed (and thus mineral resources) to be divided along sectoral lines (along the two above-described variants), the surface (and thus fishing rights) to be shared between all states (with the following variations: the whole surface to be commonly shared; each state to receive an exclusive zone and one single common zone in the center to be shared. The second variant is deemed not practical, because of the small size of the whole sea).

• Current situation

Russia, Kazakhstan and Azerbaijan have agreed to a solution about their sectors. There are no problems between Kazakhstan and Turkmenistan, but the latter is not actively participating, so there is no agreement either. Azerbaijan is at odds with Iran over some oil fields that the both states claim. There have been occasions where Iranian patrol boats have opened fire at vessels sent by Azerbaijan for exploration into the disputed region. There are similar tensions between Azerbaijan and Turkmenistan (the latter claims that the former has pumped more oil than agreed from a field, recognized by both parties as shared). Less acute are the issues between Turkmenistan and Iran. Regardless, the southern part of the sea remains disputed.

• • Russia and Kazakhstan signed a treaty, according to which, they divide the northern part of the Caspian Sea between them into two sectors along the median line. Each sector is an exclusive zone of its state. Thus all resources, seabed and surface are exclusive to the particular state.
  • Russia and Azerbaijan signed a similar treaty about their common border.
  • Kazakhstan and Azerbaijan signed a similar treaty about their common border.
  • Iran doesn't recognize the bilateral agreements between the other littoral states, but this has limited practical implications, because it doesn't have common borders with Russia and Kazakhstan. Also Iran continues to insist on a single multilateral agreement between all five littoral states (as the only way to achieve 1/5-th share).
  • The position of Turkmenistan is unclear.

After Russia adopted the median line sectoral division and the three treaties already signed between some littoral states this is looking like the realistic method for regulating the Caspian borders. The Russian sector is fully defined. The Kazakhstan sector is not fully defined, but is not disputed either. Azerbaijan's, Turkmenistan's and Iran's sectors are not fully defined. It is not clear if the issue of Volga-access to vessels from Azerbaijan and Kazakhstan is covered by their agreements with Russia and also what the conditions are for Volga-access for vessels from Turkmenistan and Iran.

Eurasia Canal

In July 2007], in order to boost his oil-rich country's access to markets, Kazakhstan's President Nursultan Nazarbaev planned a 700km link between the Caspian and Black sea. The "Eurasia Canal" would transform landlocked Kazakhstan and all Central Asian countries into maritime states, enabling them to significantly increase trade volume. While the canal would traverse Russian territory, it would benefit Kazakhstan through its Caspian Sea ports.

Characteristics and ecology

The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, though it is not a freshwater lake.

The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it is endorheic, i.e. there is no natural outflow (other than by evaporation). Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans. The Caspian became landlocked about 5.5 million years ago. The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians claim that a medieval rising of the Caspian caused the coastal towns of Khazaria, such as Atil, to flood. In 2004, the water level was -28 metres, or 28 metres (92 feet) below sea level.

Over the centuries, Caspian Sea levels have changed in synchronicity with the estimated discharge of the Volga, which in turn depends on rainfall levels in its vast catchment basin. Precipitation is related to variations in the amount of North Atlantic depressions that reach the interior, and they in turn are affected by cycles of the North Atlantic Oscillation. Thus levels in the Caspian sea relate to atmospheric conditions in the North Atlantic thousands of miles to the north and west. These factors make the Caspian Sea a valuable place to study the causes and effects of global climate change.

The last short-term sea-level cycle started with a sea-level fall of 3 m from 1929 to 1977, followed by a rise of 3 m from 1977 until 1995. Since then smaller oscillations have taken place. These changes have caused major environmental problems.

Transportation

Several scheduled ferry services operate on the Caspian Sea, including:

• line between Turkmenbashi, Turkmenistan (formerly Krasnovodsk) and Baku
• line between Baku and Aktau

Freezing

The northern portion of the Caspian Sea freezes in winter, and in the coldest winters ice will form at the south.

From Wikipedia