Major Water Bodies of the Earth PDF

Major Water Bodies of the Earth Introduction with Seenfromspace, the Earth looks blue and watery. This is because two-thirds of it is covered water.The water is held in oceans, seas, lakes,...

Major Water Bodies of the Earth Introduction with Seenfromspace, the Earth looks blue and watery. This is because two-thirds of it is covered water.The water is held in oceans, seas, lakes, glaciers and rivers. oceansare the vast open expanse of water. Seas are partially enclosed by land. While oceans and hold seas are saline (salty) water bodies, lakes and rivers carry fresh water. A few lakes may saline water. cycle. All the water on our planet goes round and round in a great cycle, called the hydrologic Waterthat falls to the ground as rain is soaked up by the Earth (groundwater), some is taken up by plants and animals, and some is added to water bodies like lakes, rivers and oceans. transpiration) + Surface water evaporates and forms clouds. Water is also lost from plants (by and animals. Clouds condense, precipitate as rain and become part of the Earth's water system. Lakesand rivers provide the fresh water needed by plants and animals to exist. Not only is water also necessaryfor carrying out the 'various reactionS that take place within our bodies, it is requiredfor the chemical reactions that are carried out in laboratories and factories. Also, activities likewashing and cleaning would not be possible without water. It is therefore, hardly surprising that early civilisations arose and River Valley Civilisation flourishedin the river valleys of L Baikal River Indus, River Nile, River L Balkhash Tigris and Euphrates and the (Chinese) Black Sea Yellow River. Harappanand Vedic Civilisations Yellow Importanceof Rivers iterra n ea: South 1. The soil of the river is very Mesopota n an China fertile. Hence, agriculture is und Babylon Civilisation easier here than elsewhere. Egypt Ancient Arabian Sea Bay of Civilisation 2. The inhabitants of this place Bengal can get water for their use, INDIAN OCEAN their cattle and their fields. It is very easy to sink wells or dig canals in the soft soil of these rivers. Rivers are a source of food. People can obtain food by fishing and by growing crops. 5. The rivers provide soft clayfor building houses. Riversmake transportation and communication very easy. Rivers can be used for inland transport of people and cargo. Wateris a valuable natural resource and it tends to get polluted by various human activities. It is ourforemostduty and obligation to protect, preserve and conserve this resource. 45  Major Oceans, Seas, Lakes and Rivers of the World Oceans of the World There are four main oceans - the Pacific Ocean the An ocean is a vast, continuous body Atlantic Ocean, the Indian Ocean and the Arctic Ocean. of water that surrounds the continents. The merging of first three of these oceans gives rise to the fifth ocean - the Southern Ocean. metres The Southern Ocean is also known as the Antarctic Ocean because it surrounds the continent Antarctica. 2000 o o o 1. The Pacific Ocean 4000 o It is the deepest and the largest ocean. It covers nearly one-third of the Earth's surface. The o 5 502m 6000 deepest part of the Earth's crust, the Mariana Trench lies in this ocean floor. The average a. 7 236m 8000 7 450m depth of the Pacific Ocean is about 4250 m. 8 380m It is bounded on the west by Asia and 10000 8,848m Australia and on the east by North and South America. 11,033m The International Date Line passes through This diagram compares the depth of thedeepest the Pacific Ocean. known point in each ocean with the heightoj Mount Everest. 2. The Atlantic Ocean It is the second largest ocean, about 'half the Coast and Coastline size of the Pacific Ocean. It has an average Coast: The boundary between land and seais depth of 3300 m. called the coast. Coasts may be borderedb) The Americas lie to the west of the Atlantic cliffs, dunes or pebble beaches. Ocean and Europe and Africa to its east. It Coastline: The coastline is the line reachedby connects to the Arctic Ocean through the the highest tides each year. Denmark Strait, GreenlandSea, NorwegianSea and the Barents Sea. It has a very long and indented which provides good sites for fheltered harbours. When the coastline is indented, deep water comes close to the harbour and provides a large entrance for ships. The Iharbour is protected from strong winds, Uangerous currents and there is no problem of silting. Some of the world's best seaports (e.g., London, New York, Montreal) are along the Atlantic coast. The shipping routes across the Mid-Atlantic Ridge North Atlantic Ocean connect North America Submerged in the middle ofthe Atlantic Oceanis and Western Europe. It is therefore, the busiest a mountain range called the Mid-Atlantic Ridge bcean for trade and commerce. Some ofits high peaks form islands, like Iceland'  Indian Ocean 3. The The Indian Ocean is the third largest ocean and named after a country. the only ocean It has an average depth of 3960 m. It is borderedby Africa on the west, Asia on the north and Australia in the east. In early times it served as the trade link between the Far East and the Western world. It continuesdown south as the Southern Ocean. 4. The Southern Ocean Ocean Facts The Southern Ocean is the fourth largest in size. l. The Pacific Ocean is so huge that all the Its depth ranges between 4000-5000 m. continents could easily fit into it. It lies in the Southern Hemisphere. 2. The explorer Ferdinand Magellan named the ocean 'Pacific' meaning calm The northern boundary of the Southern Ocean merges with the southern extension of the or tranquil. Indian Ocean. 3. The North Pole is situated in the middle ot The ocean is characterised by the presence of the Arctic Ocean; there is no land at the large and small icebergs. North Pole. 5. The Arctic Ocean It is the smallest ocean. It has an average depth of 1205 m. It lies in the Northern Hemisphere, within the Arctic Circle. It extends into the Atlantic Ocean and the Bering Strait connects it with the Pacific Ocean. Most of the Arctic Ocean remains frozen with thick ice for most of the year. It is a floating raft of ice. Usefulness of Oceans I. Oceansprovide Iprge amounts of water to the atmosphere through evaporation. Water vapour in the air provides freshwaterin the form of rain and snow. Thus the hydrological balance is maintained. Oceanshave a inoderating influence on the climate of coastal regions. Withthe development of shipping, oceans provide cheap means ottransport. Theocean is a valuable source of y enewable energy. The tidal energy is converted into electricity by using special generators. Oceansare a source of mineral and mineral oils like petroleum and natural gas. Withits rich variety of marine life, the ocean is an important source of food. In Subarctic regions, the warm ocean currents keep the coast free from ice and make it available for fishing.  Major Seas of the World A sea is an.expanse of water, shallower and smaller Terms to Note than an ocean. It may be partially or completely surrounded by land. 1. Island: An island is a piece of land completely surrounded tha by water. The water body or sea that separates a coastal zone from the open ocean is called a marginal "a. A Example: Australia marginal sea may be surrounded by islands, 2. Archipelago: An archipelago is a chain archipelagos or peninsulas. If the salt water body is Q cluster of islands, or a sea containing a clustä completely surrounded by land, it is called an inland of islands. sea. Example: Andaman and NicobarIsland: A marginal sea is an extension of an ocean. For example, the Bering Sea is an extension of the Pacific 3. Peninsula: A peninsula is a piece of land Ocean, the MediterraneanSea is the eastern extension joined with a larger landmasson oneside of the Atlantic Ocean, while the CaribbeanSea is the surrounded by water on three sides. western extension of the Atlantic Ocean. The Arabian Example: Southern India Sea is the northern extension of the Indian Ocean; Among the inland seas, the Caspian Sea is the largest. Water The northern part is drained by the Volga River, Land making it an almost freshwater lake. The southern part of the sea is more saline. Water The Dead Sea has the highest salinity among water bodies. Major Water bodies of the World ARCTIC OCEAN North- Sca L. Onega L.BaikaI Bering Sea R. The Great Lakes Bla Aral Sea Mediterranean NORTH Sea 6 PACIFIC R. St. Lawrence NORTH Caspian Sea OCEAN ATLANTIC 'F?ORT1f R.Mississippi O C E AN Dead Sea L. Chilika PACIFIC OCEAN Caribbean? Sea Red Sea -Arabian Sea L. Vic ria INDIAN OCEAN. s:bLfi SOUTH SOUTH PACIFIC L,Titicaca ATLANTIC R. Darling R Murray OCEAN OCEAN SOUTHERN OCEAN  Sea Facts often described 1. The Dead Sea,from Jordan river.as a 'salt lake', gets its water The salt content of the Dead Sea is 10 times sea water. that of normal animalsDue to this there is no life (fish, aquatic or vegetation) in the DeadSea. That is how it got its name, Dead Sea. Due to Aligh salinity, the human body can easily float in it. 2. The Black Sea is surrounded by six countries - Turkey, Romania, Ukraine, Bulgaria, Russia and Georgia. 3. The Red Sea is part of a thriving Shipping route between Europe, the Persian Gulf and East Asia. 4. The BeringSea is home to a large number of seabirds and marineanimals. Some of the rarest of rarespecies of whales live in these waters. 5. The NorthSea is the largest fishing ground in the world. 6. TheAral Sea is slowly drying up. Once the world's fourth largest inland sea, it began losing waterever since 1950s when soviet engineers began divertingthe two rivers that sustain it, theAmu Darya and the Syr Darya, in order to grow cotton in the desert.' MajorNaturalLakes of the World A IPO is a Pater body surrounded by land on all sides.It may be natural or artificially created, Transition from Sea to Lake Lakesare found on 411continents, ,except Antarctica. Salt water sea QJakeand an inland sea are differentiated by the mayeach is formed. Salt water body closed off from sea. Now A lakeis a body of water that has collected in a called Inland sea. basin from precipitation, snow melt runoff and groundwaterinflux. It naturally holds freshwater. Example:The Great Lakes, Lake Titicaca, Lake Baikal Fresh water flows into it from rivers and melting glaciers. Salinity decreases. An inlandsea is a pody of water created by an increasedsea level, pausing water to move on andoff a continent over geologic time. Ifsalinity decreases significantly, a freshwater Example:The Caspian Sea was formed when its basin lake is formed. filledupbythe rising sea levels that flushed over the land. en the sea withdrew,the basin was high enough and A freshwaterlake can become saline if it containedthe sea water. Although the Caspian Sea is now becomes open to the sea, for example, the fedbystreams Baltic Sea. and snow melt, and has an average salin- 10'abouthalfway between freshwater and ocean water, it The Black Sea has alternated between fresh wasnot actually It created by streams and snow melt, Hence and saltwater conditions over time. is an Importance of Lakes Lakes provide us with a numberof environmentaland commercial benefits. 1. Lakes are the best available freshwater source on the Earth's surface. 2. Lakes provide water for drinking, agriculture and industrial uses. 3. Lakes work to replenish groundwater. Migratory birds at Lake Chilika, which India's largest salt water lagoon. 4. Lakes serve as commercial fishing grounds. A lagoon is a shallow body of water separate 5. Lakes help in the maintenance of the aquatic from a larger body of water by barrier island ecosystem. or reefs. 6. Lakes are a popular tourist destination. Major Natural Lakes of the World 1. Lake Baikal: Located in southeastern Siberia (Russia), it is the oldest and the deepest lake. holds 20% of the world's unfrozen surface freshwater. 2. The Great Lakes: Located in eastern North America (USA), the chain of five lakes - Lake Superior, Lake Huron, Lake ake Superior Ontario Michigan, Lake Ontario and Lake Erie form the largest group of freshwater lakes. 3. Lake Onega: Located in north west Wisconsin L ke Huron e Ontyric Russia, this is Europe's second largest Lake Michigan freshwater lake. Nearly 50 rivers drain Michigan into this lake. ak rie It was formed during the last Ice Age Pennsylvania almost 12,000 years ago, through the carving activity of glaciers. Peru and Bolivia, Lake Titicaca is the larges 4. Lake Titicaca: Located on the border between the world's highest commercially navigabll freshwater lake in South America. It is also water body. three 5. Lake Victoria: Located between the this is countries, Kenya, Uganda and Tanzania, lake the largest freshwater lake in Africa. The African Lake Chilika occupies a shallow depression in the plateau and is the source of the river Nile. 6. Lake Chilika: Located in Odisha, on the east coast of India, it is Asia's largest brackish water lagoon. It provides wintering ground for migratory birds in the Indian subcontinent. Chainofislands Bay of Beng al  5. Important Rivers of Asia * River Indus: The longest and most importantriver of Pakistawstarts its journeyfromthe jibetan Himalayae; flows down into India and Pakistan and drains into the arabian Important tributaries of the Indus are gaskar,- Nubra, Beas, RavL Chenab andEurn! * River Ganga: Starting its journey from the Gangotri glacier at For-nuki in the mighty imalayag, this €01y river of the Hinduß makes its way through the NorthernPlainsOf ndia and Bangladesh and drains into the pay of Bengal} * River Yangtze (Chang Jiang): This 6300 kri river is the AsiÅ and the'bid @ngest in the world. Originating in -the-tjbetpn_Platea1.u of Chinå, the river COUrses mostly through mountains and serves a border between Émprovinces in It empties into the Fast China Sea, * River Huang He: Also called the Veilöw Rive} due to the imparted bythe$ft it carries, the river is frone to devastating f1004S in its lower course. For this reason it is also referred to as The river rises in the eastern part of the gunlun mountains in est Chida, traverses a distance of $464 -kri through nine provincesof China, and finally drains into the yæ_Seå River 0b: Originating in the Mountains-of Russij, this $90 kry010ngriver winds its way across WesternSiberiå to its outlet through the Gulf of 0b into the[Fara Sea of the rctic Ocean. The river is navigable and facilitates cargo ttransportfrom the interiorsof ussia to trading centres and Minor Water Bodies Bay Gulf Strait A bay is a — A gulfis a ßrgeinlet oftnezVGiéh A strait is a that directly connects to a germain body ofw$erSUchV enclosed andFatestwjrandmasse an bcean.eagr It ise Exam le: the Example: The the éclosed by land. e%uwGu11 Example: ay omnkål, the GulfofCalifornia, GulfofGuinea, TheStrait of Gibraltar separates Gulf of Carpentaria and connects -Bisca the to the Bay entic Ocean. StraitofGibraltc  Waterpollution is the pntarninatjon of water with saftg„ sewage md hdustrid w ustroys the balmce of "fe eventually a stream. which Whenthe cycles of the biosphere are disturbed within firnit4,natureis able to store the balance by it' own survival mechanism. For example, when river water is polluted due to washing and bathing, it is cleaned up as it flows JownstrearrVby the microorganisms and algae which ihhabit it. However, if the rate at which the water is polluted Sewage and far e*ceeds the rate at which the microorganisms and Dumpingof Oilspill wastewater trash aquaticflora can purify y, or if the¯organisrns fhemselvesare due to the Fluting agent€, then the damage Is¯alrnost EiéØérsibI&. Jn¯such a situationall settlements dotting the river bank will get pollutedwater, whi%h in turn will _leadto a host of PaterreIated_diseaseSand problemå Causes of Water Pollution I. Sewage and waste matter: Human activities produce @mestic, industri4V and @üeulturaV wastewater that pollute lakes and rivers. Sewage is the term used for wastewater that often contains@eces, uringand laundryyaste. Sewage is @odégradableand most of it is broken down by the environment. However, untreated sewage water can contaminate the and cause-adiseases like in humans. Industrial waste consists offtÖiiö chemicals that are released from tåetorieÉ and enter the Eater system and food chaip. Most of the chemicals like Plastic, rubber, metal, glass, detergent, and qsbestös are biodegradable, hence fertilisers, synthetic fabric are non remain in the environment for @ätSf They biodegradable. Paper, wood, organic waste cause harm to humans as well as aquatic life (rotting fruits and vegetables) are forms. For example, mercury poisoning in biodegradable. mans results in a disease This means that paper can be broken down into Agricultural runoff from the fields contain Simpler and harmless substances over a period Of chemicals like fertilisers, pesticides and Lime by microrganisms like bacteria and fungi. ihsecticides, sediment eroded_from-thelaod, Plastic, on the other hand, does not get degraded and "féodlpr6cessing—wa$tes. and are harmful to plants and animalS. 2. Marine Dumping: Non biodegradable garbage and of Aquatic Ecosystem litter from household activities are dumped into the Fish and other aquatic animals get Aquatic plants and animals depend upon theO*vo *ntangled in polythene bagg and 'Offocater to dissolved in thc water for their survival. Sewage Ideattl. Toxic industrial effluents and domestic and domestic wastes like fruifs and wastes that are éümped pollute the water@and vegetables also need oxygen for their —thus d&siroy_the ecosystem, competing wi th the a@ätic life formsfthe pollutants cause the oxygen level in the water to decrease 3. Oil Spills and Leakage: Accidental éiGpijTs cause This affects the f$ßal.k)fthe organi.h the death of of sea birßs andAfifarinw year. 4. Radioactive waste: If OOZIéåöwastewcomes if @ntac€with underground wat", the @4iationS get absorbed in water and then enter our body food ch4ih. 5. Leaking sewer lines, undergroundgas and oil pipes: These and make it 6. Global warming: Accumulation of and other greenhouse -gases the atmosphere ses the water temperaturevThis results in the death of many species of @Liatic-organismt Victimof an oil spill, this sea bird is covered 7. Natural causes: Volcanic activity and floods add with oil. Its feathers are stuck and it is unable ndesirable into the water and cause atéi to fly. ollution Comparison of Major Water Bodies Ocean Sea Lake River A sea is an A lake is A river is a I of water iinuous body of water t and than surroundedbdonallsi ows from its an ocean. t may be partially Itmaybenatural or artificially completely surrounded by created. highland source, through Oceans sustain the or the lowlands towards land. Lakes are a freshwater VYt010gical cycle'nd are open sea, ocean or lake. a valuable_soerce of Two types of sea are source and theyprovid€€åtéi It is a valuable o source evwableænergy. recognised for ustrial uses. s wa r. Oceans moderate the A marginal sea separates the Lake replenish groundwater, Navigable rivers enable from fishing he g0 Warm ocean currents An inland sea is The fertile plains all keep the coast Over tinyean inland em valleys of rivers suppo and@lefishinP sea nutransform into a Lakes are a +rian%settlemeåis It is a source00hy ectnclty.