FOREWORD - Ministry Of Earth Sciences

How are Oceans important to us?Oceans are a huge storehouse of resources like minerals (metals, oil,natural gas, chemicals etc.), food (fish, prawns, lobsters etc.) andenergy (waves, water currents, tides etc.). We have been using oceansfor transporting goods (in ships and oil tankers) and for recreationpurposes (beaches, water sports etc.). We have also been using oceansto dump all municipal waste, industrial effluents, pesticides used inagriculture etc. resulting from activities of the ever-growingpopulation.In addition, oceans control weather andclimate and thus considerably influence theenvironment. Even the quality of air that webreathe depends greatly on the interactionbetween the oceans and the atmosphere.Oceans have served as channels of adventureand discovery. From expeditions to seas farand near, we have understood how MotherEarth works, how the sea-floor is formed and,how parts of the continents have movedthousands of kilometers over a long period.Off-shore oil platformThus, there are many reasons to study theoceans and benefit from it.... .. 5

EquatorEquatorP A N G A E AAbout 225 million years ago(Triassic Period)L A U R A S I AGONDWANALANDIndiaTETHYSSEAIndiaAbout 200 million years ago(Jurassic Period)IndiaEquatorSea-floor spreading and driftingContinentsWay back in 1912, a German astronomer and meteorologist,Alfred Wegener proposed that continents are slowly movingrelative to each other and shifting their positions. If we moveAfrica and South America near to each other, the oppositecoasts, including continental shelves fit together so well.Fossils like Glossopteris (a plant fossil) and Lystrosaurus (a fossilreptile), which were extinct 200 million years ago, which areessentially land inhabitants are now scattered across severalcontinents. All these suggest that once upon a time, there wasone single landmass for which the name PANGAEA - meaningall Earth- has been given. Look at the pictures carefully andyou would notice how India migrated from the icy Southernhemisphere to Northern hemisphere by crossing the equatorcalculated at an average speed of about 5 cm per year! Youwould also notice that huge oceans are formed due toseparation of continents from one another. This involves thespreading of ocean-floor on either side of the mid-oceanicridges (huge mountain chains buried under ocean water - seefigure on page no.8) and creation of new crust at the spreadingcentres.About 135 million years ago (Cretaceous Period)NorthAmericaAsiaIndiaIndiaEquatorSouthAmericaEquatorAfricaAustraliaAntarcticaAbout 65 million years ago (beginning of Paleogene Period)Today6 ... ..

Fossil evidence of theTriassic land reptileLystrosaurus.AFRICAINDIAFossil remains ofCynognathus, aTriassic land reptileapproximately3m long.SOUTH AMERICAAUSTRALIAFossil remains ofthe fernGlossopteris,found in all of thesouthern continents,show thatthey were oncejoined.ANTARCTICAFossil remains of the freshwaterreptile Mesosaurus.If the continents are joined together (about 200 million years ago) we can also trace certainfossils of plants and animals across the continents as shown in the above figure as colouredbands. This is one of the outstanding contribution of Snider-Pellegrini and Wegener.It is the break-up of PANGAEA, a large rigid slab- a plate, into many plates and their driftingaway due to tectonics - an internal dynamic force, that has led to the present disposition of thecontinents. This process is called plate tectonics, a concept which was introduced some 40years ago. Continents are made up of more than one plate, along with parts of ocean basins.The map shows the shapes and locations of these plates and the directions in which theymove. Most earthquakes and volcanoes occur where plates collide.The Pieces of the PuzzleEarth's crust is like a gigantic puzzlemade up of a dozen or so pieces. Themap shows the shapes and locationsof these pieces, and the directions inwhich they move. Most earthquakesand volcanoes occur where platescollide.Plate boundariesDirection of plate movementVolcanoesEarthquake zones... .. 7

121. Indus fan2. Bengal fanHow does the Ocean-floor look like?The ocean-floor looks very much like our land. It has soaring mountains,plunging valleys and rolling plains. There are mountain chains that aremightier than the Himalaya, called the mid-oceanic ridges, which run in themiddle of all the major oceans for a total length of about 74,000 km. Midoceanicridges are centres of sea-floor spreading where new ocean crust iscreated by outpouring of lava. This new crust continuously spreads awayfrom the mid-oceanic ridges - something like a conveyor belt! Finally theoceanic crust descends or gets pushed down into deep trenches which areabout 3 to 6 km deeper than the adjacent sea-floor (see figure above). This is howthe destruction of oceanic crust occurs. All along the trenches, lava comesout at temperatures of above 800 o to 1000 o C and builds up a chain of volcanicislands (along landward side), followed by frequent earthquakes.Main features of the ocean floor right from coastal plain to the abyssal plains.14123456789310111111121091331. Continental Rise2. Continental Shelf3. Abyssal plain4. Canyon5. Continental Slope6. Island arc7. Volcano8. Oceanic trench9. Guyot10. Seamounts11. Transform faults12. Oceanic ridge13. Volcanic island14. Continent8 ... ..

This zone is also known as island arc or Ring of Fire (see figure at the bottom). Volcanic rocks arefound mainly on mountains and ridges, but other areas of the sea-floor are covered bysediments or mud giving a smooth appearance. For most part of the ocean, sea-floor is darkas sunlight reaches only up to 200 meters from the sea surface. The water in the deep parts ofoceans (about 1,000 meters) is very cold (2 to 4 0 C)!Cross section of the Ocean: Land to deeper parts of the oceanIf we take a geophysical traverse from Mumbai westwards across the Arabian sea we willfind different levels of the ocean floor telling us all the mysteries of the submerged lands andalso unexplored fascinating deeps. Our new petroleum deposits are indeed located on thecontinental shelf, west of Mumbai.Baseline(either normal or straight)200 M350 M2000m Isobath + 100MLow WaterContinentFoot of Slope (Max. change in gradient)ContinentalShelfSlope60 MAbyssalPlainRidgeSubmarineTerritorial Sea Baseline(TSB)Sedimentary RockLandInternalWaters0CoastalWatersTerritorial SeaContiguous ZoneExclusive Economic Zone12 24Nautical Miles from Territorial Sea Baseline (TSB)Ocean Crust50Kurile trenchJapan trenchAleutiantrench... .. 9Java (Sunda)trenchRyuku trenchPhilippinetrenchIzu Bonin trenchMariana trenchChallenger DeepPACIFICOCEANEquatorBougainville trenchTonga trenchKermadec trenchMiddle AmericatrenchPeru-Chile trenchPuerto Rico trenchSouth SandwichtrenchRing of FireAleutian islands in theGulf of Alaska and Javatrench in South East Asiaare classic examples forzones of island arc -Ring of Fire.

How do scientists study the Oceans?A well-equipped research ship is the most important mobile researchstation required to study the sea. Looking at the oceans extending upto the horizon is both amazing and interesting. As the ship movesaway from the coast towards the deeper part of the ocean, the muddy/greenish colour turns to a deep blue colour and dolphins and flyingfish may be seen jumping out of water. Rough weather can sometimesmake the scientists on board the ship feel sea-sick. But the voyage isgenerally adventurous and challenging.Ocean scientists known as oceanographers map the sea-floor featuresby using an echo sounder. It emits sound pulses from the ship towardsthe bottom from where they are reflected to the surface, and the timetaken is recorded. Knowing the velocity of sound in ocean water, theyfind out the water depth below the ship. Present day multi-beam echosounders provide wide coverage of the sea-floor depths simultaneously.A side-scan sonar deployed at shallow water depths gives a picture ofthe features of the sea-floor and sunken ships and similar objects.What lies beneath the sea-floor? Sound of different frequencies canpenetrate through the sea-floor, get reflected and come back to the58134271. Coastal Research Vessel2. Crawler3. Deep Water Data Buoy4. Floating OTEC Plant5. Island6. Remotely operable vehicle7. Sub-bottom Profiling8. Wave Energy Plant610 ... ..

Side-scan sonarNet monitorReceiver321ship. Through such seismic investigations, scientists are able tofigure out what materials are there below and what theirstructures are.4Scientists use a specially designed grab to collect samples fromthe sea-floor sediment or mud. Long, cylindrical samples (cores)of sediments are obtained using a corer.65A sediment trap is used to “trap” sediment particles that aresettling through sea water. They provide information on theprocesses going on in the water column.Nets are used to capture relatively small organisms that liveat/near the sea surface. Scientists study the types andabundances of these organisms and understand their ecology.Measuring properties of water at various depths in the oceanhelps in understanding how ocean water moves at differentdepths. This can be done by lowering instruments from thesea surface to sea-bottom, which continuously measure thetemperature, salinity and other properties of seawater.Scientists go down the sea in ‘submersibles’ to directly observeseafloor features and make various other observations of marinelife and nature of sediments.78Submersible1. The pilot guides the submersible usingthese hand controls.2. These powerful lights help the pilot tofind his way.3. This part is see-through, so the pilotcan look around.4. Deep Flight gets its power from tenbatteries (five along each side).5. Bottles filled with oxygen allow thepilot to breathe.6. These wings don't move. They keepthe submersible steady in the water.7. Engines, called thrusters, turn thepropellers.8. Propellers spin around quickly, pushingthe submersible forward.Fans : (see top fig. on page 8) It is interesting to note that in the Bay of Bengal, there is a huge fan called"Bengal Fan" which is made up of sediments brought in by the Ganges and Brahmaputra rivers.This is considered to extend for nearly 3000 km with a maximum width of about 1400 km. Similarly,the Arabian sea is fed by voluminous sediments by the mighty Indus river draining the Himalayanranges. The sediment thickness exceeds 10 km and covers nearly 1500 km in length with a widthof about 960 km. This beautiful structure in the Arabian sea is known as "Indus Fan".... .. 11

Latitude40°NLongitude40°E 80°E 120°E 160°E 160°W 120°W 80°W 40°W 0°W20°NEquator20°S40°STemperature difference between surface and depth of 1000 mLess than 18°C22° to 24°C18° to 20°C20° to 22°CMore than 24°CDepth less than 1000mDo Ocean water masses move?Oceans are not just a body of stagnant water. Ocean water movesfrom one place to another. Waters at different depths move in differentdirections and at different speeds. Surface waters move because ofwind. Waters at depths also move because of differences in density,temperature and salinity. Such are called currents. Gravitationalattraction, primarily of the moon and the sun, produces tides.Currents are like rivers in the oceans. They can carry enormousamounts of water. For example, the Antarctic Circumpolar Current cantransport 100 million cubic metres of seawater per second! Somecurrents containing mud travel at speeds of 4m/sec. They are knownto have transported blocks weighing as much as 9,000 kg!Water currents transport heat, sediment particles, dissolved oxygenand nutrient elements from one place to another. This is crucial becauseall forms of marine life needs oxygen and nutrients for their growth.12 ... ..

Floating Oil Rig1Do the Oceans hold any economicpotential?Oceans contain a wide spectrum of mineral, energy- and foodresources. They are the earth's biggest storehouse of minerals includingoil and gas. Although these are available on land, our demand forresources has been rising continuously because of rapid increase inworld population and demand for comforts and amenities. Besides,mineral resources are not renewable, once mined and used, they arelost. To form again, it takes several millions of years and this is thereason why they are known as "non-renewable" resources.2Seabed3Oil1. These floats stop the rig fromsinking.2. Cables with anchors on them stopthe rig from moving.3. This pipe goes into the seabed asfar as the oil. The oil is thenpumped up.... .. 13

Who owns these resources and whocan utilize them?The United Nations held three conferences (between 1967 and 1982)on this aspect and finally the United Nations Convention on the Law ofthe Sea was signed in 1982. The Convention laid down rules andregulations to rationally manage oceanic resources and conserve themfor future generations. The oceans have been divided into severalzones: Territorial sea (12 nautical miles (n.m.) from coastline), ExclusiveEconomic Zone (EEZ; 200 n.m. from coastline ; see sketch below), and theInternational Area of the Seabed (beyond the EEZ). Coastal nations haveexclusive rights to explore and exploit all the resources within theirrespective EEZ’s. Resources in the international area are a commonheritage of mankind.KandlaVeravalINDIAIndia has an EEZ of2 million sq km, whichis 2/3 of our land area.BhubaneswarKolkataMumbaiRatnagiriVisakhapatnamKakinadaMarmagoaLakshadweepIslandsChennaiMangaloreKochiTuticorinAndamanandNicobar IslandsVizhinjamKanyakumariSri LankaExclusive Economic Zone14 ... ..

16 integrationsbarometer 2007Det är viktigt att understryka att det storleksmässigt skiljer sigmycket mellan de tre olika grupperna när det gäller storlek. Avdetta följer att ju större en grupp är, desto större är chansen attallmänheten bevittnar kränkningar mot den berörda gruppen.Det är vid kvantitativa beskrivningar av kränkningsnivån är detviktigt att nivån relateras till gruppens storlek.Vad gäller allmänhetens bevittnande av verbala rasistiskakränkningar mot tre minoritetsgrupper visar IB 2007 att närdet gäller muslimer så har nästan 4 av 10 bevittnat verbalakränkningar. Dessutom har nästan hälften dessa kränkningarbevittnats vid upprepade tillfällen. Svarta är också en gruppsom utsatts för många kränkande kommentarer; 3 av 10 uppgeratt de bevittnat kränkningar av svarta. För både muslimeroch svarta sker det ingen signifikant förändring av kränkningsbevittnandet,utan det ligger på samma nivå som 2005. När detgäller judar ligger bevittnandet på en jämförelsevis lägre nivå.Med tanke på gruppens storlek är det dock anmärkningsvärtatt 14 procent uppger att de varit vittne till verbala kränkningarsom kan ha sin grund i en antisemitisk föreställning. En rimligtolkning av detta resultat är att den höga nivån av rapporteradeverbala kränkningar till en väsentlig del avser judar ochjudenhet i allmänhet, och inte att den i sin helhet är koppladtill Sverige. Jämfört med tidigare mätning sker en signifikantförändring 2007 som innebär att de som uppger att de aldrigbevittnat kränkningar mot judar minskar. Det kan vara värtatt uppmärksamma att den totala andelen som bevittnat nedsättandekommentarer gentemot de tre minoritetsgruppernaförblir ganska konstant i de tre redovisade mätningarna 2004–2007 (med undantag av kränkningar mot svarta som minskarnågot över tid, från 34 till 30 procent).Bevittnandet av beteendemässiga kränkningar håller sig relativtstabilt under hela mätperioden. En viss minskning verkar dockske när det gäller kränkande beteenden upprepade gånger motsvarta. I likhet med tidigare mätning kvarstår den betydandeskillnaden mellan verbala och beteendemässiga kränkningar.Endast 4 procent har varit vittne till kränkande beteende motjudar vilket ska jämföras med 14 procent för verbala kränkningar.Drygt en tiondel uppger att de bevittnat kränkandebeteenden mot svarta och muslimer. En marginell andel på 4procent har när det gäller båda grupperna bevittnat kränkandebeteenden fyra gånger eller fler. Inga statistiska förändringarsker i relation till föregående år för någon av tre grupperna.Viljan att själv engagera sig mot rasismNär det gäller frågan om allmänhetens handlingspotential förantirasistiskt engagemang visar IB 2007 att allmänheten i Sverigeär mest benägen att bojkotta företag, därefter kommer

Location MapKrishna Godavari (K.G.)Onshore & OffshoreOil & Gas fieldsVijayawadaKrishna RiverNizampatnamNizampatnambay200 meters depth contour lineTanukuPalakolluwell AmalapuramModi well NarsapurMachilipatnamGodavari RiverWESTERNOFFSHOREOil & Gas fieldsRajahmundryDelhiINDIABay of BengalMumbai Bay ofBengalK.G.BASINChennaiKakinadaBayOil and GasOcean sediments are repository of vast oil(petroleum) and natural gas deposits. They formwhen organic matter of dead micro-organisms isburied by mud on the sea-floor. Due to hightemperatures and pressures at great depths, thisorganic matter is converted into oil and natural gas.India has several offshore oil and gas fields inBombay High, Gulf of Cambay, Cauvery, Krishna-Godavari and Mahanadi basins.Gas HydrateAt low temperatures and high pressures, naturalgas (methane) gets into water molecules to form gashydrate, a relatively newly discovered mineraldeposit that occurs in ocean sediments. One cubicmeter of gas hydrate, when brought to the surfaceis expected to yield 164 cubic meters of natural gas!.This can be done and utilised as a future resource.Location MapWestern Offshore Oil & Gas fieldsKodinarDiuPatraMid TaptiNorth TaptiUmrat -1SuratHaziraSouth TaptiDamanMuktaPannaBasseinMumbaiUranNeelamHeeraAlibagLEGENDRatnaMurud... .. 17Oil FieldGas FieldShrivardhan

A rich haul of finfishOceans as a source of foodIndeed oceans are primary source of staple food to large coastalcommunities. A large number of finfish and shellfish includingshrimps, lobsters, squid, cuttlefish, prawn etc. are harvestedalong the entire coastline. Our nation is in the front rank ofglobal fish production. The country’s estimated potential forproduction is about 3.93 million tonnes of fish and shellfish.India is a major exporter of sea food items like squid, cuttlefish,lobster and a variety of fish, besides shrimp. Export of marineproducts amounted to 2,90,000 tonnes valued at Rs. 3501 croresin 1995-96 and has increased to 4,24,000 tonnes valued at Rs.5957 crores in 2001-2002.Studies on Deep Ocean Water MaricultureZone of High Primary ProductivityExperiments show increasedphytoplankton biomass insurface seawater mixed withdeep seawater in 1:1 ratio ascompared to surface seawaterNutrient rich cold deep sea waterSEA FLOORAcoustic surveys (using echo sounder) have been used in recenttimes to locate dense populations of fish. The country hasinitiated a multi-disciplinary and multi-institutionalprogramme aimed at making an assessment of the marine livingresources beyond 70m water depth.MaricultureMariculture is an alternative for increasing the production ofover-harvested or depleted stocks. Creation of artificial reefsand sea-farming projects are good for replenishing resourcesthat are degraded.20 ... ..

Medicines and Sea vegetablesfrom the OceanMedicinal plantAbout 30% of the faunal and floral species of our planet inhabitin the sea. It is believed that life originated in oceans. Somecompounds extracted from marine organisms have shown tobe anti-viral, anti-tumour, anti-biotic and may be developedinto drugs.Exploration and recovery of such drugs are one of theimportant goals of our marine exploration programme.Sea vegetables are used as food, animal feeds, dyes, medicinesand cosmetics. Sea weeds (algae) are rich in protein - higherthan even in meat, and highly enriched in calcium (higher thanin milk).These are also used as a possible prevention against cancer,blood pressure and other illnesses. Some of the well knownsea vegetables are arame, bladderwrack, dulse, hijiki, kelp, kombu,nori and wakame.Medicinal drugs... .. 21

CoralsWhat are Coral Reefs?Coral reef, AustraliaReefs are solid limestone structures created on the shallow sea bedmainly by dead biological communities - coral and algae are thecommon ones known to us. Coral larvae secrete calcareous shells oftheir own and succeeding ones grow on the shells of the dead corals.Coral reefs in the shallow waters create a varied, colourful andfascinating ecosystem.They develop in shallow depths of tropical seas with ample sunshinewhere the temperature ranges between 18 0 and 32 0 C. Lakshadweepislands are made up of coral reefs developed on oceanic basement.Extensive coral reefs also occur in the Andaman and Nicobar islands,Gulf of Mannar and Gulf of Kutch. The Great Barrier Reef on the eastcoast of Australia is the longest animal-made structure, extending forabout 3,000 km.22 ... ..

Energy from the OceansOcean Thermal Energy ConversionIn the present day conditions of severe power shortage, it is importantto develop alternate non-conventional energy resources. Oceans offera variety of environments for the production of energy, which arerenewable and non-polluting.The surface of the sea isoften windy. Big windmills,called wind turbines, could beattached to the seabed andused to make electricity fromthe wind.Wind blowing across the seaturns the windmill blades.The spinning blades power amachine called a turbineinside the windmill, whichproduces electricity.Using cold sea-bottom water and warm surface water, it is possible toharness energy. Such a programme is called Ocean Thermal EnergyConversion (OTEC). Ocean is a large collector of solar energy which ismainly responsible for generating currents. India will be deployingvery soon a 1-Megawatt floating OTEC technology demonstrationpilot plant, 60 km off Tuticorin in Tamil Nadu.Wind blowing across the ocean surface produces waves. Ocean wavescan be used to produce electrical energy. This is made possible usingthe temperature difference between warm surface water and colddeep water. A small wave energy plant has been installedat Vizhinjam in Kerala.SeabedWind PowerSea level rises and falls mainly due to gravitational attractionof the Sun and the Moon. These are called tides. As a result,sea water gushes into rivers during high tide and goes backto the ocean during low tide twice everyday. By constructinga dam, water can be stored during high tide and on itsflowing back to the ocean can be made to run turbines forproducing electricity.... .. 23

Diatoms with silica shellsLife in the OceansLife originated in the oceans. Marine scientists are carrying outresearch on sediments from hot spring areas to understand how lifeoriginated on the Earth. Oceans have supported life in a variety offorms - from microscopic algae to gigantic blue whales. Of an estimated30 million species of flora and fauna on our planet, oceans contributeto nearly 20% (about 5,00,000 species).What are marine sediments made up of?Mud or sediment that covers large areas of the ocean floor is made upof (1) clays and sands brought by rivers, (2) the shells and organicmatter of dead organisms that once lived in sea surface waters, (3)chemical compounds that are precipitated from sea water, (4) particlesthat form near hot spring areas and (5) sediments formed from thedisintegration and decomposition of ocean floor rocks. About 3.8million tons of dust from outer space is estimated to reach the oceanfloor every year.Certain parts of the sea-floor contain large amounts of calcareous(CaCO 3) and siliceous (SiO 2) shells, which are useful to man. Inaddition to having economic value, marine sediments enable us tounderstand the conditions under which they were laid down on thesea floor.Microscopic calcium carbonateshells of organismsCrystals in ocean sediments24 ... ..

Can we know the climates of the past?Yes, this is what some marine scientists attempt. Because of widespreadpollution by industries, automobiles etc., large amounts of carbon dioxide(CO 2) and certain other gases are being added to the atmosphere. Thesegases allow solar heat to come in but do not allow the heat to go back toouter space resulting in the green house effect.The CO 2level has increased by ~30% since 1800’s (from 280 to 360 partsper million; for short, ppm). It is predicted to amount to ~560-1000 ppmby 2100 AD. This will have an effect on the volume of sea-water and riseof sea level.If the present trend of CO 2emission continues, the earth’s health wouldbe greatly affected, and the consequences may be disastrous. By the endof the present century, global atmospheric temperature may rise by anaverage of 1.4-5.8 o C and the sea level by 9-88 cm (10-20 cm rise in thelast century). There will be frequent storms. Global climate will changeand so will the agricultural pattern. To make and improve such predictionsit is necessary to know variations in the past climate. Study of changes oftemperature of the oceans becomes a matter of utmost importance.Climatic conditions related to temperature, rainfall etc., during the lastone hundred years are known from instruments. We can also get a certainamount of information from historical data. But how to know theconditions of the distant past, is a crucial question.Marine sediment samples provide an excellent window into the climatichistory. The remains of marine organisms embedded in them, the type ofclay minerals present and the chemical composition of sediments giveinformation on the age of the sediment and how the climate was whenthe sediment was deposited. In this way, oceanographers havereconstructed climatic and oceanographic conditions of the past severalmillion years!Studies of marine sediment cores have revealed interesting informationof the past climate. About 11,000 years ago, the sea level was lower by100 m or even more. The earth’s climate fluctuated between cold andwarm with periodicities of 23000, 41000 and 100000 years. Severe climaticconditions that wiped off dinosaurs that once roamed on the earth’ssurface are recorded in marine sediments.1960195019401930192019101900Deep sea sediment core.. note different layers of sand, shale, sandstone, limestone withorganic remains!... .. 25The absence of oxygen causes refractory parts of the organic debris to be leftundecomposed and the sediment to remain undisturbed in the annual layers. The darklayers are the densest and represent winter sedimentations. The lighter and less denselayers are composed of diatoms and represent spring and summer sedimentation.1890 year

PotteryChariotDwaraka undersea expeditionphotographsAcoustic image of apossible river courseHeritage in the Oceans : Are there manmadeobjects and structures on the sea bed?Surprisingly, evidences of earlier heritage are to be found in the oceansalso. It is the marine archaeologists who study underwater culturalheritage; they deal with material remains in the form of submergedancient habitation/port installations and ships that sank due toaccidents or during wars. We find ancient port towns like Dwaraka,Bet Dwaraka and Somnath off Gujarat and Poompuhar off TamilNadu, which got submerged as the sea level rose during the past 11,000years. Archaeological structures were discovered at depths of 40 m,30 km off Gujarat coast in the Gulf of Khambat in Gujarat. More than2,000 artifacts (man made objects) have been collected. These includebroken pottery, semi-precious stones and stone ornaments with holes.A number of anchors of different varieties suggest that Bet Dwarakawas a potential site of a proto-historic settlement. House basementlikefeatures, channel like features indicating good drainage,and tanks with steps have also been found.Under water archaeologicalstructures26 ... ..

Are Our Oceans polluted?With a large population concentrated in coastal areas, we are pollutingthe oceans in several ways through discharge of industrial and urbanwastes, harbour activities (like fish landing, cargo handling, dumpingof ship washings, spillage of oil and ores), oil exploration, oil slicks,land run-off etc. Toxic metals like cadmium, copper, lead, mercury,nickel, zinc etc. reach the oceans through industrial discharges.Human activities in coastal regions are already having a serious impacton the marine environment and marine life. The timehas come for co-ordinated efforts to protect coastalareas and monitor the health of the oceans. This ismainly because estuaries, lagoons, beaches, sand dunes,mangroves and coral reefs along the coast are some ofour most important heritages. They serve variedpurposes but most importantly as incomparably richsources of biological diversity.MangrovesEast Coast of IndiaOil rigEstuarycarrying pollutants!... .. 27

Does the benevolent Ocean get furious?During monsoon, winds are strong, producing huge waves. Whenthey strike the coast, the waves cause considerable damage to propertyand life and erode beaches. This is called coastal erosion that is prevalentin many coastal areas. Often, man-made structures near ports andharbours add to the problem of coastal erosion.Tsunami damage, AlaskaTsunamis are large, rapidly moving ocean waves triggered by a majordisturbance of the ocean floor. They are usually caused by anearthquake but sometimes can be produced by submarine landslidesor volcanic eruptions. These waves typically travel at speeds of about600 mph. As they reach shallow water, the waves slow down butgreatly increase in height (3-20m), and thedistance between them shrinks. Theycause enormous damage to coastalpopulation and property.Violent volcanic eruptions in the oceanssometimes send out materials rangingfrom boulders to fine ash. Fine particlesgo up to several kilometers and aretransported around the globe. Forexample, the 1883 Krakatoa volcanicexplosion in Indonesia released so muchdust into the atmosphere that the earthwas plunged into darkness for severaldays!Sea FloorTSUNAMIAs the TSUNAMIapproaches the shore,the water column pilesup increasing the waveheight to dramaticproportions5 hours after Earthquake 10 hours after Earthquake17 hours after earthquake 22 hours after earthquakeExplosive volcano28 ... ..

Maitri researchstation at AntarcticaPenguinsBallonexperiments atthe AntarcticastationHow important is Antarctica to us?The air gets warmerIce melts into the seaThe sea level risesMelting IceAs the atmoshpere warmsup, the ice in the Arctic andAntarctic starts to melt.The water goes back intothe oceans, making the sealevel rise.The icy continent of Antarctica and the surrounding ocean, calledthe Southern Ocean, provide vital insights into the tectonic history ofthe earth and intricate processes like global warming, sea level riseand ozone depletion, which have a direct bearing on the sustenanceof man on this planet. The Southern Ocean is also important in thecontext of cycling of nutrient elements and climate because it containssites of deep water convection and also because its surface waterscontain large amounts of unutilized nutrients. Shrimp-like krill is animportant source of food. If due to atmospheric warming up, Antarcticand Arctic ice start melting this will considerably rise the sea level (seefigure at the left) and result in the submergence of part of coastal plains allover the world.Antarctica is perhaps the least polluted part of the earth. Study ofsome of the parameters of its environment forms the data base tounderstand the changes that have taken place in some of its earlierneighbours, which moved out, over a long period of time extendingover about 200 million years. A number of studies have been initiatedby different countries in different parts of this continent.Realising the scientific importance of this region, India has engagedherself in Antarctic research. A research station called DakshinGangotri was established in Antarctica in 1983, while a second stationMaitri was set-up in 1991. The country launched its first expedition toAntarctica in 1981. Scientists from several organisations andinstitutions have participated in 23 such expeditions so far from Indiato gather samples and data for scientific research.... .. 29

What is Satellite Oceanography?Satellite Oceanography is the study of the oceans using satelliteimageries. The digital reflectance data obtained by special sensors ofthe Landsat, SPOT, Indian Remote Sensing (IRS) and other satellitesare processed to get varied pictures of the ocean surface to interpretthe temperature, chlorophyll content, salinity, turbidity etc. and alsoto demarcate areas of abundant fish and other faunal population,ocean currents, oil slicks etc. Temporal data help in the periodicmonitoring of the different parameters.30 ... ..

Career opportunitiesEducational and Research InstitutionsNational Institute ofOceanography, GoaSeveral institutions offer M.Sc. courses in ocean-related fields forscience graduates: Universities of Mangalore, Goa, Cochin, Andhraand Berhampur, Central Institute of Fisheries Education (CIFE) etc.Besides these, marine research is conducted at the National Instituteof Oceanography (NIO, Goa, Mumbai, Cochin, Visakhapatnam), GeologicalSurvey of India (GSI, Kolkata, Visakhapatnam, Mangalore), National Centerfor Antarctic and Oceanic Research (NCAOR, Goa), National Instituteof Ocean Technology (NIOT, Chennai), Ocean Science and TechnologyCells (OSTC) of Department of Ocean Development at nine places(see map below), National Geophysical Research Institute (NGRI,Hyderabad), Oil and Natural Gas Commission (ONGC), Indian Instituteof Technology (IIT, Mumbai, Chennai, Kharagpur), Banaras HinduUniversity (BHU, Varanasi), Centre for Earth Science Studies (CESS,Thiruvananthapuram), College of Fisheries (CF, Mangalore), Central MarineFisheries Research Institute (CMFRI, Kochi) and a few other places.National Institute ofOcean Technology , ChennaiDelhi... .. 31OSTCCSMCRICSMCRI -Central Salt and Marine Chemical ResearchInstitute, BhavanagerINCOIS -Indian National Centre for Ocean InformationCentre, HyderabadBhavnagarCIFEOSTCNIOOSTCCMLRECMFRIOSTCCESSMumbaiNGRIPanaji (GOA)INCOISHyderabadTanjoreMangaloreOSTCNIOTAnna ChennaiOSTCKochiThiruvananthapuramOSTCOSTCGSIBerhampurOSTCVisakhapatnamKolkataKharagpur

Save the Oceans!Oceans are important to us in many ways. We are dependenton them for resources. Oceanic processes directly orindirectly control the climate and our environment. Marineresources, environment and ecosystem need to be protectedfrom man-made influences. Although man has conqueredthe outer space, he has not yet fully understood the oceans -our inner space. Large parts of the oceans are still unexplored.There are still many gaps in our understanding; severalmysteries of the oceans have yet to be unravealed. The nationlooks to bright and enthusiastic students like you to continuethe exciting and fascinating journey of ocean exploration.32 ... ..

Glossary0 Kilometres1020Layer 2 OceanicAcoustic methods30(Density 3.00)Layer 3 CrustGranitic(Density 3.00)Methods that use propagation of sound waves for variousMetamorphic layer40(Density 2.60)studies.50Basic Layer (Density 3.00)(?amphibolite)Bathymetry60Measurement of ocean water depth.Continental marginThe ocean floor adjacent to continents including shelf, slope7080M-discontinuityMantle (Density 3.40)and rise.Fig. - 1Continental shelfThe shallow gently sloping sea-floor extending from the shorelineStrike-slip faultto a zone where the slope markedly increases.CrustThe outermost layer of the earth. Its thickness is about 10 kmbeneath the oceans and 30-35 km beneath the continents. (see figs.1 & 3)CurrentsCurrents, more specifically, ocean currents are ocean watermasses that move from one part of the ocean to another. Theymove at different water depths and are due to winds, anddifferences in temperature and density of sea water.EarthquakeNormal FaultA violent disturbance at the earth's crust or mantle felt and/orReverse faultrecorded above the ground.Fig. - 2EcologyGrabThe study of how living creatures interact in the environment.Echo-sounderAn instrument used for measuring ocean water depths usingsound energy.ErosionThe transport of rocky or weathered material by ice or water orwind.EstuaryThe mouth of a river where fresh water from the river and seawater mix.Exclusive Economic Zone (EEZ)An area extending up to 200 nautical miles from coastline. Acoastal nation has sovereign rights over the mineral resourcesof this region.FaultA fracture (in a rock) along which the two blocks of rock havemoved relative to each other. (see fig. 2)FossilAn imprint of an animal or plant preserved in sedimentaryrocks.Gas hydrateA deposit that forms when molecules of natural gas are lockedup in a water molecule at high pressure and low temperature.At surface temperature and pressure, it expands 164 times.An instrument used for collecting samples of surface sedimentsfrom the ocean floor.Greenhouse effectThe effect of atmospheric carbon dioxide and other gases thatallow solar radiation to pass through but prevent the long -wavelength radiation from going out to space, thus increasingatmospheric temperature. It is similar to the effect in a greenhousethat is used to grow plants in temperate regions. Hence theterm “greenhouse effect”.International Area of the SeabedThe area of the sea-floor beyond the Exclusive Economic Zone.LavaMolten rock material that is brought up to the surface by avolcano or along a fissure.MagmaMolten rock material that is below the earth’s surface.Mid-oceanic ridgesSubmarine mountain chains that run in the middle of all themajor oceans. They are characterised by volcanic and earthquakeactivity. (see fig.4)Multibeam echo sounderAn instrument that uses a number of individual narrow beamsof sonic energy to get a detailed and accurate topographic map ofthe seafloor.... .. 33Oceanic crustContinetal crust

Oceanic crustLithosphereAsthenosphereTrenchContinetnal crustNautical mileIt is equal to 1.15 statutory mile or 1852m or 1.852 kmNutrientsElements other than carbon, hydrogen and oxygen that arerequired for the synthesis of organic matter. Commonnutrients are nitrates and phosphates.OceanographyStudy of the oceans/seasOcean trenchA narrow, deep depression on the sea-floor, usually severalthousand kilometers long and up to 10 km deeper than theadjacent seafloor. Here, the oceanic plate goes down beneaththe adjacent plate. (see fig.3)Placer mineralsMinerals with high specific gravity and high resistance tochemical weathering which are deposited in rivers, lakes,beaches and near shore regions. They contain many valuableelements like thorium, rare earth elements, titanium,zirconium and iron. Placer deposits found in offshore regionsand as raised beaches indicate sea level changes.Volcanic arcOceanic Continental Convergence - Fig. - 3LithospherePresent4 3 2 1 1 2 3 4Normal magnetic polarityReversed magnetic polarityLithosphereZone of magma injection, cooling,and "locking in" of magnetic polarityMid-oceanic ridgeAge beforepresent(million of years)Calculatedmagnetic profileassuming seafloorspreadingObservedmagnetic profilefrom oceanographicsurveyFig. - 4PhosphoriteA mineral deposit found in more than 1000 m water depth,which contains phosphorus and rare earth elements.RadiationTransport of energy from one region to another without amedium i.e., heating of the earth by the sun's rays.SalinityThe amount of dissolved salt present in seawater expressed inparts per thousand.SeaAn enclosed or semi-enclosed body of saline water that islarge compared to most estuaries and embayments but smallcompared to oceans.Sea-floor spreadingA process that is driven by sea-floor volcanism whereby oceaniccrust is created (at mid-oceanic ridges) and destroyed (at thetrenches). The spreading is recognised by investigations onmagnetic polarity. (see fig.4 )Seismic investigationsInvestigations that are carried out to find out the structure ofsediments / rocks beneath the seafloor.SeismicRelated to earthquake or vibrations of the earth.Seismic wavesWaves that are generated by earthquakes or man-madeexplosions.Side scan sonarAn instrument that is towed behind a ship at shallow waterdepths to obtain information on sea-floor features. (see fig. onpage 11)SubmersibleAn underwater vehicle (manned or unmanned) equippedwith instruments to collect samples and data of the sea-floorand water column. (see fig. on page 11)TonneEqual to 0.984 tpm (1000 kgm)United Nations Convention on the Law of the Sea (UNCLOS)UNCLOS sets out the rules and regulations pertaining to theutilization of oceanic mineral resources and to the preservationsof the marine environment.VolcanoesA vent or fissure on the earth’s surface or sea-floor thorughwhich lava comes out.34 ... ..

Amazing facts about the OceansFACTSThe amount of water contained by the oceans is around 326million cubic miles (1.4 billion cubic km).The five Oceans (biggest to smallest) are the Pacific, Atlantic,Indian, Southern (Antarctic), and the Arctic.The Pacific Ocean is the biggest of the five oceans. It covers anarea of more than 63 million sq.miles (163 million sq. km).Sea is smaller than ocean. About 54 seas are recognised.Salinity The saltiness (salinity) of the ocean is measured inparts per thousand (ppt). The average salinity is 35 ppt, whichmeans 35 units of salt in every 1,000 units of water.Temperature varies widely in the ocean. It ranges from 28°F(-2°C) in the Arctic and Southern oceans to 97°F (36°C), duringthe summer, in the Arabian Gulf.Fastest Fish in the sea is the sailfish. (110kph or 70mph).Biggest coral reef in the world is great barrier reef of Australia.Diatoms are a kind of plankton. Their shells are used to makedynamite.Killer whale 7 m (23 ft) long.Penguins are good swimmers and can stay underwater for about18 minutes.Deepest diver Sperm whale-can reach depths of 9,800 ft (3,000m).Tallest seaweed Giant kelp - nearly 197 ft (60 m) tall.Biggest marine animal Blue whale - recorded length 102 ft(31 m), weight is 193 tons.RECORDSHighest recorded wave The greatest wave ever recorded wascreated by a massive landslide in an inlet in Alaska (July 9,1958). The falling rock caused a wave to surge up the oppositeside of the bay, which reached a height of 1,740 ft (530 m).Deepest part of the ocean The Challenger Deep in the MarianaTrench, between Japan and Papua New Guinea, has a maximumrecorded depth of 36,198 ft (11,033m).Biggest tides The difference in height between high and lowwater in the Bay of Fundy, in Canada, is 53.5 ft (16m).Highest submarine mountain The top of Mount Kea in thePacific Ocean is 33,476 ft (10,203 m) above the seafloor. It issignficantly higher than Mount Everest, the tallest mountainon land, (29,037 ft or 8,850 m).EXPLORATION:1831-36 Charles Darwin travels on his famous voyage on boardthe Beagle, making observations (regarding wildlife) that ledto the revolutionary theory of natural selection.1872-76 The voyage of the HMS Challenger- the firstcomprehensive oceanographic research expedition.1920 Echo sounding equipment first used.Ocean Websiteswww.noaa.gov/www.ocean.udel.edu/deepsea/www.usborne-quicklinks.comwww.jncc.gov.uk/mermaid/www.mcsuk.org/www.bbc.co.uk/nature/blueplanet/Eon Period Million Years BPQuaternary 1.6 million years*(Pleistocene +Holocene) to 10,000 Yr BPNeogene 23Paleogene 65Cretaceous 135Precambrian Paleozoic Mesozoic Cenozoic... .. 35Geological Time ScaleJurassic 205Triassic 250Permian 290Carboniferous 355Devonian 410Silurian 438Ordovician 410Cambrian 570Proterozoic 2500Archean4000 million years*Pleistocene period has highestrecord of glaciationsBP = Before PresentOcean Highlightsc. 2.5 million years ago Primitive human beings appear65 million years ago Primitive whales swim in the oceans100 million years ago The age of reptiles, dinosaurs on land, andichthyosaurs and plesiosaurs in the ocean.200-180 million years ago Supercontinent Pangaea begins to break up300 million years ago The age of fish500 million years ago Life exists only in oceans3,800 million years ago The condensation of atmospheric watercauses the true oceans to form4,600 billion years ago Earth forms

E P I L O G U EDear Friends,Our country is gifted with vast oceans around us and theresources are indeed enormous! With the passage of time, weshall depend more and more on our oceans for food, energyand transportation.Oceans have remained a mystery for long. However, with theadvent of multi-disciplinary ocean sciences and technologies,our understanding of various interesting and amazingprocesses, which influence oceans, is improving.Compiling wide ranging aspects of ocean in a lucid andillustrative form demands significant efforts, sincerity anddedication. Many colleagues have put in their ideas and thisbooklet is an outcome of their untiring efforts. My special thanksare due to Prof. K.V. Subbarao and the Geological Society ofIndia.Through this booklet, an attempt is made to stimulate youngergeneration and attract them to learn about oceans.10 th September 2003Harsh GuptaSecretaryDepartment of Ocean Development36 ... ..