必修8Module1DeepSouthAntarctica:theLastContinentAntarcticaisthecoldestplaceonEarth.It’salsothedriest.Withannualrainfallclosetozero,Antarcticaistechnicallyadesert.Coveringabout14millionsquarekilometersaroundtheSouthPole,itisthefifthlargestcontinentintheworld.Ahighmountainrange,theTrans-Antarcticrange,runsfromeasttowest,cuttingthecontinentintwo.Therearevolcanoestoo,buttheyarenotveryactive.Antarcticaholds90%oftheworld’sice,andmostofitsfreshwater(70%)isinafrozenstate,ofcourse.98%ofthesurfaceiscoveredpermanentlyintheicecap.Onaverageitistwokilometersthick,butinsomeplacesitreachesadepthoffivekilometers.Strongwindsdrivenbygravityblowfromthepoletothecoastline,whileotherwindsblowroundthecoast.Itisdifficulttoimagineamoreinhospitableplace.YetAntarcticaisfullwildlife,whichhasadaptedtoitsextremeconditions.Therearedifferenttypesofpenguins,flyingbirds,seals,andwhales.ButthelongAntarcticwinternight,whichlastsfor182days(thelongestperiodofcontinuousdarknessonearth),aswellastheextremecoldandlackofrainfall,meansthatfewtypesofplantscansurvivethere.Onlytwotypesoffloweringplantsarefound,whiletherearenotreesonthelargecontinent.Therestoftheplantsaremadeupofmosses,algaeandlichen.Someformsofalgaehaveadaptedtogrowonice.Mostoftheicehasbeenthereforthousandsofyears.Asaresult,ithasbecomeawindowonthepast,andcangiveresearcherslotsofusefulinformation.Gasesandminerals,intheformofvolcanicdusttrappedintheice,cantellusalotaboutwhattheworld’sclimatewaslikeinpastages.Antarcticrocksarealsoveryimportantforresearch.Mostofthemaremeteoritesfromouterspace.Onerock,knownasthe“Alien”rock,maycontainevidenceofextra-terrestriallife.SincemostAntarcticrocksaredarkincolour,theystandoutagainstthewhitebackgroundandareeasytoidentifyandcollect.Antarcticawasthelastcontinenttobediscovered.ButmorethantwothousandyearsagoGreekgeographersbelievedthattherewasalargelandmassinthesouthwhichbalancedthelandinthenorth.TheycalleditAnti-Arktikos,orAntarcica:theoppositeofArcitc.WhenEuropeansdiscoveredthecontinentofAmericain15thcentury,thegreatageofexplorationbegan.However,progresstotheSoutholewasslow.Notuntilthelate18thcenturydidtheBritishexplorerJamesCookcrosstheAntarcticCircle,butheneversawland.Thenin1895,aNorwegiancalledCarstensBorchgrevinkbecamethefirstmantosetfootontheAntarcticmainland.Theracetothepolehadbegun.Itwasfinallyreachedon11thDecember,1911bytheNorwegianRoaldAmundsen.TodayscientistsfrommanycountriestraveltoAntarcticatostudyitsresources.Aspiritofinternationalfriendshiphasreplacedtherivalrythatexistedbetweenmanyoftheearlierexplorers.In1961,atreatysignedby12countries,includingBritain,France,andtheUSAmadeAntarcticatheworld’sbiggestnaturereserve.Theaimofthetreatyistopreventthecommercialandmilitaryuseofthecontinent.Inparticular,itaimstokeepAntarcticafreefromnucleartestsandradioactivewaste;topromoteinternationalscientificprojects;andtoendargumentsaboutwhoownstheland.Todaycountriesrepresenting80%oftheworld’spopulationhavesignedthetreaty.Antarcticahasbecomeperhapsthemostsuccessfulsymbolofman’seffortstoworktogetherforprogressandpeace.HowFailureBecameSuccessOn8thAugust,1914,27menwhohadrepliedtoanadvertisementinTheTimesboardedashipleavingfortheAntarctic.ThenameoftheshipwastheEnduranceandthecaptainwasanIrishmancalledErnestShackleton.TheaimofthejourneywastocrossthefrozencontinentviatheSouthPole–journeyof1,800miles.Shackletonthoughtthejou...
