Kwizigidi zeminyaka eyadlulayo, iAntarctica yayiyinxalenye yeGondwana, ummandla omkhulu womhlaba ofumaneka kuMazantsi eHemisphere. Ngeli xesha, ummandla ngoku ogutyungelwe ngumkhenkce wawunemithi ekufuphi neSouth Pole.
Ukufunyanwa kweefosili ezintsonkothileyo zale mithi ngoku kubonisa indlela ezi zityalo zichume ngayo noko anokuthi afane noko amahlathi njengoko amaqondo obushushu eqhubeka enyuka kule mihla.
U-Erik Gulbranson, ingcali kwi-paleoecology kwiYunivesithi yaseWisconsin-Milwaukee, wachaza ukuba, i-Antarctica igcina imbali ye-ecologic ye-polar biomes ehamba malunga ne-400 yezigidi zeminyaka, eyona nto ipheleleyo yendalo yezityalo.
Ingaba iAntarctica ingaba nemithi?
Xa uthi krwaqu kumoya obandayo waseAntarctica, kuba nzima ukuba nomfanekiso-ngqondweni wamahlathi achumileyo awayefudula ekho. Ukufumana iifosili, uGulbranson neqela lakhe kuye kwafuneka babhabhe besiya kumathafa ekhephu, benyuka phezu komkhenkce kwaye banyamezele imimoya ebanda kakhulu. Nangona kunjalo, ukusuka malunga nezigidi ezingama-400 ukuya kwi-14 yezigidi zeminyaka eyadlulayo, imbonakalo yelizwekazi elisemazantsi yayahluke kakhulu kwaye ichume kakhulu. Nemozulu yayipholile, ukanti uhlaza olwalukhula kwiindawo ezisezantsi kwakusafuneka lunyamezele ubumnyama beeyure ezingama-24 ebusika nokukhanya okungapheliyo emini ehlotyeni, ngokufanayo neemeko zanamhlanje.
UGulbranson kunye noogxa bakhe baphanda ukutshabalala kobunzima bePermian-Triassic, okwenzeka kwiminyaka eyi-252 yezigidi eyadlulayo kwaye kwabangela ukufa kweepesenti ezingama-95 zeentlobo zomhlaba. Kukholelwa ukuba oku kutshabalala kubangelwe zizixa ezikhulu zeegesi zegreenhouse eziphuma kwiintaba-mlilo, nto leyo ebangele amaqondo obushushu angenarekhodiweyo kunye neelwandle ezineasidi. Kukho ukufana phakathi koku kutshabalala kunye nokutshintsha kwemozulu yangoku, okungekuko kangako kodwa kusaphenjelelwa ziigesi zegreenhouse, utshilo uGulbranson.
Ngexesha eliphambi kokuphela kobunzima bePermian, imithi yeGlossopteris yayiyeyona ntlobo ibalaseleyo yomthi kumahlathi asemazantsi epolar, utshilo uGulbranson kudliwanondlebe neLive Science. Le mithi inokufikelela kubude obuziimitha ezingama-65 ukuya kwi-131 (iimitha ezingama-20 ukuya kwezingama-40) kwaye inamagqabi amakhulu, asicaba amade ngaphezu kwengalo yomntu, ngokutsho kukaGulbranson.
Ngaphambi kokuphela kwePermian, le mithi yayigubungela umhlaba phakathi kwe-35th parallel South kunye ne-South Pole. (I-35th parallel emazantsi sisangqa sesibanzi esiziimitha ezingama-35 kumzantsi we-equatorial plane yoMhlaba. Inqumla uLwandlekazi lweAtlantiki, uLwandlekazi lwaseIndiya, iAustralasia, uLwandlekazi lwePasifiki, kunye noMzantsi Melika.)
Iimeko ezichaseneyo: Ngaphambi nasemva
Ngo-2016, ngexesha lokufuna iifosili ukuya e-Antarctica, uGulbranson kunye neqela lakhe bakhubeka kwelona hlathi liphambili libhalwe kwincam yencam esemazantsi. Nangona bengawuchazanga umhla ochanekileyo, baqikelela ukuba yakhula malunga ne-280 yezigidi zeminyaka eyadlulayo ngaphambi kokuba ingcwatywe ngokukhawuleza kuthuthu lwentaba-mlilo, eyayigcina ikwimeko egqibeleleyo ukuya kwinqanaba leeselula, njengoko abaphandi baxelayo.
Ngokutsho kukaGulbranson, kufuneka batyelele i-Antarctica ngokuphindaphindiweyo ukuze baqhubele phambili baphonononga iziza ezibini ezineefosili zangaphambili nasemva kokuphela kwePermian. Amahlathi aye atshintsha emva kokuphela, iGlossopteris ayisekho kunye nomxube omtsha wemithi evuthulukayo kunye nehlala eluhlaza, njengezihlobo zeginkgo zanamhlanje, ezithatha indawo yayo.
UGulbranson ukhankanye ukuba bazama ukufumanisa ukuba yintoni kanye kanye ebangele ukuba utshintsho lwenzeke, nangona ngoku bengenakuqonda kakhulu ngalo mba.
UGulbranson, naye oyingcaphephe kwi-geochemistry, wachaza ukuba izityalo ezivalelwe ematyeni zigcinwe kakuhle kangangokuba iiproteni zazo ze-amino acid zisenokukhutshwa. Ukuphanda ngezi zixhobo zemichiza kunokuba luncedo ukuqonda ukuba kutheni le mithi isinda ekukhanyeni okungaqhelekanga emazantsi kwaye yintoni eyabangela ukubhubha kukaGlossopteris, wacebisa.
Ngethamsanqa, kuphando lwabo olongezelelweyo, iqela lophando (elibandakanya amalungu avela e-US, eJamani, eArgentina, eItali naseFransi) baya kuba nokufikelela kwiinqwelo-moya ukuze basondele kwiindawo ezinqabileyo kwiiNtaba zeTransantarctic, apho amahlathi asele efile. zibekwe. Iqela liya kuhlala kwindawo iinyanga eziliqela, lithatha uhambo lwe-helicopter ukuya kwiindawo ezingaphandle xa imozulu ivumela. Ukukhanya kwelanga kwiiyure ezingama-24 kulo mmandla kuvumela uhambo olude kakhulu lwemini, kunye nohambo lwasezinzulwini zobusuku olubandakanya ukunyuka intaba kunye nomsebenzi wasendle, ngokukaGulbranson.
