Ezigidini zeminyaka edlule, i-Antarctica yayiyingxenye yeGondwana, indawo enkulu eseNingizimu Nenkabazwe. Phakathi nalesi sikhathi, indawo manje embozwe yiqhwa empeleni yayiyikhaya lezihlahla eduze neSouth Pole.
Ukutholakala kwezinsalela eziyinkimbinkimbi zalezi zihlahla manje kubonisa indlela lezi zitshalo ezichuma ngayo nokuthi amahlathi ayofana kanjani ngokunokwenzeka njengoba amazinga okushisa eqhubeka ekhuphuka osukwini lwanamuhla.
U-Erik Gulbranson, uchwepheshe we-paleoecology eNyuvesi yaseWisconsin-Milwaukee, waveza ukuthi, i-Antarctica ilondoloza umlando wemvelo wezinto eziphila ezindaweni ezishisayo ezithatha iminyaka engaba yizigidi ezingu-400, okuyisisekelo esiphelele sokuvela kwezitshalo.
Ingabe i-Antarctica ingaba nezihlahla?
Lapho ubheka umkhathi obandayo wase-Antarctica, kunzima ukubona ngeso lengqondo amahlathi aluhlaza ake aba khona. Ukuze bathole izinsalela zezinsalela, uGulbranson nethimba lakhe kwadingeka bandize baye ezindaweni eziyisithwathwa, baqwalaze phezu kwezinguzunga zeqhwa futhi bakhuthazelele umoya obandayo oshubile. Kodwa-ke, kusukela eminyakeni engaba yizigidi ezingu-400 kuya kweziyi-14 edlule, indawo yezwekazi eliseningizimu yayihluke kakhulu futhi iluhlaza kakhulu. Isimo sezulu naso sasipholile, nokho uhlaza olwalukhula ezindaweni eziphansi kwakusadingeka lubekezelele ubumnyama bamahora angu-24 ebusika nokukhanya okungapheli kwemini ehlobo, okufanayo nezimo zanamuhla.
UGulbranson nozakwabo bacwaninga ngokuqothulwa kwenqwaba yePermian-Triassic, okwenzeka eminyakeni eyizigidi ezingu-252 edlule futhi kwabangela ukufa kwamaphesenti angama-95 ezinhlobo zezilwane zomhlaba. Lokhu kushabalala kukholakala ukuthi kubangelwe inqwaba yamagesi abamba ukushisa aphuma ezintaba-mlilo, okubangele amazinga okushisa aqopha umlando kanye nezilwandle ezineasidi. Kukhona ukufana phakathi kwalokhu kushabalala kanye nokushintsha kwesimo sezulu kwamanje, okungekubi kangako kodwa okusathonywa amagesi abamba ukushisa, kusho uGulbranson.
Esikhathini esingaphambi kokuqothulwa kwenqwaba ye-Permian, izihlahla ze-Glossopteris zaziyizinhlobo ezivelele zezihlahla emahlathini aseningizimu ye-polar, kusho uGulbranson engxoxweni ne-Live Science. Lezi zihlahla zingafinyelela ubude obungamamitha angu-65 kuya kwangu-131 (amamitha angu-20 kuya kwangu-40) futhi zinamaqabunga amakhulu, ayisicaba amade ngisho kunengalo yomuntu, ngokusho kukaGulbranson.
Ngaphambi kokushabalala kwePermian, lezi zihlahla zazimboza umhlaba phakathi kwe-35th parallel South and South Pole. (I-35th parallel eningizimu iyindilinga ye-latitude engama-degree angu-35 eningizimu yendiza yenkabazwe yoMhlaba. Inqamula uLwandlekazi i-Atlantic, i-Indian Ocean, i-Australasia, i-Pacific Ocean, naseNingizimu Melika.)
Izimo ezihlukene: Ngaphambi nangemuva
Ngo-2016, ngesikhathi sohambo lokuyofuna izinsalela ezitholakala e-Antarctica, u-Gulbranson nethimba lakhe bathola ihlathi lokuqala eliqoshiwe elivela esigxotsheni esiseningizimu. Yize bengakalukhombi usuku oluqondile, baqagela ukuthi yachuma cishe eminyakeni eyizigidi ezingama-280 emuva ngaphambi kokuba ingcwatshwe ngokushesha emlotheni wentaba-mlilo, okuwugcine usesimweni esiphelele kuze kufike ezingeni lamaselula, njengoba abacwaningi babike.
Ngokusho kukaGulbranson, badinga ukuvakashela i-Antarctica ngokuphindaphindiwe ukuze baqhubeke bahlole izindawo ezimbili ezinezinsalela zamathambo kusukela ngaphambi nangemva kokushabalala kwePermian. Amahlathi abe noshintsho ngemva kokushabalala, lapho i-Glossopteris ingasekho kanye nenhlanganisela entsha yezihlahla ezivuthuluka nezihlala ziluhlaza, njengezihlobo ze-ginkgo yesimanje, ethatha indawo yayo.
UGulbranson uveze ukuthi bayazama ukuthola ukuthi yini ngempela edale ukuthi izinguquko zenzeke, yize okwamanje bengenakho ukuqonda okukhulu ngalolu daba.
UGulbranson, naye onguchwepheshe we-geochemistry, waveza ukuthi izitshalo ezimbozwe edwaleni zigcinwe kahle kangangokuthi izingxenye zazo zama-amino acid zamaprotheni zisengakhishwa. Ukuphenya ngalezi zakhi zamakhemikhali kungase kube usizo ukuqonda ukuthi kungani izihlahla zasinda ekukhanyeni okuyinqaba eningizimu nokuthi yini eyabangela ukubhubha kukaGlossopteris, wasikisela.
Ngenhlanhla, ocwaningweni lwalo oluqhubekayo, ithimba labacwaningi (elihlanganisa amalungu avela e-US, eJalimane, e-Argentina, e-Italy nase-France) lizokwazi ukufinyelela izindiza ezinophephela emhlane ukuze lisondele ezindaweni ezimangelengele eziNtabeni Zase-Transantarctic, lapho amahlathi avulekele khona. zitholakala. Ithimba lizohlala kule ndawo izinyanga ezimbalwa, lithatha uhambo lwendiza enophephela emhlane liye ezindaweni ezingaphandle uma isimo sezulu sivuma. Ukukhanya kwelanga okungamahora angama-24 esifundeni kuvumela uhambo olude kakhulu losuku, ngisho nohambo lwaphakathi kwamabili olubandakanya ukuqwala izintaba nomsebenzi wasendle, ngokusho kukaGulbranson.
