Ukufudumala kwihlabathi liphela: Iqondo lokuchithwa kungabonakali kwiminyaka engama-200 kumachibi angaphantsi kwe-arctic

Kanani

Amachibi aseCanada angaphantsi komhlaba

Ukwehla kwemvula ngohlobo lwekhephu eliqwalaselweyo kwiminyaka yakutshanje kwi kwimimandla engaphantsi kweArctic ICanada ikhokelele ekumeni okukhathazayo kwiSithili seLake.

Esi sisigqibo ekufikelelwe kuso ngabaphandi abathile beYunivesithi yaseLaval, iYunivesithi yaseWilfrid Laurier, iYunivesithi yaseBrock kunye neDyunivesithi yaseWaterloo kuphononongo olupapashwe kwiiveki ezimbalwa ezidlulileyo kwiphepha elisemthethweni lejenali yezenzululwazi iGeophysical Research Letters. Ukutyhila obunye ubungqina, ukuba ngaba abonelanga kukucaca kwe ukufudumala kwehlabathi.

Abaphandi bafikelele kwesi sigqibo emva kokufunda amachibi angama-70 kufutshane ne-Old Crow, Yukon nase Churchill, Manitoba, Canada. Uninzi lwamachibi afundisiweyo ayengaphantsi kwemitha enye ubunzulu. Ngokutsho kohlalutyo olwenziwe, ngaphezulu kwesiqingatha samachibi akwiindawo ethe tyaba kwaye ejikelezwe ngamatyholo abonisa iimpawu zokuphambuka.

Le ngxaki ivela ikakhulu ekunciphiseni kwamanzi avela kwi- ncibilika. Umzekelo, ukusukela ngo-2010 ukuya ku-2012 umyinge wemvula yobusika e-Churchil wehle ngama-76 mm xa kuthelekiswa nomyinge orekhodwe phakathi kuka-1971 no-2000. ibhengezwe kwi2010.

Kwezi ntlobo zamachibi, imvula enje ngekhephu imele phakathi kwama-30% ukuya kuma-50% obonelelo lwamanzi ngonyaka. Uhlobo lokomisa oluqwalaselwe ngabaphandi belungazange lubonwe ngaphambili kule minyaka ingama-200 idlulileyo. Ngaphaya koko, uhlalutyo lwe-isotopic olwenziwe kwi-phytoplankton luhlala luqokelelene kwiibhedi zamachibi lubonisa ukuba amachibi aligcinile ibhalansi ye-aquifer iminyaka engama-200.

Oluzinzo lwaphazamiseka ngesiquphe kwiminyaka embalwa eyadlulayo. Ukuba imeko yehlobo kunye nobusika obunekhephu elincinci iyaqhubeka, njengoko bekuxelwe kwangaphambili yimodeli yemozulu, uninzi lwamachibi asezantsi e-arctic anokugqibela omile ngokupheleleyo. Kunzima ukuqikelela zonke iziphumo zelahleko yale ndawo yokuhlala, kodwa kuyinyani ukuba iziphumo zendalo ziya kuba zibalulekileyo.

I-snowmelt ngumthombo obalulekileyo wamanzi kumachibi amaninzi asezantsi kwe-arctic, kodwa iimodeli zemozulu ziqikelela ukuba imvula enje ngekhephu iya kuncipha kweminye imimandla, ineziphumo ezibonakalayo kwindalo. Kule nqaku, kusetyenziswe iiparameter ezintathu, ezinje ngedatha yamanzi edikeni ngokudibeneyo, iigradient zetafile yomhlaba (ukusuka kuvule itundra ukuya kumahlathi avaliweyo) kunye nesiqabu sendawo yokuchonga amachibi asemngciphekweni wentshabalalo phantsi kweemeko Amanzi onyibilikayo asezantsi kumhlaba ongaphantsi kweArctic- I-Old Crow Plains, Yukon, kunye ne Hudson Bay Shoals, Manitoba, Canada.

Amachibi abekwe kwiindawo ezinzulu kunye nakwiindawo ezivulekileyo zetundra zibonisa imbuyekezo yenkqubo phakathi kwemilinganiselo yesalathi se-paleoclimatic yolwandle i-oksijini isotopu (δ18O) ngaphezulu kwemikhankaso emininzi yesampulu, ekhutshwe kwiselulosi efunyenwe kwiidipozithi zomhlaba zamva nje. Le mbuyekezo ibangelwe ngumphunga onamandla otyetyisiweyo ngo-18O ophendula amanzi aphantsi kunomyinge wokuhamba kwamanzi ekhephu kule minyaka idlulileyo.

Kuyaphawuleka ukuba amachibi amaninzi ayesondele ekumeni ngokupheleleyo phakathi ehlotyeni lowama-2010, elalandela ubusika obunemvula ephantsi ngohlobo lwekhephu. Ngokusekwe kwiirekhodi ze-paleoimnological yezi ntlobo zamachibi, iimeko ezomileyo kakhulu zika-2010 zisenokwenzeka ukuba azange zenzeke kule minyaka ingama-200 idlulileyo. Ezi zigqibo zondla inkxalabo yokuba ukwehla kokuhamba kwikhephu elinyibilikayo kuya kukhokelela kukomisa okukhulu kumachibi angenzulwanga kolu hlobo lwembonakalo.

Más información: I-WWF ixhalabile malunga nesantya kunye namandla okutshintsha kwemozuluUmkhenkce wase-Arctic unyamalala ngezinga lokurekhodaUkukhathazeka kokunyamalala komkhenkce kwiArctic

 

Imithombo: Iincwadi zoPhando lwezeMvelo


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