Isicatshulwa esivela kumdlalo bhanyabhanya «La Carretera»
Singalikhankanya igama elithi "ubusika benyukliya" ngexesha elithile, njengesiphumo sesiganeko esibi okanye imeko yemozulu. Umzekelo, into elindelweyo inokwenzeka ukuba ICampi Flegrei supervolcano. Ukupholisa ngesiquphe ukuba umhlaba uza kubandezeleka kuya kufana kakhulu nobusika benyukliya. Kodwa yintoni kanye kanye?
Olu hlobo lobusika luluvo olubandakanya ixesha lemozulu eliza kubakho emva kwemfazwe yenyukliya. Iziphumo ziya kuba zibi kakhulu kangangokuba kuya kuvela into ebizwa ngokuba yi "bottleneck". Ukuthetha ngokulinganayo, kukunyamalala okukhawulezileyo kwamanani apheleleyo okanye ayinxalenye yohlobo okanye yabemi. Esi siganeko sikhokelela kwinto ebizwa ngokuba yi "genetic drift" ethi nayo, ngokuchaseneyo, ikhuthaze ukuvela kwendalo. Sisiphumo sokusabela kwikhonkco apho kungekho zintlobo ziya kusindiswa, kwaye ekuye kwanyanzeleka ukuba abantu badlule kuzo kwimbali yabo.
Iziphumo zobusika benyukliya
Ngamafutshane, ubusika benyukliya yinto yemozulu ebangelwa kukusetyenziswa ngokungakhethiyo kweebhombu zenyukliya. Ukupholisa umhlaba kuya kuvela enkulu amafu othuli aya kunyuka aye kwi-stratosphere. Lo mmandla, ophakathi kwe-10 kunye ne-50 yeekhilomitha ukuphakama, ungagcwalisa ngento leyo inokuthintela ukuhamba kwelanga. Ayisiyiyo kuphela kwimfazwe eneebhombu zeatom, kulandela ukuba i-supervolcano iya kuba nefuthe elifanayo ngenxa yeekholamu ezinkulu zezinto ezikhutshiweyo eziphakamileyo.
Ngokungafaniyo nobusika obuqhelekileyo esibaziyo, oku kungadala ukuncipha kokungena kwelanga. Kwizinto eziphilayo ezenza i-photosynthesis, oko kuya kuthetha ukufa okupheleleyo okanye okukhethiweyo kohlobo. Enye into engenakulindeleka kukuba, nangona isaziwa ukuba iziphumo zayo ziya kuba zibi, elo lifu lothuli unokuhlala ezulwini iinyanga ezininzi. Zingaphi ezinye ezingakumbi, umonakalo omkhulu kwizinto eziphilayo. Ukusuka ekufeni kwezityalo, kuya kuza emva kwayo, ukutshabalala emva kwetyathanga lokutya. Emva kwezityalo, izityalo ezitya uhlaza zaziza emva kwazo, emva kwazo izidla inyama. Kungenzeka ukuba kuxhomekeke kubukhulu kunye nendawo, umoya ongenakuphefumla ngokwawo ubangele ukuba izilwanyana zife kwangoko kwimimandla. Ngokwezinye iithiyori, le meko ikwasetyenziswe njengenkcazo yokuphela kweedinosaurs yimeteorite ebangele iziphumo ezifanayo.
Kwenzeka njani ukuba ibhotile?
"Ibhotile" ligama elisetyenziswe kwibhayoloji ukubhekisa kumaxesha adlulileyo apho, kuthotho lweziganeko, inani leentlobo liye lancitshiswa kakhulu kwinani lade lafikelela nasekutshabalaleni. Izizathu zithande ukuba zihlala zihlala zikhatshwa ziintlekele ezinkulu. Ke xa ngaphambi kokuba sibe nenani elikhulu labemi elinokwahluka okukhulu kwemfuza, ngoku incinci kwaye ayifani kwaphela.
Konke oku kukhokelela ekuboneni ukuba umahluko omncinci ukhokelela ku Imizila yemfuza yokuhamba, ngenxa yobuchwephesha kunye nohlengahlengiso oluguqukayo. Kwimbali nganye ebhaliweyo, bekunjalo. Abasindileyo kule ntlekele, njengobusika benyukliya, bakhawulezisa imizila yabo yemfuza kunye nokuziphendukela kwemvelo, ngaloo ndlela bevelisa iintlobo ezintsha zezinto eziphilayo. Uninzi (okanye olomeleleyo) imikhwa yemfuza ikholisa ukuzinzisa kwaye iqhubeke, kwaye ezibuthathaka okanye ezincinci zitshabalale.
Abantu bayifumana nini?
Kwiminyaka engama-75.000 eyadlulayo. Yaziwa njenge ntlekele kaToba, le supervolcano ifunyenwe e-Indonesia. Kungoku nje ichibi ngenxa yomngxuma omkhulu. Kuqikelelwa ukuba iintlobo zabantu zancitshiswa zangamawaka ambalwa abantu. Ukongeza, ukuhla okwahlukileyo kwezinye iintlobo kungqinelana ngexesha elinye.
Nangona besikhe sathetha ngeentaba-mlilo, ngenxa yobudlelwane babo nobusika benyukliya, iithintelo zahluke kakhulu. Oko kukuthi, abakwazanga kuphela ukusuka kwiziphumo zemozulu, kodwa kwizibetho okanye kwizifo. Umzekelo, isibetho esimnyama esasihlala eMbindi Yurophu. Okanye ngaphezulu, njengokuqhuma, indlala kunye nezifo njengoko kwenzekile e-Iceland kuqhushumbe lweLake ngo-1783.