Umlando wokuqala wokushintsha kwesimo sezulu. Lapho i-methane ilawula isimo sezulu

Bekuhlale kushiwo njalo ukuguquka kwesimo sezulu kuyinto yesimanjemanje, ebangelwa ikakhulu ukukhishwa kwegesi ebamba ukushisa emkhathini, njenge imethane ne-CO2, eyenziwe ngabantu kusukela ekuguqulweni kwezimboni. Kodwa-ke, ungacabangani uma ngingakutshela ukuthi eminyakeni eyizigidigidi zeminyaka selokhu kwakhiwa uMhlaba kube nezinye izinguquko zesimo sezulu?

Umkhathi womhlaba awukaze ufane njalo nanamuhla. Kube ngezinhlobo eziningi zezingoma. Uyini umlando wokuqala wokushintsha kwesimo sezulu?

Lapho i-methane ilawula isimo sezulu

Cishe eminyakeni eyizigidigidi ezi-2.300 eyedlule, amagciwane amancane angajwayelekile aphefumulela impilo entsha kuleyo planethi "encane" yangaleso sikhathi. Imayelana ne-cyanobacteria. Bagcwalisa iplanethi ngomoya. Kodwa-ke, kunenkolelo yokuthi esikhathini eside ngaphambi kwalesi sikhathi, elinye iqembu lezinto ezinama-cell eyodwa lagcwala umhlaba futhi lalingalenza lihlaleke. Sikhuluma ngama-methanogens.

Ama-Methanogens yizinto ezineseli elilodwa ezingaphila kuphela ngaphansi kwezimo lapho akukho oksijini futhi bahlanganisa i-methane ngesikhathi semetabolism yabo njengomkhiqizo odoti. Namuhla singathola kuphela ama-methanogens ezindaweni ezinjengamathumbu ezinto ezikhanyayo, phansi kwezidumbu nakwezinye izindawo emhlabeni lapho i-oxygen ingekho.

Njengoba sazi, i-methane igesi yokushisa okushisa ukuthi kugcina ukushisa okuphindwe izikhathi ezingama-23 kune-carbon dioxide, ngakho-ke kucatshangwa ukuthi eminyakeni eyizigidi eziyizinkulungwane ezimbili zokuqala zomhlaba, ama-methanogens abusa. I-methane eyenziwe yilezi zidalwa idale umthelela wokushisa okushisayo ngemiphumela emikhulu esimweni sezulu seplanethi yonke.

Namuhla, i-methane iqhubeka kuphela emkhathini iminyaka eyishumi, ngenxa yokuba khona komoya-mpilo. Kodwa-ke, uma umkhathi womhlaba wawungenawo ama-molecule e-oxygen, i-methane ingaqhubeka iminyaka engaba ngu-10 10.000. Ngaleso sikhathi, ukukhanya kwelanga kwakungasenamandla njengoba kunjalo manje, ngakho-ke inani lemisebe efinyelela ebusweni bomhlaba ngaleyo ndlela lifudumeza iplanethi, belincane kakhulu. Yingakho, ukwandisa izinga lokushisa lomhlaba futhi wakhe indawo yokuhlala, i-methane yayidingeka ukubamba ukushisa.

Umphumela wokushisa kwesimo sendawo yakudala

Ngenkathi umhlaba wakheka cishe eminyakeni eyizigidi eziyizinkulungwane ezingama-4.600 edlule, iLanga likhiphe ukukhanya okulingana no-70% walokho elikwenzayo namuhla. Yingakho, ngaphambi kwesikhathi sokuqala seqhwa (cishe eminyakeni eyizigidi eziyizinkulungwane eziyi-2.300 edlule) umkhathi wawuncike ngokuphelele kumphumela wokushisa.

Ochwepheshe bokushintsha kwesimo sezulu bacabanga e-ammonia njengegesi lokushisa okugcina ukushisa emkhathini wakudala, ngoba lokhu kuyigesi enamandla abamba ukushisa. Kodwa-ke, ngokungabikho komoya-mpilo womoya, imisebe ye-ultraviolet evela eSun ibulala i-ammonia ngokushesha, okwenza i-methane ibe igesi eyayihamba phambili ngaleso sikhathi.

Kumnikelo wokushisa emkhathini nomphumela wokushisa okushisa futhi sifaka i-CO2. Ngaleso sikhathi, ukugxila kwakhe kwakuphansi kakhulu, yingakho kungabanga yimbangela yomphumela wokushisa. I-CO2 ikhishwe kuphela emkhathini ngokwemvelo, ngezintaba-mlilo.

Indima ye-methane nenkungu epholile iplanethi

Indima kaMethane ekulawuleni isimo sezulu sakudala yaqala cishe eminyakeni eyizigidi eziyizinkulungwane eziyi-3.500 edlule, lapho ama-methanogen enza i-methane gas olwandle njengomkhiqizo odoti. Le gesi ibambe ukushisa okuvela eLangeni esifundeni esibanzi se-electromagnetic spectrum. Iphinde yavumela ukudlula kwemisebe ye-ultraviolet, ngakho-ke phakathi kwalezi zici ezingezwe nge-CO2 ekhona, bagcina iplanethi isezingeni lokushisa okungahlalwa kulo.

Ama-Methanogens asinda kangcono emazingeni okushisa aphezulu. Njengoba izinga lokushisa likhula, kanjalo nomjikelezo wamanzi nokuguguleka kwamatshe kwanda. Le nqubo yokuguguleka kwamatshe, ikhipha i-CO2 emkhathini. Kakhulu ukuhlushwa kwe-methane ne-CO2 emkhathini kwafana.

I-chemistry yomkhathi yabangela ama-molecule e-methane ukuba enze i-polymerize (akha amaketanga ama-molecule e-methane axhunyaniswe ndawonye) futhi akhe ama-hydrocarbon ayinkimbinkimbi. Lawa ma-hydrocarbon ajiya abe yizinhlayiya, eziphakeme kakhulu, bakha inkungu esawolintshi.  Leli fu lothuli lwezinto eziphilayo lakhokhela umphumela wokushisa ngokufaka ukukhanya okuvela emisebeni yelanga bese liyikhuphula libuyele esikhaleni. Ngale ndlela, kunciphise ukushisa okufika ebusweni beplanethi futhi kwaba neqhaza ekupholiseni kwesimo sezulu nasekunciphiseni ukukhiqizwa kwemethane.

I-Thermophilic methanogens

Ama-Thermophilic methanogens yiwo asinda emazingeni okushisa aphakeme kakhulu. Ngalesi sizathu, lapho kwakhiwa inkungu ye-hydrocarbon, njengoba amazinga okushisa omhlaba esepholile futhi ehla, ama-thermophilic methanogens awanakuphila ezimweni ezinjalo. Ngesimo sezulu esibandayo kanye nenani elilimazayo le-thermophilic methanogen, izimo emhlabeni zashintsha.

Umkhathi ubungagcina kuphela ukugxila kwe-methane phezulu kakhulu uma i-methane ngabe kukhiqizwe ngejubane eliqhathaniswa nelamanje. Kodwa-ke, ama-methanogen awakhiqizanga i-methane eningi njengabantu emisebenzini yethu yezimboni.

Ama-Methanogens ngokuyisisekelo adla i-hydrogen ne-CO2, akhiqiza i-methane njengomkhiqizo odoti. Abanye abanye badla i-acetate namanye amakhemikhali ahlukahlukene avela ekonakaleni kwe-anaerobic kwezinto eziphilayo. Kungakho, namuhla, ama-methanogens Bachuma kuphela esiswini sezilwane ezi-ruminants, udaka olugcwala emasimini elayisi agcwele nezinye izindawo ze-anoxic. Kodwa njengoba umoya wakudala wawungenawo umoya-mpilo, yonke i-hydrogen eyayikhishwa izintaba-mlilo yayigcinwa olwandle futhi yayisetshenziswa ama-methanogen, ngoba yayingenawo umoya-mpilo ongatholakalela amanzi.

Inkungu yomphumela we- "green greenhouse"

Ngenxa yalomjikelezo wempendulo enhle (izinga lokushisa eliphakeme, ama-methanojeni amaningi, i-methane eyengeziwe, ukushisa okwengeziwe, izinga lokushisa elengeziwe…) iplanethi yaba yindawo yokushisa okushisayo kangangokuba ama-microorganisms e-thermophilic kuphela akwazi ukujwayela le ndawo entsha. Kodwa-ke, njengoba ngishilo ngaphambili, kwakhiwa inkungu evela ngama-hydrocarbon ahambisa lesi sehlakalo ngemisebe ye-ultraviolet okwenza isimo sezulu sipholile. Ngale ndlela, ukukhiqizwa kwe-methane kumisiwe futhi amazinga okushisa nokwakheka komkhathi kuzoqala ukuzinza.

Uma siqhathanisa inkungu naleyo ye- I-Titan, isathelayithi enkulu kunazo zonke yeSaturn, siyabona ukuthi futhi inombala ofanayo wewolintshi ohambelana nongqimba oluminyene lwezinhlayiya ze-hydrocarbon, olwakhiwa lapho i-methane iphendula ngokukhanya kwelanga. Kodwa-ke, lolo ungqimba lwama-hydrocarbon lwenza ubuso beTitan bube ngu -179 degrees Celsius. Lo mkhathi ubanda ukwedlula iplanethi yoMhlaba ebinayo emlandweni wayo wonke.

Ukube ifu le-hydrocarbon yoMhlaba belifinyelele ebunzimeni obunabo i-Titan's, belizokhipha ukukhanya kwelanga okwanele ukumelana nomphumela onamandla wokushisa okushisa we-methane. Ubuso bonke beplanethi ngabe bube yiqhwa, ngaleyo ndlela kubhubhise wonke ama-methanogens. Umehluko phakathi kweTitan noMhlaba ukuthi le nyanga yeSaturn ayinayo i-CO2 namanzi, ngakho-ke i-methane iyahwamuka kalula.

Ukuphela kwesikhathi se-methane

Inkungu eyakhiwa yi-methane ayizange ihlale ingunaphakade. Kube nokuqhekeka kathathu selokhu iProterozoic ne-methane kungachaza ukuthi kungani zenzeka.

I-glaciation yokuqala ibizwa ngokuthi yi-Huronian glaciation futhi ngaphansi kwamadwala amadala kakhulu atholakala ngaphansi kwamadiphozi awo e-glacial kukhona i-detritus ye-uraninite ne-pyrite, amaminerali amabili akhombisa izinga eliphansi kakhulu le-oxygen yasemkhathini. Kodwa-ke, ngaphezu kwezingqimba zeqhwa, kubonakala itshe elibomvu elibomvu eliqukethe i-hematite, amaminerali akhiwa izindawo ezicebile oksijini. Konke lokhu kukhombisa ukuthi i-Huraciation glaciation yenzeka ngqo lapho amazinga e-oksijeni asemkhathini eqala ukukhuphuka.

Kule ndawo entsha ecebe kakhulu nge-oxygen, i-methanogen kanye nezinye izidalwa ze-anaerobic ezake zabusa iplanethi, zanyamalala kancane kancane noma zabonwa ngokuya zivaleleke ezindaweni ezivinjelwe kakhulu. Eqinisweni, ukuhlushwa kwe-methane bekuyohlala kufana noma kuphakeme kunanamuhla, ukube amazinga e-oxygen ayegcinwe ephansi.

Lokhu kuchaza ukuthi kungani Emhlabeni, ngesikhathi seProterozoic, bekungekho glaciations cishe iminyaka eyi-1.500 billion, yize iLanga lalisabuthaka impela. Kucatshangwe ukuthi ukuphakama kwesibili komoya-mpilo osemkhathini, noma i-sulfate encibilikisiwe, nakho bekungadala iziqephu ze-ice age, ngokunciphisa umphumela wokuvikela we-methane.

Njengoba ukwazi ukubona, umkhathi womhlaba awuzange ube njalo njengoba unjalo namuhla. Kwenzeka ukuthi ayinayo i-oxygen (i-molecule esiyidingayo namuhla ukuze siphile) nalapho i-methane ilawula khona isimo sezulu futhi yabusa iplanethi. Ngaphezu kwalokho, ngemuva kweminyaka yeqhwa, ukuminyana komoya-mpilo kukhuphukile kuze kube yilapho kuzinza futhi kulingana nokukhona njengamanje, kuyilapho i-methane incishiselwe ezindaweni ezinemikhawulo. Njengamanje, ukugcwala kwe-methane kuyanda ngenxa yokukhishwa okuvela emisebenzini yabantu futhi kunegalelo kumphumela wokushisa nokushisa kwamanje kwesimo sezulu.