Ucwaningo lubonisa ukuthi zonke izihlahlana, imivini nezihlahla ezisizungezile zidlala indima ebalulekile ekumunceni ikhabhoni eyeqile emkhathini. Kodwa ngesinye isikhathi, izitshalo zingathatha ikhabhoni eningi kangangokuthi usizo lwazo ekulweni nokushintsha kwesimo sezulu luqala ukuncipha. Kuyokwenzeka nini ngempela lokhu? Ososayensi bazama ukuthola impendulo yalo mbuzo.
Selokhu kwaqala iNguquko Yezimboni ekuqaleni kwekhulu lama-20, inani lekhabhoni emkhathini elibangelwa imisebenzi yabantu liye lenyuka kakhulu. Besebenzisa amamodeli wekhompiyutha, ababhali, eshicilelwe ku-Trends in Plant Science, bathola ukuthi ngesikhathi esifanayo, i-photosynthesis yanda ngo-30%.
“Kufana nomsebe wokukhanya esibhakabhakeni esimnyama,” kusho uLukas Chernusak, umlobi ocwaningayo futhi oyisazi sezinto eziphilayo nezindawo eziphilayo e-James Cook University e-Australia.
Kwanqunywa kanjani?
U-Chernusak nozakwabo basebenzise idatha evela ezifundweni zezemvelo zango-2017, ezikala i-carbonyl sulfide etholakala kuma-ice cores namasampula omoya. Ngaphezu kwe-carbon dioxide, izitshalo zithatha i-carbonyl sulfide phakathi nomjikelezo wazo we-carbon yemvelo futhi lokhu kuvame ukusetshenziselwa ukukala i-photosynthesis emhlabeni wonke.
“Izitshalo zasemanzini zimunca cishe u-29% wesisi esikhishwayo, obekungaba nomthelela ekugxilweni kwe-CO2 emkhathini. Ukuhlaziywa kwemodeli yethu kubonise ukuthi iqhaza le-photosynthesis yasemhlabeni ekuqhubeni le nqubo yokuthathwa kwekhabhoni likhulu kunezinye izinhlobo eziningi ezisikisele,” kusho uChernusak.
Kodwa abanye ososayensi abaqiniseki kangako ngokusebenzisa i-carbonyl sulfide njengendlela yokulinganisa i-photosynthesis.
U-Kerry Sendall uyisazi sebhayoloji e-Georgia Southern University ofunda ukuthi izitshalo zikhula kanjani ngaphansi kwezimo ezihlukene zokuguquguquka kwesimo sezulu.
Ngenxa yokuthi ukumuncwa kwe-carbonyl sulfide izitshalo kungahluka kuye ngenani lokukhanya ezikutholayo, u-Sendall uthi imiphumela yocwaningo “ingase ilinganiswe ngokweqile,” kodwa futhi uphawula ukuthi izindlela eziningi zokulinganisa i-photosynthesis yomhlaba zinezinga elithile lokungaqiniseki.
Iluhlaza futhi ishubile
Kungakhathaliseki ukuthi i-photosynthesis iye yanda kangakanani, ososayensi bayavuma ukuthi ikhabhoni eningi isebenza njengomanyolo wezitshalo, isheshisa ukukhula kwazo.
“Kunobufakazi bokuthi amahlamvu ezihlahla aseminyene futhi nezinkuni ziminyene,” kusho uCernusak.
Ososayensi abavela eLabhorethri Kazwelonke ye-Oak Ride baphinde baphawula ukuthi lapho izitshalo zichayeka emazingeni akhulayo e-CO2, ubukhulu bembotshana emaqabunga buyanda.
USendall, ezifundweni zakhe zokuhlola, wadalula izitshalo inani eliphindwe kabili lekhabhoni dioxide ezivame ukuyithola. Ngaphansi kwalezi zimo, ngokubona kuka-Sendall, ukwakheka kwezicubu zamaqabunga kwashintsha ngendlela yokuthi kube nzima kakhulu ukuthi izilwane ezidla uhlaza zizidle.
Iphoyinti lokuthinta
Izinga le-CO2 emkhathini liyakhuphuka, futhi kulindeleke ukuthi ekugcineni izitshalo ngeke zikwazi ukubhekana nakho.
"Impendulo ye-carbon sink ekukhuphukeni kwe-CO2 yasemkhathini isalokhu iwukungaqiniseki okukhulu kunawo wonke ekufanisweni komjikelezo wekhabhoni emhlabeni wonke kuze kube manje, futhi kuwumbangela omkhulu wokungaqiniseki ekuqageleni kokushintsha kwesimo sezulu," i-Oak Ride National Laboratory iphawula kuwebhusayithi yayo.
Ukususwa komhlaba ukuze kulinywe noma ezolimo kanye nokukhipha uphethiloli wezinto ezimbiwa phansi kunomthelela omkhulu kumjikelezo wekhabhoni. Ososayensi banesiqiniseko sokuthi uma isintu singayeki ukwenza lokhu, iphuzu elibalulekile alinakugwenywa.
Ukukhishwa kwekhabhoni okwengeziwe kuzovaleleka emkhathini, ukugcwala kwawo kuzokwanda ngokushesha, futhi ngesikhathi esifanayo, ukushintsha kwesimo sezulu kuyokwenzeka ngokushesha,” kusho uDaniel Way, isazi sezinto eziphilayo eziphilayo eWestern University.
Yini esingayenza?
Ososayensi baseNyuvesi yase-Illinois kanye noMnyango Wezolimo bazama izindlela zokuguqula izitshalo ukuze zikwazi ukugcina ikhabhoni ethe xaxa. I-enzyme ebizwa ngokuthi i-rubisco inesibopho sokuthwebula i-CO2 ye-photosynthesis, futhi ososayensi bafuna ukuyenza isebenze kahle.
Ukuhlolwa kwakamuva kwezitshalo eziguquliwe kubonise ukuthi ukuthuthukiswa kwekhwalithi ye-rubisco kwandisa isivuno cishe ngo-40%, kodwa ukusebenzisa i-enzyme yezitshalo eguquliwe esikalini esikhulu sokuhweba kungathatha iminyaka engaphezu kweshumi. Kuze kube manje, ukuhlolwa kwenziwe kuphela ezitshalweni ezivamile njengogwayi, futhi akucaci ukuthi i-rubisco izoshintsha kanjani izihlahla ezithatha ikhabhoni eningi.
Ngo-September 2018, izinhlangano zezemvelo zahlangana e-San Francisco ukuze zenze uhlelo lokulondoloza amahlathi, abathi “kuyikhambi elikhohliwe lokushintsha kwesimo sezulu.”
"Ngicabanga ukuthi abenzi bezinqubomgomo kufanele baphendule kulokho esikutholile ngokubona ukuthi i-terrestrial biosphere njengamanje isebenza njengendawo yokucwilisa ikhabhoni esebenzayo," kusho uCernusak. "Into yokuqala okufanele yenziwe ukuthatha isinyathelo ngokushesha ukuvikela amahlathi ukuze akwazi ukuqhubeka nokuthatha ikhabhoni futhi aqale ukusebenza ngokushesha ukuze akhiphe umkhakha wamandla."