Coral a yankunan da ba na wurare masu zafi ba

Gudun ƙaura zuwa pole na nau'ikan coral yana nufin abin da ya haifar da hauhawar yanayin teku, inda corals ke mulkin mallaka na yanayi mai sanyi a cikin ƙoƙari na kauce wa murfin murjani, hauhawar matakan teku da ƙarancin teku. [dubious - tattauna] A cikin zamanin Anthropocene, sauyin yanayi na duniya ya rushe muhimman matakai na halitta kuma ya haifar da canje-canje masu lura a cikin yankin ruwa. Yayinda coral reefs ke furewa a yankuna masu zafi kamar Great Barrier Reef, har ma da ban mamaki, kuma watakila mafi ban tsoro; shine ci gaban nau'ikan coral na wurare masu zafi a yankuna na matsakaici, wanda ya faru a cikin shekaru goma da suka gabata. Ana kwatanta reefs na coral akai-akai da "canaries a cikin ma'adinin kwal," waɗanda masu hakar ma'adinai suka yi amfani da su azaman alamar ingancin iska. A cikin wannan hanyar, "kwararrun murjani suna da hankali ga canje-canjen muhalli waɗanda zasu iya lalata wasu wuraren zama a nan gaba, "  ma'ana za su kasance na farko da za su nuna ainihin tasirin dumamar duniya a duniyar halitta. 

## Takaitaccen taƙaitaccen canjin yanayi

### Abubuwan da suka faru a lokacin dumamar duniya
Canjin yanayi ba sabon abu ba ne. Rayuwar Ruwa koyaushe tana da saukin kamuwa da dumama da sanyaya na Duniya. Corals na zamani sun fara bayyana sama da shekaru miliyan 200 da suka gabata a zamanin Jurassic, kuma sun tsira daga bala'o'i da yawa na duniya tun daga wannan lokacin, gami da lokutan lokacin da CO<sub>2</sub> na yanayi ya fi girma fiye da yanzu. Tsarin halittu na coral reef na yanzu yana fuskantar barazana ta hanyar dalilai da yawa ciki har da hauhawar yanayin teku. Mutane da yawa sun lalace ta hanyar lalata ayyukan kamun kifi, wanda ya haɗa da amfani da dinamite da taru. Sauran, a kan shelf na nahiyar, an rufe su da laka daga rushewa ƙasa. Rashin gurɓata daga biranen bakin teku da aikin gona na iya haifar da nauyin abinci mai gina jiki wanda ke haifar da reefs da algae ke mamayewa ko lalacewar gurɓataccen abu. Guguwa mai tsanani na iya shafar murjani da hanzarta rushewar reef.

### Abubuwan da ke faruwa a halin yanzu na dumamar duniya
Abubuwan da mutane suka haifar ciki har da karuwar hayaki mai guba - karuwar CO2 na yanayi da sauran iskar gas mai guba mai guba kamar methane, nitrous oxide da halocarbons - da canje-canje ga rufe ƙasa - wanda ke nufin maye gurbin gandun daji masu duhu tare da amfanin gona da ciyawa - sun haifar da wannan saurin karuwa a cikin zafin jiki, wanda ya faru a cikin shekaru 50 da suka gabata. Baya ga waɗanda aka jera a baya, dumamar duniya ta kuma haifar da ci gaban mummunar matsala, gami da raguwa mai tsanani a cikin yawan krill  da kuma yaduwar 'gwanin ƙayoyi' starfish, sea urchins da jellyfish; dukansu suna ba da gudummawa ga lalacewar coral reefs da mazaunansu. Amma launin ruwan coral, hauhawar matakin teku da ƙarancin teku suna haifar da babbar barazana fiye da waɗannan abubuwan da ba su dace ba. Haɗin tasirin su ya haifar da raguwar kusan kashi 50% na coral reefs na duniya,  kuma ya tilasta sauran corals su bar gidajensu na wurare masu zafi don mallaki ruwan sanyi. Dukkanin lalacewarsu da ƙauracewarsu suna da tasirin gani da bala'i a duk yanayin halittu na ruwa.

## Barazanar murjani a yankuna masu zafi

### Ruwan murjani

Akwai dangantaka ta symbiotic tsakanin coral polyps da photosynthesising algae da ake kira zooxanthellae, ba tare da shi ba, babu wanda zai tsira. Lokacin da Yanayin zafi na teku ya wuce kusan 29 ° C ko fiye, har ma da kwanaki biyu, dangantakar da ke tsakanin murjani da zooxanthellae ya zama mara daidaituwa. Tun da dabba ta murjani ta kasa girbe isasshen makamashi a wannan lokacin, tana fitar da zooxanthellae, kuma ta zama fari, aka. 'dukiya'. 'Amma ba tare da wannan babban tushen Abinci mai gina jiki ba, coral nan da nan ya lalace; sai dai idan yanayin ruwa ya fadi kuma an maye gurbin zooxanthellae. Kodayake yana yiwuwa ga corals su murmure daga farfadowa, yana ɗaukar shekaru da yawa, kuma karuwar kwanan nan a sikelin da kuma yawan abubuwan da suka faru na farfadowar duniya yana nufin ba a ba reefs lokacin da suke buƙatar farfado. A cikin 2010 kadai, kashi 80% na murjani na Indonesia sun mutu, kuma a cikin 2016, kashi 29% na Babban Barrier Reef ya ɓace. A cewar National Oceanic and Atmospheric Association, kusan kashi 75% na coral reefs na duniya sun sami isasshen zafi don haifar da fure tsakanin 2014 da 2017.https://www.worldwildlife.org/pages/everything-you-need-to-know-about-coral-bleaching-and-how-we-can-stop-it Wani abu ne na duniya, tare da kashi 2% kawai na reefs na Indo-Pacific dauke da coral mai rai kamar yadda suka yi a cikin shekarun 1980. Wannan yana nufin ci gaban reef da lalacewar jiki dole ne a daidaita su sosai, in ba haka ba halaka haɗari ne.&nbsp;

### Hawan matakin teku
Coral reefs sun tsira sama da miliyoyin shekaru, duk da isasshen canji a cikin yanayi da matakan teku, a kan yawancin sake zagayowar glacial-interglacial. Rashin reefs a baya an danganta shi da sauye-sauye - ko dai matakan teku sun ragu sosai har aka fallasa murjani kuma suka halaka, ko kuma ruwan ya tashi sosai har murjani suka nitse - Reefs na Duniya suna fuskantar sabon barazanar halaka a matakin da ba a taɓa gani ba. Abin da yake sabo a halin yanzu shine sikelin da mitar hauhawar matakin teku da dumama, haɗe da karuwar yawan CO2 na yanayi, da sauran abubuwan damuwa da ayyukan ɗan adam masu cutarwa suka haifar. Warming a ƙarshen glaciation na ƙarshe ya kasance a matsakaita game da 1 ° C a kowace shekara dubu, kuma tun daga lokacin ya tashi da digiri 0.5 a cikin karni da ya gabata. Hakazalika, matakan teku sun tashi a lokacin glaciation na ƙarshe a matsakaicin matsakaicin 1m a kowace shekara 100, kuma tun daga lokacin ya karu da 25 cm, wanda ke da matsala saboda corals sun dogara da kusanci da rana don photosynthesize. Duk da yake yawan zafin jiki da hauhawar matakin teku na ƙarni na gaba ba a taɓa gani ba, za su faru a cikin wani yanayi daban-daban.

## Manazarta