Coral na Elkhorn
| Coral na Elkhorn | |
|---|---|
 | |
| Conservation status | |
 Critically Endangered (en)  (IUCN 3.1) | |
| Scientific classification | |
| Kingdom | Animalia |
| Phylum | Cnidaria (en)  |
| Class | Anthozoa (en) |
| Order | Scleractinia (en) |
| Dangi | Acroporidae (en) |
| Genus | Acropora (en)
|
| jinsi | Acropora palmata Lamarck, 1816
|
Coral na Elkhorn, (Acropora palmata) muhimmiyar murjani ce a cikin Caribbean. Nau'in yana da tsari mai rikitarwa tare da rassa da yawa waɗanda suka yi kama da na ƙaho; saboda haka, sunan gama gari. Tsarin reshe yana haifar da mazauni da mafaka ga wasu nau'ikan reef da yawa. An san murjani na Elkhorn da girma da sauri tare da matsakaicin ci gaban 5 zuwa 10 cm (2.0 zuwa 3.9 in) a kowace shekara. Suna iya haifuwa ta hanyar jima'i da kuma ba tare da jima'i ba, kodayake haifuwa ba tare da saduwa ba ya fi yawa kuma yana faruwa ta hanyar tsari da ake kira raguwa.
Kodayake murjani na Elkhorn ya mamaye Caribbean a farkon shekarun 1980, jinsin ya ragu sosai a lambobi. Masana kimiyya sun kiyasta cewa tsakanin 1980 da 2006, lokacin da aka lissafa shi a cikin Dokar Dabbobi Masu Hadari (ESA), yawan jama'a ya ragu da kusan 97%. Wannan raguwa ya faru ne saboda dalilai daban-daban, gami da cututtuka, ci gaban algae, canjin yanayi, ƙarancin teku, da ayyukan ɗan adam. A watan Mayu na shekara ta 2006, an lissafa murjani na Elkhorn a hukumance a matsayin mai barazana a cikin ESA tare da wani nau'in a cikin nau'in Acropora, murjani na staghorn. Wasu kokarin kiyayewa yanzu suna nan don kare jinsin da kuma inganta karuwar bambancin kwayar halitta tsakanin jinsin
Bayani game da nau'ikan
[gyara sashe | gyara masomin].jpg)
Bayyanawa
[gyara sashe | gyara masomin]Coral na Elkhorn yana samar da tsarin ƙaho mai kama da ƙaho wanda ya ƙunshi calcium carbonate. Wadannan tsarin na iya zama sama da mita 2 (> 6 ft.) tsawo da mita 13 (43 ft) fadi kuma suna da duhu, launin ruwan kasa-jaune.[1]
Abinci
[gyara sashe | gyara masomin]Babban tushen kayan abinci na Elkhorn coral ya fito ne daga algae na photosynthetic, zooxanthellae, waɗanda ke zaune a cikin sel na coral.[2] Sabili da haka, murjani na Elkhorn sun dogara sosai da hasken rana don abinci, suna barin murjani na Alkhorn mai rauni ga karuwar turbidity ko tsabtace ruwa. A lokacin abubuwan da suka faru, ko kuma lokutan dogon lokaci na karuwar turbidity, Elkhorn coral na iya samun abinci mai gina jiki daga madadin tushen abinci ta hanyar ciyar da tacewa.[3]
Zooxanthellae
[gyara sashe | gyara masomin]Kamar yadda aka ambata, murjani na Elkhorn suna da algae na musamman da ke zaune a cikin ƙwayoyin su da aka sani da zooxanthellae . Zoothanthellae sun cika bukatun abinci mai gina jiki ta amfani da photosynthesis, tsari wanda ke canza carbon dioxide da ruwa zuwa sukari da iskar oxygen. Elkhorn coral yana samar da mazauni ga waɗannan algae kuma, bi da bi, suna karɓar tushen iskar oxygen mai yawa, yana ba su damar girma da sauri.[1]
Gudanar da mai tacewa
[gyara sashe | gyara masomin]Elkhorn coral kuma na iya amfani da dabarun ciyar da tace don samun abinci. Da daddare, Elkhorn coral suna amfani da yatsunsu don kwace zooplankton mai iyo kyauta daga ruwa. Zooplankton ya kammala ƙaura na yau da kullun. Da safe, zooplankton ya nutse zuwa zurfin teku inda masu cin nama ba su da yawa, sannan suka zo da dare, sai suka tashi zuwa saman. Ta hanyar mayar da hankali ga ayyukan su na farauta da dare, murjani na Elkhorn yana kashe karancin makamashi wajen kama adadi mai yawa na ganima.[1] Koyaya, saboda ciyar da tacewa ya fi ƙarfin makamashi fiye da dogaro da zooxanthellae, murjani na Elkhorn zai koma ga wannan hanyar ciyarwa ne kawai lokacin da yanayin ruwa ba shi da kyau kuma ya toshe hasken rana.[4]
Gida
[gyara sashe | gyara masomin]Coral na Elkhorn suna rayuwa a cikin wuraren da ba su da zurfi, wanda ke ba su damar samun haske. Kamar dukkan dabbobi, Elkhorn coral yana buƙatar iskar oxygen don rayuwa, mafi yawansu suna samun ta hanyar algae na musamman, photosynthetic da ke zaune a cikin kyallen su da ake kira zooxanthellae. Sabili da haka, don taimakawa zooxanthellae samar da iskar oxygen mai yawa, Elkhorn coral yana rayuwa a yankuna masu zurfi tsakanin mita 1 zuwa 5 don tabbatar da cewa haske mai yawa ya kai zooxantellase, yana kara yawan photosynthesis.[1][4]
Yankin Elkhorn
[gyara sashe | gyara masomin]
Gidan zama
[gyara sashe | gyara masomin]Ana samun waɗannan murjani a cikin ruwa mai tsabta, mai zurfi a duk faɗin Bahamas, Florida, Caribbean, da kuma bayan zuwa gabar arewacin Venezuela.[2] Yankin da ya fi arewacin da Elkhorn coral ke zaune yana kusa da bakin tekun Broward County, Florida.[5] Ana samun su a cikin ruwa mai zurfi, mai cike da tashin hankali daga mita 1 zuwa 5, murjani na Elkhorn yana bunƙasa mafi kyau a yankuna masu ƙarfi inda aikin raƙuman ruwa ke da yawa. Wannan nasarar ita ce saboda aikin raƙuman ruwa yana ƙara raguwa, wanda ke ba da damar samar da sabbin yankuna.[1][2]
Juyin Halitta
[gyara sashe | gyara masomin]Saboda raguwa da saurin girma, murjani na Elkhorn sune tushe na farko a ci gaban murjani na Caribbean. A cikin shekaru 5,000 da suka gabata, Elkhorn coral, Staghorn coral, da Star coral sun ƙunshi reefs na kudu maso gabas.[3] Bincike ya nuna cewa murjani na Elkhorn ya samo asali ne a lokacin Mid-Pliocene, shekaru miliyan 5.2-2.58 da suka gabata.[6] Yanayin da ba shi da kwanciyar hankali a wannan lokacin ya ba da damar murjani na Elkhorn ya bunƙasa a lokacin abubuwan da suka faru. A lokacin abubuwan da suka faru na kankara, matakan teku suna tashi kuma suna haifar da karuwar ƙarfin raƙuman ruwa. Kamar yadda aka ambata a baya, murjani na Elkhorn yana aiki mafi kyau a cikin mahalli da ba su da zurfi kuma suna fuskantar canje-canje masu ƙarfi, wanda ke taimakawa wajen tsarin haihuwa.[2][6]
Ayyukan muhalli
[gyara sashe | gyara masomin]Ta hanyar ayyukan su na yanayin halittu, murjani na Elkhorn yana ƙara darajar kasuwanci na murjani.
Ayyukan gine-ginen dutse
[gyara sashe | gyara masomin]Kamar tushe na gida, Elkhorn coral yana tallafawa al'ummomin coral reef. Rashin rassan su masu kama da lattice sun haifar da wuraren zama iri-iri da suka bambanta a cikin yanayin ƙasa, wanda hakan ke tallafawa yawan kifaye daban-daban.[7] Wadannan wuraren zama suna tallafawa wuraren kifi da kare kifi daga masu cin nama, suna kara bambancin reef.[4] Wannan bambancin da ya fi girma ya sa reefs ya fi jan hankali ga masu yawon bude ido, don haka ya kara darajar tattalin arzikin su.
Tsaro na guguwa
[gyara sashe | gyara masomin]Coral na Elkhorn yana ba da kariya daga guguwa zuwa rairayin bakin teku da reefs. Rashin rassan su masu kauri suna shan makamashi na raƙuman ruwa, bi da bi, suna watsar da ƙarfin da ke fadowa a bakin rairayin bakin teku.[8] Tare da karancin karfi, kadarorin bakin teku suna fuskantar karancin lalacewa, rage bukatar kudi da ake buƙata don dawo da gidaje da abubuwan rayuwa na mutane da yawa.
Tarihin rayuwa
[gyara sashe | gyara masomin]_(San_Salvador_Island,_Bahamas)_1_(15946092620).jpg)
Shekaru da girma
[gyara sashe | gyara masomin]Yankunan murjani na Elkhorn sun rayu tsawon ƙarni. Wadannan yankuna suna girma 5-10 cm (2-4 inci) a kowace shekara, suna kaiwa matsakaicin girman a cikin shekaru 10 zuwa 12.[5] Elkhorn coral mai lafiya na iya girma har zuwa 13 cm (5 inci) a tsawon reshe a shekara, yana mai da su ɗaya daga cikin nau'ikan coral masu saurin girma. Coral na Elkhorn na iya ɗaukar diamita na 4 m (12 feet) da faɗin da 2 m (6 feet) tsawo.[2] A karkashin yanayi mai wahala, yankunan coral na Elkhorn da raguwa sun ragu sosai. Misali, shafin da aka kafa Fortuna Reefer Vessel bai nuna wani ci gaba ba a cikin shekaru goma da suka gabata saboda damuwa.[2] Coral na Elkhorn yana haifar da kauri, ƙungiyoyi masu haɗuwa da aka sani da bishiyoyi. Thickets suna ba da mafaka ga wasu rayukan ruwa kamar kifi, crustaceans, da invertebrates na ruwa, kuma sun ƙunshi polyps iri ɗaya da yawa waɗanda suka girma tare.[2] Wadannan kungiyoyi masu yawa suna ba da kariya ga bakin teku daga manyan raƙuman ruwa da guguwa.
Halitta na haihuwa
[gyara sashe | gyara masomin]Haihuwar jima'i
[gyara sashe | gyara masomin]Coral din Elkhorn wani nau'i ne na lokaci guda, ma'ana cewa a cikin kowane yanki na coral ana samar da kwai da maniyyi.[2] Duk da haka, yawanci ba ya faruwa. Don samun nasarar haihuwa, ana buƙatar iyaye biyu daban-daban. Yawan haifuwa mai nasara yana da ƙarancin Elkhorn coral wanda ke iyakance ci gaban sabbin yankuna. Halin yiwuwar samun nasarar haifuwa yana da ƙarancin ƙwayoyin Elkhorn saboda kusan kashi 50% na ƙwayoyin ƙwayoyin cuta na Elkhor nuni ne na musamman.[9] Tsarin haihuwar murjani na Elkhorn yana faruwa sau ɗaya a kowace shekara, bayan cikakken wata a ƙarshen lokacin rani, a cikin watanni na Yuli, Agusta, ko Satumba. Ana saki gametes ne kawai na 'yan dare ta hanyar watsa shirye-shirye ƙwai da maniyyi a cikin ginshiƙi na ruwa. Da zarar an cika su, ƙwai suna tasowa a cikin tsutsotsi waɗanda ke zaune a kan wurare masu wuya kuma suna fara girma na sabon yanki.[3]
Haihuwar jima'i
[gyara sashe | gyara masomin]Mafi yawanci, coral na Elkhorn suna haifuwa ba tare da jima'i ba, irin haihuwar su na yau da kullun. A lokacin guguwa, raƙuman ruwa masu ƙarfi, ko rikice-rikice na jirgin ruwa, raguwar murjani sun fashe kuma ana jigilar su zuwa wasu yankuna inda sabbin yankuna zasu iya farawa. Sabbin yankuna sun yi daidai da yankunan iyayensu, yayin da haihuwar jima'i ke haifar da sababbin nau'ikan kwayoyin halitta. Har ila yau, sabanin haihuwar jima'i, raguwa na iya faruwa a kowane lokaci na shekara.[3]
Tarihi da na yanzu
[gyara sashe | gyara masomin]Bayanan da ke akwai akan rarraba da yalwar murjani na Elkhorn ba su da yawa. Wuraren yanzu na murjani na Elkhorn sun haɗa da kudancin Florida da yankunan arewacin Tekun Mexico.[3] Coral na Elkhorn kuma suna cikin tsibirin Bay na Honduras.
Muhimmanci
[gyara sashe | gyara masomin]Akwai wurare huɗu masu mahimmanci ga murjani na Elkhorn waɗanda ke da mahimmanci ga kiyaye wannan nau'in. Takamaiman yankuna da aka tsara da kuma karewa ta Dokar Halitta mai Hadari a matsayin wuraren zama masu mahimmanci sun haɗa da yankuna a Florida (1,329 murabba'in kilomita na mazaunin ruwa), Puerto rico (3,582 murabba'i kilomita na mazaunan ruwa), St.John / St.Thomas (121 murabba'in mil na mazaunin ruwa), da kuma yankin St.Croix (126 murabba'i mil na mazaunan ruwa).[4][10]
Yawan jama'a na tarihi da na yanzu
[gyara sashe | gyara masomin]Al'ummar murjani na Elkhorn sun mamaye yankin kudu maso gabashin Arewacin Hemisphere. Saboda abubuwan da suka faru, cututtuka, da canjin yanayi, yawan mutanen Elkhorn ya ragu sosai tun daga shekarun 1980. Gabaɗaya, 80-98% na yawan coral reef na Caribbean sun ɓace. Binciken da aka yi daga 2005-2015 ya nuna cewa yawan coral na Elkhorn yana da raguwar sau 0.4-0.7 a cikin yawan mulkin mallaka a duk faɗin kewayon da yake zaune.[11] Wannan raguwa yana nuna cewa duk da kokarin kiyayewa, yawan jama'a har yanzu yana raguwa. Gabaɗaya, babu ƙididdigar ƙididdigatattun ƙididdigas na yanzu ko na tarihi saboda ƙarancin fasaha.
Ƙuntatawa na tarihin rayuwa
[gyara sashe | gyara masomin]Abubuwa da yawa suna iyakance adadin bayanai game da tarihin rayuwar murjani na Elkhorn. Wadannan dalilai sun hada da buƙatar ƙarin kayan aiki don tantance canje-canjen yawan jama'a na gaba, haihuwar jima'i, da rikice-rikicen muhalli.[3]
Jerin Dokar Dabbobi Masu Hadari (ESA)
[gyara sashe | gyara masomin]Rashin murjani na Elkhorn
[gyara sashe | gyara masomin]A cikin jerin ESA, an jera murjani na Elkhorn tare da murjani na Staghorn, A. cervicornia, saboda murjani suna da nau'i ɗaya. Duk da yake an gane su a matsayin nau'o'i biyu daban-daban a cikin wallafe-wallafen kimiyya, suna zaune a cikin irin wannan kewayon kuma suna da halaye iri ɗaya.[12]
Tun daga shekarun 1980s, yawan coral na Elkhorn ya ragu da sauri da kimanin kashi 97%.[13] Elkhorn coral da farko an gane shi a matsayin dan takara don jerin ESA a watan Yunin 1991, amma an cire shi daga jerin 'yan takara a shekarar 1997 saboda rashin isasshen shaida game da matsayinsu da barazanar su. Koyaya, an sake ƙara su cikin wannan jerin a cikin 1999 saboda tabbacin tabbacin raguwar yawan jama'arsu. A watan Afrilu na shekara ta 2004, an sauya su daga jerin nau'ikan 'yan takara zuwa jerin nau'in damuwa.[12]
Roƙo don lissafin murjani na Elkhorn
[gyara sashe | gyara masomin]A shekara ta 2004, Hukumar Kula da Kifi ta Kasa (NMFS) ta karɓi takarda don lissafin murjani na Elkhorn, murjani na Staghorn, da nau'in jinsin, A. prolifera, a matsayin ko dai barazana ko haɗari. NMFS ta yanke shawarar cewa korafin ya ƙunshi bayanai masu mahimmanci kuma ya kafa Atlantic Acropora Biological Review Team (BRT) don sake duba matsayin waɗannan nau'ikan murjani.[13] BRT ta haɗa da ƙungiyar ƙwararru daban-daban daga fannoni daban-daban na kimiyya, gami da masu kiyaye murjani.[12] BRT ta buga wani bita na matsayi a ranar 3 ga Maris, 2005, wanda ya taƙaita abubuwan da suka dace, wallafe-wallafen da aka buga game da waɗannan nau'ikan, tsokaci daga jama'a, da kuma kimantawa game da kokarin kiyayewa na yanzu.[1][13]
Lissafin ESA kamar yadda ake barazana
[gyara sashe | gyara masomin]Binciken matsayin BRT ya kammala cewa ESA ya kamata ta lissafa murjani na Elkhorn a matsayin nau'in da ke fuskantar barazana, saboda muhimmancin gudummawar da ke tattare da yanayin halittu da kuma tsananin barazanar da ke tasiri ga nau'in. A matsayin nau'in da ya kasance mai yawa, babban ci gabansa ya ba shi damar ci gaba da canje-canje na matakin teku. Halin reshe ya haifar da gidaje da kariya ga sauran kwayoyin reef da yawa. Tun lokacin da ya ragu, babu wani nau'in murjani da ya iya cika waɗannan ayyukan yanayin halittu. Kamar yadda aka ambata, jinsin suna fuskantar barazanar da yawa, wanda ya haɗa da amma ba'a iyakance su ga cututtuka ba, zafin jiki da ke haifar da fari, da lalacewar jiki daga guguwa. BRT ta yanke shawarar cewa murjani na Elkhorn ba shi da haɗari don halaka, amma zai iya zama haka a nan gaba saboda girman yawan jama'arta ya yi ƙasa kuma an yi hasashen tsananin barazanar zai karu.[12]
Bayan sake nazarin rahoton matsayin BRT na 2005, NMFS ta buga doka ta ƙarshe game da matsayin murjani na Elkhorn a ranar 9 ga Mayu, 2006. Daga ranar 8 ga Yuni, 2006, an lissafa nau'in a matsayin barazana a karkashin Dokar Dabbobi Masu Hadari ta 1973. [13]
Binciken sake rarrabawa
[gyara sashe | gyara masomin]A cikin shekara ta 2012, an tattauna game da matsayin murjani na Elkhorn da kuma ko ya kamata a sake rarraba shi daga barazanar zuwa haɗari. Dalilin da ke bayan wannan canjin da aka gabatar shi ne ci gaba da raguwar yawan jama'a tun lokacin da ESA ta lissafa a cikin 2006 da kuma shaidar gazawar daukar ma'aikata a cikin jama'a da yawa. Rashin raguwar yawan jama'a yana iya haifar da haɗari da yawa kamar ƙarancin teku da matakan damuwa.
Koyaya, yawancin membobin masana kimiyya da jama'a sun nuna rashin jituwa da wannan sake rarraba da aka tsara. Magana da yawa sun yi nuni da lokuta na karuwar yawan jama'a da dawo da su tare da wasu da ke ambaton yawan jama'aa da ƙididdigar bambancin kwayoyin halitta da kuma samfuran yawan jama'ar. Mutane da yawa sun yi jayayya cewa an sami gagarumin ci gaba a cikin ayyukan sabuntawa masu aiki, kuma suna tsoron cewa lissafin wannan murjani a matsayin mai haɗari zai iya rushewa da kuma hana kokarin kiyayewa.
A watan Satumbar 2014, NMFS ta buga doka ta ƙarshe game da matsayin lissafin nau'ikan coral masu gina reef 65. Wannan ya haɗa da sake kimanta matsayin murjani na Elkhorn. An ajiye murjani a matsayin barazana saboda damuwa daga jama'a cewa lissafa shi a matsayin mai haɗari na iya tasiri ga ayyukan sabuntawa da ke gudana yayin da mutane zasu iya ganin su ba su da amfani.[9]
Barazanar yanzu
[gyara sashe | gyara masomin]
Matsalar Duniya
[gyara sashe | gyara masomin]Coral na Elkhorn yana fuskantar barazanar duniya da yawa kamar canjin yanayi, ƙarancin teku, da yawan kamun kifi.[1]
Canjin yanayi
[gyara sashe | gyara masomin]Kamar sauran nau'o'in, coral na Elkhorn yana fuskantar barazanar Canjin yanayi. Canjin yanayi yana nufin dumama yawan zafin jiki na duniya wanda ya haifar da hayakin carbon. Yanayin zafi na yanayi yana ƙara yawan zafin ruwa. Kamar yadda aka ambata, murjani na Elkhorn suna da algae na musamman da ake kira zooxanthellae, suna rayuwa a kan kyallen takarda, wanda ke ba da fa'idodi da yawa. Koyaya, lokacin da yanayin zafi na ruwa ya yi zafi, murjani na Elkhorn yana fitar da zooxanthellae. Ba tare da zooxanthellae ba, coral na Elkhorn da farko ya rasa tushen iskar oxygen, sannan launi, sannan yawanci ya mutu. [ana buƙatar hujja]Bugu da ƙari, canjin yanayi yana ƙara tsananin guguwa, wanda zai iya kashe yawan coral na Elkhorn.[1]
Rashin ƙwayoyin cuta na teku
[gyara sashe | gyara masomin]Elkhorn coral kuma yana fuskantar barazanar acidisation na teku. [ana buƙatar hujja][ana buƙatar ƙa'ida] Acidification na teku yana nufin karuwar acidity na ruwan teku wanda ya haifar da karuwar kasancewar carbon dioxide, sakamakon hayakin carbon. Kwayar Elkhorn coral an yi ta da calcium carbonate. Carbon dioxide yana samar da haɗin sunadarai tare da ruwa kuma, ta hanyar halayen sunadarai, cire ions na carbonate wanda corals ke buƙatar yin calcium carbonate. Tare da ƙananan ions na carbonate, kwarangwal na murjani sun fi rauni kuma sun fi sauƙi.[1]
Kifi da yawa
[gyara sashe | gyara masomin]Kamar corals da yawa, Yawan kamun kifi yana shafar coral na Elkhorn ta hanyar rage yawan kifaye da ke cin abinci mai cutarwa macroalgae. Macroalgae ya lalata murjani na Elkhorn ta hanyar samar da sunadarai masu guba da kuma rage iskar oxygen da ke kusa. Macroalgae na iya kara cutar da murjani na Elkhorn ta hanyar sauƙaƙe ci gaban pathogen. Har ila yau, macroalgae yana rage adadin wuraren da suka dace inda Elkhorn coral larvae ke haɗe, yana rage ikon Elkhor n reefs don murmurewa.[14]
Matsalar cikin gida
[gyara sashe | gyara masomin]Rashin gurɓataccen ruwa na cikin gida, wanda aka fi sani da Ruwa mai guba, yana da mummunar tasiri ga murjani na Elkhorn ta hanyar kara yaduwar cutar fararen fata, yawan macroalgae, da kuma kara yawan ruwan sama.
Cutar fararen fata
[gyara sashe | gyara masomin]Kwayoyin cututtukan mutane da aka samu a cikin ruwan da ba a kula da shi ba suna da lahani musamman ga murjani na Elkhorn. Serra marcescens, wanda aka fi sani da Cutar fararen cutar, yana da kisa sosai kuma yana iya yaduwa.[15] Cutar ta fara haifar da murjani don fitar da mucus mai ƙanshi, sannan ya biyo bayan samar da mummunan rauni, wanda ya fadi, yana cire kwayar murjani. Wadannan cututtukan suna girma da sauri, kuma suna iya girma har zuwa 10.5 cm2 a kowace rana, suna haifar da asarar nama na 2.5 cm2 a rana.[16] Wannan cuta ta taimaka wajen sanya murjani na Elkhorn a cikin jerin nau'ikan da ke cikin haɗari a cikin 2006 bayan wani lamari na Serra marcescens ya shafe kashi 75% na murjani na Caribbean a cikin 2005. [1][15]
Girman abinci mai gina jiki - girma na algae
[gyara sashe | gyara masomin]Ruwa mai guba wanda ba a kula da shi ba ya ƙunshi matakan gina jiki masu yawa, wanda ke kara girma na macroalgae. Kamar yadda aka ambata a sama, wannan ci gaban macroalgae yana da lahani ga rayuwar Elkhorn.[14]
Turbidity - ruwan sama
[gyara sashe | gyara masomin]Wani abin damuwa shine karuwar turbidity na ruwa. Wannan karuwar turbidity na iya haifar da batutuwa masu yawa kamar ruwan da ba a kula da shi ba da kuma ayyukan yaduwar rairayin bakin teku. Coral na Elkhorn suna rayuwa a cikin yankuna masu zurfi, suna ba da damar photosynthetic zooxanthellae su sami haske mai yawa. Lokacin da ruwa ya zama mai duhu, ko hazo, ana hana samun wannan haske. Tare da karancin haske, karancin photosynthesis yana faruwa, kuma ta haka ne zooxanthellae ke samar da karancin iskar oxygen. Kamar yadda aka bayyana a baya, yawancin murjani na oxygen da ke karɓa daga zooxanthellae ne, don haka ba tare da wannan oxygen ba, murjani na Elkhorn na iya saurin kafara kuma ya mutu.[17]
Dukkanin wadannan damuwa da kansu suna raunana murjani. Gabaɗaya suna rage damar da corals ke da shi na tsira daga kowane damuwa.
Kokarin kiyayewa
[gyara sashe | gyara masomin]Kokarin da ake yi kafin a lissafa
[gyara sashe | gyara masomin]Kafin lissafin ESA a cikin 2006, babu wata hanyar tsarawa don kare murjani na Elkhorn. Wasu takardu tare da ka'idoji sun wanzu; duk da haka, babu takardun da aka ambata musamman da sunan Elkhorn coral ko wasu murjani na Acropora.
Yawancin ka'idojin da ke akwai an yi niyya ne don kare murjani daga tasirin jiki da aka samu ta hanyar kayan kamun kifi, ratayewa, da kuma kwantar da jirgin ruwa. Dokar Florida tana kare murjani na Scleractinia da murjani na Milleporina daga tattarawa, cinikin kasuwanci, da lalacewar jiki kai tsaye. Puerto Rico kuma ta kafa irin waɗannan dokoki don kare murjani da ƙarfafa kiyayewa. A shekara ta 2001, Hukumar Kula da Gidajen Kasa ta kafa wuraren tunawa na kasa guda biyu - Virgin Islands Coral Reef da Buck Island Reef National Monument. Halitta waɗannan abubuwan tunawa guda biyu sun kafa dubban kadada na yankunan da ba a cire su ba.[13]
Duk da yake Amurka tana da wasu manufofi a wurin kafin jerin, wasu kasashe da yawa ba su yi ba. Ganin cewa kewayon murjani na Elkhorn ya shimfiɗa tare da gabar tekun kasashe daban-daban, rashin daidaituwa a cikin manufofi ya gabatar da batun. Jerin hukuma na murjani na Elkhorn ya ba da izinin kafa takamaiman kariya.
Manufofin kiyayewa
[gyara sashe | gyara masomin]NMFS ta buga shirin farfadowa a watan Maris na shekara ta 2015, wanda a bayyane ya bayyana manufofin kiyayewa da kokarin Elkhorn coral. Wannan takardar ta nuna cewa manyan manufofi sune kara yawan wannan nau'in da kuma kare bambancin kwayoyin halitta a duk faɗin kewayonsa.[18]
Wannan burin na ƙarshe yana da mahimmanci musamman ga kiyayewa. Coral na Elkhorn suna iya haifar da jima'i da haihuwar jima'i; duk da haka, haihuwar jimaʼi ya fi yawa, wanda ya haifar da kusan kashi 50% na Elk Horn su kasance mutane.[9] Rashin bambancin kwayar halitta ya sa jinsin ya fi fuskantar barazana kuma, sabili da haka, muhimmiyar mayar da hankali ga kiyayewa.
Ayyukan sabuntawa
[gyara sashe | gyara masomin]Yawancin ayyukan sabuntawa na Elkhorn coral sun haɗa da ƙirƙirar wuraren da aka kiyaye, waɗanda aka nufa don inganta haifuwa da girma ta hanyar rage wasu barazanar ga jinsin.
A ranar 26 ga Nuwamba, 2008, NMFS ta ba da doka ta ƙarshe, wacce ta fara aiki a ranar 26 ga Disamba, 2008, wacce ta sanya murabba'in kilomita 2,959 (7,664 sq km) a matsayin muhimmiyar mazaunin murjani na Elkhorn. Gidan da aka bayyana ya ƙunshi yankuna daban-daban guda huɗu, waɗanda suka haɗa da bakin tekun da ke kewaye da Florida, Puerto Rico, yankin St. John da St. Thomas, da St. Croix. Wadannan yankuna an zaba su musamman saboda suna dauke da fasalulluka na farfajiyar da ake bukata don kiyaye Elkhorn. Don ƙara yawan abubuwan da suka faru na jima'i da na haihuwa, jinsunan suna buƙatar wurare masu wuya a cikin zurfin ruwa daga matsakaicin layin ruwa zuwa kusan mita 30.[4]
A shekara ta 2009, gwamnatin Amurka ta kafa Dokar Amincewa da sake saka hannun jari ta Amurka, wanda ya ba da kudade don kiyaye murjani ta hanyar sashen National Oceanic and Atmospheric Administration (NOAA). Wannan kudade ya ba da damar kirkirar cibiyar sadarwar coral nurseries a duk faɗin ruwan da ke bakin tekun kudancin Florida da tsibirin Virgin Islands na Amurka don dawo da coral na Elkhorn. Gidajen yara sun tabbatar da taimako wajen gudanar da bincike na kwayar halitta wajen sauƙaƙe ci gaban reef gaba ɗaya da maidowa.[9]
Gyara
[gyara sashe | gyara masomin]Ko da shekaru 14 bayan an lissafa shi a matsayin barazana, murjani na Elkhorn ya kasance haka. Wannan gazawar a wani bangare ne saboda lokaci da hanyoyin makamashi da aka buƙaci a baya don sake farfado da coral reefs na Elkhorn. Wadannan hanyoyin suna buƙatar murjani don a shuka su na watanni zuwa shekaru a cikin yara kafin a dasa su a cikin teku. Koyaya, sabon bincike ya nuna cewa ana iya dasa murjani na Elkhorn a cikin teku bayan makonni biyu kawai da aka haife shi a cikin ɗakin yara. Wannan raguwa a lokacin kula da yara ya sa ya zama kusan sau 30 mafi arha don sake Elkhorn coral yanzu. Wannan raguwar farashi ya sa ya fi sauƙi ga kasashe su dawo da kogin su.[19]
Manazarta
[gyara sashe | gyara masomin]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Crabtree, R. E (2014).
- ↑ 2.0 2.1 2.2 2.3 2.4 Fisheries, NOAA (2019-12-30). "Elkhorn Coral | NOAA Fisheries". NOAA (in Turanci). Retrieved 2020-04-14. Cite error: Invalid
<ref>tag; name ":0" defined multiple times with different content - ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "Welcome to the NOAA Institutional Repository |". repository.library.noaa.gov. Retrieved 2020-04-14. Cite error: Invalid
<ref>tag; name ":1" defined multiple times with different content - ↑ 4.0 4.1 4.2 4.3 4.4 "Endangered and Threatened Species; Critical Habitat for Threatened Elkhorn and Staghorn Corals". Federal Register. 2008-11-26. Retrieved 2020-04-14. Cite error: Invalid
<ref>tag; name ":3" defined multiple times with different content - ↑ 5.0 5.1 "Species Profile". ecos.fws.gov. Retrieved 2020-04-14. Cite error: Invalid
<ref>tag; name ":5" defined multiple times with different content - ↑ 6.0 6.1 McNeill, Donald (October 1997). "Earlier (late Pliocene) first appearance of the Caribbean reef-building coral Acropora palmata: Stratigraphic and evolutionary implications". Geology. 25 (10): 891. Bibcode:1997Geo....25..891M. doi:10.1130/0091-7613(1997)025<0891:ELPFAO>2.3.CO;2 – via ResearchGate.
- ↑ Lirman, Diego (July 1999). "Reef fish communities associated with Acropora Palmata: relationship to benthic attributes". Journal of Marine Science - Miami. 65: 235–252 – via ResearchGate.
- ↑ Ferrario, Filippo; Beck, Michael W.; Storlazzi, Curt D.; Micheli, Fiorenza; Shepard, Christine C.; Airoldi, Laura (2014-05-13). "The effectiveness of coral reefs for coastal hazard risk reduction and adaptation". Nature Communications (in Turanci). 5 (1): 3794. Bibcode:2014NatCo...5.3794F. doi:10.1038/ncomms4794. ISSN 2041-1723. PMC 4354160. PMID 24825660.
- ↑ 9.0 9.1 9.2 9.3 "Endangered and Threatened Wildlife and Plants: Final Listing Determinations on Proposal To List 66 Reef-Building Coral Species and To Reclassify Elkhorn and Staghorn Corals". Federal Register. 2014-09-10. Retrieved 2020-04-15. Cite error: Invalid
<ref>tag; name ":6" defined multiple times with different content - ↑ Fisheries, NOAA (2019-12-30). "Critical Habitat for Elkhorn and Staghorn Corals | NOAA Fisheries". NOAA (in Turanci). Retrieved 2020-04-15.
- ↑ Miller, Margaret (September 29, 2016). "Reef-scale trends in Florida Acropora spp. abundance and the effects of population enhancement". PeerJ. 4: e2523. doi:10.7717/peerj.2523. PMC 5047146. PMID 27703862.
- ↑ 12.0 12.1 12.2 12.3 "Endangered and Threatened Species: Final Listing Determinations for Elkhorn Coral and Staghorn Coral". Federal Register. 2006-05-09. Retrieved 2020-04-15. Cite error: Invalid
<ref>tag; name ":7" defined multiple times with different content - ↑ 13.0 13.1 13.2 13.3 13.4 "Welcome to the NOAA Institutional Repository |". repository.library.noaa.gov. Retrieved 2020-04-15. Cite error: Invalid
<ref>tag; name ":8" defined multiple times with different content - ↑ 14.0 14.1 Zanevald (June 7, 2016). "Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales". Nature Communications. 7: 11833. Bibcode:2016NatCo...711833Z. doi:10.1038/ncomms11833. PMC 4899628. PMID 27270557. Cite error: Invalid
<ref>tag; name ":10" defined multiple times with different content - ↑ 15.0 15.1 Sutherland (August 2011). "Human Pathogen Shown to Cause Disease in the Threatened Eklhorn Coral Acropora palmata". PLOS ONE. 6 (8): e23468. Bibcode:2011PLoSO...623468S. doi:10.1371/journal.pone.0023468. PMC 3157384. PMID 21858132.
- ↑ Patternson (July 2002). "From the Cover: The etiology of white pox, a lethal disease of the Caribbean elkhorn coral, Acropora palmata". Proceedings of the National Academy of Sciences. 99 (13): 8725–8730. Bibcode:2002PNAS...99.8725P. doi:10.1073/pnas.092260099. PMC 124366. PMID 12077296 – via ResearchGate.
- ↑ Hernandez-Delgado (January 2010). "Sediment Stress, Water Turbidity, and Sewage Impacts on Threatened Elkhorn Coral (Acropora palmata) Stands at Vega Baja, Puerto Rico". Proceedings of the 63rd Gulf and Caribbean Fisheries Institute. 63: 83–92 – via ResearchGate.
- ↑ "Endangered and Threatened Species; Availability of the Final Recovery Plan for Staghorn and Elkhorn Corals". Federal Register. 2015-03-06. Retrieved 2020-04-15.
- ↑ Chamberland, Valerie (October 2015). "Restoration of critically endangered elkhorn coral (Acropora palmata) populations using larvae reared from wild-caught gametes". Global Ecology and Conservation. 4: 526–537. doi:10.1016/j.gecco.2015.10.005 – via ResearchGate.