da Ruwa Murjani tsaunuka ne da aka kafa a kasan teku ta hanyar nazarin halittu na kwayoyin halitta da ake kira polyps. Ana samun waɗannan sifofin halittu a cikin ruwa mai zurfi na tekuna masu zafi inda zafin jiki ke tsakanin 20 zuwa 30ºC. Suna da matuƙar mahimmanci ga muhalli da kayyade tekuna da rayayyun halittu.
Saboda haka, za mu keɓe wannan labarin don gaya muku duk halaye, asali da mahimmancin murjani reefs.
Menene murjani reefs
Coral polyps suna cikin ajin Anthozoa (phylum Cnidaria), kuma tsarin jikinsu yana da sauƙi. Suna da simmetry na radial da rami da aka kafa ta nau'i biyu na nama, wanda aka raba ta hanyar septum.
Jikin murjani yana da budi, ko baki, domin duka ciyarwa da kuma fitar. Suna da jerin tarkace a cikin bakinsu, wanda suke amfani da su don kama abin da suka gani.
Akwai murjani masu laushi da murjani masu kauri, na biyun kuma su ne murjani masu gina reef. An ba da taurin saboda suna samar da Layer na calcite (crystalline calcium carbonate) a jiki.
Wadannan polyps suna samar da yankuna masu yawa tare da haɗin jima'i da haifuwa na jima'i, kuma ci gaban su yana buƙatar ruwa mai laushi, dumi, bayyananne da tashin hankali. Ci gaban waɗannan yankuna ya haifar da tsarin da aka gina a matsayin mafaka ga magudanan ruwa da kuma abin jan hankali na rayuwa da abinci.
Dangane da yanayin yanayin ƙasa da yanayin yanayin muhalli na yankin, an samar da nau'ikan murjani iri uku na asali. Ɗayan ita ce ɓangarorin murjani na littoral da ke tasowa a bakin tekun. Sauran nau'ikan su ne shingen reefs da atolls (tsibirin da aka samar da zoben murjani reefs da tsakiyar tafkin) nesa da bakin teku.
Coral reefs suna zaune da nau'ikan chlorophyll, macroalgae (launin ruwan kasa, ja, da kore), da kuma algae na coralline. Dabbobin suna da nau'ikan murjani da yawa, kifi, masu invertebrates, dabbobi masu rarrafe (kunkuru na ruwa) har ma da dabbobi masu shayarwa na ruwa irin su manatees.
Invertebrates sun haɗa da katantanwa, dorinar ruwa, squid, jatan lande, kifin tauraro, urchins na teku da soso. Mafi girman murjani reefs a duniya sune Coral Triangle a kudu maso gabashin Asiya da Great Barrier Reef a Ostiraliya. Hakazalika, rairayin bakin teku na Mesoamerican-Caribbean da kuma Tekun Bahar Maliya.
Duk da mahimmancin su ga ilimin halittun ruwa da bambancin halittu na duniya, murjani reefs suna fuskantar barazana. Barazana ga waɗannan halittun sun haɗa da ɗumamar yanayi, gurɓacewar teku, da haƙar ma'adinai na murjani.
Har ila yau, akwai barazanar ilimin halitta, irin su yawan yawan nau'in cin murjani irin su kambi-na-ƙaya starfish.
Gabaɗaya halaye
murjani reef kowane tsayi ne akan gadon teku a zurfin mita 11 ko ƙasa da haka. Yana iya zama bankin yashi ko dutse, ko ma na'urar wucin gadi da wani jirgin ruwa ya yi. A cikin yanayin murjani reefs, haɓakawa ne ta hanyar biomes ke haifar da exoskeletons na calcareous.
Coral reefs suna bunƙasa a cikin tekuna masu zafi a duniya, a cikin Amurka tare da Gulf of Mexico, Florida, da Pacific Coast daga California zuwa Colombia. Ana kuma samun su a bakin tekun Atlantika na Brazil da kuma cikin Caribbean, gami da nahiyoyi da kuma bakin tekun tsibiri.
A Afirka suna tafiya a bakin tekun Atlantika masu zafi, yayin da a Asiya ana samun su a cikin Bahar Maliya, Tsibirin Indo-Malay, Australia, New Guinea, Micronesia, Fiji, da Tonga. An yi kiyasin cewa ruwan murjani zai kai murabba'in kilomita 284 zuwa 300, kashi 920 cikin dari na yankin Indo-Pacific ne. 000% na murjani reefs na duniya ana rarraba tsakanin Indonesia, Australia da Philippines.
Morphology
Polyps suna da simmetric radially, kuma ramin jikin ya kasu kashi-kashi ta radial partitions, wato suna kama da jakar (coelenterate). Wannan jakar, wanda ake kira lumen ko hanji, ya haɗa da buɗewa zuwa waje (baki).
Ana amfani da baki don shigar abinci da fitar da sharar gida. Narkewa yana faruwa a cikin lumen, ko lumen, na tasoshin ciki. An kewaye bakin da zoben tentacles., wanda sukan yi amfani da su wajen kama abin da suka yi na ganima su kai bakinsu. Wadannan tentacles suna da kwayoyin cutar da ake kira nematoblasts ko cnidocytes.
Cnidoblasts sun ƙunshi wani rami da ke cike da wani abu mai ƙura da murɗaɗɗen filaments. A ƙarshensa akwai wani tsawo mai mahimmanci wanda, lokacin da aka tayar da shi ta hanyar taɓawa, yana fitar da filaments masu tangle.
Filayen suna nutsewa a cikin wani ruwa mai zafi kuma suna shiga jikin abin ganima ko maharin. Jikin waɗannan dabbobin ya ƙunshi nau'i biyu na sel. Na waje ana kiransa ectoderm, na ciki kuma ana kiransa da endoderm.. Tsakanin yadudduka biyu akwai wani abu na gelatin da ake kira mesoplasty. Coral polyps ba su da takamaiman gabobin numfashi, kuma ƙwayoyin su suna ɗaukar iskar oxygen kai tsaye daga ruwa.
Dinoflagellates (microscopic algae) suna rayuwa a cikin m nama mai translucent na murjani polyps. Waɗannan algae, waɗanda aka sani da zooxanthellae, suna kula da alaƙar alama tare da polyps.
Wannan symbiosis shine mutualism (duka kwayoyin halitta a cikin dangantaka suna amfana). Zooxanthellae suna ba da mahaɗan carbon da nitrogen zuwa polyps, kuma polyps suna ba su ammonia (nitrogen). Ko da yake wasu yankuna na murjani ba su da zooxanthellae, kawai waɗancan yankuna na murjani waɗanda suka baje kolin wannan ƙungiyar sun kafa reefs.
Coral Reef Nutrition
Baya ga samun abubuwan gina jiki da zooxanthellae ke bayarwa. Murjani polyps kuma suna farauta da dare. Don yin wannan, suna shimfiɗa ƙananan ƙwanƙolin kashin baya don kama ƙananan dabbobin ruwa. Waɗannan ƙananan dabbobin wani yanki ne na zooplankton da igiyoyin ruwa ke ɗauka.
Yanayin muhalli
Murjani reefs suna buƙatar yanayin ruwa mara zurfi, dumi da tsinke. Ba za su ci gaba a cikin ruwa ba inda zafin jiki ya kasance ƙasa da 20 ºC, amma yanayin zafi sosai zai shafe su da mummunan yanayin, yanayin zafin su shine 20-30 ºC.
Wasu nau'ikan na iya haɓakawa a cikin ruwan sanyi tsakanin zurfin mita 1 zuwa 2.000. Misali, muna da Madrepora oculata da Lophelia pertusa, waɗanda ba su da alaƙa da zooxanthellae kuma fararen murjani ne.
Coral ba zai iya tasowa a cikin zurfin teku ba saboda zooxanthellae yana buƙatar hasken rana don photosynthesis.
Ina fatan cewa tare da wannan bayanin zaku iya ƙarin koyo game da murjani reefs da halayensu.