Akesananan Lakes na Kanada
Raguwar hazo a cikin yanayin dusar ƙanƙara da aka lura a cikin recentan shekarun nan a cikin yankuna arctic Kanada ta haifar da bushewar damuwa daga Yankin Tafkin.
Wannan shi ne matsayin da wasu masu bincike suka cimma daga Jami'ar Laval, da Jami'ar Wilfrid Laurier, da Jami'ar Brock da kuma Jami'ar Waterloo a wani binciken da aka buga makonnin da suka gabata a shafin hukuma na mujallar kimiyya ta Geophysical Research Letters. Bayyana ƙarin tabbaci, idan har yanzu basu isa ga bayyane na warming duniya.
Masu binciken sun yanke wannan hukuncin ne bayan nazarin tabkuna 70 da ke kusa da Old Crow, Yukon da Churchill, Manitoba, Kanada. Yawancin tafkunan da aka yi karatun ba su kai zurfin mita ba. Dangane da binciken da aka gudanar, fiye da rabin tabkunan da ke wasu yankuna masu fadi kuma kewaye da dazuzzuka, sun nuna alamun yin lalata.
Wannan matsalar ta zo ne musamman daga ragin ruwan da yake zuwa daga narke. Misali, daga 2010 zuwa 2012 matsakaicin ruwan sama na hunturu a Churchil ya ragu da 76 mm idan aka kwatanta da matsakaita da aka rubuta tsakanin 1971 da 2000. Bushewar wasu tabkuna, wanda ya zama ido ga ido a karon farko a 2010, ya ma fi haka furta a cikin 2013.
Ga ire-iren wadannan tabkuna, hazo a cikin yanayin dusar ƙanƙara yana wakiltar tsakanin 30% zuwa 50% na samar da ruwa shekara-shekara. Nau'in bushewar da masu bincike suka lura da shi ba a taba ganin irin sa ba a cikin shekaru 200 da suka gabata. Bugu da ƙari kuma, nazarin isotopic da aka gudanar a kan phytoplankton ya kasance yana tarawa a cikin gadajen tabkin yana nuna cewa tabkuna sun kiyaye ma'aunin ruwa na shekaru 200.
Ba zato ba tsammani aka katse wannan kwanciyar hankali 'yan shekarun da suka gabata. Idan yanayin bazara da damuna mai ƙarancin dusar ƙanƙara ta ci gaba, kamar yadda ƙirar yanayi ta annabta, da yawa daga cikin ƙananan tafkuna masu zurfin zurfin ruwa na iya ƙarshe bushewa gaba ɗaya. Yana da wahala a hango duk illolin asarar wannan mazaunin, amma gaskiya ne cewa sakamakon muhalli zai zama da mahimmanci.
Snowmelt shine tushen ruwa mai mahimmanci ga yawancin tafkuna masu yawa, amma samfuran yanayi suna hasashen cewa hazo a cikin yanayin dusar ƙanƙara zai ragu a wasu yankuna, tare da mahimman abubuwan da suka shafi muhalli. A cikin wannan labarin, ana amfani da sigogi guda uku kamar su isotopic data na ruwan tafki tare, gradients na terrestrial cover herbal (daga bude tundra zuwa rufaffiyar gandun daji) da kuma yanayin yanayin kasa don gano tabkunan da ke da saukin lalatawa a karkashin yanayin mananan raƙuman ruwa mai narkewa a cikin shimfidar wurare biyu-Arctic Plains, Yukon, da Hudson Bay Shoals, Manitoba, Kanada.
Kogunan da suke duka a cikin ruwa da kuma a cikin tafki na bude tundra sun nuna diyya ta tsari tsakanin ma'aunin mai nuna alama na isotopes oxygen na ruwa (-18O) akan kamfen samfu da yawa, wanda aka samo daga cellulose da aka samo a cikin wuraren kwanan nan. Ana danganta wannan biyan diyyar ne saboda tsananin ƙarancin ruwa da aka wadata a 18O wanda ke amsar ƙasa da matsakaicin ruwan dusar ƙanƙara a cikin 'yan shekarun nan.
Abin lura ne cewa tabkuna da yawa sun kusan isa ga yanke duka azaba a lokacin tsakiyar bazara na shekara ta 2010, wanda ya biyo bayan hunturu da ƙarancin ruwa a yanayin dusar ƙanƙara. Dangane da bayanan tarihi na waɗannan nau'ikan tabkuna, yanayin busassun yanayi na 2010 mai yiwuwa ba su faru a cikin shekaru 200 da suka gabata ba. Wadannan yanke shawara sun ciyar da damuwar cewa raguwar kwararar daga dusar ƙanƙara zai haifar da bushewa mai yawa daga tabkuna masu zurfi a cikin waɗannan nau'ikan shimfidar wurare.
Ƙarin Bayani: WWF ta damu da sauri da zafin canjin yanayi, Kankunan Arctic yana ɓacewa a farashin da aka kafa, Damuwar bacewar kankara a cikin Arctic
Harshen Fuentes: Rubuce-rubucen Rubuce-rubucen Nazarin Gudanarwa