Furewar bazara

**Furen bazara** shine haɓakar haɓakar phytoplankton mai ƙarfi (watau haja) wanda yawanci yana faruwa a farkon bazara kuma yana wuce ƙarshen bazara ko farkon lokacin rani. Wannan al'amari na yanayi halayen yanayi ne na yanayin zafi na Arewacin Atlantika, ƙananan iyaka, da ruwan teku.   Phytoplankton blooms yana faruwa lokacin da girma ya wuce hasara, duk da haka babu wani ma'anar da aka yarda da ita a duniya game da girman canji ko kofa na yalwa wanda ya zama fure. Girman, girman sararin samaniya da tsawon lokacin fure ya dogara da nau'ikan kwayoyin halitta da kwayoyin halitta. Abubuwan da ke tattare da kwayoyin halitta sun haɗa da samuwan haske, abubuwan gina jiki, zafin jiki, da kuma tsarin jiki wanda ke tasiri ga samun haske,      da kuma abubuwan da ke tattare da kwayoyin halitta sun hada da kiwo, lysis na viral, da phytoplankton physiology.  Abubuwan da ke haifar da farawa fure har yanzu ana muhawara sosai (duba zurfin zurfi ).

## Hanyar gargajiya
 
A cikin bazara, ƙarin haske yana samuwa kuma ƙaddamar da ginshiƙi na ruwa yana faruwa yayin da yanayin zafi ke ƙaruwa da ruwan sama (wanda ake kira ƙaddamar da zafi). A sakamakon haka, an hana cakuda tsaye kuma ana fitar da phytoplankton da abubuwan gina jiki a cikin Yankin euphotic. Wannan yana haifar da babban abinci mai gina jiki da kuma yanayin haske mai haske wanda ke ba da damar saurin girma na phytoplankton.

Tare da shimfidar zafi, ana iya haifar da furanni na bazara ta hanyar salinity saboda shigar da ruwa mai laushi, daga tushe kamar babban kogi. Wannan nau'in stratification yawanci yana iyakance ga yankunan bakin teku da estuaries, gami da Chesapeake Bay .  Ruwa mai laushi yana tasiri ga yawan amfanin gona ta hanyoyi biyu. Na farko, saboda ruwan sha ba shi da yawa, yana kwance a saman ruwan teku kuma yana haifar da ginshiƙi na ruwa. Na biyu, ruwan sha sau da yawa yana ɗauke da abubuwan gina jiki  wanda phytoplankton ke buƙatar aiwatar da matakai, gami da photosynthesis.

Saurin karuwa a cikin ci gaban phytoplankton, wanda yawanci ke faruwa a lokacin fure na bazara, ya taso ne saboda phytoplanktan na iya haifuwa da sauri a ƙarƙashin yanayin girma mafi kyau (watau, matakan abinci mai gina jiki, haske mai kyau da zafin jiki, da ƙananan asarar daga kiwo da haɗuwa a tsaye). Dangane da haifuwa, nau'ikan phytoplankton da yawa na iya ninka aƙalla sau ɗaya a kowace rana, yana ba da damar karuwa mai yawa a cikin girman kayan phytoplanktan. Misali, girman hannun jari na yawan jama'a wanda ya ninka sau ɗaya a rana zai karu sau 1000 a cikin kwanaki 10 kawai. Bugu da ƙari, akwai jinkiri a cikin amsawar kiwo na zooplankton mai cin ganyayyaki a farkon furanni, wanda ke rage asarar phytoplankton. Wannan lag yana faruwa ne saboda akwai karancin zooplankton na hunturu da yawa kuma yawancin zooplanktan, kamar copepods, suna da lokutan ƙarni mafi tsawo fiye da phytoplankton.

Fure-fure na bazara yawanci yana wucewa har zuwa ƙarshen bazara ko farkon lokacin rani, a wannan lokacin fure-furuwa ya rushe saboda raguwar abinci mai gina jiki a cikin ginshiƙan ruwa da karuwar matsin kiwo ta zooplankton. Abinda ya fi iyakancewa a cikin yanayin ruwa yawanci nitrogen (N). Wannan shi ne saboda yawancin kwayoyin ba su iya gyara nitrogen na yanayi a cikin siffofin da za a iya amfani da su (watau ammonium, nitrite, ko nitrate). Koyaya, ban da ruwan bakin teku, ana iya jayayya, cewa ƙarfe (Fe) shine mafi ƙuntataccen abinci saboda ana buƙatar gyara nitrogen, amma ana samun sa ne kawai a cikin ƙananan yawa a cikin yanayin ruwa, yana fitowa daga guguwar ƙura da leaching daga duwatsu. Phosphorus na iya zama mai iyakancewa, musamman a cikin yanayin ruwa mai laushi da yankunan bakin teku na wurare masu zafi.

A lokacin hunturu, iska mai iska da yanayin sanyi na ruwa sun rushe ginshiƙan ruwa da aka kafa a lokacin rani. Wannan rushewa yana ba da damar haɗuwa a tsaye na ginshiƙi na ruwa kuma yana cika abubuwan gina jiki daga ruwa mai zurfi zuwa ruwa mai zurfin da sauran Yankin euphotic. Koyaya, haɗuwa a tsaye yana haifar da asarar gaske, kamar yadda ake ɗaukar phytoplankton a ƙasa da yankin euphotic (don haka numfashi su ya wuce samar da farko). Bugu da ƙari, rage hasken (ƙarfi da tsawon yau da kullun) a lokacin hunturu yana iyakance yawan ci gaba.

## Sauran hanyoyin
A tarihi, an bayyana furanni ta hanyar zurfin zurfi Sverdrup, wanda ya ce furanni suna haifar da zubar da jini. Hakazalika, Winder da Cloern (2010) sun bayyana furanni na bazara a matsayin martani ga karuwar zafin jiki da wadatar haske. Koyaya, an ba da sabbin bayani kwanan nan, gami da cewa furanni suna faruwa saboda:

* Haɗuwa tsakanin ci gaban phytoplankton da kiwo na zooplankton.
* Farawar kusan farfajiyar ƙasa a cikin bazara.
* Haɗuwa da ginshiƙi na ruwa, maimakon rarraba 
* Rashin tashin hankali 
* Ƙara ƙarfin haske (a cikin yanayin ruwa mai zurfi). 
* Eddies (duba 'Aikin eddies a farkon fure na bazara na Arewacin Atlantic") 

## Matsayin eddies a farkon furewar bazara ta Arewacin Atlantic
Wani binciken da aka yi a shekarar 2012 ya nuna cewa farawar furewar Arewacin Atlantic saboda guguwa ne. Eddies, ko raƙuman ruwa na zagaye, suna ko'ina a duk faɗin teku na duniya kuma suna taka muhimmiyar rawa a cikin haɗakar teku. A Arewacin Atlantic, ruwan sama ya fi sanyi kuma ya fi yawa a arewa kuma ya fi zafi kuma ya fi sauƙi a kudu. Wannan ya kafa gradient na kwance. Juyawa na duniya yana kula da wannan gradient ta hanyar hana ruwa mai yawa daga zamewa a ƙarƙashin ruwa mai haske. Eddies, duk da haka, na iya haɗuwa da ruwa mai yawa a ƙarƙashin ruwa mai sauƙi, yana saita shimfidar tsaye wanda ke iyakance zurfin haɗuwa ta tsaye (wanda ke haifar da ƙananan haɗuwa). 

Hanyoyin da ke iyakance zurfin cakuda tsaye ana iya kiransu 'ƙididdigar sakewa' (misali eddies, hasken rana), wanda ke gasa da hanyoyin da ke kara cakuda tsaye (kuma suna zurfafa cakuda). Wannan ya hada da convection da iskõki na gaba. Convection ya fi karfi a cikin hunturu lokacin da sanyaya ya fi karfi. Convection yana ƙara zurfin haɗuwa a tsaye, wanda zai iya motsa phytoplankton daga hasken da suke buƙata don girma.

Lokacin da convection ya raunana kuma iska ta sauya shugabanci a cikin bazara, tasirin sake fasalin gyare-gyare ya zama mai rinjaye. Phytoplankton suna makale kusa da farfajiyar, suna ƙara bayyanarsu ga haske. Wannan yana haifar da ci gaban phytoplankton, wanda ke haifar da farawar fure na bazara na Arewacin Atlantic kwanaki 20-30 da suka gabata fiye da yadda zai faru tare da yanayin zafi kadai.

## Ci gaban arewa
A mafi girma latitudes, fure na bazara yana faruwa daga baya a cikin shekara. Wannan ci gaba zuwa arewa shine saboda bazara tana faruwa daga baya, yana jinkirta yanayin zafi kuma yana ƙaruwa a cikin hasken da ke inganta furanni. Binciken da Wolf da Woods suka yi (1988) ya nuna shaidar cewa furanni na bazara suna bin ƙaura zuwa arewacin isotherm na 12 ° C, yana ba da shawarar cewa ana iya sarrafa furanni ta hanyar iyakancewar zafin jiki, ban da ƙaddamarwa.&nbsp;

A manyan latitudes, gajeren lokacin zafi yawanci yana haifar da fure daya a tsakiyar bazara. Wadannan furanni sun fi karfi fiye da furanni na bazara na yankuna masu matsakaici saboda akwai tsawon hasken rana don photosynthesis ya faru. Har ila yau, matsin kiwo yana da ƙarancin gaske saboda yawan yanayin sanyi a mafi girman latitudes yana jinkirta metabolism na zooplankton.

Furewar bazara sau da yawa ta ƙunshi jerin furanni na jerin nau'ikan phytoplankton daban-daban. Succession yana faruwa ne saboda nau'o'i daban-daban suna da mafi kyawun abinci mai gina jiki a wurare daban-daban kuma sun kai ga girma a lokuta daban-daban. Canje-canje a cikin nau'ikan phytoplankton masu rinjaye suna iya haifar da abubuwan halitta da na jiki (watau muhalli). Misali, yawan ci gaban diatom ya zama iyakance lokacin da aka ƙare samar da silicate.   Tunda wasu phytoplankton ba sa buƙatar silicate, kamar dinoflagellate, yawan ci gaban su yana ci gaba da ƙaruwa.

Misali, a cikin yanayin teku, diatoms (diamita na sel mafi girma fiye da 10 zuwa 70 μm ko mafi girma) yawanci suna mamayewa da farko saboda suna iya girma da sauri. Da zarar silicate ya ƙare a cikin muhalli, ƙananan dinoflagellates suna maye gurbin diatoms.   An lura da wannan yanayin a Rhode Island,   da Massachusetts da Cape Cod Bay. A ƙarshen fure na bazara, lokacin da aka rasa mafi yawan abubuwan gina jiki, yawancin jimlar phytoplankton biomass ƙananan ne, wanda aka sani da ultraphytoplankton (diamita na tantanin halitta <5 zuwa 10 μm).  Ultraphytoplankton na iya ci gaba da ƙananan, amma na yau da kullun, a cikin yanayin da aka lalata abinci mai gina jiki saboda suna da yanki mafi girma zuwa rabo, wanda ke ba da ingantaccen yaduwa. Ana iya tantance nau'ikan phytoplankton da ke kunshe da fure ta hanyar nazarin bambancin launin fata na photosynthetic da aka samu a cikin chloroplasts na kowane nau'in.&nbsp;&nbsp;

## Canji da tasirin canjin yanayi
Canje-canje a cikin alamu (misali, lokacin farawa, tsawon lokaci, girman, matsayi, da kuma sararin samaniya) na abubuwan da suka faru na bazara na shekara-shekara an rubuta su da kyau. Wadannan bambance-bambance suna faruwa ne saboda sauye-sauye a yanayin muhalli, kamar ƙarfin iska, zafin jiki, shigar da ruwa mai laushi, da haske. Sakamakon haka, alamu na fure na bazara suna iya zama masu hankali ga Canjin yanayi na duniya.

An sami alaƙa tsakanin zafin jiki da tsarin fure na bazara. Misali, bincike da yawa sun ba da rahoton alaƙa tsakanin farkon fure na bazara da karuwar zafin jiki a tsawon lokaci. Bugu da ƙari, a cikin Long Island Sound da Gulf of Maine, furanni suna farawa daga baya a cikin shekara, suna da amfani, kuma suna da tsawo a lokacin shekarun sanyi, yayin da shekarun da suka fi zafi suna nunawa a baya, gajeren furanni masu girma.

Yanayin zafi na iya daidaita girman fure. A cikin Narragansett Bay, Rhode Island, binciken da Durbin et al. (1992)  ya nuna cewa karuwar 2 ° C a cikin zafin jiki na ruwa ya haifar da sauyawa na makonni uku a cikin balaga na copepod, *Acartia hudsonica*, wanda zai iya kara yawan kiwo na zooplankton. Oviatt et al. (2002)  sun lura da raguwa a cikin tsananin fure na bazara da tsawon lokaci a cikin shekaru lokacin da yanayin ruwan hunturu ya fi zafi. Oviatt et al. sun ba da shawarar cewa raguwar ta kasance ne saboda karuwar matsin kiwo, wanda zai iya zama mai tsanani don hana fure na bazara daga faruwa gaba ɗaya. 

Miller da Harding (2007)  sun ba da shawarar canjin yanayi (yana tasiri ga yanayin hunturu da tasirin ruwa mai laushi) yana da alhakin sauyawa a cikin tsarin fure na bazara a cikin Chesapeake Bay. Sun gano cewa a lokacin dumi, shekaru masu laushi (kamar yadda ya saba da sanyi, shekaru masu bushe), girman sararin samaniya na furanni ya fi girma kuma an sanya shi a gefen teku. Har ila yau, a cikin waɗannan shekarun, biomass ya fi girma kuma mafi girma biomass ya faru daga baya a cikin bazara.

## Manazarta