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Abin da ya faru na Azolla

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Abin da ya faru na Azolla
Rashin sanyaya na duniya da hypothetical event (en) Fassara
Bayanai
Zangon lokaci Eocene (en) Fassara
Fern na zamani Azolla filiculoides . Fure-fure na nau'in da suka danganci sun ja Duniya cikin duniyar kankara ta yanzu.

Abubuwan da suka fure a Azolla wani lamari ne na paleoclimatology wanda aka yi la'akari da cewa ya faru ne a tsakiyar zamanin Eocene, [1] kimanin shekaru miliyan 49 da suka gabata, lokacin da ake zaton fern na ruwan sha mai tsabta mai suna Azolla ya faru ne da Tekun Arctic. Yayin da fern ya mutu kuma ya nutse zuwa cikin teku mai tsayi, an haɗa su cikin tururi a cikin kimanin shekaru 800,000; an yi hasashen cewa sakamakon raguwar carbon dioxide ya taimaka wajen juyar da duniyar daga yanayin "greenhouse Earth" na Paleocene-Eocene Thermal Maximum, lokacin da duniyar ta kasance mai zafi sosai don tururuwa da itatuwa su bunƙasa a kan sanduna, zuwa gidan kankara na yanzu da aka sani da Late Cenozoic Ice Age.

Shaidar ilimin ƙasa game da taron

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δ 18 O - wakili don zafin jiki - a cikin shekaru miliyan 65 da suka wuce. Lamarin na Azolla ya nuna ƙarshen mafi kyawun Eocene da farkon raguwar yanayin zafi na duniya na dogon lokaci. .

A cikin sedimentary yadudduka a ko'ina cikin Basin Arctic, naúrar ta kai aƙalla 8 m a cikin kauri (ba a dawo da kasan mafi tsayi ba, amma yana iya kaiwa 20 m+ ) ana iya ganewa. Wannan naúrar ta ƙunshi madaidaicin yadudduka; siliceous clastic yadudduka wakiltar bango sedimentation na planktonic kwayoyin, saba zuwa ruwa sediments, canzawa tare da kauri-milimita laminations kunshe da burbushin halitta Azolla . [2] Hakanan za'a iya gano wannan kwayoyin halitta a cikin nau'i na gamma radiation spike, wanda aka lura a ko'ina cikin kogin Arctic, yin taron ya zama taimako mai amfani a cikin layi mai layi da aka haƙa a wurare daban-daban. Gudanar da ilimin jijiyoyi da daidaitawa tare da babban rikodin jujjuyawar geomagnetic yana ba da damar ƙididdige tsawon lokacin taron a 800,000 shekaru. [1] Lamarin ya zo daidai daidai da mummunan raguwar matakan carbon dioxide, wanda ya faɗi daga 3500. ppm a farkon Eocene zuwa 650 ppm a lokacin wannan taron. [3]

Azolla

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Azolla has been deemed a "super-plant" as it can draw down as much as a tonne of nitrogen per acre per year[4] (0.25 kg/m2/yr); this is matched by 6 tonnes per acre of carbon drawdown (1.5 kg/m2/yr). Its ability to use atmospheric nitrogen for growth means that the main limit to its growth is usually the availability of phosphorus: carbon, nitrogen and sulphur being three of the key elements of proteins, and phosphorus being required for DNA, RNA and in energy metabolism. The plant can grow at great speed in favourable conditions – modest warmth and 20 hours of sunlight, both of which were in evidence at the poles during the early Eocene – and can double its biomass over two to three days in such a climate.[1] This rate of growth pushes the plants deep under away from sunlight where death and carbon sequestration occur.

Yanayin da ke ƙarfafa taron

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Fayil:Early Eocene Arctic basin.PNG
Tsarin nahiyar a lokacin farkon Eocene ya haifar da wani kwandon Arctic mai nisa.

A farkon Eocene, Tsarin nahiyar ya kasance kamar yadda aka yanke teku ta Arctic kusan gaba ɗaya daga manyan teku. Wannan yana nufin cewa haɗuwa - wanda aka bayar a yau ta hanyar ruwa mai zurfi kamar Gulf Stream - bai faru ba, wanda ya haifar da ginshiƙi na ruwa mai kama da Black Sea na yau.[5] Babban yanayin zafi da iskõki sun haifar da babban evaporation, ƙara yawan teku, kuma - ta hanyar karuwar ruwan sama - babban fitarwa daga koguna wanda ke ciyar da kwandon.[6] Wannan ruwa mai laushi mai laushi ya zama Layer nepheloid, yana iyo a saman teku mai zurfi.[7] Ko da 'yan centimeters na ruwa mai laushi zai isa ya ba da izinin mulkin mallaka ta Azolla; Bugu da ƙari, wannan ruwan kogi zai kasance mai wadata da ma'adanai kamar phosphorus, wanda zai tara daga laka da duwatsu da ya yi hulɗa da su yayin da ya haye nahiyoyi. Don ci gaba da taimakawa ci gaban shuka, an san yawan carbon (a cikin nau'in carbon dioxide) a cikin yanayi da yawa a wannan lokacin.[3]

Fure-fure kadai ba su isa su sami wani tasiri na yanayin ƙasa ba; don jawo CO2 har abada kuma ya haifar da Canjin yanayi, dole ne shuke-shuke da aka binne su su su rufe carbon kuma ragowar ta zama ba za a iya isa ga kwayoyin da ke lalacewa ba. Ƙashin anoxic na kwandon Arctic, sakamakon ginshiƙi na ruwa, ya ba da izini ga wannan kawai; yanayin anoxic yana hana aikin kwayoyin da ke lalacewa kuma yana ba da damar tsire-tsire su zauna ba tare da lalacewa ba har sai an binne su da laka.

Tasirin Duniya

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Da 800,000 shekaru na Azolla Bloom episodes da 4,000,000 km2 (1,500,000 sq mi) kwandon da za a rufe, ko da ta hanyar ƙididdiga masu ra'ayin mazan jiya fiye da isassun carbon za a iya raba su ta hanyar binne shuka don lissafin raguwar kashi 80% a cikin CO 2 ta wannan sabon abu kaɗai. [ ] Wasu dalilai kusan sun taka rawa. Wannan digo ya ƙaddamar da sauyawa daga greenhouse zuwa duniyar kankara na yanzu; Arctic ya yi sanyi daga matsakaicin yanayin zafin teku na 13 °C zuwa yau − 9 °C, [1] da sauran duniya sun sami irin wannan canji. Wataƙila a karon farko tun lokacin da " Ƙasashen Ƙwallon Ƙwallon Ƙwallon Ƙwallon Ƙwallon Ƙwallon Ƙasa" (fiye da rabin biliyan a baya), duniyar ta kasance tana da ƙanƙara a duka sandunan ta. Ragewar yanayin yanayin ƙasa cikin sauri tsakanin 49 zuwa 47 shekaru miliyan da suka wuce, a kusa da taron Azolla, ya bayyana; dropstones (wanda aka ɗauka azaman shaida na kasancewar glaciers) sun zama ruwan dare a cikin ruwan Arctic daga baya. An saita wannan tare da bayan bayanan a hankali, sanyaya na dogon lokaci; ba sai 15 shekaru miliyan da suka gabata cewa shaidar da ke yaɗuwar daskarewar polar arewa ta zama ruwan dare gama gari. [8]

Sauran Bayani

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Duk da yake Tekun Arctic mai kyau shine samfurin aiki mai yiwuwa, masana kimiyya masu shakku sun nuna cewa zai yiwu yankunan Azolla a cikin kogin kogin Laguna ko tafkunan ruwa mai laushi su shiga cikin Tekun Arctic ta hanyar karfi mai karfi, yana cire buƙatar ruwa mai lawu.[8][9]

Tunanin tattalin arziki

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Much of the current interest in oil exploration in the Arctic regions is directed towards the Azolla deposits [ana buƙatar hujja]. The burial of large amounts of organic material provides the source rock for oil, so given the right thermal history, the preserved Azolla blooms might have been converted to oil or gas. In 2008 a research team was set up in the Netherlands devoted to Azolla.Samfuri:Simple Horizontal timeline

Manazarta

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  1. ↑ 1.0 1.1 1.2 1.3 Brinkhuis H, Schouten S, Collinson ME, Sluijs A, Sinninghe Damsté JS, Dickens GR, Huber M, Cronin TM, Onodera J, Takahashi K, Bujak JP, Stein R, van der Burgh J, Eldrett JS, Harding IC, Lotter AF, Sangiorgi F, van Konijnenburg-van Cittert H, de Leeuw JW, Matthiessen J, Backman J, Moran K (2006). "Episodic fresh surface waters in the Eocene Arctic Ocean". Nature. 441 (7093): 606–609. Bibcode:2006Natur.441..606B. doi:10.1038/nature04692. PMID 16752440. S2CID 4412107. |hdl-access= requires |hdl= (help) Cite error: Invalid <ref> tag; name "Brinkhuis2006" defined multiple times with different content
  2. ↑ Waddell, L.M.; Moore, T.C. (2008). "Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate" (PDF). Paleoceanography. 23 (1): n/a. Bibcode:2008PalOc..23.1S12W. doi:10.1029/2007PA001451.
  3. ↑ 3.0 3.1 Pearson, P.N.; Palmer, M.R. (2000). "Atmospheric carbon dioxide concentrations over the past 60 million years". Nature. 406 (6797): 695–699. Bibcode:2000Natur.406..695P. doi:10.1038/35021000. PMID 10963587. S2CID 205008176. Cite error: Invalid <ref> tag; name "Pearson2000" defined multiple times with different content
  4. ↑ Belnap, J. (2002). "Nitrogen fixation in biological soil crusts from southeast Utah, USA". Biology and Fertility of Soils. 35 (2): 128–135. Bibcode:2002BioFS..35..128B. doi:10.1007/s00374-002-0452-x. S2CID 41924008.
  5. ↑ Stein, R. (2006). "The Paleocene-Eocene ("Greenhouse") Arctic Ocean paleoenvironment: Implications from organic-carbon and biomarker records (IODP-ACEX Expedition 302)" (abstract). Geophysical Research Abstracts. 8: 06718. Retrieved 2007-10-16.
  6. ↑ Greenwood, D.R., Basinger, J.F. and Smith, R.Y. 2010. How wet was the Arctic Eocene rainforest? Estimates of precipitation from Paleogene Arctic macrofloras. Geology, 38(1): 15 - 18. doi:10.1130/G30218.1
  7. ↑ Gleason, J.D.; Thomas, D.T.; Moore, T.C.; Blum, J.D.; Owen, R.M. (2007). "Water column structure of the Eocene Arctic Ocean from Nd-Sr isotope proxies in fossil fish debris" (PDF). Retrieved 2007-11-03. The Sr-Nd isotopic record is [...] indicative of a poorly mixed ocean and highly stratified water column with anoxic bottom waters. A stable, "fresh" water upper layer was likely a pervasive feature of the Eocene Arctic Ocean[dead link] (full text of a similar article at doi:10.1029/2008PA001685)
  8. ↑ 8.0 8.1 Tim Appenzeller (May 2005). "Great green north". National Geographic. Archived from the original on March 26, 2008. Cite error: Invalid <ref> tag; name "NatGeo" defined multiple times with different content
  9. ↑ Neville, L.A., Grasby, S.E., McNeil, D.H., 2019, Limited freshwater cap in the Eocene Arctic Ocean. Scientific Reports (2019)9:4226. doi:10.1038/s41598-019-40591-w
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