气候变化领域集成服务门户(CCPortal): Algal photophysiology drives darkening and melt of the Greenland Ice Sheet

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DOI	10.1073/pnas.1918412117
	Algal photophysiology drives darkening and melt of the Greenland Ice Sheet
	Williamson C.J.; Cook J.; Tedstone A.; Yallop M.; McCutcheon J.; Poniecka E.; Campbell D.; Irvine-Fynn T.; McQuaid J.; Tranter M.; Perkins R.; Anesio A.
发表日期	2020
ISSN	0027-8424
起始页码	5694
结束页码	5705
卷号	117 期号:11
英文摘要	Blooms of Zygnematophycean “glacier algae” lower the bare ice albedo of the Greenland Ice Sheet (GrIS), amplifying summer energy absorption at the ice surface and enhancing meltwater runoff from the largest cryospheric contributor to contemporary sea-level rise. Here, we provide a step change in current understanding of algal-driven ice sheet darkening through quantification of the photophysiological mechanisms that allow glacier algae to thrive on and darken the bare ice surface. Significant secondary phenolic pigmentation (11 times the cellular content of chlorophyll a) enables glacier algae to tolerate extreme irradiance (up to ∼4,000 μmol photons·m−2·s−1) while simultaneously repurposing captured ultraviolet and short-wave radiation for melt generation. Total cellular energy absorption is increased 50-fold by phenolic pigmentation, while glacier algal chloroplasts positioned beneath shading pigments remain low-light–adapted (Ek ∼46 μmol photons·m−2·s−1) and dependent upon typical nonphotochemical quenching mechanisms for photoregulation. On the GrIS, glacier algae direct only ∼1 to 2.4% of incident energy to photochemistry versus 48 to 65% to ice surface melting, contributing an additional ∼1.86 cm water equivalent surface melt per day in patches of high algal abundance (∼104 cells·mL−1). At the regional scale, surface darkening is driven by the direct and indirect impacts of glacier algae on ice albedo, with a significant negative relationship between broadband albedo (Moderate Resolution Imaging Spectroradiometer [MODIS]) and glacier algal biomass (R2 = 0.75, n = 149), indicating that up to 75% of the variability in albedo across the southwestern GrIS may be attributable to the presence of glacier algae. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Cryosphere; Glacier algae; Greenland Ice Sheet; Melt; Photophysiology
语种	英语
scopus关键词	chlorophyll; greenland ice sheet; ice; phenol derivative; unclassified drug; water; absorption; algal growth; Article; biomass; cell composition; cell energy; chloroplast; controlled study; energy; glacier; ice sheet darkening; light; light absorption; melting point; Moderate Resolution Imaging Spectroradiometer; nonhuman; nonphotochemical quenching; photoactivation; photochemistry; photon; photophysiology; photoregulation; pigmentation; population abundance; priority journal; radioactive forcing; radioactivity; short wave radiation; ultraviolet radiation; Greenland; ice cover; metabolism; microalga; photosynthesis; physiological feedback; physiology; sea level rise; Feedback, Physiological; Greenland; Ice Cover; Microalgae; Photosynthesis; Sea Level Rise
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/158850
作者单位	Williamson, C.J., Bristol Glaciology Centre, University of Bristol, Bristol, BS8 1HH, United Kingdom; Cook, J., Department of Geography and Earth Science, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3FL, United Kingdom; Tedstone, A., Bristol Glaciology Centre, University of Bristol, Bristol, BS8 1HH, United Kingdom; Yallop, M., School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, United Kingdom; McCutcheon, J., School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Poniecka, E., School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, United Kingdom; Campbell, D., Department of Biology, Mount Allison University, Sackville, NB E4L3M7, Canada; Irvine-Fynn, T., Department of Geography and Earth Science, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3FL, United Kingdom; McQuaid, J., School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Tranter, M., Bristol Glaciology Centr...
推荐引用方式 GB/T 7714	Williamson C.J.,Cook J.,Tedstone A.,et al. Algal photophysiology drives darkening and melt of the Greenland Ice Sheet[J],2020,117(11).
APA	Williamson C.J..,Cook J..,Tedstone A..,Yallop M..,McCutcheon J..,...&Anesio A..(2020).Algal photophysiology drives darkening and melt of the Greenland Ice Sheet.Proceedings of the National Academy of Sciences of the United States of America,117(11).
MLA	Williamson C.J.,et al."Algal photophysiology drives darkening and melt of the Greenland Ice Sheet".Proceedings of the National Academy of Sciences of the United States of America 117.11(2020).