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Hydrothermal (NN)-N-15-N-15 abundances constrain the origins of mantle nitrogen 期刊论文
NATURE, 2020, 580 (7803) : 367-+
作者:  Zhao, Steven;  Jang, Cholsoon;  Liu, Joyce;  Uehara, Kahealani;  Gilbert, Michael;  Izzo, Luke;  Zeng, Xianfeng;  Trefely, Sophie;  Fernandez, Sully;  Carrer, Alessandro;  Miller, Katelyn D.;  Schug, Zachary T.;  Snyder, Nathaniel W.;  Gade, Terence P.;  Titchenell, Paul M.;  Rabinowitz, Joshua D.;  Wellen, Kathryn E.
收藏  |  浏览/下载：14/0  |  提交时间：2020/05/13

Nitrogen is the main constituent of the Earth'  s atmosphere, but its provenance in the Earth'  s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth'  s accretion versus that subducted from the Earth'  s surface is unclear(1-6). Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare (NN)-N-15-N-15 isotopologue of N-2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle delta N-15 (the fractional difference in N-15/N-14 from air), N-2/Ar-36 and N-2/He-3. Our results show that negative delta N-15 values observed in gases, previously regarded as indicating a mantle origin for nitrogen(7-10), in fact represent dominantly air-derived N-2 that experienced N-15/N-14 fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the (NN)-N-15-N-15 data allow extrapolations that characterize mantle endmember delta N-15, N-2/Ar-36 and N-2/He-3 values. We show that the Eifel region has slightly increased delta N-15 and N-2/Ar-36 values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts(11), consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has delta N-15 values substantially greater than that of the convective mantle, resembling surface components(12-15), its N-2/Ar-36 and N-2/He-3 ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume delta N-15 values may both be dominantly primordial features.


  
Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (10) : 5196-5203
作者:  Fierce, Laura;  Onasch, Timothy B.;  Cappa, Christopher D.;  Mazzoleni, Claudio;  China, Swarup;  Bhandari, Janarjan;  Davidovits, Paul;  Al Fischer, D.;  Helgestad, Taylor;  Lambe, Andrew T.;  Sedlacek, Arthur J., III;  Smith, Geoffrey D.;  Wolff, Lindsay
收藏  |  浏览/下载：8/0  |  提交时间：2020/05/13
black carbon  direct radiative forcing  absorption enhancement  aerosol mixing state  
Primary productivity below the seafloor at deep-sea hot springs 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2018, 115 (26) : 6756-6761
作者:  McNichol, Jesse;  Stryhanyuk, Hryhoriy;  Sylva, Sean P.;  Thomas, Francois;  Musat, Niculina;  Seewald, Jeffrey S.;  Sievert, Stefan M.
收藏  |  浏览/下载：10/0  |  提交时间：2019/11/27
deep-sea hydrothermal  vents  chemosynthesis  Campylobacteria  ecophysiology  NanoSIMS  
Time-dependent view of an isotope effect in electron-nuclear nonequilibrium dynamics with applications to N-2 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2018, 115 (23) : 5890-5895
作者:  Ajay, Jayanth S.;  Komarova, Ksenia G.;  Remacle, Francoise;  Levine, R. D.
收藏  |  浏览/下载：0/0  |  提交时间：2019/11/27
diabatic electronic states  nuclear phase  electronic coherence  photodissociation  nonstationary states  
Mechanism of SOA formation determines magnitude of radiative effects 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2017, 114 (48) : 12685-12690
作者:  Zhu, Jialei;  Penner, Joyce E.;  Lin, Guangxing;  Zhou, Cheng;  Xu, Li;  Zhuang, Bingliang
收藏  |  浏览/下载：5/0  |  提交时间：2019/11/27
SOA  mixing state  radiative effects  future climate  
Vigorous lateral export of the meltwater outflow from beneath an Antarctic ice shelf 期刊论文
NATURE, 2017, 542 (7640) : 219-222
作者:  Garabato, Alberto C. Naveira;  Forryan, Alexander;  Dutrieux, Pierre;  Brannigan, Liam;  Biddle, Louise C.;  Heywood, Karen J.;  Jenkins, Adrian;  Firing, Yvonne L.;  Kimura, Satoshi
收藏  |  浏览/下载：5/0  |  提交时间：2019/04/09
Time-resolved x-ray absorption spectroscopy with a water window high-harmonic source 期刊论文
SCIENCE, 2017, 355 (6322) : 264-+
作者:  Pertot, Yoann;  Schmidt, Cedric;  Matthews, Mary;  Chauvet, Adrien;  Huppert, Martin;  Svoboda, Vit;  von Conta, Aaron;  Tehlar, Andres;  Baykusheva, Denitsa;  Wolf, Jean-Pierre;  Worner, Hans Jakob
收藏  |  浏览/下载：4/0  |  提交时间：2019/11/27