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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  
Signature of Geochemistry on Density-Driven CO2 Mixing in Sandstone Aquifers 期刊论文
WATER RESOURCES RESEARCH, 2020, 56 (3)
作者:  Erfani, Hamidreza;  Babaei, Masoud;  Niasar, Vahid
收藏  |  浏览/下载：6/0  |  提交时间：2020/07/02
Drivers of productivity and its temporal stability in a tropical tree diversity experiment 期刊论文
GLOBAL CHANGE BIOLOGY, 2019, 25 (12) : 4257-4272
作者:  Schnabel, Florian;  Schwarz, Julia A.;  Danescu, Adrian;  Fichtner, Andreas;  Nock, Charles A.;  Bauhus, Juergen;  Potvin, Catherine
收藏  |  浏览/下载：14/0  |  提交时间：2020/02/17
biodiversity  drought  ecosystem functioning  neighbourhood  overyielding  Sardinilla experiment  structural diversity  tree species diversity  tropical plantation forest  
Effect of Surface Water Stage Fluctuation on Mixing-Dependent Hyporheic Denitrification in Riverbed Dunes 期刊论文
WATER RESOURCES RESEARCH, 2019, 55 (6) : 4668-4687
作者:  Hester, Erich T.;  Eastes, Lauren A.;  Widdowson, Mark A.
收藏  |  浏览/下载：4/0  |  提交时间：2019/11/26
river  stream  nitrogen  oxygen  hyporheic zone  hyporheic exchange  
Long-term dietary shift and population decline of a pelagic seabird-A health check on the tropical Atlantic? 期刊论文
GLOBAL CHANGE BIOLOGY, 2019, 25 (4) : 1383-1394
作者:  Reynolds, S. James;  Hughes, B. John;  Wearn, Colin P.;  Dickey, Roger C.;  Brown, Judith;  Weber, Nicola L.;  Weber, Sam B.;  Paiva, Vitor H.;  Ramos, Jaime A.
收藏  |  浏览/下载：9/0  |  提交时间：2019/04/09
Ascension Island  bio-indicators  carbon-13  marine ecosystem function  nitrogen-15  Onychoprion fuscatus  sooty tern  South Atlantic  stable isotope  
Models of Single-Well Push-Pull Test With Mixing Effect in the Wellbore 期刊论文
WATER RESOURCES RESEARCH, 2018, 54 (12) : 10155-10171
作者:  Wang, Quanrong;  Shi, Wenguang;  Zhan, Hongbin;  Gu, Haochen;  Chen, Kewei
收藏  |  浏览/下载：8/0  |  提交时间：2019/04/09
Radial dispersion  Parameter estimation  Solute transport  Modeling  
Latitude-dependent finescale turbulent shear generations in the Pacific tropical-extratropical upper ocean 期刊论文
NATURE COMMUNICATIONS, 2018, 9
作者:  Zhang, Zhiwei;  Qiu, Bo;  Tian, Jiwei;  Zhao, Wei;  Huang, Xiaodong
收藏  |  浏览/下载：6/0  |  提交时间：2019/11/27
Counterintuitive effects of global warming-induced wind patterns on primary production in the Northern Humboldt Current System 期刊论文
GLOBAL CHANGE BIOLOGY, 2018, 24 (7) : 3187-3198
作者:  Mogollon, Rodrigo;  Calil, Paulo H. R.
收藏  |  浏览/下载：2/0  |  提交时间：2019/04/09
Bakun'  s hypothesis  build up of atmospheric CO2  eddy-driven effects  global warming-induced wind intensification  latitudinal variability of primary production  Northern Humboldt Current System  response of biological production  
Transient Groundwater Travel Time Distributions and Age-Ranked Storage-Discharge Relationships of Three Lowland Catchments 期刊论文
WATER RESOURCES RESEARCH, 2018, 54 (7) : 4519-4536
作者:  Kaandorp, V. P.;  de Louw, P. G. B.;  van der Velde, Y.;  Broers, H. P.
收藏  |  浏览/下载：5/0  |  提交时间：2019/04/09
Catchment hydrology  groundwater dynamics  forward particle tracking  young water fractions  travel time distributions  SAS-functions