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Ice retreat in Wilkes Basin of East Antarctica during a warm interglacial 期刊论文
NATURE, 2020, 583 (7817) : 554-+
作者:  T. Blackburn;  G. H. Edwards;  S. Tulaczyk;  M. Scudder;  G. Piccione;  B. Hallet;  N. McLean;  J. C. Zachos;  B. Cheney;  J. T. Babbe
收藏  |  浏览/下载:21/0  |  提交时间:2020/08/09

Uranium isotopes in subglacial precipitates from the Wilkes Basin of the East Antarctic Ice Sheet reveal ice retreat during a warm Pleistocene interglacial period about 400,000 years ago.


Efforts to improve sea level forecasting on a warming planet have focused on determining the temperature, sea level and extent of polar ice sheets during Earth'  s past interglacial warm periods(1-3). About 400,000 years ago, during the interglacial period known as Marine Isotopic Stage 11 (MIS11), the global temperature was 1 to 2 degrees Celsius greater(2)and sea level was 6 to 13 metres higher(1,3). Sea level estimates in excess of about 10 metres, however, have been discounted because these require a contribution from the East Antarctic Ice Sheet(3), which has been argued to have remained stable for millions of years before and includes MIS11(4,5). Here we show how the evolution of(234)U enrichment within the subglacial waters of East Antarctica recorded the ice sheet'  s response to MIS11 warming. Within the Wilkes Basin, subglacial chemical precipitates of opal and calcite record accumulation of(234)U (the product of rock-water contact within an isolated subglacial reservoir) up to 20 times higher than that found in marine waters. The timescales of(234)U enrichment place the inception of this reservoir at MIS11. Informed by the(234)U cycling observed in the Laurentide Ice Sheet, where(234)U accumulated during periods of ice stability(6)and was flushed to global oceans in response to deglaciation(7), we interpret our East Antarctic dataset to represent ice loss within the Wilkes Basin at MIS11. The(234)U accumulation within the Wilkes Basin is also observed in the McMurdo Dry Valleys brines(8-10), indicating(11)that the brine originated beneath the adjacent East Antarctic Ice Sheet. The marine origin of brine salts(10)and bacteria(12)implies that MIS11 ice loss was coupled with marine flooding. Collectively, these data indicate that during one of the warmest Pleistocene interglacials, the ice sheet margin at the Wilkes Basin retreated to near the precipitate location, about 700 kilometres inland from the current position of the ice margin, which-assuming current ice volumes-would have contributed about 3 to 4 metres(13)to global sea levels.


  
Understanding the Interfacial Behavior of Typical Perfluorocarboxylic Acids at Surfactant-Coated Aqueous Interfaces 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2020, 125 (13)
作者:  Cheng, Shumin;  Du, Lin;  George, Christian
收藏  |  浏览/下载:14/0  |  提交时间:2020/08/18
Langmuir film  Lipid  Mixed monolayer  Air-water interface  sea spray aerosol  Perfluorocarboxylic acids  
Exchange Dynamics of Typical Emerging and Legacy Persistent Organic Pollutants at the Air-Water Interface Over a Strongly Human-Influenced Large River Estuary 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2020, 125 (13)
作者:  Guo, Tianfeng;  Li, Yuanyuan;  Lin, Tian;  Wu, Zilan;  Jiang, Yuqing;  Guo, Zhigang
收藏  |  浏览/下载:8/0  |  提交时间:2020/08/18
BDE-209  PCB  air-water gas exchange  transport pathway  source-sink fate  
Children drinking private well water have higher blood lead than those with city water 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (29) : 16898-16907
作者:  Gibson, Jacqueline MacDonald;  Fisher, Michael;  Clonch, Allison;  MacDonald, John M.;  Cook, Philip J.
收藏  |  浏览/下载:26/0  |  提交时间:2020/07/09
drinking water  private well  children'  s health  lead exposure  blood lead  
Increase in beaver dams controls surface water and thermokarst dynamics in an Arctic tundra region, Baldwin Peninsula, northwestern Alaska 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (7)
作者:  Jones, Benjamin M.;  Tape, Ken D.;  Clark, Jason A.;  Nitze, Ingmar;  Grosse, Guido;  Disbrow, Jeff
收藏  |  浏览/下载:11/0  |  提交时间:2020/08/18
Arctic Tundra  Beavers  Surface Water  Thermokarst  
Adaptation time to magnified flood hazards underestimated when derived from tide gauge records 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (7)
作者:  Lambert, Erwin;  Rohmer, Jeremy;  Le Cozannet, Goneri;  van de Wal, Roderik S. W.
收藏  |  浏览/下载:7/0  |  提交时间:2020/08/18
Sea-level rise  extreme water level  waves  coastal adaptation  joint probability  
Estimation of global coastal sea level extremes using neural networks 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (7)
作者:  Bruneau, Nicolas;  Polton, Jeff;  Williams, Joanne;  Holt, Jason
收藏  |  浏览/下载:9/0  |  提交时间:2020/08/18
sea water anomaly  extremes  storm surges  GESLA database  machine learning  
A remnant planetary core in the hot-Neptune desert 期刊论文
NATURE, 2020, 583 (7814) : 39-+
作者:  David J. Armstrong;  Thé;  o A. Lopez;  Vardan Adibekyan;  Richard A. Booth;  Edward M. Bryant;  Karen A. Collins;  Magali Deleuil;  Alexandre Emsenhuber;  Chelsea X. Huang;  George W. King;  Jorge Lillo-Box;  Jack J. Lissauer;  Elisabeth Matthews;  Olivier Mousis;  Louise D. Nielsen;  Hugh Osborn;  Jon Otegi;  Nuno C. Santos;  ;  rgio G. Sousa;  Keivan G. Stassun;  Dimitri Veras;  Carl Ziegler;  Jack S. Acton;  Jose M. Almenara;  David R. Anderson;  David Barrado;  Susana C. C. Barros;  Daniel Bayliss;  Claudia Belardi;  Francois Bouchy;  ;  sar Briceñ;  o;  Matteo Brogi;  David J. A. Brown;  Matthew R. Burleigh;  Sarah L. Casewell;  Alexander Chaushev;  David R. Ciardi;  Kevin I. Collins;  Knicole D. Coló;  n;  Benjamin F. Cooke;  Ian J. M. Crossfield;  Rodrigo F. Dí;  az;  Elisa Delgado Mena;  Olivier D. S. Demangeon;  Caroline Dorn;  Xavier Dumusque;  Philipp Eigmü;  ller;  Michael Fausnaugh;  Pedro Figueira;  Tianjun Gan;  Siddharth Gandhi;  Samuel Gill;  Erica J. Gonzales;  Michael R. Goad;  Maximilian N. Gü;  nther;  Ravit Helled;  Saeed Hojjatpanah;  Steve B. Howell;  James Jackman;  James S. Jenkins;  Jon M. Jenkins;  Eric L. N. Jensen;  Grant M. Kennedy;  David W. Latham;  Nicholas Law;  Monika Lendl;  Michael Lozovsky;  Andrew W. Mann;  Maximiliano Moyano;  James McCormac;  Farzana Meru;  Christoph Mordasini;  Ares Osborn;  Don Pollacco;  Didier Queloz;  Liam Raynard;  George R. Ricker;  Pamela Rowden;  Alexandre Santerne;  Joshua E. Schlieder;  Sara Seager;  Lizhou Sha;  Thiam-Guan Tan;  Rosanna H. Tilbrook;  Eric Ting;  Sté;  phane Udry;  Roland Vanderspek;  Christopher A. Watson;  Richard G. West;  Paul A. Wilson;  Joshua N. Winn;  Peter Wheatley;  Jesus Noel Villasenor;  Jose I. Vines;  Zhuchang Zhan
收藏  |  浏览/下载:20/0  |  提交时间:2020/07/06

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune '  desert'  (1,2)(a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b(3), which is thought to have an unusually massive core, and recent discoveries such as LTT9779b(4)and NGTS-4b(5), on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune'  s but an anomalously large mass of39.1-2.6+2.7Earth masses and a density of5.2-0.8+0.7grams per cubic centimetre, similar to Earth'  s. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than3.9-0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation(6). Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.


Observations of TOI-849b reveal a radius smaller than Neptune'  s but a large mass of about 40 Earth masses, indicating that the planet is the remnant core of a gas giant.


  
Abrupt increase in harvested forest area over Europe after 2015 期刊论文
NATURE, 2020, 583 (7814) : 72-+
作者:  Guido Ceccherini;  Gregory Duveiller;  Giacomo Grassi;  Guido Lemoine;  Valerio Avitabile;  Roberto Pilli;  Alessandro Cescatti
收藏  |  浏览/下载:19/0  |  提交时间:2020/07/06

Fine-scale satellite data are used to quantify forest harvest rates in 26 European countries, finding an increase in harvested forest area of 49% and an increase in biomass loss of 69% between 2011-2015 and 2016-2018.


Forests provide a series of ecosystem services that are crucial to our society. In the European Union (EU), forests account for approximately 38% of the total land surface(1). These forests are important carbon sinks, and their conservation efforts are vital for the EU'  s vision of achieving climate neutrality by 2050(2). However, the increasing demand for forest services and products, driven by the bioeconomy, poses challenges for sustainable forest management. Here we use fine-scale satellite data to observe an increase in the harvested forest area (49 per cent) and an increase in biomass loss (69 per cent) over Europe for the period of 2016-2018 relative to 2011-2015, with large losses occurring on the Iberian Peninsula and in the Nordic and Baltic countries. Satellite imagery further reveals that the average patch size of harvested area increased by 34 per cent across Europe, with potential effects on biodiversity, soil erosion and water regulation. The increase in the rate of forest harvest is the result of the recent expansion of wood markets, as suggested by econometric indicators on forestry, wood-based bioenergy and international trade. If such a high rate of forest harvest continues, the post-2020 EU vision of forest-based climate mitigation may be hampered, and the additional carbon losses from forests would require extra emission reductions in other sectors in order to reach climate neutrality by 2050(3).


  
Drinking water quality from rural handpump-boreholes in Africa 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (6)
作者:  Lapworth, D. J.;  MacDonald, A. M.;  Kebede, S.;  Owor, M.;  Chavula, G.;  Pallas, H.;  Wilson, P.;  Ward, J. S. T.;  Lark, M.;  Okullo, J.;  Mwathunga, E.;  Banda, S.;  Gwengweya, G.;  Nedaw, D.;  Jumbo, S.;  Banks, E.;  Cook, P.;  Casey, V
收藏  |  浏览/下载:17/0  |  提交时间:2020/08/18
groundwater  water quality  boreholes  handpumps  SDG 6  Africa  climate