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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:19/0  |  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.


  
Changes in floral nectar are unlikely adaptive responses to pollinator flight sound 期刊论文
ECOLOGY LETTERS, 2020
作者:  Pyke, Graham H.;  Ren, Zong-Xin;  Trunschke, Judith;  Lunau, Klaus;  Wang, Hong
收藏  |  浏览/下载:8/0  |  提交时间:2020/06/29
Evolution  floral nectar production  nectar sugar concentration  plant adaptation  pollinator behaviour  pollinator flight sound  
Vertical angular momentum constraint on lunar formation and orbital history 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (27) : 15460-15464
作者:  Tian, ZhenLiang;  Wisdom, Jack
收藏  |  浏览/下载:8/0  |  提交时间:2020/06/29
moon formation  orbital evolution  angular momentum  
The Insulating Effect of Methane Clathrate Crust on Titan's Thermal Evolution 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (13)
作者:  Kalousova, Klara;  Sotin, Christophe
收藏  |  浏览/下载:10/0  |  提交时间:2020/06/16
Titan  clathrates  thermal evolution  ocean  
Characteristics of the global copper raw materials and scrap trade systems and the policy impacts of China's import ban 期刊论文
ECOLOGICAL ECONOMICS, 2020, 172
作者:  Hu, Xiaoqian;  Wang, Chao;  Lim, Ming K.;  Chen, Wei-Qiang
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/02
Copper raw materials  Copper waste and scrap  Multiplex trade network  Evolution and correlation  Policy impacts  China'  s import ban  
The arms race between bacteria and their phage foes 期刊论文
NATURE, 2020, 577 (7790) : 327-336
作者:  Hirschey, Matthew
收藏  |  浏览/下载:20/0  |  提交时间:2020/07/03

Bacteria are under immense evolutionary pressure from their viral invaders-bacteriophages. Bacteria have evolved numerous immune mechanisms, both innate and adaptive, to cope with this pressure. The discovery and exploitation of CRISPR-Cas systems have stimulated a resurgence in the identification and characterization of anti-phage mechanisms. Bacteriophages use an extensive battery of counter-defence strategies to co-exist in the presence of these diverse phage defence mechanisms. Understanding the dynamics of the interactions between these microorganisms has implications for phage-based therapies, microbial ecology and evolution, and the development of new biotechnological tools. Here we review the spectrum of anti-phage systems and highlight their evasion by bacteriophages.


  
Geomorphic transience moderates topographic controls on tropical canopy foliar traits 期刊论文
ECOLOGY LETTERS, 2020, 23 (8) : 1276-1286
作者:  Chadwick, K. Dana;  Asner, Gregory P.
收藏  |  浏览/下载:8/0  |  提交时间:2020/06/01
Foliar traits  imaging spectroscopy  landscape evolution  rock derived nutrients  
Offspring polymorphism and bet hedging: a large-scale, phylogenetic analysis 期刊论文
ECOLOGY LETTERS, 2020, 23 (8) : 1223-1231
作者:  Scholl, Joshua P.;  Calle, Leonardo;  Miller, Nick;  Venable, D. Lawrence
收藏  |  浏览/下载:7/0  |  提交时间:2020/05/20
Bet hedging  life history evolution  offspring polymorphism  reproductive biology  seed heteromorphism  
Formation and Evolution of the Large-Scale Magnetic Fields in Venus' Ionosphere: Results From a Three Dimensional Global Multispecies MHD Model 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (11)
作者:  Ma, Yingjuan;  Toth, Gabor;  Nagy, Andrew;  Luhmann, Janet;  Russell, Christopher
收藏  |  浏览/下载:6/0  |  提交时间:2020/05/13
Venus Ionosphere  multi-species MHD  large-scale magnetic field  Formation  Evolution  
Parasitoids as drivers of symbiont diversity in an insect host 期刊论文
ECOLOGY LETTERS, 2020, 23 (8) : 1232-1241
作者:  Hafer-Hahmann, Nina;  Vorburger, Christoph
收藏  |  浏览/下载:2/0  |  提交时间:2020/05/13
adaptation  aphids  Aphis fabae  defensive symbiois  experimental evolution  immune system  Lysiphlebus fabarum  maintenance of diversity  parasitoid wasps  specificity