新着論文紹介(2013.3.18) Nature, Science, PNAS
◉Nature
1.Warmer climate disturbs food web
Nature 507,
143 (13 March 2014) doi:10.1038/507143b
The authors
inferred the diets of flesh-footed shearwaters by looking at ratios of carbon
and nitrogen isotopes in the birds' feathers. They found levels of heavy
isotopes fell in shearwater feathers over the years, hinting that the birds are
eating animals that are lower on the food chain.
2.Global seismic network takes to the seas
Nicola Jones
12 March 2014
Two kinds of
seismic wave detectors have lately developed. One is Autonomously Deployed
Deep-Ocean Seismic System (ADDOSS), which uses gliders that convert wave motion
into thrust. The wave-powered gliders are able to wirelessly retrieve data from
seismometers on the ocean floor. The other is the Mobile Earthquake Recorder in
Marine Areas by Independent Drivers (MERMAID) system, which use free-floating
hydrophone that can detect pressure waves from earthquakes.
3.Climate change: China must publicize its emissions reports
Yuan-Feng Wang & Yu-Rong Zhang
Nature 507,
169 (13 March 2014) doi:10.1038/507169a
4.Air pollution and forest water use
Christopher D. Holmes
Nature 507,
E1–E2 (13 March 2014) doi:10.1038/nature13113
5.Geology: Earth's deep water reservoir
Hans Keppler
Nature 507,
174–175 (13 March 2014) doi:10.1038/507174a
6.Hydrous mantle transition zone indicated by
ringwoodite included within diamond
D. G. Pearson, F. E. Brenker, F. Nestola, J. McNeill, L. Nasdala, M. T.
Hutchison, S. Matveev, K. Mather, G. Silversmit, S. Schmitz, B. Vekemans &
L. Vincze
Nature 507,
221–224 (13 March 2014) doi:10.1038/nature13080
A hydrous
transition zone may have a key role in terrestrial magmatism and plate
tectonics, yet despite experimental demonstration of the water-bearing capacity
of these phases, geophysical probes have provided conflicting results. They
report X-ray diffraction, Raman and infrared spectroscopic data that provide
the first evidence for the terrestrial occurrence of any higher-pressure
polymorph of olivine: They find ringwoodite included in a diamond from Juina,
Brazil. The water-rich nature of this inclusion, indicated by infrared absorption,
along with the preservation of the ringwoodite, is direct evidence that, at
least locally, the transition zone is hydrous, to about 1 weight per cent. The
finding also indicates that some kimberlites must have their primary sources in
this deep mantle region.
◉Science
7. NEWSMAKERS
Climate
Scientist Breaks Into the Geology Club
Geologist and climate
scientist Maureen Raymo becomes the first woman to win the British Wollaston
Medal in the 183-year history of the prize.
8.How Earth Can
Cool Without Plunging Into a Deep Freeze
Richard A. Kerr
Science 14 March
2014: 1189.
[DOI:10.1126/science.343.6176.1189]
A geochemical model
published online this week in Scienceexpress reports suggests that Earth's
temperature controls have built-in restraints, rooted in the chemistry of rock
and flowing water, that have kept the planet habitable for eons.
9.Simplicity
amid Complexity
Isaac Held
Science 14 March
2014: 1206-1207.
[DOI:10.1126/science.1248447]
Despite the
complexity of Earth's climate system, the influence of human activities on
climate can be identified and predicted.
10.Changes in
Seismic Anisotropy Shed Light on the Nature of the Gutenberg Discontinuity
Caroline Beghein,
Kaiqing Yuan, Nicholas Schmerr, and Zheng Xing
Science 14 March
2014: 1237-1240.
Published online 27
February 2014 [DOI:10.1126/science.1246724]
The boundary
between the lithosphere and asthenosphere is associated with a platewide
high–seismic velocity “lid” overlying lowered velocities, consistent with
thermal models. Seismic body waves also intermittently detect a sharp velocity
reduction at similar depths, the Gutenberg(G) discontinuity, which cannot be explained
by temperature alone. They compared an anisotropic tomography model with
detections of the G to evaluate their context and relation to the lithosphere-asthenosphere
boundary (LAB). They find that the G is primarily associated with vertical
changes in azimuthal anisotropy and lies above a thermally controlled LAB,
implying that the two are not equivalent interfaces. The origin of the G is a
result of frozen-in lithospheric structures, regional compositional variations
of the mantle, or dynamically perturbed LAB.
◉PNAS
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