新着論文紹介(2014.1.21) Nature, Science, PNAS
◉Nature
1.Landslide triggered earthquakes
Nature 505,
264 (16 January 2014) doi:10.1038/505264a
Large earthquakes
often cause landslides, but in an unusual reversal, a massive landslide in a US
copper mine in April 2013 might have resulted in a series of small earthquakes.
2.Past warmth drives glacial melting
Nature 505,
265 (16 January 2014) doi:10.1038/505265b
3.Sea-level swings get more extreme
Nature 505,
265 (16 January 2014) doi:10.1038/505265d
Thomas Wahl and his
colleagues compared sea-level measurements collected between 1900 and 2011 with
atmospheric data for the Gulf of Mexico coastline. They found that typical
differences in sea level between summer and winter have increased during the
past two decades.
4.Researchers question rescued polar expedition
Alexandra Witze
15 January 2014
5.Climate change: The case of the missing heat
Jeff Tollefson
15 January 2014
6.Earth science: River incision revisited
Roman A. DiBiase
Nature 505, 294–295 (16 January 2014)
doi:10.1038/505294a
7.A signature of transience in bedrock river incision
rates over timescales of 104–107 years
Noah J. Finnegan, Rina Schumer & Seth Finnegan
Nature 505, 391–394 (16 January 2014)
doi:10.1038/nature12913
8.Amazon River carbon dioxide outgassing fuelled by
wetlands
Gwenaël Abril, Jean-Michel Martinez, L. Felipe Artigas, Patricia
Moreira-Turcq, Marc F. Benedetti, Luciana Vidal, Tarik Meziane, Jung-Hyun Kim,
Marcelo C. Bernardes, Nicolas Savoye, Jonathan Deborde, Edivaldo Lima Souza,
Patrick Albéric, Marcelo F. Landim de Souza & Fabio Roland
Nature 505, 395–398 (16 January 2014)
doi:10.1038/nature12797
Here we show that
wetlands pump large amounts of atmospheric CO2 into river waters in the
floodplains of the central Amazon. We estimate that Amazonian wetlands export
half of their gross primary production to river waters as dissolved CO2 and
organic carbon, compared with only a few per cent of gross primary production
exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland
carbon export is potentially large enough to account for at least the 0.21
petagrams of carbon emitted per year as CO2 from the central Amazon River and
its floodplains.
◉Science
9.Temporal
Constraints on Hydrate-Controlled Methane Seepage off Svalbard
C. Berndt, T.
Feseker, T. Treude, S. Krastel, V. Liebetrau, H. Niemann, V. J. Bertics, I.
Dumke, K. Dünnbier, B. Ferré, C. Graves, F. Gross, K. Hissmann, V. Hühnerbach,
S. Krause, K. Lieser, J. Schauer, and L. Steinle
Science 17 January
2014: 284-287. [DOI:10.1126/science.1246298]
We corroborate that
hydrates play a role in the observed seepage of gas, but we present evidence
that seepage off Svalbard has been ongoing for at least 3000 years and that
seasonal fluctuations of 1° to 2°C in the bottom-water temperature cause
periodic gas hydrate formation and dissociation, which focus seepage at the
observed sites.
◉PNAS
10.Role of ocean
heat transport in climates of tidally locked exoplanets around M dwarf stars
Yongyun Hu and Jun
Yang
PNAS 2014 111 (2)
629-634; published ahead of print December 30, 2013,
doi:10.1073/pnas.1315215111
11.Poleward
expansion of mangroves is a threshold response to decreased frequency of
extreme cold events
Kyle C. Cavanaugh,
James R. Kellner, Alexander J. Forde, Daniel S. Gruner, John D. Parker, Wilfrid
Rodriguez, and Ilka C. Feller
PNAS 2014 111 (2)
723-727; published ahead of print December 30, 2013,
doi:10.1073/pnas.1315800111
We used 28 y of
satellite imagery to demonstrate that the area of mangrove forests has doubled
at the northern end of their historic range on the east coast of Florida. This
expansion is associated with a reduction in the frequency of “extreme” cold
events (days colder than 4 °C). Our analyses provide evidence for a threshold
response, with declining frequency of severe cold winter events allowing for
poleward expansion of mangroves.
◉Nature Communications
12.Helium anomalies suggest a fluid pathway from mantle
to trench during the 2011 Tohoku-Oki earthquake
Yuji Sano, Takahiro
Hara, Naoto Takahata, Shinsuke Kawagucci, Makio Honda, Yoshiro Nishio, Wataru
Tanikawa, Akira Hasegawa, Keiko Hattori
Nature Communications 5, Article number: 3084
doi:10.1038/ncomms4084
We report a sharp
increase in mantle- derived helium in bottom seawater near the rupture zone 1
month after the earthquake. The timing and location indicate that fluids were
released from the mantle on the seafloor along the plate interface. The
movement of the fluids was rapid, with a velocity of ~4 km per day and an
uncertainty factor of four. This rate is much faster than what would be
expected from pressure-gradient propagation, suggesting that over-pressurized
fluid is discharged along the plate interface.
