10/30/2013

Open Campus


Ciao! I’m reporting about the open campus, which was held on the 25th of October. Though the weather was not good, we had almost a thousand visitors. Our division worked so hard for this big annual event to let the public know about how purely “FUN” science is. I think researchers should always appreciate the funding and opportunities that are supported by public taxes, thus informing about our research is definitely essential. Our volunteers did a fantastic job communicating with visitors. I hope our exhibits helped visitors feel closer to science and find the meaning of science in our society. I appreciated that I had an opportunity to organize this cool event and many thanks to all the volunteers. Needless to say, drinks tasted super good after this event ;)

Big Cheers,







新着論文紹介 This Week’s New Paper (2013/10/22) Elsevier

Chemical Geology
1.    Uranium concentrations and 238U/235U isotope ratios in modern carbonates from the Bahamas: assessing a novel paleoredox proxy
Stephen J. Romaniello , Achim D. Herrmann , Ariel D. Anbar
Keywords
Uranium Isotopes; Bahamas; Carbonates; 238/235

2.  Geochemistry of Mesozoic and Cenozoic sediments in the northern Qaidam basin, northeastern Tibetan Plateau: Implications for provenance and weathering
Xing Jian , Ping Guan , Wei Zhang , Fan Feng
Keywords
Qaidam basin; provenance; chemical weathering; paleoclimate; CIA; source composition model


Earth and Planetary Science Letters
3.  The fidelity of paleomagnetic records carried by magnetosome chains
Greig A. Paterson , Yinzhao Wang , Yongxin Pan
Keywords
magnetotactic bacteria; sedimentary magnetism; relative paleointensity; magnetofossils; magnetic interactions

4.  Comparison of Ba/Ca and δ18O as freshwater proxies: A multi-species core-top study on planktonic foraminifera from the vicinity of the Orinoco River mouth
André Bahr , Joachim Schönfeld , Julia Hoffmann , Silke Voigt , Ralf Aurahs , Michal Kucera , Sascha Flögel , Anna Jentzen , Axel Gerdes
Keywords
foraminiferal Ba/Ca; δ18O of seawater; Ba desorption; Orinoco; Globigerinoides ruber

5.  Globally strong geomagnetic field intensity circa 3000 years ago
Hoabin Hong , Yongjae Yu , Chan Hee Lee , Ran Hee Kim , Jingyu Park , Seong-Jae Doh , Wonnyon Kim , Hyongmi Sung
Keywords
strong geomagnetic field intensity; archeomagnetism; paleointensity; secular variation; dipolar field; non-dipolar field


Quaternary Geochronology
6.     Combining surface exposure dating and burial dating from paired cosmogenic depth profiles. Example of El Límite alluvial fan in Huércal-Overa basin (SE Iberia)
Angel Rod´es , Raimon Pall`as , Mar´ıa Ortu˜no , Eduardo Garc´ıa-Melendez , Eul`alia Masana
Keywords
Cosmogenic dating; Quaternary; Geomorphology; Numerical model; Eastern Betics


Quaternary International
7.    Proxies for Quaternary monsoon reconstruction on the Tibetan Plateau
Steffen Mischke , Bernd Wünnemann , Erwin Appel




2013年BBQ秋の陣!

こんにちは、M2平林です!
10月19日に開催された、横山研恒例BBQ秋の陣の様子をご紹介します!

当初、10月20日を予定していたのですが、
天気予報によると20日は雨が降るらしい…ということだったので、
急遽、19日にBBQを開催することになりました。
直前の予定変更となってしまったため、
BBQに参加できなくなってしまった人もいて残念でした…

日にちを1日前倒しにしたおかげで、快晴とはいきませんでしたが、
なんとか天気も持ちこたえてくれて、無事にBBQが開催できました!
参加人数も20人超!

直前の日程変更だったにもかかわらず、
多くの方に参加していただき、ありがとうございました。

今回はオーストラリア国立大学(ANU)の地球科学部門からの
招聘研究員であるLeslie Kinsleyさんも参加してくださり、
ANUでの昔の写真を見ながら、色々お話しました。

お酒を片手にLesさんとの議論に盛り上がる横山研のメンバー!
今回、参加できなかった方も、次回、来年春の陣に是非ご参加ください♪



10/29/2013

JOURNAL REVIEW October 22 – October 28 (Nature, Science, PNAS, Geology, Nature Communications)



NATURE

1. Robust twenty-first-century projections of ElNiño and related precipitation variability
Scott Power, François Delage, Christine Chung, Greg Kociuba & Kevin Keay
Nature 502, 541–545 (24 October 2013) doi:10.1038/nature12580
Received 05 April 2013 Accepted 16 August 2013 Published online 13 October 2013

The future of El Niño and its impact on precipitation in a warming world is clearer than previously appreciated.


SCIENCE

2.  Who's Afraid of Peer Review?
John Bohannon
Science 4 October 2013: Vol. 342 no. 6154 pp. 60-65, DOI: 10.1126/science.342.6154.60

More than 50% of scientific journals accepted a paper based on experiments that are so hopelessly flawed that the results are meaningless.

3. Ancient DNA Links Native Americans With Europe
Michael Balter
Science 25 October 2013: Vol. 342 no. 6157 pp. 409-410

The genome of a Siberian boy who died 24,000 years ago offers clues to the identity of the people who first settled the Americas. But the boy apparently descended from people who had lived in Europe or western Asia.

4. The New Core Paradox
Peter Olson
Science 25 October 2013: 431-432.[DOI:10.1126/science.1243477]

Recent results show that Earth's core has a large thermal conductivity, raising questions over how the geodynamo evolved.

5. Biodiversity Risks from Fossil Fuel Extraction
N. Butt, H. L. Beyer, J. R. Bennett, D. Biggs, R. Maggini, M. Mills, A. R. Renwick, L. M. Seabrook, and H. P. Possingham
Science 25 October 2013: 425-426.

6. Mass-Independent Oxygen Isotopic Partitioning During Gas-Phase SiO2 Formation
Subrata Chakraborty, Petia Yanchulova, and Mark H. Thiemens
Science 25 October 2013: 463-466.[DOI:10.1126/science.1242237]

7. Strong Premelting Effect in the Elastic Properties of hcp-Fe Under Inner-Core Conditions
Benjamí Martorell, Lidunka Vočadlo, John Brodholt, and Ian G. Wood
Science 25 October 2013: 466-468.
Published online 10 October 2013 [DOI:10.1126/science.1243651]

The observed shear-wave velocity VS in Earth’s core is much lower than expected from mineralogical models derived from both calculations and experiments. Elastic weakening of iron just before melting explains variations in the seismic structure of Earth’s inner core.

8. 2000 Years of Parallel Societies in Stone Age Central Europe
Ruth Bollongino, Olaf Nehlich, Michael P. Richards, Jörg Orschiedt, Mark G. Thomas, Christian Sell, Zuzana Fajkošová, Adam Powell, and Joachim Burger
Science 25 October 2013: 479-481.
Published online 10 October 2013 [DOI:10.1126/science.1245049]

Genetic and isotopic evidence document changes occurring in Europe during the Neolithic era.


PNAS

9. Holocene dynamics of the Florida Everglades with respect to climate, dustfall, and tropical storms
Paul H. Glaser, Barbara C. S. Hansen, Joe J. Donovan, Thomas J. Givnish, Craig A. Stricker, and John C. Volin
PNAS 2013 110 (43) 17211-17216; published ahead of print October 7, 2013, doi:10.1073/pnas.1222239110

A multiproxy sedimentary record indicates that changes in atmospheric circulation patterns produced an abrupt shift in the hydrology and dust deposition in South Florida wetlands over the past 4,600 y.

10. Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules
Siegfried Schobesberger, Heikki Junninen, Federico Bianchi, Gustaf Lönn, Mikael Ehn, Katrianne Lehtipalo, Josef Dommen, Sebastian Ehrhart, Ismael K. Ortega, Alessandro Franchin, Tuomo Nieminen, Francesco Riccobono, Manuel Hutterli, Jonathan Duplissy, João Almeida, Antonio Amorim, Martin Breitenlechner, Andrew J. Downard, Eimear M. Dunne, Richard C. Flagan, Maija Kajos, Helmi Keskinen, Jasper Kirkby, Agnieszka Kupc, Andreas Kürten, Theo Kurtén, Ari Laaksonen, Serge Mathot, Antti Onnela, Arnaud P. Praplan, Linda Rondo, Filipe D. Santos, Simon Schallhart, Ralf Schnitzhofer, Mikko Sipilä, António Tomé, Georgios Tsagkogeorgas, Hanna Vehkamäki, Daniela Wimmer, Urs Baltensperger, Kenneth S. Carslaw, Joachim Curtius, Armin Hansel, Tuukka Petäjä, Markku Kulmala, Neil M. Donahue, and Douglas R. Worsnop
PNAS 2013 110 (43) 17223-17228; published ahead of print October 7, 2013, doi:10.1073/pnas.1306973110

Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments.

11. Delayed detection of climate mitigation benefits due to climate inertia and variability
Claudia Tebaldi and Pierre Friedlingstein
PNAS 2013 110 (43) 17229-17234; published ahead of print October 7, 2013, doi:10.1073/pnas.1300005110 


Because of the inertia and internal variability affecting the climate system and the global carbon cycle, it is unlikely that a reduction in warming would be immediately discernible. Here we use 21st century simulations from the latest ensemble of Earth System Model experiments to investigate and quantify when mitigation becomes clearly discernible. 

12. Human and natural influences on the changing thermal structure of the atmosphere
Benjamin D. Santer, Jeffrey F. Painter, Céline Bonfils, Carl A. Mears, Susan Solomon, Tom M. L. Wigley, Peter J. Gleckler, Gavin A. Schmidt, Charles Doutriaux, Nathan P. Gillett, Karl E. Taylor, Peter W. Thorne, and Frank J. Wentz
PNAS 2013 110 (43) 17235-17240; published ahead of print September 16, 2013, doi:10.1073/pnas.1305332110

Here, we present evidence that a human-caused signal can also be identified relative to the larger “total” natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing.

13. Vegetation controls on the maximum size of coastal dunes
Orencio Durán and Laura J. Moore
PNAS 2013 110 (43) 17217-17222; published ahead of print October 7, 2013, doi:10.1073/pnas.1307580110

Here, we study foredune development using an ecomorphodynamic model that resolves the coevolution of topography and vegetation in response to both physical and ecological factors. We find that foredune growth is eventually limited by a negative feedback between wind flow and topography.

14. Changes in ecosystem resilience detected in automated measures of ecosystem metabolism during a whole-lake manipulation
Ryan D. Batt, Stephen R. Carpenter, Jonathan J. Cole, Michael L. Pace, and Robert A. Johnson
PNAS 2013 110 (43) 17398-17403; published ahead of print October 7, 2013, doi:10.1073/pnas.1316721110

We examined the capacity of environmental sensors to assess resilience during an experimentally induced transition in a whole-lake manipulation. A trophic cascade was induced in a planktivore-dominated lake by slowly adding piscivorous bass, whereas a nearby bass-dominated lake remained unmanipulated and served as a reference ecosystem during the 4-y experiment.

15. Sleep spindles in midday naps enhance learning in preschool children
Laura Kurdziel, Kasey Duclos, and Rebecca M. C. Spencer
PNAS 2013 110 (43) 17267-17272; published ahead of print September 23, 2013, doi:10.1073/pnas.1306418110

Given that sleep benefits memory in young adults, it is possible that naps serve a similar function for young children. Here we show evidence that classroom naps support learning in preschool children by enhancing memories acquired earlier in the day compared with equivalent intervals spent awake.


GEOLOGY

16. Localized tsunamigenic earthquakes inferred from preferential distribution of coastal boulders on the Ryukyu Islands, Japan
Kazuhisa Goto, Kunimasa Miyagi, and Fumihiko Imamura
Geology, November 2013, v. 41, p. 1139-1142, first published on September 6, 2013, doi:10.1130/G34823.1

The occurrence of large earthquakes and tsunamis along the Ryukyu Trench is a subject of continuing interest, the key to which is the long-term geological record. Here we describe the clast size and spatial distributions of 2900 boulders on the reefs of the Ryukyu Islands, Japan, as markers of paleotsunamis and causative tsunamigenic earthquakes.

17. Multidecadal rainfall variability in South Pacific Convergence Zone as revealed by stalagmite geochemistry
J.W. Partin, T.M. Quinn, C-C Shen, J. Emile-Geay, F.W. Taylor, C.R. Maupin, K. Lin, C.S. Jackson, J.L. Banner, D.J. Sinclair, and C.-A. Huh
Geology, November 2013, v. 41, p. 1143-1146, first published on September 6, 2013, doi:10.1130/G34718.1

Here we present an absolutely dated, subannually resolved, 446 yr stable oxygen isotope (δ18O) cave record of rainfall variability in Vanuatu (southern Pacific Ocean). The δ18O-based proxy rainfall record is dominated by changes in stalagmite δ18O that are large (1‰), quasi-periodic (50 yr period), and generally abrupt (within 5–10 yr).

18. Iron formation carbonates: Paleoceanographic proxy or recorder of microbial diagenesis?
Clark M. Johnson, James M. Ludois, Brian L. Beard, Nicolas J. Beukes, and Adriana Heimann
Geology, November 2013, v. 41, p. 1147-1150, first published on September 6, 2013, doi:10.1130/G34698.1

The chemical and isotopic compositions of carbonates are commonly used as proxies for ancient seawater or paleoenvironments. Here were use an isotope tracer that is not affected by biological processes or isotopic fractionation, the radiogenic 87Rb-87Sr system, to test the applicability of iron fromation (IF) carbonates as a paleoenvironmental proxy. These results question the use of IF carbonates to infer seawater compositions and paleoenvironmental conditions, including estimates for atmospheric CO2 contents.

19. Estuaries beneath ice sheets
Huw J. Horgan, Richard B. Alley, Knut Christianson, Robert W. Jacobel, Sridhar Anandakrishnan, Atsuhiro Muto, Lucas H. Beem, and Matthew R. Siegfried
Geology, November 2013, v. 41, p. 1159-1162, first published on September 6, 2013, doi:10.1130/G34654.1

Interactions between subglacial hydrology and the ocean make the existence of estuaries at the grounding zones of ice sheets likely. Here we present geophysical observations of an estuary at the downstream end of the hydrologic system that links the active subglacial lakes in Antarctica.

20. Carbon dioxide emission to Earth’s surface by deep-sea volcanism
Satoshi Okumura and Naoto Hirano
Geology, November 2013, v. 41, p. 1167-1170, first published on September 6, 2013, doi:10.1130/G34620.1

Large amounts of CO2 are transferred from Earth’s interior to the surface by volcanism.
Here, we measure the CO2 and H2O contents of glassy basalts produced by petit-spot volcanism. Based on the measured values and magma flux of petit-spot volcanism, we show that the rate of CO2 emission from petit-spot volcanoes contribute to the carbon cycle on Earth more that has been recognized. 

21. Shaping post-orogenic landscapes by climate and chemical weathering
Oliver A. Chadwick, Josh J. Roering, Arjun M. Heimsath, Shaun R. Levick, Gregory P. Asner, and Lesego Khomo
Geology, November 2013, v. 41, p. 1171-1174, first published on September 6, 2013, doi:10.1130/G34721.1

Here, we measure geochemical and geomorphic properties of catchments in Kruger National Park, South Africa, where granitic lithology and erosion rates are invariant, enabling us to evaluate how varying mean annual precipitation impacts hill-valley spacing or landscape dissection. Catchment-averaged erosion rates, based on 10Be concentrations in river sands, are low (3–6 m/m.y.) and vary minimally across the three sites.

22. Rapid high-amplitude variability in Baltic Sea hypoxia during the Holocene
Tom Jilbert and Caroline P. Slomp
Geology, November 2013, v. 41, p. 1183-1186, first published on September 6, 2013, doi:10.1130/G34804.1

Here we present bulk sediment geochemical records from the deep basins of the Baltic Sea that show multicentennial oscillations during intervals of past hypoxia, suggesting rapid alternations between hypoxic and relatively oxic conditions.
The results confirm the role of anthropogenic nutrient loading in driving this system into its current hypoxic state.

23. High-flying diatoms: Widespread dispersal of microorganisms in an explosive volcanic eruption
Alexa R. Van Eaton, Margaret A. Harper, and Colin J.N. Wilson
Geology, November 2013, v. 41, p. 1187-1190, first published on September 6, 2013, doi:10.1130/G34829.1

This study documents abundant freshwater diatoms in widespread tephra from the 25.4 ka Oruanui eruption of Taupo volcano, New Zealand.
Our results suggest that dispersal of microorganisms may be an overlooked feature of a number of ancient and modern eruptions, and indicate a novel pathway of microbe transport in airborne volcanic plumes

24. Abundant bacterial magnetite occurrence in oxic red clay
Toshitsugu Yamazaki and Takaya Shimono
Geology, November 2013, v. 41, p. 1191-1194, first published on September 6, 2013, doi:10.1130/G34782.1

We demonstrate that bacterial magnetites (magnetofossils) dominate magnetic mineral assemblages throughout a 76 m thickness of red clay at IODP site in the South Pacific Gyre, as well as in subsurface red clay of the North Pacific Gyre.

25. Tsunami-generated turbidity current of the 2011 Tohoku-Oki earthquake
Kazuno Arai, Hajime Naruse, Ryo Miura, Kiichiro Kawamura, Ryota Hino, Yoshihiro Ito, Daisuke Inazu, Miwa Yokokawa, Norihiro Izumi, Masafumi Murayama, and Takafumi Kasaya
Geology, November 2013, v. 41, p. 1195-1198, first published on September 6, 2013, doi:10.1130/G34777.1

We show the first real-time record of a turbidity current associated with a great earthquake, the Tohoku-Oki earthquake offshore Japan. Our discovery can be a starting point for more detailed characterization of modern tsunamigenic turbidites, and for the identification of tsunamigenic turbidites in geologic records.can live at decimeter depths within red clay.
NATURE COMMUNICATIONS

26. Sequestration of Martian CO2 by mineral carbonation
Tim Tomkinson, Martin R. Lee, Darren F. Mark & Caroline L. Smith
Nature Communications 4, Article number: 2662 doi:10.1038/ncomms3662
Received 11 June 2013 Accepted 24 September 2013 Published 22 October 2013

Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation.


Newly published paper introduction (AGU & EGU 21 - 27 Oct 2013)

新着論文(AGU, EGUほか)21-27 Oct 2013
AGU
○G3
1. Orbital pacing of Eocene climate during the Middle Eocene climate optimum and the chron C19r event – missing link found in the tropical western Atlantic
Thomas Westerhold, Ursula Röhl

2. Influence of provenance and preservation on the carbon isotope variations of dispersed organic matter in ancient floodplain sediments
Clément P. Bataille, Maria Mastalerz, Brett J. Tipple, Gabriel J. Bowen

3. Sea-ice conditions in the Okhotsk Sea during the last 550 kyr deduced from environmental magnetism
Toshitsugu Yamazaki, Seiko Inoue, Takaya Shimono, Tatsuhiko Sakamoto, Saburo Sakai

4. Timing and lock-in effect of the laschamp geomagnetic excursion in Chinese loess
Youbin Sun, Xiaoke Qiang, Qingsong Liu, Jan Bloemendal, Xulong Wang

5. Westerly jet–East Asian summer monsoon connection during the holocene
Kana Nagashima, Ryuji Tada, Shin Toyoda
日本海から得られた堆積物中のダストの化学分析から、完新世の東アジアモンスーンと偏西風の変動を復元。ゴビ砂漠とタクラマカン砂漠起源のダストが千年〜数千年スケールで変動を示している。偏西風の位置の変動が東アジアモンスーンの降水にも影響をしており、中国大陸の南北での対照的な変動を生み出していると思われる。

○GRL
1. Unprecedented recent summer warmth in Arctic Canada
Gifford H. Miller, Scott J. Lehman, Kurt A. Refsnider, John R. Southon, Yafang Zhong
近年北極海においては海氷・氷河の後退などが報告されているが、それが自然変動の範疇にあるかははっきりとしていない。ツンドラに自生する植物の放射性炭素年代測定から、カナダ北極圏東部においては最近が過去44kaで最も温暖であり、過去5kaの寒冷化の傾向を打ち消していることが示唆された(完新世初期に特に温暖だった)。

2. A recurrence-based technique for detecting genuine extremes in instrumental temperature records
Davide Faranda, Sandro Vaienti

3. Efficient gas exchange between a boreal river and the atmosphere
Jussi Huotari, Sami Haapanala, Jukka Pumpanen, Timo Vesala, Anne Ojala
河川における炭素循環はあまりよく分かっていない。フィンランドにおける30日間に渡る炭酸系の観測から、二酸化炭素に関するガス輸送速度を推定したところ、従来考えられていたよりも高い値が得られ、河川からのCO2フラックスが大きいことが示唆された。

4. Enhanced POC export in the oligotrophic northwest Pacific Ocean after extreme weather events
Kuo-Shu Chen, Chin-Chang Hung, Gwo-Ching Gong, Wen-Chen Chou, Chih-Ching Chung, Yung-Yen Shih, Chau-Chang Wang

○JGR-Oceans
1. On the Wind Mechanical Forcing of the Ocean General Circulation
X. Zhai

2. Wave power variability and trends across the North Pacific
Peter D. Bromirski, Daniel R. Cayan, John Helly, Paul Wittmann
1948年以降の北太平洋における波の力(wave power)の変動を議論。ENSO・レジームシフト・PDOなどとの関連性。

3. New zealand 20th century sea level rise: Resolving the vertical land motion using space geodetic and geological data
Abdelali Fadil, Paul Denys, Robert Tenzer, Hugh R. Grenfell, Pascal Willis
20世紀のニュージーランドの海水準は1.46±0.10 mm/yrで上昇している。潮位計と海水面の衛星観測記録から土地の隆起の影響を評価。海水準上昇には数十年スケールの3つのフェーズが見られることが分かった。

4. Temporal variability of transformation, formation and subduction rates of upper Southern Ocean waters
Eun Young Kwon
南大洋の表層・中層水の挙動を動力学的・熱力学的に評価し、海洋循環モデルを用いて亜南極モード水(SAMW)の数十年規模のモデリングを行った。冬季に混合層の水が収束し、それに続く春に等密度線に沿って沈み込み、さらに春の表層水の温暖化によって密度的に蓋をされるプロセス(成層化)がSAMWの形成に重要であることが分かった。SAMWは年々変動を示し、主に混合層の深さと関連が大きいことが分かった。また、SAMとは直接的に関係していないものの、エクマン沈降・湧昇プロセスを通じて間接的に関係していると思われる。

5. Widespread freshening in the seasonal ice zone near 140°E off the Adélie Land Coast, Antarctica, from 1994 to 2012
S. Aoki, Y. Kitade, K. Shimada, K.I. Ohshima, T. Tamura, C.C. Bajish, M. Moteki, S.R. Rintoul
南極沖の140ºE線で行われている1994-2012年の定期観測記録から、近年の表層水から底層水のすべてに淡水化の傾向が見られた。2012年には底層水塊の厚さが異常に薄く、Mertz氷舌(glacier tongue; 氷河末端)の急激な崩壊とそれに伴う海氷形成の減少との関連が示唆される。

6. Asymptotic behavior of tidal damping in alluvial estuaries
Huayang Cai, Hubert H. G. Savenije

7. Estimation of extreme sea levels over the Eastern Continental Shelf of North America
Heng Zhang, Jinyu Sheng

○Paleoceanography
1. Influence of seawater exchanges across the Bab-el-Mandab Strait on sedimentation in the Southern Red Sea during the last 60 ka.
Alexandra Bouilloux, Jean-Pierre Valet, Franck Bassinot, Jean-Louis Joron, Fabien Dewilde, Marie-Madeleine Blanc-Valleron, Eva Moreno
紅海の南端で得られた堆積物コアのMSTOC・浮遊性有孔虫δ13Cなどから、過去60kaの気候変動を復元。氷期-間氷期スケールの変動、D/Oイベント・最終退氷期の海水準上昇に伴う大陸棚の浸水と岩屑物の堆積イベントなどが見られる。

2. Recovering the true size of an Eocene hyperthermal from the marine sedimentary record
Sandra Kirtland Turner, Andy Ridgwell
地球システムモデル(cGENIE)を用いて小規模なMECOCnn2H3; ~49.2Ma)温暖化イベントの規模・継続期間、炭素インプット速度などを推定。さらに堆積プロセスのモデル化も行い、真の炭素擾乱を推定。ODP1258コアの底性有孔虫δ13C-0.95‰のエクスカージョンは大気中CO2δ13C-1.45‰の変化があれば説明できることが示された。従来法の推定から得られる量よりも2/3大きい炭素インプットが必要であると思われる。

○GBC
1. Variability of the Oxygen Minimum Zone in the Tropical North Pacific during the Late 20th Century
Takamitsu Ito, Curtis Deutsch
海洋物理・生物地球化学モデルを用いて1980年代以降の東太平洋熱帯域の酸素極小層(OMZ)の拡大の原因を評価。

2. Quantity and quality of organic matter (detritus) drives N2 effluxes (net denitrification) across seasons, benthic habitats and estuaries
Bradley D. Eyre, Damien T. Maher, Peter Squire

EGU
○Climate of the Past
1. Holocene climate variability in the winter rainfall zone of South Africa
S. Weldeab, J.-B. W. Stuut, R. R. Schneider, and W. Siebel
アフリカ南東部沖で得られた堆積物コアの浮遊性有孔虫δ18Oδ13C87/86SrεNdを用いて完新世の気候変動を復元。小氷期に最も湿潤な期間があり、南半球の偏西風の北方シフトと関連していると思われる。さらにAgulhas leakageや南極氷床へのダスト量などとの関係性も議論。

2. Pre-LGM Northern Hemisphere ice sheet topography
J. Kleman, J. Fastook, K. Ebert, J. Nilsson, and R. Caballero
地質調査や数値モデルなどを組み合わせてMIS5bMIS4の北半球氷床の高度・範囲などを推定。MIS5bから徐々に北半球の氷床が成長し4つほどとなり、MIS4には大規模氷床の数はほぼMIS5b時と同じで、その後LGMに北米氷床は一つに融合したと思われる。

3. Eurasian Arctic climate over the past millennium as recorded in the Akademii Nauk ice core (Severnaya Zemlya)
T. Opel, D. Fritzsche, and H. Meyer
ロシアのセヴェルナヤ・ゼムリャ諸島において得られたアイスコアのδ18ONaなどから過去1100年間の気候変動を復元。AD1800頃に最も寒冷であった。20世紀初頭には異常な2つのピークが確認された。δ18Oには小氷期も中世気候変調期の変動も検出されなかったが、他の時期には温暖化・寒冷化イベントなどが確認され、大気循環の変動と関連していると思われる。

4. Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology
K. T. Lawrence, I. Bailey, and M. E. Raymo
ODP982の年代モデルの再考。Gauss–Matsuyamaクロンの位置には影響はないが、3.2-3.0Maにハイエタスが確認された。

○Biogeosciences
1. Technical Note: Precise quantitative measurements of total dissolved inorganic carbon from small amounts of seawater using a gas chromatographic system
T. Hansen, B. Gardeler, and B. Matthiessen
クロマトグラフィーを用いて海水中の全炭酸を精度良く測ることのできる新手法を開発。

2. Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions
P. Peylin, R. M. Law, K. R. Gurney, F. Chevallier, A. R. Jacobson, T. Maki, Y. Niwa, P. K. Patra, W. Peters, P. J. Rayner, C. Rödenbeck, I. T. van der Laan-Luijkx, and X. Zhang
大気CO2観測記録から過去20年間の炭素のソース・シンクなどについて議論。

GSA
○GSA Bulletin

今回は発行なし