[PD Obrochta]
A depth-derived Pleistocene age model: Uncertainty estimates, sedimentation variability, and nonlinear climate change
Huybers, P. and Wunsch, C.
Paleoceanography, 19, PA1028, 2004, doi:10.1029/2002PA000857
→This paper creates a stacked isotope record for the past 780 ka with an age model that was constructed with no orbital assumptions. This was done by using average sedimentation rates and is referred to as a "depth-derived" age model. By using depth as a proxy for time, the authors note weak nonlinearities between the eccentricity and obliquity bands, resulting in the appearance of heterodyne frequencies (i.e., sum and difference tones).
Obliquity pacing of the late Pleistocene glacial terminations
Huybers, P. and Wunsch, C.
Nature 434, 491-494, 2005, doi:10.1038/nature03401
→This paper formally rejects a null hypothesis (H0) that glacial terminations are independent of obliquity variations. Similar null hypotheses for precession and eccentricity cannot be rejected. The implications are that the "100-ky cycle" in late Pleistocene glaciations is an artifact of force fitting marine sediment cores to eccentricity. The reason for an apparent 100-ky cycle during the Late Pleistocene would be due to the skipping of two to three obliquity beats, resulting in terminations every 80 or 120 ky, which would average to 100 ky.
Glacial variability over the last two million years: an extended depth-derived agemodel, continuous obliquity pacing, and the Pleistocene progression
Huybers, P.
Quaternary Science Reviews 26, 37-55, 2007, doi:10.1016/j.quascirev.2006.07.013
→This paper expands the depth derived age model over the past 2 million years, during which time 33 of the the 36 glacial terminations correspond to highs in obliquity.
[D2 山口 Yamaguchi]
Microbial production of recalcitrant dissolved organic matter: long-term carbon storage in the global ocean
Nianzhi Jiao, Gerhard J. Herndl, Dennis A. Hansell, Ronald Benner, Gerhard Kattner, Steven W. Wilhelm, David L. Kirchman, Markus G. Weinbauer, Tingwei Luo, Feng Chen & Farooq Azam
Nature Reviews Microbiology 8, 593-599 (August 2010) | doi:10.1038/nrmicro2386
Chemosynthetic origin of 14C-depleted dissolved organic matter in a ridge-flank hydrothermal system
Matthew D. McCarthy, Steven R. Beaupré, Brett D. Walker, Ian Voparil, Thomas P. Guilderson & Ellen R. M. Druffel
Nature Geoscience, 4, 32–36, 2011, doi:doi:10.1038/ngeo1015.
Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans
John W. Pohlman, James E. Bauer, William F. Waite, Christopher L. Osburn & N. Ross Chapman
Nature Geoscience, 4, 37–41, 2011, doi:doi:10.1038/ngeo1016.
→6/28の地球環境基礎講座で紹介した、海洋溶存有機物に関する最新の進展×３。１：「微生物炭素ポンプ」の概念を提唱したレビュー。海洋微生物が難分解性溶存有機物を生産して、炭素を大気から数千年スケールの長期間隔離する？ ２＆３：熱水・冷湧水の流体中溶存有機物（海底下生命圏起源？）が、“古い”海洋溶存有機物に寄与している？
[D1 川久保 Kawakubo]
A review of modern coral δ18O and Δ14C proxy records
Andra G. Grottoli and C. Mark Eakin
Earth-Science Reviews, Volume 81, Issues 1-2, March 2007, Pages 67-91, doi:10.1016/j.earscirev.2006.10.001
→現生サンゴ骨格中のδ18OとΔ14Cのレビュー（20,30年以上の連続記録のコンパイル）。過去出版されている中で、できる限りのデータをコンパイルしている。
[M2 窪田 Kubota]
Factors determining δ13C and δ18O fractionation in aragonitic otoliths of marine fish.
Thorrold et al.
Geochimica et Cosmochimica Acta, Vol. 61, No. 14, pp. 2909-2919, 1997
→Micropogonias undulutus（太平洋ニベ）の飼育実験を通して耳石アラゴナイトの酸素・炭素同位体平衡を決定する要因について議論。炭素同位体比は体長や代謝の活性度に大きく影響されるが、酸素同位体比は温度と水の酸素同位体比のみの関数となる。
[M2 中村 Nakamura]
Chinese stalagmite δ18O controlled by changes in the Indian monsoon during a simulated Heinrich event
Francesco S. R. Pausata, David S. Battisti, Kerim H. Nisancioglu & Cecilia M. Bitz
Nature Geoscience 4, 474-480 (2011) doi:10.1038/ngeo1169
→最近研究室で何度も話題になっている論文です。中国の石筍が記録するものは！？
[M2 坂下 Sakashita]
Tracking apex marine predator movements in a dynamic ocean
B. A. Block et al.
Nature, Volume 475, 7 July 2011, Pages 86-90, doi:10.1038/nature10082
→今週のNatureに掲載されたクジラやサメなどの海洋の最上位捕食者の挙動を調べた論文。電子タグを23種の生物に取り付け、2000年～2009年の10年間の研究成果をまとめている。単純だけどおもしろい研究だと思い、今回紹介した。
[M2 俵 Tawara]
Insolation Cycles as a Major Control of Equatorial Indian Ocean Primary Production
Luc Beaufort, Yves Lancelot, Pierre Camberlin, Olivia Cayre, Edith Vincent, Franck Bassinot and Laurent Labeyrie
Science, 21 November 1997: Vol. 278 no. 5342 pp. 1451-1454, DOI: 10.1126/science.278.5342.1451
→In the equatorial Indian Ocean, productivity is driven by the wind intensity of westerlies, which is related to the Southern Oscillation; therefore, it is suggested that a precession forcing on the Southern Oscillation is responsible for the observed paleoproductivity dynamics.
Tropical Pacific Forcing of Decadal SST Variability in the Western Indian Ocean over the Past Two Centuries
Julia E. Cole, Robert B. Dunbar, Timothy R. McClanahan and Nyawira A.
Muthiga
Science, 28 January 2000: Vol. 287 no. 5453 pp. 617-619, DOI: 10.1126/science.287.5453.617
→A 194-year annual record of skeletal δ18O from a coral growing at Malindi, Kenya, preserves a history of sea surface temperature (SST) change .Pacific climate variability is superimposed on a warming of as much as 1.3°C since the early 1800s. These results suggest that the tropical Pacific imparts substantial decadal climate variability to the western Indian Ocean and, by implication, may force decadal variability in other regions with strong El Niño–Southern Oscillation teleconnections.
[M1 関 Seki]
Wet periods in northeastern Brazil over the past 210kyr linked to distant climate anomalies
X. Wang, A. S. Auler, R. L. Edwaeds, H. Chang, P. S. Cristalli, P. L. Smart, D. A. Richards, and C-C Shen
Nature 432, 740-743, doi:10.1038/nature03067
→7月5日のセミナーで紹介したWang et al. (2007)で引用されていた、北西ブラジルの石筍の研究。鍾乳石の成長時期を多雨期と解釈し、北西ブラジルの湿潤期が、東アジアモンスーンの弱化期とGreenlandの寒冷期などと対応していることを示している。
