Timing of climatic events for Termination II from O2/N2, d18Oatm and CH4 records of the Dome Fuji ice core, Antarctica

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Continuous CH4 measurements with the NIPR CFA system

第6回極域科学シンポジウム分野横断セッション：[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日（木）　国立極地研究所１階交流アトリウ

High Resolution Continuous Flow Analysis System developed at the Ice Core Research Center National Institute of Polar Research

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　統計数理研究所 セミナー室2（D304

A Glycoprotein in Shells of Conspecifics Induces Larval Settlement of the Pacific Oyster Crassostrea gigas

Settlement of larvae of Crassostrea gigas on shell chips (SC) prepared from shells of 11 different species of mollusks was investigated. Furthermore, the settlement inducing compound in the shell of C. gigas was extracted and subjected to various treatments to characterize the chemical cue. C. gigas larvae settled on SC of all species tested except on Patinopecten yessoensis and Atrina pinnata. In SC of species that induced C. gigas larvae to settle, settlement was proportionate to the amount of SC supplied to the larvae. When compared to C. gigas SC, all species except Crassostrea nippona showed lower settlement inducing activities, suggesting that the cue may be more abundant or in a more available form to the larvae in shells of conspecific and C. nippona than in other species. The settlement inducing activity of C. gigas SC remained intact after antibiotic treatment. Extraction of C. gigas SC with diethyl ether (Et2O-ex), ethanol (EtOH-ex), and water (Aq-ex) did not induce larval settlement of C. gigas larvae. However, extraction of C. gigas SC with 2N of hydrochloric acid (HCl-ex) induced larval settlement that was at the same level as the SC. The settlement inducing compound in the HCl-ex was stable at 100°C but was destroyed or degraded after pepsin, trypsin, PNGase F and trifluoromethanesulfonic acid treatments. This chemical cue eluted between the molecular mass range of 45 and 150 kDa after gel filtration and revealed a major band at 55 kDa on the SDS-PAGE gel after staining with Stains-all. Thus, a 55 kDa glycoprotein component in the organic matrix of C. gigas shells is hypothesized to be the chemical basis of larval settlement on conspecifics

Declining sustainability: The case of shopping trip energy consumption

As typical shopping behavior changed from foot-based visits to neighborhood shopping streets or corner grocery stores to auto-based visits to large-scale retail stores, shopping trip energy consumption increased substantially in the Osaka metropolitan area between 1970 and 2000. Underlying this phenomenon are, among others, progress of motorization, declining household size, and diminishing households with a homemaker. The effects of these and other factors are examined through an analysis of variance of large-scale household travel survey data from 1970 and 2000. It is shown that changes in demographics and socioeconomics alone would not have produced the observed magnitude of increase in shopping trip energy consumption. The more substantial contributor has been structural change, which has presumably been caused by the urban system adjusting its elements—land use, transportation networks, facility location, retail systems, and so forth—to adapt to increased ownership and use of the automobile. © 2008 Taylor & Francis Group, LLC

The Dome Fuji ice core DF2021 chronology (0-207 kyr BP)

International audiencePrecise ice-core chronologies are essential for identifying the timing and duration of polar climatic changes as well as their phasing with the changes in other parts of the globe. However, existing ice-core chronologies beyond the last 60 kyr show relatively large disagreements with each other and with U-Th chronologies of speleothems. Here, we constructed new ice and gas age scales for the Dome Fuji (DF) core (DF2021) over the last 207 kyr by combining a Bayesian dating model and firn densification model, constrained by various types of chronological and glaciological information including new δO2/N2 age markers, precise synchronization to other high-quality chronologies (volcanic, cosmogenic, and CH4 signals), and high-resolution δ15N of N2 (reflecting past firn thickness). The new chronology is tightly constrained by synchronization to other well-dated records for the last 60 kyr, whereas it is independent from other chronologies for the older period. For the last 60 kyr, the DF2021 chronology agrees with the layer-counted ice core chronologies (GICC05 and a part of WD2014) and U-Th chronologies of speleothems within ∼200 years. For the period 60-130 kyr BP, the timing of all Dansgaard-Oeschger warming events on DF2021 agree with those of corresponding events in the U-Th dated Chinese or European speleothems mostly within 1 kyr (well within 2σ uncertainty of DF2021). The excellent agreement suggests high accuracy of our chronology, and supports the assumption of negligible phasing between the past local summer solstice insolation and δO2/N2 fractionation at bubble close-off (the basis for constructing the δO2/N2 age markers). Between 130 and 207 kyr BP (penultimate glacial period), there is a lower degree of similarity between the variations in atmospheric CH4 and speleothem calcite δ18O than in the last glacial period, making the age comparison challenging. The comparison of DF2021 with 9 U-Th dates at 7 abrupt events shows the mean difference of -0.2 ± 0.8 kyr, which is within the DF2021 uncertainty (on the order of 1.5 kyr). The DF2021 chronology agrees with the AICC2012 chronology within 2 kyr except between ∼103 and 128 kyr BP where AICC2012 is likely too young by up to ∼4 kyr. By analyzing the lag between δ18O of O2 (δ18Oatm) on DF2021 and 65°N summer solstice insolation, the relatively large error in AICC2012 is found to originate in three δ18Oatm age markers assuming a constant lag, which are off by more than 3 kyr. The phasing between δ18Οatm and orbital forcing identified in this study may be useful for future ice core dating, especially where other age constraints are weak or lacking