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CO
on C transfer to plants impacted by below-ground CH
releaseOta, Masakazu; Tanaka, Taku*
Journal of Environmental Radioactivity, 201, p.5 - 18, 2019/05
Times Cited Count：4 Percentile：16.8(Environmental Sciences)CH released from deep underground radioactive waste disposal facilities can be a belowground source of CO owing to microbial oxidation of CH to CO in soils. Environmental C models assume that the transfer of CO from soil to plant occurs via foliar uptake of CO. Nevertheless, the importance of CO root uptake is not well understood. In the present study, belowground transport and oxidation of CH were modeled and incorporated into an existing land surface CO model (SOLVEG-II) to assess the importance of root uptake on CO transfer to plants. Performance of the model in calculating the belowground dynamics of CH was validated by simulating a field experiment of 
CH injection into subsoil. The model was then applied to C transfer in a hypothetical ecosystem impacted by continuous CH input from the water table (bottom of one-meter thick soil). In a shallowly rooted ecosystem with rooting depth of 11 cm, foliar uptake of CO was significant, accounting for 80% of the C accumulation in the leaves. In a deeply rooted ecosystem (rooting depth of 97 cm), where the root penetrated to depths close to the water-table, more than half (63%) the C accumulated in the leaves was transferred by the root uptake. We found that CO root uptake in this ecosystem depended on the distribution of methane oxidation in the soil; all C accumulated in the leaves was transferred by the root uptake when methane oxidation occurred at considerable depths (e-folding depths of 20 cm, or 80 cm). These results indicate that CO root uptake contributes significantly to CO transfer to plants if CH oxidation occurs at great depths and roots penetrate deeply into the soil.
Aramaki, Takafumi*; Togawa, Orihiko; Kitamura, Toshikatsu
Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.170 - 172, 2004/02
no abstracts in English
Hamahara, Kazuhiro*; Shigemitsu, Masahito*; Noriki, Shinichiro*; Fukuyama, Ryuji*; Aramaki, Takafumi; Otosaka, Shigeyoshi
Engan Kaiyo Kenkyu, 41(1), p.53 - 60, 2003/08
no abstracts in English
C around the Bussol straitAramaki, Takafumi; Watanabe, Shuichi*; Kuji, Tomoyuki*
Proceedings of the International Symposium on Atmosphere-Ocean-Cryosphere Interaction in the Sea of Okhotsk and the Surrounding Environment, p.34 - 35, 2001/03
no abstracts in English
Aramaki, Takafumi; Mizushima, Toshihiko; Kuji, Tomoyuki*; Povinec, P. P.*; Togawa, Orihiko
Radiocarbon, 43(2B), p.857 - 867, 2001/03
no abstracts in English
C in the north pacific and the pursuit of the anthropogenic carbonAramaki, Takafumi; Watanabe, Shuichi*; Tsunogai, Shizuo*; Kuji, Tomoyuki*; Mizushima, Toshihiko; Togawa, Orihiko
JAERI-Conf 2000-019, p.73 - 75, 2001/02
no abstracts in English
Aramaki, Takafumi
JAERI-Research 99-007, 22 Pages, 1999/02
JAERI-Research-99-007.pdf:1.52MB
no abstracts in English
Yasue, Kenichi; Hirouchi, Daisuke*; Matsubara, Akihiro; Kokubu, Yoko
no journal, ,
no abstracts in English
at NOTO peninsula using C analysisYamada, Rena*; Ikemori, Fumikazu*; Nakamura, Toshio*; Minami, Masayo*; Watanabe, Takahiro; Kinouchi, Kento*; Matsuki, Atsushi*
no journal, ,
Aerosols and clouds seeded by them both affect the heat budget of the Earth, but their RF (radiative forcing) still involves large uncertainty (IPCC 2013). One of the least understood properties of aerosols is the source and contribution of the organics. Our recent observation revealed that submicron aerosol particles in Noto peninsula also have a relatively high concentration (approximately more than 50%) of carbonaceous matter throughout the year. It is difficult to presume its sources specifying its chemical species in many scenes because of its great variety. However, we can presume its source by using carbon isotope ratio. We conducted sampling in NOTOGRO (NOTO ground-based research observatory), lying at the edge of Noto peninsula, from 26th Jun to 23rd July, 2014. We corrected PM using high volume air sampler for every week. Flow rate was 700L/min, and quartz fiber filter was used for sampling. C was analyzed using AMS C system (High Voltage Engineering Europe, Model 4130-AMS) and C using IRMS (isotope ratio mass spectrometer) in Nagoya University. As a result, it was found that 4 samples collected from 26th Jun to 23rd July had approximately 70 percent modern carbon (pMC). This result shows that modern plant (and/or biomass burning) activities mainly contribute to the submicron organic particle concentration in Noto peninsula.
Jeon, H.; Ogawa, Hiroshi*; Otosaka, Shigeyoshi
no journal, ,
Radiocarbon content of marine dissolved organic carbon (DOC) can provide useful information on how organic carbon is produced, transported, and ultimately sequestered in the ocean interior. We conducted research to present the first set of full-depth profiles for DOC along a transect from the central South Pacific Ocean to Chukchi Sea. In order to measure radiocarbon contents of seawater samples, they should be processed with a specific preparation system consists of the custom quartz reactor, dedicated vacuum line and UV lamp followed by radiocarbon counting with an accelerator mass spectrometer. As the first step of the study, we have developed the irradiation procedure using a low-pressure Hg lamp and an oxidation catalyst. We present here how the system is progressing as well as what radiocarbon study in the central Pacific Ocean means for better understanding of oceanic carbon cycle.
Jeon, H.; Otosaka, Shigeyoshi; Yamashita, Yohei*; Ogawa, Hiroshi*
no journal, ,
The ocean is a huge reservoir of dissolved organic carbon that contains almost the same amount of carbon in the atmosphere. Radiocarbon signatures of dissolved organic carbon (DOC) in seawater can provide useful information on how organic carbon is produced, transported, and ultimately sequestered in the ocean's interior. In order to measure radiocarbon contents of seawater samples, they should be processed with a specific preparation system consists of the custom quartz reactor, dedicated vacuum line and UV lamp followed by radiocarbon counting with an accelerator mass spectrometer. As the first step of the study, we developed the irradiation procedure using a low-pressure Hg lamp and an oxidation catalyst. We present here not only how the system is progressing but also what radiocarbon study in the central Pacific Ocean means for better understanding of oceanic carbon cycle.
Yamada, Ryuji*; Kokubu, Yoko; Wakatsuki, Tsuyoshi*; Yasue, Kenichi
no journal, ,
Mass movements and fault movements are natural phenomena to change the local topography. Reconstruction of the movement histories and evaluation of long-term stability of topographies are crucial to assess the geological environment in future. History reconstruction based on radiocabon dating of plant material recovered from sediment deposited by the past movements requires the compilation and the comparison of existing data measured by different analysts with different methods. We compared the results of radiocarbon ages measured at different laboratories with various chemical pretreatments, using plant material samples. For older samples (about 45000 BP), dispersion in ages is greater than measurement uncertainty. However the order of weighted mean ages for each sample agrees well with stratigraphic sequence at the sampling site. It is therefore thought that the influence of the systematic error due to a specific experimental conditions is small.
Jeon, H.; Otosaka, Shigeyoshi; Yamashita, Yohei*; Ogawa, Hiroshi*
no journal, ,
Measurements of the radiocarbon content of marine dissolved organic carbon (DOC) broadened our perspective on the role of DOC in the marine carbon cycle. However fewer measurements have been performed because of methodological difficulties associated with low concentration of DOC and an overwhelming proportion of salts. In order to collect enough DOC for radiocarbon analysis, UV oxidation is one of the most commonly used methods by irradiating seawater samples with ultraviolet light. Unlike other studies where medium pressure mercury arc UV lamp are used, this study attempts to improve the system with two grid lamps in order to reduce the demand for high electric power installation and to miniaturize the instrument for easier handling. We aim to verify the performance of improved equipment by processing C reference materials as well as seawater samples.
Watanabe, Takahiro; Kokubu, Yoko; Fujita, Natsuko; Matsubara, Akihiro*; Nishio, Tomohiro*; Miyake, Masayasu; Kato, Motohisa*; Isozaki, Nobuhiro*; Torazawa, Hitoshi*; Nishizawa, Akimitsu*; et al.
no journal, ,
Radiocarbon dating by Accelerator Mass Spectrometry is widely used for earth and environmental sciences. For high-precision analyses, automatic preparation system and standard methods are needed. The preparation system by elemental analyzer (EA) has been reported. However, we should make clear the changes in background level during the preparation. In this study, we continued radiocarbon dating of international standard materials using the EA at JAEA-AMS-TONO. The radiocarbon concentrations of the standard materials were agreement with the consensus values within 
2 sigma.
Wakatsuki, Tsuyoshi*; Yamada, Ryuji*; Kokubu, Yoko
no journal, ,
Many soil slips and debris flows on the welded-tuff slopes were induced by heavy rain on July 28, 2013 in Tsuwano, Shimane. The debris flows eroded sidewalls or streambeds in river channels and the sediments driven by earlier slope movements were exposed in places. In six outcrops, we collected 53 dead wood chip samples presumably buried at the sediment deposition, and radiocarbon dating was performed. At around 418 m asl in Nayoshi district, Tsuwano, the outcrops of the black-clayey sediments are found, which are supposed to have deposited in a past dammed lake. They are distributed at upstream of a topographically-estimated deposit zone for an ancient large-scale slope failure, and the calendar-calibrated ages of these sediments ranges from 41 to 55 ka BP. It is therefore conjectured that the slope failure had occurred before 55 ka BP and the dammed lake had burst after 41 ka BP. An average deposition rate of about 0.3 m/1000 y was estimated at an outcrop of the dammed lake sediments
Jeon, H.; Otosaka, Shigeyoshi; Watanabe, Takahiro; Aze, Takahiro*; Miyairi, Yosuke*; Yokoyama, Yusuke*; Ogawa, Hiroshi*
no journal, ,
Measurements of the dissolved organic radio carbon (DOC-14) are expected to broaden our perspective on the role of DOC in the marine carbon cycle. Although the authors had succeeded in the DOC-14 analysis in seawater, it was necessary to use a large preprocessing apparatus, and the analysis has not been applied widely. We here report on the improvements to make this system safer and easier to handle. Following the previous method, DOC-14 in seawater was extracted as carbon dioxide by irradiating ultraviolet (UV), purified in a vacuum line, and the C-14 isotopic ratio was analysed with an accelerator mass spectrometer. As a major improvement, low-pressure mercury lamp which can irradiate UV of short wavelength (172 nm and 185 nm) suitable for decomposition of organic matter was used as UV source. By this improvement, the temperature increase in sample during processing was greatly reduced, and the size of the irradiation reactor was reduced to about half.
Nagai, Haruyasu; Koarashi, Jun; Atarashi-Andoh, Mariko; Ota, Masakazu; Nagano, Hirohiko
no journal, ,
no abstracts in English
Hakozaki, Masataka*; Sakamoto, Minoru*; Kokubu, Yoko; Fujita, Natsuko; Li, Z.*; Nakatsuka, Takeshi*
no journal, ,
The sacred tree, a large cedar tree, at the Zinmei Shrine in Mizunami City, Gifu Prefecture was collapsed by heavy rain. Using a part of the tree, we have started measuring its radiocarbon in order to obtain the basic data of calibration curve required for radiocarbon dating. In this presentation, we report the result of age determination of the tree.
Yasue, Kenichi*; Harada, Shunsuke*; Kokubu, Yoko; Hirouchi, Daisuke*
no journal, ,
We present the results of a pit survey conducted in the middle part of the Atera fault zone and C dating of black soil. Samples were collected continuously from the black soil on both sides of the fault at intervals of approximately 5 cm in the depth direction. The dating sample was treated with hydrochloric acid and sodium hydroxide and separated into an alkali-soluble component (humic acid) and an insoluble component (humin). As a result of the dating, the age values generally become younger from the bottom to the surface. In detail, we can see parts where the age gradually become younger towards the surface, parts where the age are almost the same continuously, and parts where the age are reversed. The parts where the age gradually decreases toward the surface is considered to be a normal forest condition where black soil gradually forms over time. A succession of the same age values suggests the formation of a rapid deposition field. The age reversal suggests that older black soil was redeposited on top. These results indicate some event. For example, it is possible that old black soil was rapidly supplied from the upper layer after the fault displacement. We must carefully consider the type of event.
