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PubMed | New York University, Kyoto University, University of Tokyo, Japan Forestry and Forest Products Research Institute and 3 more.
Type: | Journal: Scientific reports | Year: 2015

Many terrestrial plants are C3 plants that evolved in the Mesozoic Era when atmospheric CO2 concentrations ([CO2]) were high. Given current conditions, C3 plants can no longer benefit from high ambient [CO2]. Kaempferia marginata Carey is a unique understory ginger plant in the tropical dry forests of Thailand. The plant has two large flat leaves that spread on the soil surface. We found a large difference in [CO2] between the partly closed space between the soil surface and the leaves (638mol mol(-1)) and the atmosphere at 20cm above ground level (412mol mol(-1)). This finding indicates that the plants capture CO2 efflux from the soil. Almost all of the stomata are located on the abaxial leaf surface. When ambient air [CO2] was experimentally increased from 400 to 600 mol mol(-1), net photosynthetic rates increased by 45 to 48% under near light-saturated conditions. No significant increase was observed under low light conditions. These data demonstrate that the unique leaf structure enhances carbon gain by trapping soil CO2 efflux at stomatal sites under relatively high light conditions, suggesting that ambient air [CO2] can serve as an important selective agent for terrestrial C3 plants.


News Article | February 5, 2016
Site: www.materialstoday.com

Teijin Limited has developed two new fabrics in its Twaron and Technora para-aramid fibers range that can protect facilities such as lodges and evacuation shelters from airborne volcanic fragments up to 10 cm. Teijin developed the para-aramid-fiber fabrics in consultation with the Japanese Cabinet Office, the National Defense Academy and the Mount Fuji Research Institute of in accordance with the Cabinet Office’s new regulations for strengthening evacuation facilities located near volcanoes. Protecting evacuation facilities and other structures from large airborne fragments is an important issue in Japan, one of the world's more active volcanic regions. While materials such as reinforced concrete and steel offer required levels of strength and durability, transporting heavy materials and large equipment to highlands can lengthen the construction period and raise construction costs. The deteriorating effect of severe weather on steel is another problem. In simulation tests, the fabrics demonstrated their capacity to withstand fist-sized airborne fragments similar to those produced during the September 2014 eruption of Mount Ontake, located some 200 kilometers west of Tokyo. The country’s Ministry of the Environment is now using the fabrics to refurbish the roof of the Ebino Eco Museum Center in Kirishima-Kinkowan National Park on the island of Kyushu in southern Japan. Teijin says that Twaron offers six times more tensile strength than steel of the same weight, as well as improved heat resistance and elastic modulus. Technora also has increased tensile strength and resistance to impact, fatigue and chemicals. This story uses material from Teijin Limited, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.


Tsunematsu K.,University of Geneva | Tsunematsu K.,Mount Fuji Research Institute | Bonadonna C.,University of Geneva
Bulletin of Volcanology | Year: 2015

Studies of grain-size distributions of explosive volcanic eruptions provide important insights into fragmentation mechanisms and eruptive conditions and are crucial to the modeling of tephra dispersal. As a result of sedimentation processes and plume dynamics, grain-size features vary significantly both in the downwind and crosswind directions and are difficult to characterize. We have analyzed grain-size features in the downwind and crosswind directions of the two largest eruptions of the last 2000 years of Cotopaxi volcano activity (Ecuador). Crosswind grain-size variations are similar for both eruptions (i.e., layers 3 and 5), while at any given downwind distance from vent, the layer 3 deposit is coarser than the layer 5 one. This suggests that layers 3 and 5 were characterized by similar plume height but that layer 3 was advected by a stronger wind. In addition, both deposits are coarsest along the dispersal axis and become richer in ash in the crosswind direction showing a Gaussian decreasing rate. Deposit thickness also shows a Gaussian crosswind decay, but layer 3 is significantly thicker at all points than is layer 5 due to the former's larger erupted mass. Based on both quantitative analysis of field data and on numerical simulations, we show that tephra deposits associated with large explosive eruptions (i.e., plume height of 30 km) should be sampled out to at least 200 km from the vent (depending on wind speed and tropopause height) in order to derive complete grain-size distributions that are not depleted in fines. Eruptions occurring in a strong wind field at high latitudes (e.g., Iceland) require lesser representative-sampling distances because of the lower tropopause heights. © 2015, Springer-Verlag Berlin Heidelberg.


Tsunematsu K.,Mount Fuji Research Institute | Ishimine Y.,Japan National Institute of Public Health | Kaneko T.,University of Tokyo | Yoshimoto M.,Mount Fuji Research Institute | And 2 more authors.
Earth, Planets and Space | Year: 2016

The 2014 Mount Ontake eruption started just before noon on September 27, 2014. It killed 58 people, and five are still missing (as of January 1, 2016). The casualties were mainly caused by the impact of ballistic blocks around the summit area. It is necessary to know the magnitude of the block velocity and energy to construct a hazard map of ballistic projectiles and design effective shelters and mountain huts. The ejection velocities of the ballistic projectiles were estimated by comparing the observed distribution of the ballistic impact craters on the ground with simulated distributions of landing positions under various sets of conditions. A three-dimensional numerical multiparticle ballistic model adapted to account for topographic effect was used to estimate the ejection angles. From these simulations, we have obtained an ejection angle of γ = 20° from vertical to horizontal and α = 20° from north to east. With these ejection angle conditions, the ejection speed was estimated to be between 145 and 185 m/s for a previously obtained range of drag coefficients of 0.62-1.01. The order of magnitude of the mean landing energy obtained using our numerical simulation was 104 J. © 2016 The Author(s).


PubMed | Japan Forestry and Forest Products Research Institute, University of Shizuoka, Kyoto University, Nihon University and Mount Fuji Research Institute
Type: | Journal: Scientific reports | Year: 2016

Climate-induced forest die-off is widespread in multiple biomes, strongly affecting the species composition, function and primary production in forest ecosystems. Hydraulic failure and carbon starvation in xylem sapwood are major hypotheses to explain drought-induced tree mortality. Because it is difficult to obtain enough field observations on drought-induced mortality in adult trees, the current understanding of the physiological mechanisms for tree die-offs is still controversial. However, the simultaneous examination of water and carbon uses throughout dehydration and rehydration processes in adult trees will contribute to clarify the roles of hydraulic failure and carbon starvation in tree wilting. Here we show the processes of the percent loss of hydraulic conductivity (PLC) and the content of nonstructural carbohydrates (NSCs) of distal branches in woody plants with contrasting water use strategy. Starch was converted to soluble sugar during PLC progression under drought, and the hydraulic conductivity recovered following water supply. The conversion of NSCs is strongly associated with PLC variations during dehydration and rehydration processes, indicating that stored carbon contributes to tree survival under drought; further carbon starvation can advance hydraulic failure. We predict that even slow-progressing drought degrades forest ecosystems via carbon starvation, causing more frequent catastrophic forest die-offs than the present projection.


PubMed | Aichi Gakuin University, Mount Fuji Research Institute and Azabu University
Type: | Journal: Scientific reports | Year: 2016

Chronic cadmium (Cd) exposure can induce renal toxicity. In Cd renal toxicity, p53 is thought to be involved. Our previous studies showed that Cd down-regulated gene expression of the UBE2D (ubiquitin-conjugating enzyme E2D) family members. Here, we aimed to define the association between UBE2D family members and p53-dependent apoptosis in human proximal tubular cells (HK-2 cells) treated with Cd. Cd increased intracellular p53 protein levels and decreased UBE2D2 and UBE2D4 gene expression via inhibition of YY1 and FOXF1 transcription factor activities. Double knockdown of UBE2D2 and UBE2D4 caused an increase in p53 protein levels, and knockdown of p53 attenuated not only Cd-induced apoptosis, but also Cd-induced apoptosis-related gene expression (BAX and PUMA). Additionally, the mice exposed to Cd for 6 months resulted in increased levels of p53 and induction of apoptosis in proximal tubular cells. These findings suggest that down-regulation of UBE2D family genes followed by accumulation of p53 in proximal tubular cells is an important mechanism for Cd-induced renal toxicity.


Tsuji Y.,Kyoto University | Okumura T.,Wildlife Management Office | Kitahara M.,Mount Fuji Research Institute | Jiang Z.,Wildlife Management Office
Zoological Science | Year: 2016

To evaluate the seed shadow generated by wild Japanese martens (Martes melampus), we combined data on their ranging behavior from the northern foot of Mt. Fuji, central Japan (seven males and three females) with data on gut passage time obtained from martens in Toyama Municipal Family Park Zoo (three males and one female). The movement distances varied, and mean distances for 0-1, 2-3, and 4-5 h intervals were 152.4, 734.7, and 1,162.4 m, respectively, with no significant sex difference. The mean gut passage time of ingested seeds was 7.4 h (range: 0.6-51.7 h), and two-thirds were defecated within 12 h. Seeds of fleshy fruits was frequently transported to 501-1,000 m, and 20% of ingested seeds were transported > 1,000 m from feeding sites. We found positive correlations between body size and home range of the animals in Japan and their seed dispersal distances. We conclude that Japanese martens are medium-range dispersers that can transport seeds from the source to open habitats conducive for germination and/or growth, partly due to scent marking behaviors. © 2016 Zoological Society of Japan.


Mori T.,University of Tokyo | Hashimoto T.,Hokkaido University | Terada A.,Tokyo Institute of Technology | Yoshimoto M.,Mount Fuji Research Institute | And 3 more authors.
Earth, Planets and Space | Year: 2016

A phreatic eruption of Mt. Ontake, Japan, started abruptly on September 27, 2014, and caused the worst volcanic calamity in recent 70 years in Japan. We conducted volcanic plume surveys using an electric multirotor unmanned aerial vehicle to elucidate the conditions of Mt. Ontake's plume, which is flowing over 3000 m altitude. A plume gas composition, sulfur dioxide flux and thermal image measurements and a particle sampling were carried out using the unmanned aerial vehicle for three field campaigns on November 20 and 21, 2014, and June 2, 2015. Together with the results of manned helicopter and aircraft observations, we revealed that the plume of Mt. Ontake was not directly emitted from the magma but was influenced by hydrothermal system, and observed SO2/H2S molar ratios were decreasing after the eruption. High SO2 flux of >2000 t/d observed at least until 20 h after the onset of the eruption implies significant input of magmatic gas and the flux quickly decreased to about 130 t/d in 2 months. In contrast, H2S fluxes retrieved using SO2/H2S ratio and SO2 flux showed significantly high level of 700-800 t/d, which continued at least between 2 weeks and 2 months after the eruption. This is a peculiar feature of the 2014 Mt. Ontake eruption. Considering the trends of the flux changes of SO2 and H2S, we presume that majority of SO2 and H2S are supplied, respectively, from high-temperature magmatic fluid of a deep origin and from hydrothermal system. From the point of view of SO2/H2S ratios and fumarolic temperatures, the plume degassing trend after the 2014 eruption is following the similar course as that after the 1979 eruptions, and we speculate the 2014 eruptive activity will cease slowly similar to the 1979 eruption. © 2016 Mori et al.


Tyagi P.,Hokkaido University | Yamamoto S.,Hokkaido University | Yamamoto S.,Mount Fuji Research Institute | Kawamura K.,Hokkaido University
Biogeosciences | Year: 2015

Hydroxy fatty acids (FAs) in fresh snow from Sapporo, one of the heaviest snowfall regions in the world, have been studied to ascertain the airborne bacterial endotoxin concentrations and their biomass. The presence of β-hydroxy FAs (C9-C28), constituents of the Gram-negative bacterium (GNB), suggests long-range transport of soil microbes. Likewise, the occurrence of α-and β-hydroxy FAs (C9-C30 and C9-C28, respectively) in snow reveals their contribution from epicuticular waxes and soil microorganisms. Estimated endotoxin and GNB mass can aid in assessing their possible impacts on the diversity and functioning of aquatic and terrestrial ecosystems, as well as lethal effects on pedestrians through dispersal of microbes. Air mass back trajectories together with hydroxy FAs reveal their sources from Siberia, the Russian Far East and northern China by the Asian monsoon. This study highlights the role of fresh snow that reduces the human health risk of GNB and endotoxin by the scavenging from air. © Author(s) 2015.


Sakata T.,Kitasato University | Nakano T.,Mount Fuji Research Institute | Kachi N.,Tokyo Metroplitan University
Ecological Research | Year: 2014

To investigate mechanisms of adjustment of the optimum temperature for leaf photosynthesis in alpine plants, we compared the temperature responses of photosynthesis, internal conductance (gi), and the amounts of activated Rubisco (ε) in two Fallopia japonica populations growing at elevations of 100 m (K0100), and 2250 m (F2250). There was an obvious difference in photosynthesis at high temperatures between the two populations, although there was no significant difference in the CO2/O2 specificity of Rubisco. Optimum temperatures for photosynthesis were 25 and 30 °C in F2250 and K0100, respectively. The temperature response of ε was similar to that of photosynthesis. The mean values of ε decreased 25 % (F2250) and 24 % (K0100), for temperatures 5 °C above the optimum for photosynthesis. In contrast, gi exponentially increased with increasing temperature in both populations. There was no significant difference in gi between populations for any given temperature. In both populations, there were no changes in CO2 concentrations at the Rubisco active site, when temperatures were above the photosynthetic optimum temperature. This clearly shows that photosynthetic optimum temperatures were not affected by photosynthetic limitation of CO2 diffusing from intercellular air spaces to Rubisco. Furthermore, the atmospheric pressure had a minor effect on the temperature response of photosynthesis. Thus, the decrease in ε in response to elevated temperatures reduced the photosynthetic optimum temperature in highland population of F. japonica, which was adjusted to the habitat. © 2014, The Ecological Society of Japan.

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