Time filter

Source Type

Kita J.,Japan Research Institute of Innovative Technology for the Earth | Stahl H.,Scottish Association for Marine Science | Hayashi M.,The General Environmental Technos Co. | Green T.,Scottish Association for Marine Science | And 2 more authors.
International Journal of Greenhouse Gas Control | Year: 2015

In 2012, a controlled sub-seabed release of carbon dioxide (CO2) was conducted in Ardmucknish Bay, a shallow (12m) coastal bay on the west coast of Scotland. During the experiment, CO2 gas was released 12m below the seabed for 37 days, causing significant disruption to sediment and water carbonate chemistry as the gas passed up through the sediment and into the overlying water. One of the aims of the study was to investigate how the impacts caused by leakage from geological CO2 Capture and Storage (CCS) could be detected and quantified in the context of natural heterogeneity and dynamics. To do this underwater photography was used to analyze (i) the benthic megafaunal response to the CO2 release and (ii) the dynamics of the CO2 bubble streams, emerging from the seabed into the overlying water column. The frequently observed megafauna species in the study area were Virgularia mirabilis (Cnidaria), Turritella communis (Mollusca), Asterias rubens (Echinodermata), Pagurus bernhardus (Crustacea), Liocarcinus depurator (Crustacea), and Gadus morhua (Osteichthyes). No discernable abnormal behavior was observed for these megafauna, in any of the zones investigated, during or after the CO2 release. Time-lapse photography revealed that the intensity and presence of the CO2 bubble plume was affected by the tides, with the most active bubbling seen at low tides and the larger hydrostatic pressure at high tide suppressing CO2 bubbling from the seabed. © 2014 Elsevier Ltd.

Tanaka S.,Kansai Electric Power Co. | Ikeda K.,The General Environmental Technos Co. | Ikeda K.,Okayama Institute of Science and Technology | Miyasaka H.,Kansai Electric Power Co. | And 7 more authors.
Journal of Bioscience and Bioengineering | Year: 2011

Methyl viologen (MV) causes severe oxidative stress by generating superoxide in the photosystem. The marine Chlamydomonas strain W80 is highly tolerant to MV (inhibitory concentration 50% [IC 50]=110μM), and another marine Chlamydomonas strain HS5 shows also relatively a high tolerance (IC 50=12μM). These two marine strains and a freshwater Chlamydomonas reinhardtii, which is highly sensitive to MV (IC 50=0.03μM), were compared with respect to their reactive oxygen species (ROS) eliminating enzymes (superoxide dismutase, catalase, glutathione peroxidase, and ascorbate peroxidase), intracellular free amino acids, and antioxidant activities of the cell extracts. The marked difference between the marine Chlamydomonas strains and C. reinhardtii is the much higher (more than 5 fold) ascorbate peroxidase (APX) activity in the marine strains. The marine strains also kept the high APX activities (more than 100% of non-stressed condition) under the MV stressed condition, while the APX activity in C. reinhardtii was significantly decreased (36% of non-stressed condition) under the stressed condition, indicating that APX activity potentially contributes to the oxidative stress tolerance in Chlamydomonas. In addition, the levels of intracellular free proline, which is supposed to ameliorate oxidative stress, were several tens of times higher in the marine Chlamydomonas strains than in C. reinhardtii. © 2011 The Society for Biotechnology, Japan.

Aoyama M.,Meteorological Research Institute | Ota H.,The General Environmental Technos Co. | Kimura M.,The General Environmental Technos Co. | Kitao T.,The General Environmental Technos Co. | And 3 more authors.
Analytical Sciences | Year: 2012

The development of Reference Materials for Nutrients in Seawater (RMNS) has been in progress since 1993. When RMNS were produced for nitrate, silicate, and phosphate, their initial homogeneities were as low as 0.1 to 0.2% in samples of high-nutrient seawater, such as deep water from the Pacific Ocean. The relative standard uncertainties associated with instability during long-term (4.8 years) storage were approximately 0.2, 0.2, and 0.4% for nitrate, silicate, and phosphate, respectively. No instability was observed for 1.9 to 6.4 years based on the ISO Guide 35:2006 criteria; however, the relative standard uncertainties associated with instability during long-term storage were larger than the initial homogeneities of RMNS. RMNS produced by state-of-the-art techniques are currently available for global use to improve the comparability of nutrients data in the open ocean and, as discussed here, are reliable candidates to be used for certified reference materials. © 2012 The Japan Society for Analytical Chemistry.

Tanikawa T.,Japan Forestry and Forest Products Research Institute | Hirano Y.,Nagoya University | Dannoura M.,Kyoto University | Yamase K.,Hyogo Prefectural Technology Center for Agriculture | And 5 more authors.
Plant and Soil | Year: 2013

Aim: Ground-penetrating radar (GPR) has been applied to detect coarse tree roots. The horizontal angle of a root crossing a scanning line is a factor that affects both root detection and waveform parameter values. The purpose of this study was to quantitatively evaluate the influence of root orientation (x, degree) on two major waveform parameters, amplitude area (A, dB × ns) and time interval between zero crossings (T, ns). Methods: We scanned four diameter classes of dowels in a sandy bed as simulated roots using a 900 MHz antenna from multiple angles to clarify the relationships between the parameters and x. Results: Angle x strongly affected reflection images and A values. The variation in A(x) fitted a sinusoidal waveform, whereas T was independent of x. The value of A scanning at 90° was estimated by A values of arbitrary x in two orthogonal transects. The sum of T in all reflected waveforms showed a significant linear correlation with dowel diameter. Conclusions: We clarified that root orientation dramatically affected root detection and A values. The sum of T of all reflected waveforms was a suitable parameter for estimating root diameter. Applying grid transects can overcome the effects of root orientation. © 2013 Springer Science+Business Media Dordrecht.

Yamamoto M.,Hokkaido University | Shimamoto A.,The General Environmental Technos Co. | Fukuhara T.,The General Environmental Technos Co. | Tanaka Y.,Japan National Institute of Advanced Industrial Science and Technology | Ishizaka J.,Nagoya University
Organic Geochemistry | Year: 2012

Seasonal and depth variation in the flux of glycerol dialkyl glycerol tetraethers (GDGTs) and TEX86 (TEX86H and TEX86L) values in sinking particles was examined by conducting a 21month time-series sediment trap experiment at a mooring station (WCT-2, 39°N, 147°E) in the mid-latitude NW Pacific. The aim was to understand the sinking process of GDGTs in the water column and the preservation of the TEX86 signal in the water column and sediment surface. In the shallow trap, the sinking flux of GDGTs showed maxima from May 1998 to February 1999. The maximal peaks in sinking flux corresponded to peaks in the sinking flux of organic carbon, opal and lithogenic material. GDGT concentration in the total fine fraction and the caldarchaeol/crenarchaeol ratio at three depths (ca. 1300-4800m) varied synchronously, implying rapid vertical transport of GDGTs to deeper water with a sinking velocity >260mday-1 below ca. 1300m. The changes in TEX86-based temperature were different from those in contemporary sea surface temperature (SST). The former was lower than the SST from May to December and corresponded to the temperature at the thermocline, whereas it was higher than the SST from December to May. The annual average sinking flux of the GDGTs decreased with depth. The GDGT half-depth, the depth range over which half of the GDGT is lost, was calculated to be 3108-3349m, implying that GDGTs were well preserved during sinking. The flux-weighted average TEX86-based temperature was constant with depth and corresponded roughly to mean annual SST. The findings support a previous hypothesis that the GDGTs produced in surface water are preferentially delivered to the deeper water column via grazing and repackaging in larger particles. The constant TEX86 at different depths indicates that it was not affected by degradation in the water column. The preservation efficiency of GDGTs was 1.0-1.3% at the water-sediment interface. Despite significant GDGT degradation, there was a small difference in TEX86 values between sinking particles and surface sediment. © 2012 Elsevier Ltd.

Shigemitsu M.,Hokkaido University | Yamanaka Y.,Hokkaido University | Yamanaka Y.,Japan Science and Technology Agency | Watanabe Y.W.,Hokkaido University | And 2 more authors.
Earth and Planetary Science Letters | Year: 2010

We used moored time-series sediment traps to collect settling particles at station KNOT (44°N, 155°E; trap depth 770m) in the western subarctic Pacific (WSAP) from October 1999 to May 2006. Particulate nitrogen content (PN) and isotope ratios (δ15NPN) were measured in the samples collected. The general pattern of variation in δ15NPN results showed lower values during the spring bloom periods and summer, and higher values during winter. To interpret the processes controlling such variations quantitatively and reveal some implications for paleoceanographic use of δ15NPN, we developed an ecosystem model that included nitrogen isotopes. This model was validated with an observed data set and successfully reproduced the seasonal variations of δ15NPN. In simulations, the lower δ15NPN during the spring bloom period was caused mainly by the highest proportion of dead large phytoplankton (diatom) in PN within a year, the highest f-ratio of the year, and phytoplankton assimilation of nitrate with the lowest δ15N of the year. The lower δ15NPN in summer was due to the high relative proportion of dead non-diatom small phytoplankton and microzooplankton fecal pellet with the lowest δ15N values among all the PN components in our model. The higher δ15NPN in winter was mainly caused by the highest proportion of zooplankton components in PN, with higher δ15N values than phytoplankton components, and the enhanced δ15N values of ammonium induced by nitrification and its subsequent assimilation by phytoplankton. Our identification of nitrification as one cause of higher δ15NPN in winter is consistent with previous findings in a proximal marginal sea, the Okhotsk Sea, with an ecosystem model simpler than our model. This might indicate that the cause of higher δ15NPN in winter is common in the WSAP. In our model, we optimized the isotope effect of each process using our observational data of δ15NPN and δ15N of nitrate published elsewhere as constraints, and investigated the sensitivity of the annual flux-weighted mean of δ15NPN to the isotopic fractionation effects. As a result, we found that the isotope effects of nitrate assimilation appear to be different for non-diatom small phytoplankton and large diatom, and the annual flux-weighted mean of δ15NPN can be influenced to some extent by the isotope effect of nitrification. © 2010 Elsevier B.V.

Tanikawa T.,Japan Forestry and Forest Products Research Institute | Ikeno H.,University of Hyogo | Dannoura M.,Kyoto University | Yamase K.,Hyogo Prefectural Technology Center for Agriculture | And 2 more authors.
Plant and Soil | Year: 2016

Aim: Ground penetrating radar (GPR), a nondestructive tool that can detect coarse tree roots, has not yet become a mature technology for use in forests. In this study, we asked two questions concerning this technology: (i) Does the leaf litter layer influence root detection and major indices based on the time interval between zero crossings (T) and the amplitude area (A)? (ii) Can GPR images discriminate roots of different plant species? Methods: Roots buried in a sandy bed, which was covered with different thicknesses of leaf litter, were scanned using a 900 MHz GPR antenna. Roots of four plant species in the bed were also scanned. Results: Leaf litter decreased root reflections without distorting the shape of the hyperbolas in the radar profile. A values decreased with increasing litter thickness, whereas T was independent of litter thickness. For all species combined, GPR indices were significantly correlated with root diameter. Conclusions: Leaf litter dramatically decreased root detection, but the influence of the litter could be ignored when the sum of T for all reflection waveforms (ΣT) is adopted to estimate root diameter. To use A values to detect roots, litter should be removed or equalized in thickness. Radar profiles could not reliably differentiate among roots belonging to plants of different species. © 2016 Springer International Publishing Switzerland

Hirano Y.,Nagoya University | Hirano Y.,Japan Forestry and Forest Products Research Institute | Yamamoto R.,Kobe University | Dannoura M.,Kobe University | And 8 more authors.
Plant and Soil | Year: 2012

Aims: Tree roots in forest soils can be detected using nondestructive ground-penetrating radar (GPR). However, few studies have investigated root detection frequency; i. e., how many and which roots are identified in a radar profile out of the total quantity of roots present in a forest stand. The objective of this study was to quantify root detection frequency and uncertainty, including relationships between root detection and radar parameters using 1.5 GHz GPR in a Pinus thunbergii forest on sandy soils. Methods: We compared the vertical distribution of 829 excavated roots with distributions identified visually in radar profiles using GPR on 17 transects. Results: The detection frequency for number of roots less than 1.0 cm in diameter was only 6.6 %, but 54 % of roots that were larger than 1.0 cm were detected. Roots larger than 2.0 cm were identified with less frequency by GPR at deeper depths (20-30 cm) than were shallower roots. Conclusion: Our study indicates that GPR methods estimate root biomass to be 68 % of the excavated root biomass and that the detection frequency for number of roots in radar profiles using GPR is related to root biomass, although there is uncertainty in the attenuation of radar waves with depth, soil water condition and root orientation. © 2012 Springer Science+Business Media B.V.

Yamamoto M.,Hokkaido University | Shimamoto A.,The General Environmental Technos Co. | Fukuhara T.,The General Environmental Technos Co. | Tanaka Y.,Japan National Institute of Advanced Industrial Science and Technology
Geochimica et Cosmochimica Acta | Year: 2016

Branched glycerol dialkyl glycerol tetraethers (branched GDGTs) are commonly found in distal marine sediments. However, their presence in the water column, source and delivery process are not fully understood. In this study, we examined seasonal and depth variation in the flux of branched GDGTs in sinking particles and underlying sediment at 39°N, 147°E in the mid-latitude NW Pacific from November 1997 to August 1999. Branched GDGTs showed synchronous variation in their sinking flux at different depths, and the variation was similar to that of lithogenic material of eolian dust origin. Their degrees of cyclization and methylation were nearly constant and bear some resemblance to those of alkaline soils. This suggests that westerly winds transport branched GDGTs to the study site via the atmosphere from continental Asia. The sinking flux of branched GDGTs was higher in 1999 than in 1998, presumably reflecting changes in the migration path of Asian dust in response to the El Niño-Southern Oscillation. Synchronous variation in branched GDGT concentrations at different depths implies rapid vertical transport of branched GDGTs to deep water with a sinking velocity exceeding 260 m d−1. The sinking flux of the branched GDGTs decreased with increasing depth, but the rate of decrease was much smaller than those of other compounds. The preservation efficiency of branched GDGTs was 3.5–6.4% of surface inputs at the water–sediment interface, which is much higher than those of isoprenoid GDGTs (1.0–1.3%) and other compounds. The branched and isoprenoid tetraether (BIT) index values were extremely low (i.e. <0.0015) in comparison with any other studies so far. The BIT values in the surface sediment were five times higher than those in sinking particles, which is attributed to the preferential preservation of branched GDGTs in oxic environments. © 2016 Elsevier Ltd

Tamunaidu P.,Kyoto University | Matsui N.,The General Environmental Technos Co. | Okimori Y.,The General Environmental Technos Co. | Saka S.,Kyoto University
Biomass and Bioenergy | Year: 2013

The current study was initiated to evaluate the potential of sugar saps from nipa (Nypa fruticans) palm as sustainable feedstock for ethanol production. Nipa palms managed as plantations on four sites was chosen for this study with palms within 8-100 years of age. All palms studied were found to have the potential to produce sugar saps from 0.4 to 1.2Ld-1 per palm. Further chemical characterization of its saps gave a total composition of 159-214gkg-1 mainly composed of sucrose, glucose and fructose. In addition, the elemental analysis gave 5gkg-1 of inorganics with Na, K and Cl being its main inorganic elements. Preliminary batch fermentative assays using Saccharomyces cerevisiae showed that nipa saps can be converted to ethanol within 30-48h in conditions with and without nutrient supplementation. Furthermore, the fermentation trends were similar to sugarcane sap with high ethanol conversions up to 96.9% and 95.5% achieved for both nutrient conditions. Further analysis on inorganic elements before and after fermentation showed that specific elements of Mg, Ca, P and S were significantly reduced and could have assisted the fermentation. Based on the results obtained from sap collection, chemical characterization and fermentation, the ethanol potential from nipa planted at a density of 1000ha-1 would range from 4550-9100Lha-1y-1. Conclusively, nipa sap showed some interesting characteristics which makes it a potential feedstock for ethanol production. © 2013 Elsevier Ltd.

Loading The General Environmental Technos Co. collaborators
Loading The General Environmental Technos Co. collaborators