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Volume 46 (2010)
- Issue 4 Pages 161-
- Issue 3 Pages 119-
- Issue 2 Pages 71-
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Volume 46, Issue 1
Displaying 1-6 of 6 articles from this issue
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ORIGINALS
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RABIN MALLA, NOBUYUKI NAGAO, KOSUKE MAEZONO, YASUHIRO TANAKA, KAZUHIRO ...Article type: ORIGINALS
2010 Volume 46 Issue 1 Pages 1-15
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSA simple mathematical biomass model was formulated based on the logistic growth equation. In the model, the growth rate parameter ‘rt’ was related to the daily environmental factors like temperature, light and nutrient. The environmental factors were represented in the model with their respective functional equations. The other parameter, maximum biomass density ‘Bmax’ was considered constant on long term. The test plants used for simulation were two floating macrophytes Eichhornia crassipes (Mart.) Solms and Spirodela polyrhiza; and two emergent macrophytes Lythrum anceps (Koehne) Makino and Phragmites japonicus. When applied, the model simulated cumulative biomass results matched fairly well with the observed cumulative biomass ranging from apparently no discrepancies to 8% discrepancies in 2006 and 2007. However, only one model simulated cumulative biomass result of E. crassipes in 2005 saw a discrepancy of 20% against the observed biomass. The Bmax parameter value of L. anceps and P. japonicus measured intermittently during 4 to 5 years of their establishment in the pond varied by several fold with the possibility of stabilization of their value measured in 2009. As an illustration, the model was used to simulate biomass at different biomass densities limits keeping lower limits to 50% of Bmax. The simulation results were in consistent with the notion of maximum sustainable yield (MSY). Similarly, the model was used to simulate cumulative biomass production by macrophytes under different climatic and water environment conditions. In general, the model is simple and flexible; parameters are easy to measure and could be obtained from public domains. However, in the present level of this study the estimated parameters of mortality and measured parameter Bmax needs revision until their values are stabilized.View full abstractDownload PDF (1098K) -
MASAFUMI TATEDA, YASUHARU KUGUE, YOUNGCHUL KIM, YUKIO SATOArticle type: ORIGINALS
2010 Volume 46 Issue 1 Pages 17-24
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSCompost tea is an attractive method to control diseases on many occasions. Because the main mechanism by which compost tea suppresses a disease is biological, the fermentation temperature of making compost tea is a very important factor for obtaining better efficacy of disease suppression. In this study, the influence of compost tea fermentation temperature on the efficacy of suppression against cucumber powdery mildew was investigated. Our results clearly indicate that compost teas were greatly influenced by fermentation temperature, and its efficacy was found to be greatest at 30－40 ℃. A different suppression mechanism might exist at 10 ℃ fermentation temperature. The 2 species of fungi isolated from compost teas were Mortierella sp. and Mucor sp., and disease suppression mechanisms might be different in these 2 species. Further study is needed to understand the mechanisms of disease suppression by compost teas.View full abstractDownload PDF (715K) -
SATOSHI FUKUSHIMAArticle type: ORIGINALS
2010 Volume 46 Issue 1 Pages 25-34
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSSurveys were conducted to clarify the long-term changes of environmental conditions and aquatic organisms in 1996 and 2008 in an urban stream. Water quality in 1996 had recovered compared to past conditions, with BOD concentration about 5 mg/l. By 2008, water quality had recovered further, with BOD not more than 2 mg/l. The number of fish species had increased from 2–13 in 1996 to 7–14 by 2008. Macroinvertebrate species had increased more than 2.5-fold: more than 40 species were identified. Periphytic diatom species also more than doubled: 52–58 species were identified. Results show the relationship between the recovery of water quality and numerical changes in the assemblages of fish, macroinvertebrates and periphytic diatoms. Additionally, results suggest that stream morphology, bed materials, and crossing structures affected the changes in fish. Changes in macroinvertebrates occurred according to bed materials and water temperature.View full abstractDownload PDF (1303K) -
ZHONGFANG LEI, YINGEN HUANG, KAZUYA SHIMIZU, ZHENYA ZHANGArticle type: ORIGINALS
2010 Volume 46 Issue 1 Pages 35-45
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSDicyandiamide (DCD) is widely used as nitrification inhibitor in soil. In order to examine the influence of DCD application on pollutant removals through soil infiltration treatment (SIT), three soil columns with different constituents were run under hydraulic loading rate of 0.01–0.02 m3/m2/d in parallel in laboratory. The results indicated that effective removals of COD (90.68–92.11%), TP (>99%), and NH3–N (98.96–99.72%) maintained during 1.5 mg/l of DCD application. The performance of TN removal differed among columns: little detrimental effects observed on two columns (B and C) with TN removal being 86.87–93.10%, while detrimental to one column (A) with only 26.19% of TN removal achieved. Enzyme activity assay showed that DCD application inhibited the expression of urease activity at all depths of soil in the three columns, and the inhibition effect of DCD on activities of nitrate reductase (NAR) and nitrite reductase (NIR) differed among the three columns. An unbalanced nitrification/denitrification process occurred in the column (A) with deteriorated TN removal, resulting from DCD inhibition on both NAR and NIR activities at all soil depths. The relationship was also disclosed between the activity of urease, NIR, NAR, or catalase and influencing factors including influent COD/TN, soil C/N, and TN removal.View full abstractDownload PDF (1322K) -
GANG CHEN, YULIN ZHOU, JIE MING LI, MOTOO UTSUMIArticle type: ORIGINALS
2010 Volume 46 Issue 1 Pages 47-57
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSWe described a SYBR green-based quantitative PCR (qPCR) as an approach to estimate the relative abundances of Eubacteria and Archaea in methane fermentation process with soybean curd residue as substrates. Eubacterial and Archaeal primers were selected according the specificity and performance in qPCR firstly, then, optimization of three parameters (forward and reverse primer concentration, annealing temperature) was attempted using a Box–Behnken design under the response surface methodology (RMS) for enhancing the accuracy and sensitivity of qPCR. Quantitative PCR with the optimal conditions was applied for monitoring of microbial population dynamics during methane fermentation process.View full abstractDownload PDF (4114K) -
TOMOKO YAMAMOTO, PING GUI, TOSHIFUMI OSAKA, YOSHITAKA EBIE, KAIQIN XU, ...Article type: ORIGINALS
2010 Volume 46 Issue 1 Pages 59-69
Published: 2010
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSThe vegetation of macrophytes is known to be an important factor in order to succeed in wastewater treatment with constructed wetlands (CWs). The aim of present study is to select the effective macrophyte species for wastewater treatment performance. The removal efficiencies of BOD, CODMn, nitrogen and phosphorus were evaluated among ten different macrophyte species in laboratory-scale subsurface flow CWs under the same experimental conditions (e.g. loading rate, climate and flow pattern). In all experimental systems excluding the Hibiscus canabinus-planted CW, high and stable performance on BOD and CODMn removal was maintained during the experimental periods. However, there are differences in nutrient removal among macrophyte species. Especially, CWs planted with Canna generalis and Zizania latifolia were highly effective for wastewater treatment in these CWs. On the other hands, CWs planted with Typha latifolia and Phragmites australis which were commonly used in CWs showed an average purification performance.View full abstractDownload PDF (964K)
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