Methane and CO2 fluxes from an Indonesian peatland used for sago palm (Metroxylon sagu Rottb.) cultivation: Effects of fertilizer and groundwater level management

Tropical peatland is a vast potential land source for biological production, but peatland is a major natural source of greenhouse gases, especially methane (CH₄). It is important to evaluate the changes in greenhouse gas emissions induced by cultivation practices for sustainable agricultural use of tropical peatland. We investigated the effects of fertilizer application and the groundwater level on CH₄ and carbon dioxide (CO₂) fluxes in an Indonesian peat soil. The crop cultivated was sago palm (Metroxylon sagu Rottb.), which can grow on tropical peat soil without drainage and yield great amounts of starch. CH₄ emission through sago palm plants was first estimated by collecting gas samples immediately after cutting sago suckers using the closed chamber method. The CH₄ fluxes ranged from negative values to 1.0 mg C m⁻² h⁻¹. The mean CH₄ flux from treatment with macroelements (N, P, and K) and microelements (B, Cu, Fe, and Zn) applied at normal rates did not differ significantly from that of the No fertilizer treatment, although increasing the application rates of macroelements or microelements by 10-fold increased the CH₄ flux by a factor of two or three. The relationship between CH₄ flux and the groundwater table was regressed to a logarithmic equation, which indicated that to maintain a small CH₄ flux, the groundwater table should be maintained at <−45 cm. The CO₂ fluxes ranged between 24 and 150 mg C m⁻² h⁻¹, and were not significantly affected by either fertilizer treatments or the groundwater level. The inclusion of sago palm suckers in a chamber increased CH₄ emission from the peat soil significantly. Thus, gas emissions mediated by certain kinds of palm plants should not be disregarded.     

Maternal provisioning of sequestered defensive steroids by the Asian snake <Emphasis Type="Italic">Rhabdophis tigrinus</Emphasis>

Summary.   Rhabdophis tigrinus obtains defensive steroids (bufadienolides) from its diet and sequesters those compounds in specialized structures on its neck known as nuchal glands. Hatchling snakes lacking these steroids must acquire them from toads consumed as prey. Here we show that females provision bufadienolides to their offspring in amounts correlated to the quantity in their own nuchal glands; thus, chemically protected mothers produce defended offspring. Bufadienolides can be provisioned to embryos via deposition in yolk and by transfer across the egg membranes within the oviducts. Maternally provisioned bufadienolides persist in the nuchal glands of juvenile snakes from the time of hatching in late summer until the following spring, when toads of ingestible size become abundant. Therefore, maternal provisioning may provide chemical protection from predators for young R. tigrinus in the absence of dietary sources of bufadienolides.     

Detecting crucial dispersal pathways using a virtual ecology approach: A case study of the mirid bug <Emphasis Type="Italic">Stenotus rubrovittatus</Emphasis>

Detecting dispersal pathways is important both for understanding species range expansion and for managing nuisance species. However, direct detection is difficult. Here, we propose detecting these crucial pathways using a virtual ecology approach, simulating species dynamics using models, and virtual observations. As a case study, we developed a dispersal model based on cellular automata for the pest insect Stenotus rubrovittatus and simulated its expansion. We tested models for species expansion based on four landscape parameters as candidate pathways; these are river density, road density, area of paddy fields, and area of abandoned farmland, and validated their accuracy. We found that both road density and abandoned area models had prediction accuracy. The simulation requires simple data only to have predictive power, allowing for fast modeling and swift establishment of management plans.     

Effect of grinding and heating on Ni2+ uptake properties of waste paper sludge

Uptake properties of Ni2+ were examined for unmilled and milled paper sludge calcined at various temperatures to develop a new usage of waste paper sludge. Since paper sludge mainly consists of cellulose ([C6H(10)O5]n) fibers, calcite (CaCO3), kaolinite (Al2Si2O5(OH)4) and talc (Mg3Si(4)O(10)(OH)2), amorphous and crystalline CaO(MgO)-Al(2)O(3)-SiO(2) compounds are formed by calcining paper sludge. Wet and dry milling treatments were performed to accelerate solid-state reaction to form the above mentioned target compounds. The crystalline phases originally present decompose at increasing calcining temperature (up to 800 degrees C) in the order cellulose 相似文献   

Composting of food refuse from a student restaurant in Hokkaido University

Over a period of 21 months, we composted food refuse from a student restaurant in Hokkaido University using a commercially available composting machine. The machine had two reactors, each with a working volume of 250 l. The refuse was mixed with sawdust in a ratio of 5 l sawdust to 10 kg refuse, and this mixture was fed into the machine daily. We studied the characteristics of the refuse, the composting mixture, and the finished compost in an effort to optimize the operating parameters. We also evaluated the effectiveness of the composting process by determining the decomposition rates of the composting materials. The optimum moisture content of the composting mixture was between 30% wet basis (wb) and 40% wb in this machine. The composting machine worked well when the first reactor was filled with composting mixture and 0.5 kg lime was added once per week. The mass of the materials supplied was reduced by 84% over the study period. The decomposition rate of the volatile matter in all composting materials was 66%. The mass of the food refuse supplied was 14.8 kg/day on average, and the moisture content of the refuse was 77% wb on average. Received: October 4, 1999 / Accepted: April 4, 2000     

Toxicity and metabolism of copper pyrithione and its degradation product, 2,2'-dipyridyldisulfide in a marine polychaete

We conducted acute toxicity tests and sediment toxicity tests for copper pyrithione (CuPT) and a metal pyrithione degradation product, 2,2′-dipyridyldisulfide [(PS)₂], using a marine polychaete Perinereis nuntia. The acute toxicity tests yielded 14-d LC₅₀ concentrations for CuPT and (PS)₂ of 0.06 mg L⁻¹ and 7.9 mg L⁻¹, respectively. Sediment toxicity tests resulted in 14-d LC₅₀ concentrations for CuPT and (PS)₂ of 1.1 mg kg⁻¹ dry wt. and 14 mg kg⁻¹ dry wt., respectively. In addition to mortality, sediment avoidance behavior and decreases in animal growth rate were observed; growth rate was the most susceptible endpoint in the sediment toxicity tests of both toxicants. Thus, we propose lowest observed effect concentrations of 0.3 mg kg⁻¹ dry wt. and 0.2 mg kg⁻¹ dry wt. for CuPT and (PS)₂, respectively, and no observed effect concentrations of 0.1 mg kg⁻¹ dry wt. for both CuPT and (PS)₂. The difference in the toxicity values between CuPT and (PS)₂ observed in the acute toxicity test was greater than the difference in these values in the sediment toxicity test, and we attribute this to (PS)₂ being more hydrophilic than CuPT. In addition to the toxicity tests, we analyzed conjugation activity of several polychaete enzymes to the toxicants and marked activity of palmitoyl coenzyme-A:biocides acyltransferase and UDP-glucuronosyl transferase was observed.     

Deposition velocity of PM2.5 sulfate in the summer above a deciduous forest in central Japan

In order to increase knowledge of aerosol dry deposition for the regional assessment of acid deposition and transboundary air pollution in East Asia, an experimental study on PM2.5 sulfate deposition was implemented in the early summer of 2009. The experimental field was located in a deciduous forest at the foot of Mt. Asama, central Japan. Aerosol fluxes were obtained using the aerodynamic gradient method. Three aerosol samplers were placed on an experimental tower at 21, 24 and 27 m above the ground surface, and collected PM2.5 on filters for chemical analysis. Vertical concentration differences between 21 m and 27 m of PM2.5 sulfate were detected significantly when the concentration exceeded 1 μg m^?3. Mean deposition velocity was estimated to be 0.9 ± 1.0 cm s^?1 in the daytime and 0.3 ± 0.3 cm s^?1 in the nighttime. In the case that a height-dependent correction in the roughness sub-layer was taken into account, the deposition velocities increased more, especially in daytime. Higher deposition velocities in the daytime were associated with larger friction velocities and unstable conditions. The deposition velocities observed in this study were in agreement with other experimental results found in the literature. On the other hand, they were higher than those calculated by theoretical models. Two empirical parameterizations (Wesely, M.L., Cook, D.R., Hart, R.L., 1985. Measurement and parameterization of particulate sulfur dry deposition over grass. Journal of Geophysical Research 90, 2131–2143; Ruijgrok, W., Tieben, H., Eisinga, P., 1997. The dry deposition of particles to a forest canopy: a comparison of model and experimental results. Atmospheric Environment 31, 399–415) were validated by the observations. The general trend of higher daytime and lower nighttime deposition velocities was similar among the observation and the two parameterizations. The large variability found in the measurement was not reproduced by the parameterizations, because it is attributable to random error from the differences between the samplers. The observations were in accordance with the parameterization of Ruijgrok et al. (1997) for a forest, although much larger than that of Wesely et al. (1985) for grasslands. This indicates the large difference in aerosol deposition velocities between forests and grasslands.     

Blooming of Microcystis aeruginosa in the reservoir of the reclaimed land and discharge of microcystins to Isahaya Bay (Japan)

Purpose

In the reservoir created in the reclaimed land in Isahaya Bay, Japan, Microcystis aeruginosa, which produces microcystins (MCs), bloomed every year, and the water with high levels of MCs in the reservoir has been often drained to Isahaya Bay to adjust the water level. The principal aims of this study are to clarify the water conditions suitable for blooming of M. aeruginosa in the reservoir, to follow the amount of distribution of MCs inside and outside the reservoir, and to discuss how blooming of M. aeruginosa is controlled in the reservoir and how MCs produced by Microcystis spread or accumulate in the aquatic environment.

Method

We monitored the water quality (temperature, salinity, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus) in the reservoir with seasonal blooming of microalgae including phytoplankton and M. aeruginosa using the concentrations of chlorophyll ?? and MCs, respectively, and collected the surface sediment in the reservoir and the bay to determine the MC content using the ELISA method.

Result

M. aeruginosa bloomed in extremely low DIN conditions of the water in warm seasons (spring and late summer to autumn). The year-mean standing stock of MCs was approximately 34.5?kg in the water and 8.4?kg in the surface sediment in the reservoir. Approximately 64.5?kg of MCs was discharged with the effluent to the bay in a year.

Conclusion

Since a large amount of MCs always suspends in the water in the reservoir and it has been discharged to the bay, suspension-feeding animals are exposed most seriously to the high levels of MCs occurring in these areas. We need to pay attention to the danger of widespread dispersal of MCs and biological concentration of MCs by fish and clam inside and outside the reservoir.     

Transformation of microflora during degradation of gaseous toluene in a biofilter detected using PCR-DGGE

A laboratory-scale biofiltration system, the rotatory-switching biofilter (RSB), was operated for 199 days using toluene as a model pollutant. The target gaseous pollutant for the biofiltration experiment was approximately 300 ppmv of toluene. Toluene removal efficiency (RE, %) was initially approximately 20% with a 247-ppmv concentration (0.9 g m(-3)) of toluene during the first 10 days. Although the RE decreased several times whenever nitrogen was consumed, it again reached almost 100% when the nitrogen source was in sufficient supply. Denaturing gradient gel electrophoresis (DGGE) analysis was employed to assess the transformation ofmicroflora during operation of the biofilter The results based on a 16S rRNA gene profile showed that the microbial community structure changed with operation time. Although the microflora changed during the initial period (before day 40), transformation of the bacterial component was hardly observed after day 51. Statistical analyses of the DGGE profiles indicated that the bacterial community was almost unaffected by the environmental factors, such as adding ozone, high-level nitrogen supply, increase of loading toluene, and the shutdown of the RSB. The DGGE profile using tmoA-like genes, which encode proteins belonging to the hydroxylase component mono-oxygenases involved in the initial attack of aerobic benzene, toluene, ethylbenzene, and xylene degradation, confirmed the existence of toluene-degrading bacteria. There were at least four kinds of toluene-degradable bacteria having tmoA-like genes up to day 36, which decreased to two species after day 40. Sequence analysis after DGGE profiling revealed that Burkholderia cepacia, Sphingobacterium multivorum, and Pseudomonas putida were present in the biofilter. Only Alicycliphilus denitrificans was present throughout the whole operation period. In the initial stage of operating the RSB, many types of bacteria may have tried to adapt to the conditions, and subsequently, only selected bacteria were able to grow and to degrade toluene.     

Cascade utilization of water chestnut: recovery of phenolics, phosphorus, and sugars

Overgrowth of aquatic plants, such as water chestnut, has been reported as a regional problem in various areas. We proposed cascade utilization of water chestnut through the recovery of phenolics, phosphorus, and sugars. Phenolics were extracted using 50 g (wet weight) of biomass with 300 mL of acetone, methanol, or hot water, and the yields of total phenolics were 80.2, 56.2, and 49.7 mg?g^?1 dry weight of native biomass, respectively. The rate of eluted phosphorus in the phenolic extraction step was 8.6, 14.8, and 45.3 % of that in the native biomass, respectively, indicating that the use of polar organic solvents suppressed phosphorus elution at the phenolic extraction step. Extraction of phosphorus following the phenolic extraction was combined with alkaline pretreatment (1 % NaOH solution) of biomass for saccharification; 64.1 and 51.0 % of phosphorus in the native biomass were extracted using acetone and methanol for the phenolic extraction, respectively. Saccharification following the alkaline pretreatment showed that the glucose recovery rates were significantly increased (p?<?0.05) with the phenolic extraction step compared to alkaline pretreatment alone. This finding indicates that extraction of phenolics not only provides another useful material but also facilitates enzymatic saccharification.