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Bhattarai R Kalita PK Yatsu S Howard HR Svendsen NG 《Journal of environmental management》2011,92(3):803-812
Soil erosion due to water and wind results in the loss of valuable top soil and causes land degradation and environmental quality problems. Site specific best management practices (BMP) are needed to curb erosion and sediment control and in turn, increase productivity of lands and sustain environmental quality. The aim of this study was to investigate the effectiveness of three different types of biodegradable erosion control blankets- fine compost, mulch, and 50-50 mixture of compost and mulch, for soil erosion control under field and laboratory-scale experiments. Quantitative analysis was conducted by comparing the sediment load in the runoff collected from sloped and tilled plots in the field and in the laboratory with the erosion control blankets. The field plots had an average slope of 3.5% and experiments were conducted under natural rainfall conditions, while the laboratory experiments were conducted at 4, 8 and 16% slopes under simulated rainfall conditions. Results obtained from the field experiments indicated that the 50-50 mixture of compost and mulch provides the best erosion control measures as compared to using either the compost or the mulch blanket alone. Laboratory results under simulated rains indicated that both mulch cover and the 50-50 mixture of mulch and compost cover provided better erosion control measures compared to using the compost alone. Although these results indicate that the 50-50 mixtures and the mulch in laboratory experiments are the best measures among the three erosion control blankets, all three types of blankets provide very effective erosion control measures from bare-soil surface. Results of this study can be used in controlling erosion and sediment from disturbed lands with compost mulch application. Testing different mixture ratios and types of mulch and composts, and their efficiencies in retaining various soil nutrients may provide more quantitative data for developing erosion control plans. 相似文献
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The use of tree species for phytoremediation of contaminated soil offers the advantage of a large biomass in which to store
contaminants. We investigated the cadmium (Cd) and zinc (Zn) accumulation ability of Evodiopanax innovans, a common deciduous tree species belonging to the Araliaceae family and widely found in secondary forests in Japan. Sampling
was conducted at an old silver mine. Leaf samples were collected from nine tree species, including E. innovans. The seasonal variation of metal concentrations in the leaves and the detailed distribution of metals in the leaves and twigs
of E. innovans were measured. We also analyzed the contents of organic acids in the leaves. The highest concentration of Cd in the leaves
of E. innovans was 118 μg/g, which exceeds the threshold level for being considered a Cd hyperaccumulator (100 μg/g). For Zn, the highest
value was 1040 μg/g in leaves, which is less than required to qualify as a Zn hyperaccumulator. Both Cd and Zn were found
to accumulate in the petioles and veins of leaves and the bark of twigs. Since the oxalic acid content of leaves showed a
weak correlation with Cd concentration, oxalic acid may play an important role in the accumulation of Cd. Taking both the
Cd concentration level and the biomass of this woody plant into consideration, it may be possible to use E. innovans for the phytoremediation of Cd-contaminated soils. 相似文献
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Strontium to calcium ratios were observed along longitudinal sections of statoliths of nine neon flying squid, Ommastrephes bartrami (LeSueur, 1821), including three mature females (422 to 454 mm mantle length, ML; 207 to 306 d old) obtained from the North
Pacific (27–35°N; 144–150°E) during winter and six immature males and females (187 to 226 mm ML; 126 to 164 d old) collected
from 39°N; 145°E and 39°N; 169°W during summer. The distances between the nucleus (core) and the edge of the dorsal dome were
approximately 660 to 690 μm in mature females and 450 to 510 μm in the immature squid. Sr/Ca ratios were determined at intervals
of 30 μm between the nucleus and edge of the dorsal dome. Sr/Ca ratios were higher in areas near the nuclei and peripheral
portions of the dorsal dome than in the middle portions of the statoliths (270 to 420 μm from the nuclei, corresponding to
ages of 60 to 90 d) in mature females; thus a U-shaped pattern was evident. Sr/Ca ratios in the six immature squid decreased
from nucleus to the dorsal dome; in three squid the ratios slightly increased toward the dorsal dome edge. The observed Sr/Ca
ratios in immature squid were considered to represent younger portions of the U-shaped pattern. In the present study we discuss
this pattern in relation to environmental and biological conditions of O. bartrami, which undertakes seasonal migrations between spawning grounds in the Subtropical Domain and feeding grounds in the Subarctic
Domain and Transitional Zone in the North Pacific Ocean. Although Sr/Ca ratios are potentially affected by ambient water temperature
and ontogenetic conditions, including somatic growth and statolith growth, it was impossible to evaluate each environmental
and biological effect separately, as variations in these factors are complicated and effects could be interdependent.
Received: 11 April 1997 / Accepted: 27 December 1997 相似文献
4.
Hata Akihiko Meuchi Yuno Liu Miaomiao Torii Shotaro Katayama Hiroyuki 《Food and environmental virology》2023,15(1):8-20
Food and Environmental Virology - The hollow fiber ultrafiltration (HFUF)-based microbial concentration method is widely applied for monitoring pathogenic viruses and microbial indicators in... 相似文献
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In order to investigate changes in the mutagenicity of fenitrothion during its biodegradation in solution, measurements were conducted at intervals in batch cultures incubated under anaerobic or aerobic conditions. Fenitrothion-degrading bacteria were obtained from a green onion field on the west side of Gifu University, Japan. Fenitrothion was almost completely decomposed by day 12 under both types of incubation condition. The indirect mutagenicity of the solution to strains YG1029 and YG1042, however, increased markedly during anaerobic biodegradation. The increase in mutagenicity was partially due to amino-fenitrothion, a metabolite formed during anaerobic biodegradation of fenitrothion. 相似文献
6.
Comparison of feeding habits of myctophid fishes and juvenile small epipelagic fishes in the western North Pacific 总被引:1,自引:0,他引:1
Kaori Takagi Akihiko Yatsu Hiroshi Itoh Masatoshi Moku Hiroshi Nishida 《Marine Biology》2009,156(4):641-659
To examine the potential trophic competition between myctophids and small epipelagic fishes in the nursery grounds in spring,
we compared the stomach contents of dominant myctophids (Symbolophorus californiensis, Ceratoscopelus warmingii and Myctophum asperum; n = 179) and juvenile epipelagic fishes (Japanese sardine, Sardinops melanostictus, Japanese anchovy, Engraulis japonicus, chub mackerel, Scomber japonicus, and spotted mackerel, S. australasicus; n = 78) that were simultaneously collected at nighttime with a midwater trawl net around the Kuroshio-Oyashio transition zone
in the western North Pacific. It was clear that the neritic copepod Paracalanus parvus s.l. was the most abundant species in NORPAC samples (0.335 mm mesh size) taken at the same stations. Diets of dominant myctophid
fishes differed from those of the juvenile epipelagic fishes; Japanese sardine and anchovy mostly preyed upon P. parvus s.l. (23.6% of stomach contents in volume) and Corycaeus affinis (16.1%), respectively. Both chub and spotted mackerels mainly preyed upon the seasonal vertical migrant copepod, Neocalanus cristatus (15.9 and 14.7%, respectively). On the contrary, myctophid fishes probably do not specifically select the abundant neritic
copepods. Namely, S. californiensis mostly preyed upon a diel vertical migrating copepod, Pleuromamma piseki (22.7 and 30.6% in stomach of juvenile and adult, respectively), while C. warmingii and M. asperum preyed on Doliolida (43.0% in stomach of juvenile C. warmingii), appendicularians (11.0% in stomach of juvenile M. asperum), and Ostracoda (6.3% in stomach of adult C. warmingii). Feeding habits of myctophid fishes seem adapted to their prey animals; low rate of digested material (less than 30% in
volume) in stomachs of S. californiensis may be linked to the movement of P. piseki, hence S. californiensis can easily consume this copepod at night since they are more concentrated at night than daytime. High rate of digested material
(over 40%) of M. asperum and adult C. warmingii suggest that they feed not only at night but also during the daytime in the midwater layer. Thus, myctophid fishes actually
fed in the surface layer but less actively than the small epipelagic fishes. These results suggest that the potential for
direct food competition between myctophids and small epipelagic fishes is low in the nursery ground, but there remains a possibility
of indirect effects through their prey items, since the above gelatinous animals feed on common prey items as juveniles of
Japanese sardine and anchovy. 相似文献
7.
Inaba Rokuta Tasaki Tomohiro Kawai Kosuke Nakanishi Shotaro Yokoo Yusuke Takagi Shigesada 《Journal of Material Cycles and Waste Management》2022,24(1):155-165
Journal of Material Cycles and Waste Management - Japan has been promoting 3R (reduce, reuse, and recycle) policies for several decades, but the recycling rate of the whole country has leveled off,... 相似文献
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