• Ocean and Polar Research
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• v.25 no.4
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• pp.493-501
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• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg of korean rockfish (130 fish) with an average body weight of 153.8g was stocked. Over a 107-day culture period, fish reached final density of $51.7kg/m^3$ (initial density, $33.3kg/m^3$) on the basis of the culture tank volume. On a daily basis, added water amounted to 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN) concentrations were below 1mg/l and nitrite nitrogen $(NO_2-N)$ concentrations were within the range of 1-3mg/l on most sampling days. TAN was removed from bead and sand filters and it was removed or produced in the sedimentation basin. Basically, $NO_2-N$ was removed in the bead and sand filters, while it was either removed or produced in the sedimentation basin. Nitrate nitrogen $(NO_3-N)$ was produced in the bead filters and removed from the sand filter and sedimentation basin. The foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (755) and protein were 10.9g and 1.4g, respectively. Whole water quality parameters were within the levels commonly recommended for fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the smallscale system used in present experiment. At least, the present study still provides some basic information for further studies of this kind of system.

• Journal of Environmental Impact Assessment
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• v.30 no.3
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• pp.155-163
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• 2021

The number of trees to be removed trees (ART) in the environmental impact assessment is an environmental indicator used in various parts such as greenhouse gas emissions and waste of forest trees calculation. Until now, the ART has depended on the forest tree density of the vegetation survey, and the uncertainty of estimating the amount of removed trees has increased due to the sampling bias. A full-scale survey can be offered as an alternative to improve the accuracy of ART, but the reality is that it is impossible. As an alternative, there is an individual tree detection using aerial image (ITD), and in this study, we compared the ARTs estimated by full-scale survey, sample survey, and ITD. According to the research results, compared to the result of full-scale survey, the result of ITD was overestimated by 25. While 58 were overestimated by the sample survey (average). However, as the sample survey is an estimate based on random samples, ART will be overestimated or underestimated depending on the number and size of quadrats.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.187-192
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• 1991

This study was carried out to estimate the stand volume for Japanese larch(Larix leptolepis) by Strand sampling method. The data collected for this study were based on the 380 sample plots from the field survey, which were distributed in the major part of Korea(Kyeongi, Kangweon, Chungbuk, Chungnam, Chunbuk and Kyeongbuki), and the plotless sampling instrument such as dendrometer, spiegel relascope and tele-relascope were used. The procedure for this study is summarized briefly as follows : 1. There were not only significant differences between volume estimation by Strand sampling method and that by plot survey method, and the relationship was y=bx, where b approached nearly 1. Therefore, the stand volume of Japanese larch could by estimated by Strand sampling method. 2. The value measured by three different plotless sampling instruments did not showed any significant differences between instruments and observers, density and instruments, and ground slope and instruments. 3. With the stand volume, basal area height showed the highest correlation and stand form height, average height, basal area per ha correlated with the volume in thier orders. 4. The best fitted equation of stand volume estimation with basal area height by relascope was as follow. log V=-0.0375+0.8910 log GH-1.5946 1/GH Stand volume table also was obtained using the above estimeated equation. 5. The relationship between estimated value and actual value was Y=bx, where b was nearly 1. The correlation coefficient was very high and the percentage of estimated error was 4.5%.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.159-171
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• 2001

Community structure, horizontal distribution, density, and ratio between nematodes and benthic harpacticoid copepods of the meiobenthos within the sediments of inner Sihwa Lake were investigated in May 1999 and May 2000. A total of 11 and 8 classes of meiobenthic animals were identified in 1999 and 2000, respectively, which were much lower than other coastal areas. The dominant animals during both sampling periods was the nematodes, followed by sarco-mastigophorans, nauplius of crustaceans, benthic harpacticoid copepods and polychaetes. These five classes of animals comprised more than 90% of total abundance of neiobenthos presented in the samples. In 2000, a lot of polychaete larvae were identified. The most abundant animal were the size that fits in 0.063 mm sieve size. Lower density was observed upper inner part of the Sihwa Lake during both sampling periods, and higher density was observed around the Sihwa floodgates. The average density between those two numbers were observed in the samples collected in the middle of the lake. Lower nematodes to betnhic harpacticoides (N/C) ratio, a relative indicator of environmental pollution, was observed to be lower around the floodgate but higher ratios were observed in the upper inner Sihwa Lake. The present study indicated that inner upper part of the lake becomes unsuitable for the meiobenthos, and the most inner upper lake was considered to be polluted.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.238-249
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• 2005

The present study was carried out to apprehend that the pollutants originating from Jinhae Industrial Complex affect benthic polychaetous community in the northern Jinhae bay. An investigation on the macrobenthic community in Jinhae bay was conducted in September, December of 2002 and March of 2003. The benthic fauna showed mean density of 2,151 ind. $m^{-2}$ in September of 2002, 2,427 ind. $m^{-2}$ in December of 2002 and 2,394 ind. $m^{-2}$ in March of 2003. Major faunal groups are polychaetes, crustaceans and mollusks, corresponding to $73.7\%,\;12.0\%\;and\;11.7\%,$ in total mean density during all of the sampling season, respectively. The most abundant species was Lumbrineris longifolia $(24.85\%),$ followed by Tharyx sp. $(21.70\%),$ Mesochaetopterus sp. $(6.20\%),$ Heteromastus filiformis $(5.39\%),$ Prionospio sp. $(5.18\%),$ Clycinde sp. $(4.29\%),$ etc. Tharyx sp. was the highest abundant species in September of 2002, and Lumbrineris longifolia was the dominant species in another sampling seasons. The density and the species number of polychaetes were high around Chori Is. and poor near Jinhae Industrial Complex area. Cluster analysis based on the species composition showed that Jinhae bay could be divided into three regions except in March of 2003. In December of 2002, there are very distinct regions by the cluster analysis. The density of benthic polychaetes in Jinhae bay was higher than that in the other coastal area of Korea, due to the predominance by some of opportunistic species, such as Lumbrineris longifolia, Tharyx sp. and Heteromastus filiformis, etc. It means that the study area were in the process of organic enrichment.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.626-637
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• 2018

In this study, a series of survey were conducted to identify the distribution patterns of macrobenthos at the Bongam sand tidal flat in Masan Bay. We collected macrobenthos at 9 sampling sites twice in June and September of every year from 2012 to 2017 using a box core sampler (collecting area, $0.025m^2$). There was a total of 50 species with a community density of $6,388ind.m^{-2}$ and a biomass of $313.9g\;wet\;m^{-2}$ during the study period. Polychaetes had the highest number of species and density among the macrofauna, but the mollusks had the largest biomass. The number of species ranged from 10 to 25 during study period but increased to over 20 species in 2014. The density which ranged from $1,508ind.m^{-2}$ to $12,008ind.m^{-2}$ rapidly increased in 2015. The dominant species were all polychaetes such as Heteromastus filiformis, Prionospio japonicus, Hediste diadroma, and Neanthes succinea. The mean diversity index ranged from 1.2 to 1.9, richness index from 1.2 to 2.4, and evenness index from 0.5 to 0.9. From the cluster analysis results, there was a spatial difference in the similarity of faunal composition of macrobenthos and this pattern was maintained throughout the study period, that is, the temporal similarities were higher than the spatial similarities. There was a change in community composition from June 2014 to June 2015 in most of the sampling sites. During this time, the dominant species also changed from H. filiformis and N. succinea to H. filiformis and H. diadroma. The density of opportunistic species such as Capitella capitata and Polydora ligni decreased compared to the early 2000s while the population of H. diadroma increased from 2015. There was little ecological information on H. diadroma such as when and where this species occurred.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.32-37
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• 2005

The procedure of soil sampling for on-farm quick test of soil nitrate is very important to improve practical application without weighing or drying soil. To improve application of test strip reflectometer as a quick on-farm analytical procedure for the estimation of soil nitrate concentration, three sampling methods such as gravimetric sampling (GS), particle density sampling (PDS) and bulk density sampling (BDS) for on-farm analytical procedure were investigated with twelve soils of 45 to $281mg\;kg^{-1}$ nitrate nitrogen concentration. The nitrate nitrogen concentrations measured from different soils were compared with two analytical methods, ion electrode method as a standard laboratory analysis (SLA) and test strip reflectometer at three moisture conditions, viz. air dried soil, 20 and 40% of maximum water holding capacity (MWHC). Nitrate nitrogen concentration measured by test strip reflectometer was significantly correlated with that of SLA, and the coefficients of variation (CV) were in the range of 3.5 to 10.9%. These CV values less than 10.9% were thought to be acceptable for the measurement of soil nitrate as an on-farm real time analytical procedure. The nitrate nitrogen concentration by BDS for test strip reflectometer as well as ion electrode method was more similar to that of SLA compared with those by GS and PDS especially in case of moist soils. This result suggests that the BDS is more useful than GS and PDS in case of on-farm analytical procedure of soil nitrate for moist soils. Further the practical measurement by BDS could be improved by substituting the bottle cap with a larger container.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.392-407
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• 2006

This study was seasonally undertaken to investigate the benthic polychaetous community along the South-eastern coast of Geoje Is., in February 2004 to November. The macrobenthic fauna showed mean density of 953 md. $m^{-2}$ in February, 1,193 ind. $m^{-2}$ in May, 1,130 ind. $m^{-2}$ in September and 991 ind. $m^{-2}$ in November. Major faunal groups are polychaetes, crustaceans and mollusks, corresponding to 81.6%, 7.9%, 7.0% in total mean density during the sampling seasons, respectively. There was significant difference (two-way ANOVA, p<0.001) among stations in densities of polychaetes. But no significant relationship could be found between the densities of polychaetes and sampling seasons (two-way ANOVA, p>0.05). The density and the species number of polychaetes were high in the coastal area near the Jisepo port, independent of sampling seasons. Several indicator species for the organically enriched environments such as Lumbrineris longifolia, Tharyx sp., Heteromastus filiformis showed high densities during all study periods. Also Magelona japonica included in Ecolgical group I was the most abundant in the whole study period except for February. Cluster analysis on the basis of the species composition showed that the study area could be divided into 3 regions. The density of benthic polychaetes in the coastal area near Jisepo was higher than that in the other assemblages of the study area, due to some predominant opportunistic species, such as Lumbrineris longifolia, Tharyx sp. and Heteromastus filiformis. In addition, the two-way ANOVA showed significant differences among the distribution of AMBI (AZTI's Marine Biotic Index) values, both in sampling stations (p<0.001) and seasons (p<0.01). According to the classification proposed by Borja et at. (2000), the study area was slightly disturbed site.

• Journal of environmental and Sanitary engineering
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• v.21 no.1 s.59
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• pp.44-51
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• 2006

This study was conducted to investigate air quality in the underground parking lot of department store. Sampling sites were selected to the three sites in one department store. Measuring instrument started from November 3rd, 2005 to November 9, 2005. Target air quality parameters include a number of criteria pollutants such as NOx, $O_3$. The purpose of this study was to find out the present condition of indoor air quality in underground parking space of department store. Through the field measurement, the current situation and the behavior of contaminants were investigated and then was compared with the advice standards. The result of this study was as follows; The Average density of NOx gas and $O_3$ gas was maintained below the indoor air advice standards. The Average density of NOx gas and $O_3$ gas was highly measured during the weekend than during the week day. Average density of NOx gas and $O_3$ gas was highly measured at daytime than that of afternoon. Average density of NOx gas was highly measured in the center area than the other area. Average density of $O_3$ gas was highly measured at the entrance than the other area. NOx gas concentration was maintained below 0.3ppm, an average for 1 hours, as defined in the parking space law. $O_3$ gas concentration was maintained below 0.08ppm, an average for 1 hours, as defined in the parking space law.

• Journal of Forest and Environmental Science
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• v.36 no.1
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• pp.37-46
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• 2020

Vegetation carbon sequestration and regeneration are the two major parameters of forest research. In this study, we analyzed the vegetation carbon stock and regeneration of community-managed pine plantation of Kathmandu, central Nepal. Vegetation data were collected from 40 circular plots of 10 m radius (for the tree) and 1m radius (for seedling) applying a stratified random sampling and nested quadrat method. The carbon stock was estimated by Chave allometric model and estimated carbon stock was converted into CO₂ equivalents. Density-diameter (d-d) curve was also prepared to check the regeneration status and stability of the plantation. A d-d curve indicates the good regeneration status of the forest with a stable population in each size class. Diversity of trees was very low, only two tree species Pinus roxburghii and Eucalyptus citriodora occurred in the sample plots. Pine was the dominant tree in terms of density, basal area, biomass, carbon stock and CO₂ stock than the eucalyptus. The basal area, carbon stock and CO₂ stock of forest was 33±1.0 ㎡ ha^-1, 108±5.0 Mg ha^-1 and 394±18 Mg ha^-1, respectively. Seedling and tree density of the plantation was 4,965 ha^-1 and 339 ha^-1 respectively. The forest carbon stock showed a positive relationship with biomass, tree diameter, height and basal area but no relationship with tree density. Canopy cover and tree diameter have a negative effect on seedling density and regeneration. In conclusion, the community forest has a stable population in each size class, sequestering a significant amount of carbon and CO₂ emitted from densely populated Kathmandu metro city as the forest biomass hence have a potentiality to mitigate the global climate change.