• ALGAE
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• 제33권4호
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• pp.319-327
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• 2018

Ettlia sp. YC001, a highly settleable and productive microalga, was shown to be effective in removing nutrients and capturing suspended solids from eutrophic pond water. The optimum conditions for the Ettlia sp. YC001 cultivation were investigated using water from a landscape pond. The pond water was supplemented with different N : P ratios by weight, and the biomass production and nutrient removal compared in batch cultures. The maximum removal rate of N and P was with an N : P ratio of 16 : 1. Plus, the turbidity dropped to near zero within 4 days. Meanwhile, chemostat cultivation showed that the biomass productivity and nutrient removal rate increased when increasing the dilution rate, where a dilution rate of $0.9d^{-1}$ showed the highest N and P removal rate at $32.4mg\;L^{-1}\;d^{-1}$ and $1.83mg\;L^{-1}\;d^{-1}$, respectively, and highest biomass and lipid productivity at $0.432g\;L^{-1}\;d^{-1}$ and $67.8mg\;L^{-1}\;d^{-1}$, respectively. The turbidity was also reduced by 98% in the chemostat cultivation. Moreover, auto-flocculation and pH were closely connected to the turbidity removal. As a result, this study identified the optimal N : P ratio for small pond water treatment using an Ettlia sp. YC001, while also establishing the optimal conditions for nutrient removal, turbidity reduction, and biomass production.

• Fisheries and Aquatic Sciences
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• 제24권4호
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• pp.171-179
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• 2021

To better understand the ecological functioning of the coastal ecosystem in Gamak Bay on the southern coast of Korea, seasonal changes in the density, biomass, and secondary production of the copepod community were investigated. Environmental measurements (temperature, salinity, and chlorophyll a) and copepod sampling were performed seasonally from January to December 2006. The mean density of copepods (excluding nauplii) varied from 949 to 5,999 ind · m^-3; copepod density was at its highest from March to July. The copepod community comprised 32 taxa, including Calanoida, Cyclopoida, and Harpacticoida. The predominant species were Paracalanus parvus s. l., Acartia omorii, Eurytemora pacifica, Oithona similis, A. erythraea, Centropages abdominalis, Pseudodiaptomus marinus, and Calanus sinicus. There were significant spatial and seasonal variations in copepod total biomass, which ranged from 0.33 to 43.10 mg C m^-3. Mean secondary production of the copepods in Gamak Bay, estimated as 2.05 ± 1.63 mg C m^-3 d^-1 using the Huntley and Lopez growth model, was over 2 times higher than the value given by application of the Hirst and Bunker model (1.09 ± 0.85 mg C m^-3 d^-1). The daily production rate to biomass (P/B) ratio varied between 0.08 and 0.86 d^-1 (Huntley and Lopez model), and 0.18 and 0.33 d^-1 (Hirst and Bunker model). Our results emphasize the ecological significance of using models to estimate the secondary production of copepods and provides the first report of copepod production in Gamak Bay.

• 임산에너지
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• 제18권1호
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• pp.6-10
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• 1999

식재밀도에 따른 강송(Pinus densiflora forma erecta Uyeki)의 biomass 생산 및 배분 특성을 구명하기 위하여 경기도 수원시 소재 서울대학교 칠보연습림내 12년생 강송 조림지를 대상으로 본 연구를 수행하였다. 식재밀도가 1.0m×1.0m, 1.8m×1.8m, 3.0m×3.0m인 강송 조림지에서 각각 6본, 5본, 4본씩 표본목을 선정하여 부위별로 생중량을 측정하고 식재밀도에 따른 임분의 biomass 현존량 및 배분 특성을 분석하였다. 그 결과는 다음과 같이 요약된다. (1) ha당 biomass 현존량은 밀도 순으로 나타났다. (2) 식재밀도가 높을수록 가지와 침엽이 차지하는 biomass 현존량의 비율은 감소하였다. (3) 당년생 가지와 줄기의 경우 밀도가 낮을수록 수분함량이 점차 증가하는 경향을 보이나 침엽과 전년생 가지의 경우는 줄어드는 경향을 보였다. (4) 식재밀도가 높을수록 최대광합성부위가 위쪽에 나타났다.

• Journal of Plant Biotechnology
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• 제8권1호
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• pp.1-8
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• 2006

The differential response of soybean cultivars with or without sulfur (S) application was observed under fold conditions. Plant biomass decreased by sulfur deficiency but the reduction was less in Bragg variety about 26 % relative to the control than other ones over 45%, probably due to less reduction in loaves and pods. The photosynthetic rate of Bragg cultivar was also unaffected by the absence of sulfur application while it depressed in other lines. Soybean cultivars were compared in terms of storage protein, protein quality and biomass production by application of sulfur nutrition. The storage protein concentration tended to decrease without sulfur application in all the cultivars, however the differential response of protein quality only by 11S/7S ratio to sulfur nutrition status was observed: For instance, Bragg cultivar had higher biomass and protein production but protein quality decreased at sulfur deficiency. On the other hand, biomass and protein production in other cultivars remained louver at sulfur deficiency but protein quality differed genetically in spite of sulfur nutrition status. These results suggest that the response of soybean to sulfur nutrition is controlled by genotypic difference and sulfur supply status.

• 한국산림과학회지
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• 제85권3호
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• pp.453-461
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• 1996

왕대속 대나무림의 물질생산 및 무기영양물 분배를 파악하가 위하여 전라남도 순천시에 위치하고 있는 죽순대, 왕대, 솜대 등 왕대속 3개 종의 임분을 대상으로 임분별 $10m{\times}10m$ 조사구 5개씩을 설치한 후 임분구조 및 죽간(竹稈), 가지, 잎, 지하경(地下莖), 뿌리 등 지하부를 포함한 대나무 전체의 부위별 현존량, 순생산량, 생산능률, 무기영양물 분배 등을 조사분석하였다. 죽간(竹稈)의 평균흉고직경, 죽고(竹高), 흉고단 면적은 죽순대, 솜대, 왕대 임분의 순으로 컸다. 흉고직경 또는 흉고직경과 죽고를 독립변수로 하는 3개 유형의 현존량 대수회귀식을 임분별, 부위별로 유도 검정한 결과 적합도와 실용성을 고려할 때 흉고직경을 독립변수로 하는 대수회귀식(logWt=A+BlogD)이 효과적이었다. 직선 대수회귀식이 되는 흉고직경 또는 흉고직경과 수고($D^2H$)를 독립변수로 하는 2개 유형의 3개 종별 현존량 대수회귀식의 기울기와 절편간의 차이 유무를 검정한 결과 2개 유형 모두 절편간에 유의적인 차이를 보임으로써 왕대속 3개 종의 일괄추정식은 오차가 클 것으로 판단되었다. 지하부를 포함한 임분 전체의 현존량(現存量)은 죽순대 103.621t/ha, 솜대 86.447t/ha, 왕대 36.767t/ha의 순으로 많았으며 비교적 큰 차이를 보였다. 동화기관인 잎의 현존량 구성비는 6.3-7.8%이었으며, 지상부와 지하부의 현존량 비는 1.87-2.26이었다. 지하부를 포함한 임분 전체의 순생산량(純生産量)은 죽순대 6.115t/ha/yr, 솜대 5.609t/ha/yr, 왕대 3252t/ha/yr의 순으로 많았다. 순동화율(純同化率)은 죽순대 임분 2.979, 솜대 임분 2.752, 왕대 임분 2.187의 순으로 높았으며, 현존량축적율(現存量蓄積率)은 2.679-5.358의 범위를 보였다. 부위별 무기영양물 농도는 3개 종 모 두 N, P, Mg는 잎, 지하부, 죽간(竹稈)과 가지의 순으로 높았으며, Ca는 잎, 죽간과 가지, 지하부의 순이었다. 지하부를 포함한 대나무 전체의 무기영양물 함량은 N, K, Ca와 Mg, P의 순으로 많았다. 3개 종의 임분 현존량에 있어서 차이를 보이는 것은 죽간밀도(竹稈密度)는 큰 차이가 없었으나 죽간(죽稈)의 크기가 다르며, 동화기관인 잎의 현존량, 순동화율 비교적 장기간의 축적기관인 죽간 생산능률 등에서 차이가 있기 때문이었다.

• 한국환경과학회지
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• 제8권4호
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• pp.525-532
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• 1999

This study was conducted to evaluate capability of dyeing wastewater treatment for 3 type reactors. These reactors were Packed Bed Reactor(PBR), Fluidized Bed reactor(FBR) and Moving Media Complete Mixing Activated Sludge reactor(MMCMAS). Experiments of PBR and FBR were performed by various packing ratios and organic loading rates, experiments of MMCMAS were performed by various organic loading rates. In order to obtain ${SBOD}_5$ removal efficiencies of more than 90%, the F/Mv ratios of PBR, FBR, MMCMAS were 0.11 kgBOD/kgMLVSS$\cdot$d, 0.12 kgBOD/kgMLVSS$\cdot$d, and 0.37 kgBOD/kgMLSS$\cdot$d, respectively. So MMCMAS system which has more active microorganisms showed better capability of organic removal and also stronger dynamic and shock loadings than those of PBR and FBR. In PBR and FBR, the media packing ratio of 20% showed better performance of organic matters removal effciencies than 10% and 30%, but sludge production rate at media packing ratio of 30% was relatively lower than that of 10% and 20%. When more than 90% organic matters removal efficiency was obtained, the ratios of attached biomass to total biomass at PBR, FBR, MMCMAS were 89~99%, 87~98%, and 54~80%, respectively. The ratio of attached biomass to total biomass was low in MMCMAS. This was formation of thin biofilm due to shear force between rotaing disc and water. The average sludge production rates(kgVSS/kgBODrem.) of PBR, FBR and MMCMAS were 0.20, 0.29 and 0.54, respectively.

• 한국환경농학회지
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• 제30권3호
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• pp.234-242
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• 2011

BACKGROUND: Cultivation of winter cover crops is strongly recommended to increase land utilization efficiency, animal feeding material self-production, and to improve soil and environmental quality. METHODS AND RESULTS: Four major winter crops (barley, Chinese milk vetch, hairy vetch, and rye) having different C/N ratio were seeded in silt loam paddy soil in the November 2007 and the aboveground biomass was harvested on the late May 2008 to evaluate its effectiveness as green manure, and root biomass distribution was characterized at the different depth (0-60 cm) to study its effect on physical properties and carbon sequestration in soil. During this experiment, the naturally growing weed in the rice paddy soil in Korea, short awn foxtail (Alopecurus aequalis Sobol), was considered as control treatment. Above-ground biomass of all cover crops selected was significantly higher than that of the control treatment (2.8 Mg/ha). Comparatively higher above-ground biomass productivity of rye and barley (15.8 and 13.5 Mg/ha, respectively) suggested that these cover crops possibly had the highest potential as a green manure and animal feeding material. Root biomass production of different cover crops followed the same trend as that for their above ground biomass. Rye (Secale cereal) might have the highest potential for soil C accumulation (7893 C kg/ha) by root biomass development, and then followed by barley (6985 C kg/ha), hairy vetch (6467 C kg/ha), Chinese milk vetch (6671 C kg/ha), and control (5791 C kg/ha). CONCLUSION(s): Cover crops like rye and barley having high biomass productivity might be the most effective winter cover crops to increase organic carbon distribution in different soil aggregates which might be beneficial to improve soil structure, aeration etc. and C sequestration.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.699-706
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• 2022

Recently, hydrogen production is attracting attention. In this study, a process simulation was conducted on the gasification reaction to produce hydrogen using rice husks, which are produced as by-products of rice. For this purpose, Chuchung, Odae, and Dongjin rice, which are rice varieties produced in Korea, were compared with the literature. The Korean rice contained more hydrogen and less oxygen compared to the literature. As a result of the simulation, large amounts of H₂ and CH₄ and small amounts of CO₂ and CO were produced accordingly. The conditions to maximize hydrogen production were a gasification reaction temperature of 700℃ and an Steam-to-Biomass (S/B) ratio of 0.4-0.6. However, because the S/B ratio is related to the gasification catalyst degradation, the model needs to be improved through additional experiments in the future. This study showed the possibility of hydrogen production using Korean rice husks, which had not been reported.

• 한국산림과학회지
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• 제89권5호
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• pp.591-597
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• 2000

본 실험은 층층나무(Cornus controversa Hemsl)와 말채나무(Cornus walteri Wanger)의 양묘시 적정 차광율을 구명하고자 상대광도가 100%(대조구), 50%, 30%, 10% 및 2%로 조절된 피음포지에서 실시하였다. 두 수종의 수고생장은 상대광도 50%에서 가장 높은 생장을 보였고, 근원경생장은 대조구와 50%구에서 서로 비슷하게 높은 생장을 기록하였다. 물질생산량을 보면 층층나무의 전체 생산량의 경우 50%에서 자연전광의 대조구보다 높은 생산량을 보였으나 지하부의 생산량은 다소 낮았다. 말채나무는 50%에서 전체 생산량은 대조구보다 낮았으나 지상부 생산량은 다소 높은 생산량을 보였다. 30%이하의 상대광도에서는 수고생장, 근원경생장 및 물질생산량이 급격히 감소하였다. 두 수종 모두 30%에서 가장 높은 T/R율을 기록하였으며 전체적으로 말채나무의 T/R율이 층층나무의 T/R율 보다 높았다. 잎의 엽록소 a와 b 및 전체엽록소 함량은 상대광도가 낮을수록 높아지는 경향을 나타내었다.

• 농업생명과학연구
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• 제45권2호
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• pp.15-20
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• 2011

본 연구의 목적은 경남 산청 지역에 분포하는 40년생 리기다소나무 임분을 대상으로 지상부 바이오매스와 순생산량에 대하여 분석하고자 하였다. 본 연구의 결과에 의하면, 지상부 바이오매스량은 $127.7Mg\;ha^{-1}$으로 나타났고, 줄기 $103.1Mg\;ha^{-1}$, 가지 $17.2Mg\;ha^{-1}$, 잎 $7.4Mg\;ha^{-1}$으로 나타났으며, 바이오매스 함량은 줄기목질부 (71.1%) > 가지 (13.5%) > 줄기 수피 (9.6%) > 잎 (5.8%) 순으로 나타났다. 또한 지상부 순생산량은 $10.4Mg\;ha^{-1}$로 나타났고 줄기 $3.6Mg\;ha^{-1}$, 가지 $2.2Mg\;ha^{-1}$, 1년생 소지 $1.3Mg\;ha^{-1}$, 잎 $2.8Mg\;ha^{-1}$로 나타났다. 순생산량 함량은 줄기 목질부 (34.6%) > 잎 (26.9%) > 가지 (21.2%) > 소지 (12.5%) > 줄기 수피 (4.8%) 순으로 나타났다.