• 생태와환경
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• 제42권4호
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• pp.432-440
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• 2009

During the period of past fifteen years (1992~2006), variations of chlorophyll a in relation with water quality in freshwater reservoirs were investigated. This study compared total nitrogen (TN), total phosphorus (TP), chlorophyll a, Secchi depth (SD) and total suspended solids (TSS) between terrestrial freshwater reservoir and coastal freshwater reservoir systems based on their location. Regression analyses (linear and non-linear regressions) were applied for all study sites to examine relationship and interaction of these factors in the freshwater systems from in-land to coasts. The results demonstrated that chlorophyll a was significantly correlated to total phosphorus ($R^2=0.94$, P<0.0001) and was remarkably related to TSS increase ($R^2=0.63$, P<0.0001) in the selected reservoirs. The TN : TP ratio in the reservoir systems was higher than Redfield ratio (16 : 1) indicating that the reservoirs are potentially experiencing P limitation. Water quality of coastal freshwater reservoir system was more significantly decreased than the reservoirs located in in-land during the past fifteen years. The strict management of nutrient discharge into freshwater systems should implemented in the coastal reservoirs since the freshwater is introduced into coastal estuarine systems.

• 환경생물
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• 제36권4호
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• pp.558-566
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• 2018

The objective of the study was to determine nutrition regime and limitation in the Boryeng Reservoir where there's a water tunnel between Geum River and the reservoir. Evaluation was conducted through in situ algal bioassay experiments (in situ ABEs) using the cubitainer setting in the reservoirs. For in situ ABEs, we compared and analyzed variations in chlorophyll-a (CHL-a) and phosphorus concentrations in Boryeong Reservoir before and after the water tunnel construction. We then analyzed the nutrient effects on the reservoir. Analysis for nitrogen and phosphorus was done in the three locations of the reservoir and two locations of the ABEs. The in situ ABEs results showed that phosphorous and Nitrogen, the primary limiting nutrient regulating the algal biomass was not limited in the system. The treatments of phosphorus or simultaneous treatments of N+P showed greater algal growth than in the control of nitrate-treatments, indicating a phosphorus deficiency on the phytoplankton growth in the system. The water from the Geum River had 5 times higher total phosphorus (TP) than the water in the reservoir. Efficient management is required as pumping of the river water from Geum River may accelerate the eutrophication of the reservoir.

• 대한환경공학회지
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• 제27권4호
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• pp.431-437
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• 2005

본 연구에서는, 충족농도를 기준으로 영양원를 제한한 경우와 탄소원 및 질소원이 각각 두 종류씩 혼재되어 있는 경우에 대해, 수돗물 토착세균 및 Pseudomonas fluorescence P17을 접종균으로 한 BRP법을 이용하여 세균의 재증식 특성을 연구하였다. 세균재증식능은 영양원의 제한에 의해 억제되는 것으로 나타났으며, 두가지 이상의 영양원이 동시에 제한된 경우, 세균재증식능의 억제가 더욱 증가되는 상승효과를 관찰할 수 있었다. 특히 제한된 영양원에 인이 포함되어 있는 경우, 상대적으로 더욱 낮은 세균재증식능을 나타내고 있었다. 그러나 $NO_3^-$-N에 대해서는 농도가 증가할수록 세균재증식능이 감소하는 것으로 나타났다. 탄소원으로써 Glucose 및 Acetate 질소원으로 $NH_4^$-N 및 $NO_3^-$-N가 혼재되어 있는 경우를 대상으로 세균의 재증식 특성을 조사한 결과, 탄소원에 대해서는 Glucose 및 Acetate가 혼재되어 있는 경우가 각각의 탄소원을 단독으로 주입했을 경우보다 세균재증식능이 높게 나타났다. 또한 질소원에 대해서는 $NH_4^+$-N의 주입비율이 높아짐에 따라 세균재증식능이 증가하는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.140-146
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• 1999

When methanol was the sole carbon source, Methylobacterium organophilum NCIB 11278, a facultative methylotroph, accumulated Poly-$\beta$-hydroxybutyrate (PHB) as 59% (w/w) of dry cell weight under potassium limitation, 37% under sulfate limitation, and 33% under nitrogen limitation. Based on a stoichiometric analysis of PHB synthesis from methanol, it was suspected that PHB synthesis is accompanied by the overproduction of energy, either 6-10 ATP and 1 $FADH_2$ or 6 ATP and 3 NADPH to balance the NADH requirement, per PHB monomer. This was confirmed by observation of increased intracellular ATP levels during PHB accumulation. The intracellular ATP with limited potassium, sulfate, and ammonium increased to 0.185, 0.452, and 0.390 $\mu$moles ATP/g Xr (residual cell mass) during PHB accumulation, respectively. The intracellular ATP level under potassium limitation was similar to that when there was no nutrient limitation and no PHB accumulation, 0.152- 0.186 $\mu$moles ATP/g Xr. We propose that the maximum PHB accumulation observed when potassium was limited is a result of the energy balance during PHB accumulation. Microorganisms have high energy requirements under potassium limitation. Enhanced PHB accumulation, in ammonium and sulfate limited conditions with the addition of 2,4-dinitrophenol, which dissipates surplus energy, proves this assumption. With the addition of 1 mM of 2,4-dinitrophenol, the PHB content increased from 32.4% to 58.5% of dry cell weight when nitrogen limited and from 15.1 % to 31.0% of dry cell weight when sulfate limited.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 춘계학술발표회
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• pp.117-120
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• 2006

영양염과 식물성플랑크톤 그리고 식물성플랑크톤과 유기물의 관계를 평가하는 것을 목적으로 하였다. 그 결과 질소가 제한 영양염으로 나타나고 있으며 가장 제한이 되고 있는 계절은 여름으로 DIN/DIP의 비가 4.7로 나타났다. Chl.-a는 겨울철인 2 월에 비해 봄과 여름인 5월과 8월에 79%, 97%가 증가하는 것으로 나타났다. 유기물의 농도는 COD로 나타내었으며 2월에는 0.84 mg/l로서 가장 낮은 값을 나타내었으며 8월인 여름철에 가장 높은 1.12 mg/l를 나타내었다. 영양염과 Chl.-a 의 상관관계는 DIN과의 상관에서 $r^2$가 0.93, DIP과의 상관에서 $r^2$가 0.89로 매우 높게 나타났다. 이와 같은 결과는 식물성 플랑크톤의 증식이 영양염의 감소에 주요 원인이라고 할 수 있다. 또한 Chl.-a 와 COD 의 회귀분석에서 상관계수 $r^2$가 0.78 로서 상관관계가 있는 것으로 나타났으며 회귀식을 이용하여 분석한 결과 유기물의 생산량은 겨울철에는 25%, 여름철에는 40% 가 증가하는 것으로 나타났다.

• Journal of Ecology and Environment
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• 제39권1호
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• pp.31-42
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• 2016

The object of this study was to determine long-term temporal and spatial patterns of nutrients (nitrogen and phosphorus), suspended solids, and chlorophyll (Chl) in Chungju Reservoir, based on the dataset of 1992 - 2013, and then to develop the empirical models of nutrient-Chl for predicting the eutrophication of the reservoir. Concentrations of total nitrogen (TN) and total phosphorus (TP) were largely affected by an intensity of Asian monsoon and the longitudinal structure of riverine (Rz), transition (Tz), and lacustrine zone (Lz). This system was nitrogen-rich system and phosphorus contents in the water were relatively low, implying a P-limiting system. Regression analysis for empirical model, however, showed that Chl had a weak linear relation with TP or TN, and this was mainly associated with turbid, and nutrient-rich inflows in the system. The weak relation was associated with non-algal light attenuation coefficients (Kna), which is inversely related water residence time. Thus, values of Chl had negative functional relation (R² = 0.25, p < 0.001) with nonalgal light attenuation. Thus, the low chlorophyll at a given TP indicated a light-limiting for phytoplankton growth and total suspended solids (TSS) was highly correlated (R² = 0.94, p < 0.001) with non-algal light attenuation. The relations of Trophic State Index (TSI) indicated that phosphorus limitation was weak [TSI (Chl) - TSI (TP) < 0; TSI (SD) - TSI (Chl) > 0] and the effects of zooplankton grazing were also minor [TSI (Chl) - TSI (TP) > 0; TSI (SD) - TSI (Chl) > 0].

• Journal of Ecology and Environment
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• 제40권1호
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• pp.24-33
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• 2016

Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations ($t_{au}=-0.143$, z = -0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- ($t_{au}=-0714$, z = -2.351, p = 0.0187) and after the construction ($t_{au}=-0.868$, z = -4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of "TSI(SD) - TSI(CHL)" against "TSI(TP) - TSI(CHL)" showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.

• Journal of the korean society of oceanography
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• 제38권4호
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• pp.185-210
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• 2003

This paper describes and assesses the parameterisation of MP, the microplankton compartment of the carbon­nitrogen microplankton­detritus model. The compartment is 'the microbial loop in a box' and includes pelagic bacteria and protozoa as well as phytoplankton. The paper presents equations and parameter values for the autotroph and microheterotroph components of the microplankton. Equations and parameter values for the microplankton as a whole are derived on the assumption of a constant 'heterotroph fraction'. The autotroph equations of MP allow variation in the ratios of nutrient elements to carbon, and are largely those of the 'cell­quota, threshold­limitation' algal growth model, which can deal with potential control of growth by several nutrients and light. The heterotroph equations, in contrast, assume a constant elemental composition. Nitrogen is used as the limiting nutrient in most of the model description, and is special in that MP links chlorophyll concentration to the autotroph nitrogen quota.

• 생태와환경
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• 제36권2호통권103호
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• pp.139-149
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• 2003

팔당호 식물플랑크톤의 제한영양염과 생리학적 성장 특성을 평가하기 위하여 2002년 3월부터 10일까지 팔당호의 수질환경 조사와 함께 실내 배양실험을 실시하였다. 총인의 농도와 Chl. a의 상관성 분석결과, 팔당호의 호수생산성은 인의 영향을 많이 받으며 TN/TP ratio와 식물플랑크톤의 성장잠재력 실험을 통해서도 제한영양염은 인으로 평가되었다. 특히, 봄철이 다른 계절에 비해 상대적으로 용존무기인이 낮은 농도로 존재하기 때문에 높은 인 제한을 받는 것으로 나타났다. 그러나 인의 제한정도는 계절적인 변이를 나타내었으며, 시기에 따라 질소와 규소에 의한 제한가능성도 나타났다. 팔당호 식물플랑크톤 군집의 최대성장률(${\mu}_{max}$)은 0.8${\sim}$l.1$day^1$의 범위로 나타났으며, 반포화농도($K_u$)는 0.1${\sim}$O.8${\mu}M$로 5월에 $0.8{\mu}M$로 가장 높고 9월에 $0.1{\mu}M$로 가장 낮은 것으로 조사되었다. 이는 영양염 흡수에 영향을 미치는 인의 cell quota와 관련이 있는 것으로 나타났으며, 5월에 $0.13{\mu}gP/{\mu}gChl.$ 3로 낮은 값을 나타냈다. 식물플랑크톤의 성장특성 분석을 통해 팔당호에서는 봄에 비해 여름과 가을철에 발생한 식물플랑크톤의 성장이 경쟁적으로 빠르게 발달할 수 있는 잠재성이 있는 것으로 판단된다. 결과적으로, 팔당호 식물플랑크톤 성장은 주로 인에 의하여 제한되며 여름 몬순 이후 수체의 안정기동안 높은 성장을 할 수 있는 생리적 특성을 가지고 있는 것으로 추정된다.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.167-171
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• 1995

A bacterial strain C-02 using methanol as a carbon source was isolated from Gumi Industrial Estate and selected based on its rapid growth and capability of poly-$\beta$-hydroxybutyrate accumulation. Characteristics of strain C-02 showed that it belongs to the Methylococcaceae family, Type II subgroup. Strain C-02 could incorporate valerate into the PHB chain to form 3-hydroxybutyrate and 3-hydroxyvalerate (P(3HB-co-3HV)). Among various nutrient limitation tests, the nitrogen limitation test resulted in the highest content of P(3HB-co-3HV) per dry cell weight, 50$%$. Under the nitrogen limited condition, the average molecular weight of P(3HB-co-3HV) obtained was determined to be approximately $2.8\times 10^5$ daltons.