• 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].

• 한국환경복원기술학회지
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• 제20권4호
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• pp.1-13
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• 2017

The purpose of this study is to analyze a term of decade of water quality data of the Mulgum intake station on the Nakdong river(dam) to find the cause of algal blooms and to set an alternative to prevent artificial lake water pollution. Our study shows that water quality changes have regular periodic regularity and there was a certain correlation between specific analytical items. According to the analysis results of each factor, the decline in precipitation was not the main reason for algal blooms. TP concentration had a slight effect on Chl-a concentration but was not a limiting nutrient of a bloom. TN concentration had a strong correlation with Chl-a and strongly negative correlation with temperature, but was not a bloom's limiting nutrient, and was only a dependent variable. As the temperature was negatively correlated with the Chl-a concentration, it is found that the aspect of the ecological influence of the temperature was the most important factor of the phytoplankton concentration change. The N/P ratio lies under a power function with a high degree of reliability by the TP concentration, and the phenomenon appeared to be the same as the results of two other comparative areas. This result confirms that TN is dependent on TP and the biota in the lake that TN is a dependent variable whose concentration is determined by TP it. In conclusion, the increase in lake bloom is the result of a food chain change, and it is necessary to control the ecosystem by the food chain in the lake in order to reduce the lake's bloom. In particular, it is important to keep the benthic ecosystem as wide as possible in the aerobic state.

• 생물환경조절학회지
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• 제6권1호
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• pp.27-33
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• 1997

This experiment was carried out to investigate the effects of limited nutrient supply during 21 days before and after pollination stage on the growth, fruit quality and nutrient uptake of muskmelon in rockwool culture. Muskmelon, cv. Earl's Favorite seeds sowed on rockwool cube and transplanted on rockwool slab($90\times15\times7.5cm$) when 2 to 3 true leaf appeared on Sep. 6, 1991. Three kinds of nutrient composition recommended by Shizuoka university, combinated with the composition of Otsuka house A and composition Shizuoka III. One half of calcium nitrate(Ca(NO$_3$)$_2$.4$H_2O$) for limiting nitrogen supply during 21 days was treated and then fertigated the nutrient composition recommended by Shizuoka university up to harvest time. Trickling nozzles(Netafim Co. Israel) were used for fertigation of nutrient solution and noncirculating system was employed. Temperature was maintained $18^{\circ}C$ in night but 23 to $25^{\circ}C$ for 10 days after pollination for softening the fruit. The drainage ratio of nutrient solution was adjusted 20 to 30 percent. Fertigated and drained amount, and the pH and EC of nutrient solution were recorded. The concentrations of mineral elements including N, P, K, Ca, and Mg were analyzed and compared among treatments. In both autumn and winter cultivation, the limitation of nutrient supply by adjustment of nutrient composition(NO$_3$-N : 8meㆍ$\ell^{-1}$) caused the nutrient deficiency in muskmelon plant due to the limited nutrient supply. After pollination nutrient limitation by the lowering the nitrate retarded the over thickening of upper leaves of muskmelon but plant height and fresh weight of fruit were higher in the plot of nonlimited nutrient supply. The phenomena were attributed to the differences of the amount of nutrient uptake due to the limited time of nutrient solution, duration of nutrient supply and concentration of nutrient solution. These results suggested that increasing nutrient supply in the pollination stage was favorable for better appearance of fruit and improving fruit quality. Further trials would be required for the incre-ment of sugar degree of muskmelon grown in rockwool.

• 생태와환경
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• 제41권spc호
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• pp.35-41
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• 2008

본 연구는 2006년 6월 22일부터 28일까지 식물성 플랑크톤의 1차 생산력을 알아보기 위하여 영양염 첨가 실험을 실시하였다. 평가를 위한 샘플은 저수지 중앙부에서 총 10L를 채수하였으며, Cubitainer에 각각 2.5L씩 분배하였다. 대조군은 원수를 그대로 사용하였으며, 처리군 1에는 $KH_2PO_4$을 첨가하였고, 처리군 2에는 2배 더 많은 $KH_2PO_4$을 첨가하여 각각 P, 2P가 되도록 하였다. 또한 처리군 3에는 $KNO_3$를 첨가하여 $NO_3-N$가 되도록 하였으며, 처리군 4에는 $KH_2PO_4$와 $KNO_3$을 첨가하여 $P+NO_3-N$가 되도록 하여 7일 동안 변화를 관찰하였다. P(T1)와 2P(T2)가 처리된 Cubitainer의 엽록소-${\alpha}$ 농도는 실험기간 동안 점점 감소하였고, 초기의 농도에 비하여 훨씬 낮은 수치를 보였다. 그러나, $NO_3$(T3)와 $P+NO_3$(T4)가 처리된 Cubitainer의 경우, 초기의 엽록소-${\alpha}$ 농도에 비하여 뚜렷하게 증가하는 것으로 나타났다. 단기 실험의 경우 질소가 일차적인 제한요인으로 작용한 것으로 사료되었다. 장기간에 걸친 TP, TN, TN: P mass ratios의 자료에 따르면, 인이 식물 플랑크톤의 성장에 제한요인으로 작용하였고, 채집된 시기와 장소에 따라 제한염류가 변하는 것으로 연구되어 졌다. 본 연구에서 질소는 1차 제한영양염류로 작용하였고 계절적인 영향에 의한 것으로 사료되었다.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.5-11
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• 2016

Background: As the decomposition of lignocellulosic compounds is a rate-limiting stage in the nutrient mineralization from organic matters, elucidation of the changes in soil enzyme activity can provide insight into the nutrient dynamics and ecosystem functioning. The current study aimed to assess the effect of thinning intensities on soil conditions. Un-thinned control, 20 % thinning, and 30 % thinning treatments were applied to a Larix kaempferi forest, and total carbon and nitrogen, total carbon to total nitrogen ratio, extractable nutrients (inorganic nitrogen, phosphorus, calcium, magnesium, potassium), and enzyme activities (acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, ${\beta}$-glucosaminidase) were investigated. Results: Total carbon and nitrogen concentrations were significantly increased in the 30 % thinning treatment, whereas both the 20 and 30 % thinning treatments did not change total carbon to total nitrogen ratio. Inorganic nitrogen and extractable calcium and magnesium concentrations were significantly increased in the 20 % thinning treatment; however, no significant changes were found for extractable phosphorus and potassium concentrations either in the 20 or the 30 % thinning treatment. However, the applied thinning intensities had no significant influences on acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, and ${\beta}$-glucosaminidase activities. Conclusions: These results indicated that thinning can elevate soil organic matter quantity and nutrient availability, and different thinning intensities may affect extractable soil nutrients inconsistently. The results also demonstrated that such inconsistent patterns in extractable nutrient concentrations after thinning might not be fully explained by the shifts in the enzyme-mediated nutrient mineralization.

• 환경생물
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• 제33권1호
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• pp.1-6
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• 2015

전세계적으로 2000년대 이후로 남조류에 의한 녹조의 발생이 증가하고 있으며, 이와 관련된 환경 문제가 공중건강을 위협하고 인간 활동을 제한하고 있다. 1970년대 캐나다의 호수를 중심으로 수행된 다년간의 현장 연구를 통하여, 녹조발생의 핵심적인 영양 제한인자로 인이 제시되었고, 인 저감에 대한 수계 관리가 진행되었다. 그러나 2000년대 이후, 대형 담수수계에서 특히 Microcystis에 의한 녹조 현상에서는 인뿐만 아니라 질소가 남조류 녹조 발생에 미치는 영향이 부각되고 있다. 한국의 담수 수계에서도 이와 비슷한 남조류에 의한 위해성 녹조 번성 특징을 갖고 있으므로, 이러한 패러다임의 변화는 국내 담수수계의 영양염류 관리에서 중요한 의미를 갖는다. 최근 국제적인 관련 연구를 통하여, 위해성 남조류 번성을 막기 위해 제안된 방법은 다음과 같다. 1) 질소와 인을 함께 관리하는 전략, 2) 폐수의 수집 및 처리, 3) 호소 유입수의 사전처리, 4) 저니의 준설, 5) 체류시간의 단축, 6) 조류의 효율적 회수법, 7) 조류의 침강 및 응집 등이 제시되고 있다. 추가적으로 남조류의 생태학적 특성에 기반한 지속가능하고 통합적인 담수수계의 녹조 관리기법이 수립되어야 한다. 녹조를 유발하는 남조류는 척결되어야 할 생물체가 아니라, 담수 수계에 필수적인 미생물 구성원이기 때문이다.

• 생태와환경
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• 제36권2호통권103호
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• pp.161-171
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• 2003

본 연구는 도심에 위치한 얕은 인공호수의 수질변화 특성, 제한영양염 및 퇴적물 특성을 평가하기 위해서 이루어졌다. 일감호는 연 평균 엽록소 a($77.2{\pm}36.6\;{\mu}g/l)와 TP ($66.6{\pm}20.5\;{\mu}g/l)농도 그리고 영양상태지수 (>60)모두를 토대로 할 때 매우 부영양상태였다. 결빙시기와 해빙되는 시기에 수층내 무기질소와 인의 수체내 농도가 증가하였다가 여름철에는 감소하는 계절적인 변화가 나타났다. 수체내 DIN/DIP(무게비)비율과 TSI편차분석 그리고 생물검정 (AGP)실험을 통해서 질소와 인 모두가 식물플랑크톤의 성장을 제한함이 제시되었다. TSI편차분석 결과에서는 1년 중 생물검정을 통해서도 인 제한이 예측된 바 있는 9월부터 11월에 인과 질소 모두의 식물플랑크톤 성장에 대한 제한정도가 가장 큰 것으로 나타났다. 퇴적물내 인 함량(313${\pm}$155mgP/kg)은 계절에 따른 변화를 나타났고, 인용출률은 pH9에서 0.29${\pm}$0.02Pmg $m^{-2}$ $day^{-1}$로 가장 높았다. 질소함량은 평균 4,452${\pm}$283.0 mg N/kg였으며 계절에 따른 큰 차이는 없었다. 이러한 결과들은 퇴적물이 제한영양염의 공급원으로서의 중요한 역할을 수행하며, 퇴적물내 인 함량의 계절에 따른 변화가 조류의 생물량을 조절할 수 있음을 의미한다.

• 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.

• Journal of the korean society of oceanography
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• 제39권4호
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• pp.222-233
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• 2004

Using nitrogen as the limiting nutrient, the default version of a microplankton-detritus model linked chlorophyll concentration to the autotroph nitrogen. However, phosphorus dynamics were added to simulate the results of a microcosm experiment. Using standard parameter values with a single value of microheterotroph fraction in the microplankton taken from the observed range, the best simulation successfully captured the main features of the time-courses of chlorophyll and particulate organic carbon, nitrogen and phosphorus, with root-mean-square error equivalent to 29% of particulate concentration. A standard version of microbiological model assumes complete internal cycling of nutrient elements; adding a term for ammonium and phosphate excretion by microheterotrophs did not significantly improve predictions. Relaxing the requirement for constant microheterotroph fraction resulted in an autotroph-heterotroph model AH, with dynamics resembling those of a Lotka-Volterra predator-prey system. AH fitted the microcosm data worse than did MP, justifying the suppression of Lotka-Volterra dynamics in MP. The paper concludes with a discussion of possible reasons for the success of the simple bulk dynamics of MP in simulating microplankton behaviour.

• 한국환경과학회지
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• 제4권5호
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• pp.469-479
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• 1995

The increase of population and industrial activities had brought into eutrophication in the Nakdong river. A remarkable acceleration of eutrophication brought about serious problems for water supply. Therefore, for the purpose of conservation of water quality in the Nakdong river it is necessary to control nutrients. MBOD method was use to evaluate algal growth limiting factor and algal growth potential in the Nakdong river from June to August 1994. The modified biochemical oxygen demand(MBOD) depends on the amount of available inorganic nutrient and organic substrate during 5 day incubation in the dark at 2$0^{\circ}C$. The MBOD assay depends on inorganic nutrients such as P and N as well as reduced carbon and called the MBOD, the MBOD-P, and the MBOD-N, respectively. The results of bioassay by MBOD(Modified BOD) method showed that the MBOD, MBOD-P and MBOD-N value were found to be in the ranges of 3.8~96.0 mg$O_2$/l, 5.6~94.0 mg$O_2$/l and 42.0~220 mg$O_2$/l, respectively. And the the bioassay value was found to be the highest in Koryong area and the lowest in Waekwan area throughout the Nakdong river. The variations of MBOD-P and MBOD-N value showed similar tendencies to the variations of phosphorus and nitrogen value, respectively. By MBOD method, the relationships of MBOD, MBOD-P and MBOD-N value were MBOD ≒ MBOD-P 《 MBOD-N. The MBOD value was nearly equal to the MBOD-P value, and the MBOD-N value was 3 to 20 times more than the MBOD-P value, approximately. Therefore, in the Nakdong river, phosphorus was the limiting factor for algal growth during summer season. The algal growth potential as the concentration of chlorophyll-a in the summer was maximum 5 times more than standing crop as it.