• ALGAE
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• 제32권2호
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• pp.161-170
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• 2017

Fourier Transform Infrared (FTIR) spectroscopy was used to study carbon allocation patterns in response to N-starvation in the nearly ubiquitous diatom Chaetoceros muellerii. The role of gene expression, protein synthesis and transamination on the organic composition of cells was tested by using specific inhibitors. The results show that inhibition of key processes in algal metabolism influence the macromolecular composition of cells and and prior cell nutritional state can influence a cell's response to changing nutrient availability. The allocation of C can thus lead to different organic composition depending on the nutritional context, with obvious repercussions for the trophic web. This also shows that C allocation in algal cells is highly flexible and that C (and the energy associated with its allocation) can be variably and rapidly partitioned in algal cells in response to relatively short term perturbations. Furthermore, the data confirm and extend the utility of infrared spectroscopy as a probe of the metabolic state of autotrophic cells.

• ALGAE
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• 제21권4호
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• pp.433-443
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• 2006

This study was performed to understand the morphological and ecological characteristics of Peridinium bipes var. occultatum Lindem., which is the organism responsible for freshwater red tides in Sangsa dam and Miryang dam reservoirs. The samples were collected from April to July 2004 when the freshwater red tides occurred. In the study, we were able to differentiate P. bipes var. occultatum from P. bipes, a closely related species, by its smaller antapical horn size. In Miryang dam reservoir the red tide occurred only within the area of the upstream, but it was well developed in all of the water area in Sangsa dam reservoir. In 2004 average LTSI (Lake Trophic Status Index; Yang and Dickman, 1993) of Miryang dam reservoir was 3.53 of mesotrophic state and Sangsa dam reservoir was 8.59 of eutrophic state. It was determined, through culture experiments under various conditions that vitamins, trace elements, phosphorus and nitrogen were important contributing factors to the growth of P. bipes var. occultatum. A rapid toxic effect of P. bipes var. occultatum on aquatic organisms such of Daphnia magna and Oryzias latipes was not identified in this study.

• 환경영향평가
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• 제21권3호
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• pp.461-468
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• 2012

In general, long-term changes of ecological factors take a pulse form in which they interact with other factors and go through a repeated increasing and decreasing cycle. The coupling of the two approaches the grid model and the box model in ecological modeling can lead to an in-depth understanding of the environment. The study analyzes temporal variations of major storages with an energy system model that formulizes effectively the relationships among nutrients, phytoplankton, and zooplankton in the Yellow Sea and the East China Sea. An increase of light intensity and standing stock of nutrient increase the magnitude and frequency of pulsing. Also, an immense reduction of nutrient concentration can cause extinction of the pulsing and bring about a steady state. It is concluded that the nutrient loads in freshwater discharge from the Yangtze affect the cycles of major ecological components as well as water quality variables and play an important role in the marine ecosystem.

• 환경영향평가
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• 제27권3호
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• pp.307-321
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• 2018

2017년 5월부터 9월까지 제천시에 위치한 2개의 저수지인 의림지(Ur)와 솔방죽(Sr)을 대상으로 어류상 조사 및 호수생태건강성평가를 실시하였다. 조사기간 동안 채집된 어류는 7과 16속 21종이 출현하였다. 그 중 잉어과 어류가 11종(52.4%), 318개체(46.2%)가 출현하여 우점하는 것으로 나타났고, 검정우럭과(2종, 264개체, 38.4%)가 아우점하는 것으로 나타났다. 전체 출현종 중 참몰개(RA 22.7%, 156개체)가 우점종으로 나타났으며, 아우점종은 파랑볼우럭(19.5%, 134개체), 큰입배스(18.9%, 130개체)로 외래종이 차지하는 것으로 나타났다. 화학적산소요구량(COD), 총인(TP)과 엽록소-a(CHL)를 이용한 부영양화지수($TSI_{KO}$) 분석결과, 두 저수지는 중영양상태를 보이는 것으로 분석되었다. 두 저수지의 수환경영향평가를 위해 LEHA(Lentic Ecosystem Health Assessment) 다변수 모델을 적용하였고, 생태 건강도 모델 값을 산정하였다. 생태건강성평가 결과, 내성종이 각각 56.8%(Ur), 98.3%(Sr)로 나타났으며, 잡식종이 43.9%(Ur), 65.6%(Sr)로 나타나 섭식구조의 단순화로 인하여 내성종과 잡식종의 우점현상을 보였으며, 특히 큰입배스의 상대풍부도가 16.3%(Ur), 31.1%(Sr)로 나타나 생태계가 교란되어 생태건강성이 크게 악화된 것으로 나타났다. 상기 LEHA 다변수 모델을 이용한 의림지(Ur)와 솔방죽(Sr)의 생태건강성 지수 값은 각각 22(의림지), 12(솔방죽)으로서 환경부(2014)의 등급에 의거하였을 때 "악화상태(의림지)", "최악상태(솔방죽)"인 것으로 평가되었다.

• 한국물환경학회지
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• 제20권6호
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• pp.589-596
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• 2004

In this study, the reduction rates of nutrients were suggested to prevent eutrophication on the Hwaong reservoir in the year of 2008 and 2012. With EPA's WASP6 model, future water quality were simulated. In 2008, T-N would be 1.36mg/L and T-P 0.100mg/L on average. ; In 2012, T-N 2.66mg/L and T-P 0.128mg/L. With all the water quality management plans that the government authorities are carrying out, these results indicate that the reservoir would be reach the eutrophic or hypertrophic state according to the Vollenweider's trophic states. Therefore, the Hwaong reservoir requires additional plans for nutrients management. Here, the target water quality to prevent eutrophication of the reservoir sets into mesotrophic state ; T-N 0.475mg/L and T-P 0.02mg/L.(median of Vollenweider index for mesotropphic state) The reduction rates of nutrients on Namyang and Eoeun streams were estimated with uniform treatment method to meet the goal. The results showed that nutrients from two streams should be reduced up to 78% in 2008, and 84% in 2012. Since the ratio of T-N/T-P would be higher than 16 at target years, T-N was not considered as the limiting factor and was not reduced.

• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1152-1158
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• 2016

Morphological and physiological alterations occur in the digestive system of weanling piglets, compromising the performance in subsequent phases. This experiment aimed at verifying the influence of glutamine, glutamate and nucleotides on the carbon turnover in the pancreas and liver of piglets weaned at 21 days of age. Four diets were evaluated: glutamine, glutamic acid or nucleotides-free diet (CD); containing 1% glutamine (GD); containing 1% glutamic acid (GAD) and containing 1% nucleotides (ND). One hundred and twenty-three piglets were utilized with three pigs slaughtered at day zero (weaning day) and three at each one of the experimental days (1, 2, 4, 5, 7, 9, 13, 20, 27, and 49 post-weaning), in order to collect organ samples, which were analyzed for the ${\delta}^{13}C$ isotopic composition and compared by means of time. No differences were found (p>0.05) among treatments for the turnover of the $^{13}C$ in the pancreas ($T_{50%}$ = 13.91, 14.37, 11.07, and 9.34 days; $T_{95%}$ = 46.22, 47.73, 36.79, and 31.04 days for CD, GD, GAD, and ND, respectively). In the liver, the ND presented accelerated values of carbon turnover ($T_{50%}=7.36$ and $T_{95%}=24.47days$) in relation to the values obtained for the GD ($T_{50%}=10.15$ and $T_{95%}=33.74days$). However, the values obtained for the CD ($T_{50%}=9.12$ and $T_{95%}=30.31days$) and GAD ($T_{50%}=7.83$ and $T_{95%}=26.03days$) had no differences (p>0.05) among other diets. The technique of $^{13}C$ isotopic dilution demonstrated trophic action of nucleotides in the liver.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.663-665
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• 2003

A field spectroradiometer SE-590 was used to measure the spectral reflectance of water body. The reflectance was calculated as the ratio of surface water radiance to the standard whiteboard radiance nearly measured at the same time. Water samples were taken simultaneously for determining their chlorophyll-a, suspended solid (SS) and transparency. The relationships between those water quality parameters and spectral reflectance were analy zed using stepwise multiple regression to derive optimal prediction models . The multiple regression was also applied to the SE-590 simulated SPOT bands. The SPOT image of the same day was also analyzed using the same method to compare the statistical results. It showed that the multiple regression models using the SE-590 reflectance data got the best water quality prediction results. The evaluated RMS error of chlorophyll-a, SS and transparency of water quality parameters were 0.57 ug/l, 0.2 mg/l and 0.17 m, respectively, and the RMS errors were 0.36 ug/l, 0.49 mg/l and 0.42 m for SPOT data, respectively. The SE-590 simulated SPOT three bands data obtained the worst results and the RMS errors were 1.77 ug/l, 0.49 mg/l and 0.37 m, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.446-449
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• 2006

It is backscattering of solar radiation by water body that makes ocean color observable from above, either by airplanes or satellites. Given the very low direct contribution to backscattering by phytoplankton cells, it is curious why the retrieval of phytoplankton concentration from remotely observed ocean color is evidently successful. From semianalytical bio-optical models, a dataset is created of spectral absorption, scattering and backscattering coefficients as a function of chlorophyll concentration. Four scenarios are considered, 1) only molecular and no particle scattering, 2) random particle backscattering uncorrelated with chlorophyll concentration, 3) constrained random particle scattering with known backscattering ratio, and 4) constrained random scattering with random backscattering ratio. Scenario 1 only introduces moderate errors of -20% - 90%. And for scenarios 3 and 4, the errors are largely within 30% and 100%. Scenario 2 introduces the largest errors, with the retrieved chlorophyll concentration virtually uncorrelated with the true values, implying the backscattering must somehow be related to the trophic state. The results of the study suggested These 3 cases confirmed that while it is the absorption by phytoplankton that in large part decides the accuracy of chlorophyll concentration retrieval, for the success of monitoring of global ocean primary productivity we have to improve our knowledge on particle backscattering.

• 환경위생공학
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• 제14권4호
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• pp.77-84
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• 1999

Most river quality problems are generated by pollutants which are discharged into the river as a consequence of human activities. And eutrophication occurs when water is over enriched with nutrients, principally nitrate and phosphate. Both these nutrients are found in many waste products, especially sewage even when the waste is treated. Eutrophication is concerned in lakes, but it also causes problems in river. Wide growth of Phytoplankton in rivers, leads to blockage of channels, but the main concern is deoxygenation because of the increase in plant life's demand for oxygen in revers. Fish, plant and animals die due to lack of oxygen. The increase of algae floating on the tops of water looks ugly and has attracted public attention and concern in recent years. One way of controlling eutrophication is to restrict the amount of waste carrying nitrate or phosphate from entering the water in the first place. another way is to remove it from the water after it has been entered. This study was carried out to investigate on the trophic state, nutrients and Chlorophyll-a concentration in the Han River. The results were as follows:1. Concentrations of total nitrogen were 2.208~9.221(5.133)mg/$\ell$2. Concentrations of total phosphate were 0.045~0.614(0.195)mg/$\ell$3. Chlorophyll-a concentration were $0.0-25.3(9.6)mg/m^3$.4. The correlation coefficient between T-P and Chlorophyll-a concentration was r=-0.856 at Sungsan sampling site.5. The correlation coefficient was r=-0.578~-0.767, between Paldang Dam outflow and Chlorophyll-a concentration at all sampling sites.

• 한국환경과학회지
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• 제18권12호
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• pp.1383-1390
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• 2009

This study was performed to investigate the physico-chemical properties and phytoplankton concentration from February to December, 2007 in Gwangju area reservoirs. Water samples from 20 reservoirs were analyze d. As results of the water quality analysis, the average pH was 7.6 and annual pH were 6.3~9.6. The higher pH of 8.6~9.6 were showed from March to August due to eutrophication. Chlorophyll-a concentration ranged from 0.4 to $164.3\;mg/m^3$. The highest chlorophyll-a concentration was observed in August. BOD was correlated with SS, T-N, and Chlorophyll-a(R=0.82, 0.90 and 0.84) respectively. COD was correlated with BOD, SS and Chlorophyll-a(R= 0.89, 0.77 and 0.76) respectively. The T-N/T-P ratios were 4~281, so phosph orus was considered to be the limiting factor in most of points. The trophic state showed eutrophicate states in Gwangju reservoirs. Therefore it was necessary to monitor continuously. In order to monitor the reservoirs, an algae prediction system must be used.