• Journal of Environmental Science International
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• v.28 no.11
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• pp.1005-1017
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• 2019

Environmental factors and changes in phytoplankton community structure before (August 5, 2017), during (August 18 and 25) and after (August 30 and September 15) freshwater input were analyzed to investigate the effects of freshwater input from Ganwol and Bunam lakes located in the upper part of Cheonsu Bay. Due to the large amount of freshwater input in the Cheonsu Bay, the surface salinity of the bay decreased by more than 8 psu, and the thermocline existing in the bay during August weakened. In addition, hypoxic phenomena occurred temporarily in the bay as the low oxygen water mass from the freshwater lakes flowed into the bay, and chemical oxygen demand, nutrients, and N/P increased with freshwater inflow. The density of phytoplankton during the freshwater inflow increased owing to their input from the freshwater lakes. Diatom species (Eucampia zodiacus) dominated the phytoplankton community in the bay before freshwater input; nanoflagellates, chlorophyta, cyanobacteria, and diatoms (Pseudonitzschia delicatissima, Chateocceros spp.) entered during freshwater input; and after freshwater inflow ended, diatoms (Chateocceros spp.) again became predominant indicating a return to previous conditions. The amount of phytoplankton standing crops increased sharply due to the inflow of freshwater species into the bay on the second day of discharge compared to before freshwater input; pre-discharge conditions were restored at most stations except at some sites close to the Bunam Lake three days after discharge. Therefore, the large amount of freshwater flowing into the bay affects not only the geochemical circulation in the bay but also the phytoplankton community structure. In particular, the high concentration of nutrients in the freshwater lake affect the marine ecosystem of the bay during August.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.173-181
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• 1993

Seasonal distributions of nutrients and particulate organic matter were investigated in Asan Bay, Korea. Most of nutrients were high in August and low in February. The atomic ratios of inorganic nitrogen to phosphorous were close to Redfield ratio except in May when the ratio was 24.8. In May, nutrient concentrations except phosphorous decreased with salinity until $31.5{\sim}32.0%0$, but the concentrations increased again with salinity, impling that there were nutrient input sources within the estuary. Howerer, significant inverse relationships between nutrients and salinity in August suggest that nutrient sources were river discharge. Maximum chlorophyll a concentrations occurred in May. Relatively low ratios of $R_b$ to $R_a$($R_b$: fluorescence before acidification; $R_a$: fluorescence after acidification) during the study periods indicate that phytoplankton were not in good physiological condition. Relatively low ratio of particulate biogenic silica(PBSi) to particulate organic carbon(POC) and high ratios of PBSi and POC to chlorophyll a during the study periods suggest input of non-living detrital PBSi and POC from bottom in Asan Bay, where strong tidal mixing occurs.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.619-628
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• 2018

This study analyze the economic effect of chemical fertilizer. We used the input and output data, and the analysis variables include production output nitrogen, phosphoric acid, potassium, seeds, and labor. The main results are as follows. First, for spring potatoes, potassium increases to a certain level of output, but over a certain stage, the output decreases as the input increases. Optimal use of potassium in the calculation of spring potatoes can achieve the effect of reducing input costs and increasing output simultaneously. Second, radish In autumn, nitrogen increases to a certain level, but over a certain stage it represents a reverse U-shaped relationship in which output decreases as input increases. This means that reducing the amount of fertilizer input increases the output. This means that soil-related agricultural big data can contribute to the management of nutrients and greenhouse gas reduction in agricultural land.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.423-431
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• 2001

Animals are one of the important memberships of the food chain. The low-efficiency rule of nutrient transfer from one member to the next in the food chain determines the low efficiency of animal agriculture for human food. On the average, about 20% feed proteins and 15% feed energy can be converted into edible nutrients for humans. The rest proportion of feed nutrients is exposed to the environment. Environmental pollution, therefore, is inevitable as animal agriculture grows intensively and extensively. The over-loading of the environment by nutrients such as nitrogen, phosphorus from animal manure results in soil and water spoilage. The emission of gases like $CH_2$, $CO_2$, $SO_2$, NO, $NO_2$ by animals are one of the contributors for the acidification of the environment and global warming. The inefficient utilization of natural resources and the probable unsafety of animal products to human health are also a critical environmental issue. Improving the conversion efficiency of nutrients in the food chain is the fundamental strategy for solving environmental issues. Specifically in animal agriculture, the strategy includes the improvements of animal genotypes, nutritional and feeding management, animal health, housing systems and waste disposal programs. Animal nutrition science plays a unique and irreplaceable role in the control of nutrient input and output in either products or wastes. Several nutritional methods are proved to be effective in alleviating environmental pollution. A lot of nutritional issues, however, remain to be further researched for the science of animal nutrition to be a strong helper for sustainability of animal agriculture.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.769-779
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• 2017

Nutrient (i.e., nitrogen and phosphorus) budgets are required under a 'Livestock Excreta Survey'. A nutrient budget is one of the agri-environmental indicators that calculates the difference between the inputs and outputs of the amount of nutrients within a certain boundary and for a certain time period (e.g., 1 year). In this study, a nutrients budget model was developed to effectively determine the surplus of nutrients within a region in Korea. The C# program language was used in order to facilitate the deployment of a graphical user interface (GUI) and to enhance compatibility. Also, the model was developed on Windows OS, which is the commonly used operating system in Korea. The model was based on the OECD/Eurostat nutrient budget method, and it was modified to consider manure composting procedures as well. There are key features of the nutrient budget model, including directly use of the original data sets from various input and output sources, and a collectively exchange of the address in different formats. The model can quickly show the results of various spatial and temporal resolutions with the same data, as well as perform a sensitivity analysis with coefficients and easily compareresults using tables and graphs. Further, it would be necessary to study the extension of the scope of utilization, such as the application of various nutrient budget methods. It would also be helpful to investigate both pre and postprocessing information such as linking input data through online systems.

• Korean Journal of Community Nutrition
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• v.19 no.4
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• pp.372-385
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• 2014

Objectives: The purpose of this study was to develop web-based self-nutrition management u-Health program for diabetic patients (DMDMG: Diabetes Mellitus Dietary Management Guide) for achieving systematic self-management of diet. Methods: The program consisted of five parts with different contents according to the results of needs assessment. Five major parts were 1) meal management part which contains calorie prescription, meals recording and dietary assessment, 2) prevention of disease part with information of diabetes and assessment of dietary behavior, 3) dietary behavior modification part with an education on dietary behavior modification plan and dietary behavior plan, 4) meal plan containing a training section for meal plan and self constructing part for meal planning by making tables, and 5) information about myself which composed with general and physical information. The system proposed in this study provides nutrients intake results right after input of diet intake, which is possible with simultaneous calculation of input data in the server with 3,495 food and 1,821 meal data base. The nutrients analysis program was evaluated with 26 diabetic patients with two-day 24 hr recall. Results: The differences of nutrients intakes between DMDMG and CANPRO 3.0 ranged from 13.5-16.5%, which was caused by the differences of databases of the two programs. The characteristics of DMDMG were; 1) it can provide an interactive tailored nutrition management, 2) it is a practical tool of diabetes nutritional management, 3) the program gives motivation for the dietary behavior modification. Conclusions: The effectiveness of whole program needs to be conducted, but the program was an innovative tool for self-management of nutrient intakes, diet behaviors, meal management and tailored nutrition education.

• Journal of Aquaculture
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• v.13 no.1
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• pp.87-99
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• 2000

Field survey on the variational characteristics of water quality and chlorophyll a concentraion were carried out at the 25 stations for four seasons in Kogum-sudo(Straits) southern coast of Korean Peninsula from Feburuary to October in 1993. We made an analysis on biological factor as chlorophyll a concentraion as well as physicio-chemical factors such as water temperature salinity sigma-t transparency dissolved oxygen(DO) chemical oxygen demand(COD) nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and suspended solid(SS). The waters in the Kogum-sudo were not stratified due to the tidal mixing. And the high productivity in photic layer were supported by high nutrients concentration from bottom waters. The high concen-trations of suspended solid in straits had a bad influence upon marine biology of nature and cultivations. In Kogum-sudo had a sufficient nutrients for primary productivity during a year. Especially phosphate and inorganic nitrogen were high the other side silicate was very low. The source of nutrients supply depend on rather mineralization of organic matters and input of seawater from outside than input of freshwaters from lands. Phytoplankton biomass as measured by chlorphyll a concentratiion was very high all the year round and it was controlled by the combination o f several environmental factors especially of phosphate in summer and dissolved nitrogen in other seasons.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.93-100
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• 2004

The content of nutrients such as organic carbon, nitrogen, phosphorus and potassium accumulated on soil layers in Quercus mongolica forest of Mt. Songnisan National Park located at central part of Korea was measured, and then the decomposition constants and decay times of the nutrients were also calculated by the negative coefficience model(O1son,1963). The quantities of organic carton of L-layer, F-layer, H-layer and $A_1$-layer of the forest stand were 231.25 g $m^{-2}$, 291.50 g $m^{-2}$,166.91 g$m^{-2}$ and 174.51 g $m^{-2}$, respectively. The content of organic carbon and nitrogen contained in L-layer and F-layer showed large quantity than those of other layers. The large amount of phosphorus and potassium was observed at the B-layer and $A_1$-layer. On the other hand, the decomposition constants(k) of soil organic matter were as follows : organic carbon (k = 0.3657), nitrogen (k = 0.3319), phosphorus (k = 0.2050), and potassium (k = 0.0934) and the decay times needed to 99% decomposition of nutrients in soil organic matter were as follows: that is, organic carton, nitrogen, phosphorus and potassium was 13.94 years, 15.18 years, 24.79 years, and 55.11 years, respectively. By the application of Turbo Pascal Program on the inflowed and outflowed nutrients to the forest stand,87.67% (714.84 g $m^{-2}$) of organic carbon inflowed was decomposed and 81.62% (1,594.62 g $m^{-2}$) of organic carbon accumulated was decomposed. And 84.98% of nitrogen inflowed was decomposed and 70.26% of nitrogen accumulated was also decayed.50.00% of phosphorus input and 40.31% of potassium input were decomposed, and 38.40% of phosphoyus and 33.03% of potassium accumulated were also decayed, respectively. Therefore, it is suggested that Quercus mongolica forest surveyed in the present study is maintaining in steady state because input and output amounts of nutrients is shown a similar pattern.

• Journal of Environmental Science International
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• v.9 no.5
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• pp.429-436
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• 2000

In order to study on the variational characteristics of water quality and chlorolphyll a concentration the water samples were collected daily or three times a week during the period from April 1990 to November 1991 at Kukdong port located in the northern Kamak bay of Southern Korea I made an analysis on biological factor as chlorophyll a concentration as well as physico-chemical factors such as water temperature salinity sigma-t dissolved oxygen, nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and chemical oxygen demand. In Northern Kamak bay seasonal variations in physical factors such as water temperature salinity and sigma-t were very marked. On the other hand chemical factors such as nutrients concentration and COD were not so. Chemical factors, in particular silicate were influenced by input of freshwater. And the roles of silicate on the seasonal succession of phytoplankton species composition was very low. Phytoplankton biomass as measured by chlorophyll a concentration was very high all the year round and it was controlled by the combination of several factors especially of N/P ratio determined by dissolved inorganic nitrogen.

• Journal of Nutrition and Health
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• v.20 no.1
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• pp.54-64
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• 1987

The purpose of this study is to computerize all the necessary information on the daily food value and nutritional status for individuals and groups. In this research, a FOCUS-16jXT (16 bit personal computer ) compatible with IBM-PCjXT was used, and the database files and programs were created by using the dBASEIII package. The food life evaluation system consists of 3 subsystems of Reference, Nutrition Status Assessment and Food Source. The findings are summerized a8 follows: 1. Reference: This subsystem enables users to proceed to the next step, if necessary, by describing each subsystem. 2. Nutrition Status Assessment. 1) Food Habit Assessment: This subsystem determines whether the user has a good food habit or not, based on the answers for ten questions about daily food life. 2) Obesity Assessment: This subsystem calculates Broca index, which is used as a indicator of obesity. 3) Nutrient Intakes: When personal data such as age, sex, weight, height and food consumptions are input, it is possible to calculate the followings. i) Comparison between the amounts intaked and the recommended dietary daily allowances of various nutrients ii) Nutrient intakes from each food group and their composition rates for the nutrients iii) Nutrient intakes per unit body surface area iv) Composition of lipid intake 3. Food Sources: The appropriate food sources for the lacking nutrients will be recommended to the subjects.