• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.284-295
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• 1990

Dietary levels of 0%, 0225%, 0.45% inorganic phosphorus in the form of tricalcium phosphate were included in two different experimental diets, which contains 40% of wheat bran with or without extrusion. It is to examine the effects of extruded wheat bran containing different Bevels of inorganic phosphorus on the performance of broiler chicks, including the nutrient availabilities, compared with that of the diet containing non－extruded wheat bran. The results are as follows； 1. Regardless dietary levels of inorganic phosphorus, the weight gain in general was higher for the groups fed non－extruded wheat bran but little significance was seen between the groups of extruded and the non－extruded. However, the effect of dietary inclusion of inorganic phosphorus on the weight gain was evident and the gain was higher in the groups receiving the higher levies of inorgainc phosphorus but failed to observe the significant difference between the added groups of 0.225% and 0.45% of inorganic phosphorus, suggesting that a considerable amount of phytin phosphorus in wheat bran is available to meet the requirement. 2. For the feed intake, there was a tendency for the groups fed extruded wheat bran consuming more feed, compared with that of the non－extruded but little significance was observed. This was also true between the groups of receiving 0.225% and 0.45% inorganic phosphorus t The feed efficiency was improved by the addition of inorgainc phosphorus, but failed to observe the significance between the added groups. 4. The dry matter digestibility was improved in proportion to increasing the levels of inorganic phosphorus for the both groups of extruded and the non－extruded This indicates that addition of extruded wheat bran has little effects on improving the digestibility. 5. Within the added groups of 0.225% and 0.45% inorganic phosphorus, the protein digestibility was increased with including the extruded wheat bran in the diet However, the effect on body weight gain was not evident. 6. The calcium and phosphorus content of tibia was shown the tendency of increasing with increasing the dietary levels of inorganic phosphorus but close correlation with dietary levels of inorganic phosphorus was not noted in tibia contents of calcium and phosphorus.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.90-103
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• 2014

Distribution characteristics of water masses, dissolved inorganic and organic nutrients were investigated in the southern part of the East Sea of Korea in September, 2011. On the basis of the vertical profiles of temperature, salinity and dissolved oxygen, water masses in the study area were divided into 4 major groups, such as WM (water mass)-I, WM-II, WM-III, WM-IV. Their characteristics were similar to Tsushima Surface Water (TSW), Tsushima Middle Water (TMW), North Korea Cold Water (NKCW) and East Sea Proper Water (ESPW), respectively. In the vertical profiles of dissolved nutrients, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) concentrations were highest in the WM-IV, followed by WM-III, WM-II, WM-I. On the contrary, distribution of dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) were highest in the WM-I, followed by WM-II, WM-III, WM-IV. Although the DIN : DIP ratio in all of the water masses was similar to Redfield ratio(16), the DIN : DIP ratio in mixed layer was about 5.3, indicating that inorganic nitrogen is the limiting factor for the growth of phytoplankton. However, the DON proportion in dissolved total nitrogen (DTN) was about 70% in the mixed layer where inorganic nitrogen is limiting factor. Thus, enriched DON may play an important source of the nutrient for the growth of phytoplankon in the East Sea.

• Food Science of Animal Resources
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• v.28 no.1
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• pp.27-31
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• 2008

This study investigated the effects of copper and zinc sources on growth performance, nutrient digestibility, carcass traits and meat characteristics in finishing pigs. Dietary treatments included 1) inorganic copper ($CuSO_4{\cdot}5H_2O$ 30ppm), 2) organic copper (Cu-methionine, 30 ppm), 3) inorganic zinc (ZnO, 80 ppm) and 4) organic zinc (Zn-methionine, 80 ppm). ZnO treatment improved the ADFI (average daily feed intake) compared to Cu-met and Zn-met treatments (p<0.05) during 5 weeks of treatment. However, during the entire experimental period, the ADG (average daily gain), ADFI and F:G ratio (feed conversion ratio) were not significantly different among the treatments (p>0.05). DM and N digestibility were not significantly different among the treatments after 5 weeks (p>0.05). At the end of the experiment, DM and N digestibility were decreased with Zn-met treatment relative to the other three treatments. The pH value of meat from $CuSO_4$ treated pigs was greater than Zn-met and ZnO treated pigs (p<0.05). Sensory evaluation was carried out for randomly selected (n = 16) paired loin samples. Meat color levels were increased (p<0.05) with Cu treatments compared to Zn treatments. $CuSO_4$ decreased the marbling of meat relative to the other treatments (p<0.05). The firmness was greater with ZnO treatment compared to Cu-met and ZnO treatments (p<0.05). These results indicate that inorganic Zn can improve growth performance, however, inorganic Cu and Zn are as effective as organic Cu and Zn at improving nutrient digestibility, carcass traits and meat quality. This form of organic additive can be friendlier to the environment than inorganic supplements.

• Ocean and Polar Research
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• v.45 no.3
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• pp.103-111
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• 2023

To evaluate the impact of effluents from land-based fish farms on the coastal ocean of Wando, Korea, we analyzed inorganic nutrients, particulate organic carbon (POC), dissolved organic carbon (DOC), and colored dissolved organic matter (CDOM) in the effluent and influent of land-based fish farms during the summer (July) of 2021. The average concentrations of nutrients (Dissolved inorganic nitrogen, phosphorus, and silicate; DIN, DIP, and DSi, respectively) in the effluents of this study area were 17±3.7 μM, 1.4±0.7 μM, and 14±1.6 μM, respectively. The average concentrations of POC and DOC were 37±22 μM and 81±13 μM, respectively, with POC accounting for about 30% for total organic carbon in effluents. The Reduced Dissolved Inorganic Nitrogen/Total Dissolved Inorganic Nitrogen ratio (0.7), potential short-period index, indicates that the discharge of nutrients excreted by the fish and unconsumed feed into coastal water results in such nutrients being deposited and accumulated in the sediment. Subsequently, this continuous accumulation triggers the release of ammonium ions during organic matter decomposition, and the ammonium-enriched waters that encroach on fish farms as influent seem to be due to the diffusion of high concentrations of ammonium from bottom sediment. Furthermore, we used fluorescence indices to examine the characteristics of organic matter sources, obtaining mean values of 1.54±0.19, 1.06±0.06, and 1.56±0.06 for the humification index, biological index, and fluorescence index, respectively, in the effluent. These results indicate that the organic matters had an autochthonous origin that resulted from microbial decomposition, and such organic matters were rapidly generated and removed by biological activity, likely supplied from the sediment. Our results suggest that the effluent from land-based fish farms could be a potential source of deoxygenation occurrence in coastal areas.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.525-535
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• 2023

In thi study, we unveil the intricate interplay among picophytoplankton (0.2-2 ㎛) communities, warming surface water temperatures, and major inorganic nutrients within the southwestern East Sea from 2003-2022. The observed surface temperature rise, reflecting global climate trends, defies conventional seasonal patterns in temperate seas, with highest temperatures in summer and lowest in spring. Concurrently, concentrations of major dissolved inorganic nutrient display distinct seasonality, with peaks in winter and gradually declining thereafter during spring. The time course of chlorophyll-a concentrations, a proxy for phytoplankton biomass, reveals a typical bimodal pattern for temperate seas. Notably, contributions from picophytoplankton exhibited a steady annual increase of approximately 0.5% over the study period, although the total chlorophyll-a concentrations declined slightly. The strong correlations between picophytoplankton contributions and inorganic nutrient concentrations is noteworthy, highlighting their competitively advantageous responsiveness to the shifting nutrient regime. These findings reflect significant ecological implications for the scientific insights into the marine ecosystem responses to changing climate conditions.

• Environmental Engineering Research
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• v.21 no.3
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• pp.265-275
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• 2016

In this study, the microalga Neochloris oleoabundans was cultivated in a sustainable manner using diluted anaerobic digestate to produce biomass as a potential biofuel feedstock. Prior to microalgae cultivation, the anaerobic digestate was characterized and several pretreatment methods including hydrogen peroxide treatment, filtration, and supernatant extraction were investigated and their impact on the removal of suspended solids as well as other organic and inorganic matter was evaluated. It was found that the supernatant extraction was the most convenient pretreatment method and was used afterwards to prepare the nutrient media for microalgae cultivation. A bench-scale experiment was conducted using multiple dilutions of the supernatant and filtered anaerobic digestate in 16 mm round glass vials. The results indicated that the highest growth of the microalga N. oleoabundans was achieved with a total nitrogen concentration of 100 mg N/L in the 2.29% diluted supernatant in comparison to the filtered digestate and other dilutions.

• Korean Journal of Environmental Biology
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• v.31 no.2
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• pp.61-68
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• 2013

Microalgae can grow autotrophically with the supply of light, carbon dioxide and inorganic nutrients in water through photosynthesis. Generally, microalgal growth is limited by the concentrations and relative ratio of nitrogen (N) and phosphorus (P) among the nutrients in the aquatic environment. Each microalga has its specific optimum N : P ratio resulting in dominance in a particular water having similar nutrient composition. Algal bloom is an immense growth of certain microalga commonly cyanobacterium and can be sequestrated by reducing the limiting nutrient, generally P in the freshwater. Moreover, dominance of a less toxic blooming strain can be established by manipulating N : P ratio in the water. On the other hand, microalgal biomass of a certain species can be enhanced by increasing limiting nutrient and adjusting the N : P ratio to the target species. The above-mentioned eco-physiological features of microalgae can be more completely interpreted in connection with their genomic informations. Consequently, microalgal growth regulation which can be achieved on the basis of its eco-physiological and further genomic insights would be helpful not only in the control of algal bloom, but also for an increased yield of algal biomass.

• ALGAE
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• v.17 no.3
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• pp.187-194
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• 2002

A seaweed biofilter/production system of being developed to reduce the environmental impact of marine fish farm effluent in coastal ecosystems as a part of an integrated aquaculture system. Several known seaweed taxa and their cultivars have been considered as candidate biofilter organisms based on their species-specific physiological properties such as nutrient uptake kinetics and their economic value. Porphyra is an excellent cadidate and shows efficient nutrient extraction properties. Rates of ammonium uptake were maintained at around 3 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ at 150 ${\mu}M$ inorganic nitrogen at $10^{\circ}C$. Ulva is another possible biofilter candidate with an uptake rate of 1.9 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ under same conditions. A simple uptake/growth and harvest model was applied to estimate the efficiency of the biofilter/production system. The model was deterministic and used a compartment model structure based on difference equations. The efficiency of Porpyra filter was estimated over 17% of ${NH_4}^+$ removal from the contimuous supply of 100 ${\mu}mole{\cdot}l^{-1}\;{NH_4}^+\;at\;100l{\cdot}sec^{-1}$ flow rate.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.7-12
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• 2007

This study was conducted to clarify the effects of the different concentration of the nutrient solution on the early growth and the nutritional contents of hydroponically grown Aster koraiensis, Hemerocallis fulva and Plantago asiatica at 70 days after transplanting in perlite culture. Balanced nutrient solution formulated by Japanese Horticultural Experiment Station was used as the standard concentration of the nutrient solution. Overall plant growth of Aster koraiensis and Hemerocallis fulva such as plant height, stem diameter, number of loaves, fresh and dry shoot and root weight were significantly increased in 1.5 times concentration of nutrient solution. Shoot and root fresh and dry weight of hydroponically grown Plantago asiatica were significantly increased in the higher concentration of the nutrient solution, however, number of loaves and root length were significantly increased in the standard and the lower concentration of the nutrient solution. The highest contents of calcium, magnesium and sodium in plants were shown in Aster koraienxis which were grown in the 1.5 times concentration of nutrient solution, and Hemerocallis fulva and Plantago asiatica in 0.25 times of that. The contents of potassium in Aster koraiensis and Hemerocallis fulva were significantly increased when the plants were grown in the 0.5 times concentration of the nutrient solution, and that in Plantago asiatica in the 1.5 times concentration of the nutrient solution. The contents of phosphoric acid in plants as affected by the different species of Namul and the different concentration of the nutrient solution were not significant.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.421-427
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• 2020

In this study, we investigated the effect of nutrient supply periods on the fruit growth and quality of 'Duke' blueberry. The nutrient solution was contained with NO₃-N 4.6, NH₄-N 3.4, PO₄-P 3.3, K 3.0, Ca 4.6, and Mg 2.2 mmol·L^-1, and EC in the nutrient solution was 1.5 ds.m^-1. In 2017 and 2018, an individual blueberry bush was supplied with 8 L of the nutrient solution per week. In 2018, the drainage water quality of growing medium and fruit quality was investigated. The nutrient supply was started from April 01, and stopped at 15 days intervals as follows, 15 days before final harvest, at the final harvest date (June 30), 15 days after final harvest (DAFH), 30 DAFH, 45 DAFH, and 60 DAFH. The content of inorganic components in the growing medium was not significantly different by the stop time of nutrient supply, but the content of phosphorus (P₂O₅) tended to increase with the delay of stop time of nutrient supply. There were no significant differences in the fruit quality characteristics in terms of size, sugar content, and acidity among the different stop time of nutrient supply. The blueberry yield was tended to decrease with the delay of periods of nutrient supply, while the lowest yield of 1.8 kg was recorded when nutrient supply stopped at 45 and 60 DAFH.