• Journal of Environmental Science International
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• v.12 no.8
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• pp.841-846
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• 2003

The ecosystem model was applied to estimate the regional distribution of the net production(or consumption) of phytoplankton and the net uptake(or regeneration) rate of nutrients in Masan Bay for scenario analysis to find a proper management plan. At the surface level, net production of phytoplankton is 200 mgC/㎡/day at the entrance of the bay, and 400∼1000 mgC/㎡/day at the center of the bay. The inner area of the bay showed more than 2000 mgC/㎡/day. All areas of the bottom level have a net consumption, with the center of the bottom level showing more than 600 mgC/㎡/day. For dissolved inorganic nitrogen, the results showed a net uptake rate of 100∼900 mg/㎡/day at the surface level. It showed that the net regeneration is above 50 mg/㎡/day at the bottom level. For dissolved inorganic phosphorus, the net uptake rate showed 10.0∼80.0 mg/㎡/day at the surface level, and the regeneration rate showed 0∼20.5 mg/㎡/day at the bottom level. Therefore, in order to control the water quality in Masan Bay, it is important to consider the re-supplement of nutrients regenerated in the water column.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.241-246
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• 2016

A filamentous green alga Cladophora vadorum (Areschoug) Kützing, bloomed at Shangrok Beach, Buan, Republic of Korea, in September 2015. This alga is currently distributed worldwide. Concentrations of total nitrogen (TN), total phosphorus (TP), dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) were analyzed in the bloom area and compared to those of other areas in the vicinity. DIN and DIP concentrations were similar to those of other areas. However, TN and TP were as much as six and ten times higher than in other areas, respectively. As in other Cladophora species, the bloom of C. vadorum at Shangrok Beach in 2015 appears to have depended on the TP concentration in the seawater. This suggests that blooms in the area can be controlled by reducing TP.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.533-542
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• 2015

In order to investigate the effect of internal loading from sediment on algal blooming at Chusori area in Daechung Reservoir, the amount and contamination level of sediment and the release rate of total phosphorus were analyzed. The sedimentary layer was consisted with two layers, and the average depth of upper and lower ones were 0.35 and 1.44 m, respectively. The fraction of inorganic phosphorus in the sediment was higher than that of organic phosphorus, and the fractions of phosphorus which responsible for internal loading were very high as in the range of 72.7 and 80.2% of inorganic phosphorus. The C/N ratio of sediment taken with core sampler indicated the organic compounds are originated from settled algae from water body. The average release rate of total phosphorus from sediment was $6.74({\pm}0.50)mg/m^2/day$. These results indicated that the internal loading from sediment contributes the excessive algal growth at Churosi area, and the countermeasures to improve the quality of sediments are required to manage algal blooming in Daechung Reservoir.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.507-511
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• 1996

Medium optimization for xylitol production from xylose by Candida parapsilosis ATCC 22019 mutant was performed. Effect of various nitrogen sources on xylitol production was investigatied. Of inorganic nitrogenous compounds, ammonium sulfate was effective for xylitol production and yeast extract was the most suitable orangic nitrogen nutrient for enhancement of xylitol production. Effect of inorganic salts such as KH$_{2}$PO$_{4}$ and MgSO$_{4}$-7H$_{2}$0 on xylitol production was also studied. Optimal medium was selected as xylose of 50 g/l, yeast extract of 5 g/l, (NH4$_{4}$)$_{2}$SO$_{4}$ of 5 g/l, KH$_{2}$PO$_{4}$ of 5 g/l, MgSO$_{4}$-7H$_{2}$O of 0.2 g/l. In a fermentor by using the optimal medium, a final xylitol concentration of 37 g/l could be obtained from 50 g/l of xylose with a xylitol yield of 74% and a xylitol productivity of 0.58 g/1-hr. At 300 g/l xylose, fermentation was also carried out and then a final xylitol concentration of 242 g/l was obtained at 272 hours. It was corresponding to xylitol yield of 80.7% and xylitol productivity of 0.58 g/1-hr.

• Journal of Environmental Health Sciences
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• v.9 no.1
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• pp.49-62
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• 1983

Evaluation of water quality of Yeong San river and Seomjin river by using of newly simplified MBOD method was performed. Of course, thought that there is some differences between nutrient demands of heterotrophic bacteria and those of Algae which obtain it by photosynthesis, but it has little influence on evaluation of Algae Growth potential. The result of this study were as follows: 1) In both river, the value of Chemical analysis and MBOD method of inorganic salts reveals as nearly same result. 2) Though organic pollution of Seomjin river is less than that of Yeongsan but inorganic contamination is somewhat advanced BOD 2.8 ppm. and MBOD 340 ppm. in Seomjin river but BOD 22 ppm. and MBOD 480 ppm. in Yeongsan river. 3) Both river have tendency to reveal higher Nitrogen value is MBOD=MBOD -P

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.221-227
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• 2004

Nutrient utilization and plasma level of minerals were studied in lactating crossbred cows fed diet supplemented from different source of minerals. Twelve crossbred cows of first to third lactation during their mid stage of lactation were distributed equally under two groups and were fed concentrate mixture, green fodder (para grass) and finger millet straw as per requirement. Cows in group I were fed concentrate mixture supplemented with 1% mineral mixture whereas cows in group II were not supplemented with mineral mixture in the concentrate mixture but were offered additional quantity of green fodder (1 kg DM/cow/day) to compensate for the requirement of minerals. Balance study conducted towards the end of 120 days of feeding experiment indicated that the total dry matter intake in both the groups did not differ significantly. The cows in group II offered additional quantity of green fodder consumed significantly (p<0.05) more of green fodder (5.11 vs. 4.51 kg /animal/day) and the cows in group I consumed significantly (p<0.01) more of finger millet straw (1.71 vs. 0.92 kg/animal/day). The digestibility of major nutrients did not differ between the groups except for ether extract which was significantly (p<0.05) lower in cows fed additional green fodder. The total daily intake of P, Cu, Fe and Co did not differ significantly in both the groups whereas significantly higher intakes of Ca, Mg, Zn and Mn were observed in cows supplemented with inorganic source of minerals. However, supplementation through both the sources could meet the mineral requirement in group I and group II. The gut absorption (%) of all the minerals was comparable between the groups except for Mg which was significantly (p<0.05) higher in cows supplemented mineral mixture. The net retention of all the minerals was significantly more in the group supplemented with inorganic source of minerals. Except for P, Mg and Co the retention as percentage of total intake was comparable for all minerals in both the groups. Irrespective of source of mineral supplementation the average monthly blood plasma mineral levels (Ca, P, Mg, Cu, Zn, Fe) were within the normal range and comparable between the groups. Lower level of Cu observed at the start of the experimental feeding in both the groups increased with the advancement of supplemental feeding. The plasma Zn and Fe content in cows of both the groups did not vary. The blood plasma level of some minerals (Ca, P, Mg and Cu) was significantly higher towards the end of experimental feeding as compared to the initial values due to the reduction in milk yield with advancement of lactation or due to supplemental effect of minerals. It could be concluded that supplementation of minerals through inorganic source is better utilized in terms of retention as compared to green fodder (para grass), which is a moderate source of most nutrients.

• Research in Plant Disease
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• v.15 no.1
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• pp.41-45
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• 2009

In order to study a relationship between soil nutrients and rice brown spot occurrence, paddy field soils, rice grains and straws collected from different paddy fields with different disease degrees of brown spots were analyzed for inorganic nutrients. Brown spot was prevalent in the rice grown in nutrient-deficient soils, which is especially low in macronutrient elements (phosphoric acid, potassium, silicic acids) and micronurients (calcium, magnesium). The soil, however, was high in sodium while organic nutrients and pH level were similar to others. The rice straws with severe brown spot were low in inorganics such as ferrous, copper, T-N, and $P_{2}O_{5}$ while the rice grains with brown spot were low in ferrous, MgO, Zn, and Mn. In the analysis of field type and nitrogen level, the highest disease severity was found in sandy-type field soil, followed by salty-type field soil and disease severity decreased as application level of nitrogen fertilizer increased. As a summary, the most important factor for effective brown spot control in rice is maintenance of proper nutrients in sandy-type field and control of sodium level in salty-type field soil.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.106-118
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• 2001

The chemistry of porewater and exchangeable nutrients of sediment was determined to define potential influence of sediment nutrients on the water quality and the phytoplankton growth in Taechong Reservoir in March and May of 2000. The sediment-water interface showed almost anoxic state, < 0.5 mg $O_2/l$. Conductivity of the porewater was higher 1.9${\sim}$2.6 fold than that of sediment, and its variation was greater in the shallow water. Eh ranged from -12mV to -148 mV and bulk density from $1.17\;g/cm^3$ to $1.30\;g/cm^3$ and they did not differ among stations. The water content in the sediment ranged from 58% to 72% and organics from 8% to 13%, and they were higher toward the lower part of reservoir. Soil texture was in the order of sand>clay>silt and sandy sediment accounted for 97% of the total sediment. The total bacterial numbers and diatom abundance were high in the downstream of the reservoir. In porewater and exchangeable nutrients of sediment, nitrogen and phosphorus were mostly consist of the particulate form. Inorganic nitrogen was mostly composed of $NH_4$. Nitrogen of porewater was mostly an inorganic form while exchangeable nutrients were composed an organic form. However, phosphorus was composed of dissolved organic fraction in the porewater while inorganic fraction in the exchangeable nutrients. Silicon content of sediment was much exchangeable nutrients with 63%, and it was higher than in the porewater. In summary, the sediments of Taechong Reservoir were mostly composed of organics and assessed to be a eutrophic state.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1703-1718
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• 2014

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 - November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were $15.72{\pm}5.67mm$ long at the start of the experiment in October 2011, grew to a maximum of $1093{\pm}271.13mm$ by May 2012. In September, seaweed growth was reduced to a minimum of $280{\pm}70.43mm$ in length. Then, S. fulvellum began to grow again reaching $325{\pm}196.19mm$ by November 2012. Wet weight of the seaweed was $4.01{\pm}1.89g$ at the start of the experiment and reached a maximum of $109.26{\pm}34.23g$ in May. The weight gradually declined to a low of $15.12{\pm}8.40g$ in September 2012. Weight began to increase once more, rising to $39.27{\pm}21.69g$ by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged $5.0-23.5^{\circ}C$, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.