• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.53-59
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• 2010

The spatial variability in the food chain structure of an estuarine environment(Nanakita estuarine, Japan) was investigated using stable carbon and nitrogen isotope. Potential organic matter sources(TP:Terrstrial Plant, MPOM:Marine particulate organic matter, BMA:Benthic microalgae, EPOM:Estuarine particulate organic matter), sedimentary organic matter and benthic invertebrates(Nuttallia olivacea and Nereidae) were sampled at four locations with different tidal flat types(e.g. sanddy, sanddy-muddy and muddy). The main objective of the present study was to determine food sources of Nuttallia olivacea and Nereidae along with small-scale spatial variability within the community of benthic invertebrates. TP(${\delta}^{13}C=-26.6{\pm}0.76$ and ${\delta}^{15}N=2.7{\pm}0.31$) and EPOM(${\delta}^{13}C=-25.5{\pm}0.13$ and ${\delta}^{15}N=5.2{\pm}0.46$) were isotopically distinct from BMA(${\delta}^{13}C=-16.3$ and ${\delta}^{15}N=6.2$) and MPOM(${\delta}^{13}C=-19.6{\pm}0.08$ and ${\delta}^{15}N=8.9{\pm}1.70$). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -27.4 to -22.8‰ with a declining trend from the upstream to the downstream stations. The stable carbon and nitrogen isotope values of benthic invertebrates in the study site was -22.8 to -18.4‰ for ${\delta}^{16}C$ and 8.1 to 11.9‰ or ${\delta}^{15}N$, respectively. Mixing model(Isosource) calculations based on stable isotope measurements showed that benthic invertebrates of Nuttallia olivacea and Nereidae were found to be dominated by MPOM and BMA in stations. Whereas, TP and EPOM showed little influence to benthic invertebrates. The current result suggests that the different contribution for benthic invertebrates should be affected by both seasonal variation and physical factor among stations.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.167-172
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• 2007

Manure recycle is an emerging issue in agriculture in Korea these days. Farmers are keeping eye on legume mixture with grasses for nitrogen fixation and transfer to companion crops by legumes. We had a trial to investigate the effect of different legume mixtures on nitrogen fixation and transfer in spring soil. The treatment was arranged in a randomized complete block design with three replications. Three different mixtures were used(rye+hairy vetch, Italian ryegrass+crimson clover, oat+pea) and sowed in pots with paddy soil from western part of Korea(Seo Chon County). Pots with rye+vetch were transplanted from field of RDA(rural development administration) in Suwon on 2 February 2007 and other mixture treatments were sowed on early March with different sowing rate(7:3=Italian:crimson, 6:4=oat:pea). $(^{15}NH_4)_2SO_4$ solution at. $99.8\;atom%^{15}N$ was applied to the each pot at the rate of $2kg\;N\;ha^{-1}$. Application was done on 6 April at rye+vetch pots and remainder were applied on April 16. Forage were harvested from each pot at ground level in heading stage and separated into legume and grass. Total N content and $^{15}N$ value were determined using a continuous flow stable isotope ratio mass spectrometry. DM yield of rye+vetch, Italian+crimson and oat+pea were 6,607, 3,213 and 4,312 kg/ha, respectively. Proportion of N from fixation was 0.73(rye+vetch), 0.42(Italian+crimson) and 0.93(oat+pea). The percentages of N transfer from legume to grass were from 61% to 24% in different method by treatment and -35% to 21% in isotope dilution method.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.536-542
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• 2007

The responses of whole body protein and glucose kinetics and of nitrogen (N) metabolism to non-protein energy intake (NPEI) were determined using an isotope dilution approach and measurement of N balance in three adult male goats. The diets containing 1.0, 1.5 and 2.0 times ME maintenance requirement, with fixed intake of CP (1.5 times maintenance) and percentage of hay (33%), were fed twice daily for each 21 d experimental period. After an adaptation period of 11 d, N balance was determined over 3 d. On day 17, whole body protein synthesis (WBPS) and glucose irreversible loss rate (ILR) were determined during the absorptive state by a primed-continuous infusion of [$^2H_5$]phenylalanine, [$^2H_2$]tyrosine, [$^2H_4$]tyrosine and [$^{13}C_6$]glucose, with simultaneous measurements of plasma concentrations of metabolites and insulin. Ruminal characteristics were also measured at 6 h after feeding over 3 d. Nitrogen retention tended to increase (p<0.10) with increasing NPEI, although digestible N decreased linearly (p<0.05). Increasing NPEI decreased (p<0.01) ammonia N concentration, but increased acetate (p<0.05) and propionate (p<0.05) concentrations in the rumen. Despite decreased plasma urea N concentration (p<0.01), increased plasma tyrosine concentration (p<0.05), and trends toward increased plasma total amino N (p<0.10) and phenylalanine concentrations (p<0.10) were found in response to increasing NPEI. Increasing NPEI increased ILR of both glucose (p<0.01) and phenylalanine (p<0.05), but did not affect ($p{\geq}0.10$) that of tyrosine. Whole body protein synthesis increased (p<0.05) in response to increasing NPEI, resulting from increased utilization rate for protein synthesis (p<0.05) and unchanged hydroxylation rate of phenylalanine ($p{\geq}0.10$). These results suggest that increasing NPEI may enhance WBPS and glucose turnover at the absorptive state and improve the efficiency of digestible N retention in goats, with possibly decreased ammonia and increased amino acid absorption. In addition, simultaneous increases in WBPS and glucose ILR suggest stimulatory effect of glucose availability on WBPS, especially when sufficient amino acid is supplied.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.107-110
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• 1999

18 boreholes with nitrate contaminated were selected. Samples were collected 4 times between both 1995 and 1996. Stable nitrogen isotope ratio for them all was measured and the contribution to contamination from several sources like fertilizer, sewage, cropland. and landfill was analysed. Nitrogen source for 11 sampling sites of T-3, L-1. O-1∼O-4, F-2∼F-5, and G-2 considered to come from chemical fertilizer and its contribution was around 60% or more. T-4. T-5 were located downward the downtown, which were influenced bydomestic sewage and its contribution were 70.7% and 54.7%. Nitrate concentration of G-2 was 17.7 mg/L, among which 60.7% was estimated to come from landfill leachate. T-1 and T-2 were located in the small village, in which 42.2 and 43.4% of nitrogen was to come from domestic sewage but 52.8% and 56.0% were from fertilizer sprayed in the cropland. L-2 was near livestock by which it was estimated to be influenced, in which 59.9% of nitrogen was from cropland. F-1 was in the cropland, by which 50.0% was influenced and 49.5% was estimated from organic matter of animals.

• Analytical Science and Technology
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• v.32 no.6
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• pp.262-270
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• 2019

The stable isotopic composition of bone collagen plays an important role in reconstructing palaeodiet, nutrition, palaeoenvironment and their lifestyle. This is the first case in extracting palaeodietary information and breastfeeding pattern of Goryeo people using stable isotope analysis due to the lack of human remains in this period. We analyzed human bone collagen excavated from Gyeongju Donggung palace and Wolji pond No.3. The average values of δ¹³C and δ¹⁵N are as follows: (δ¹³C(‰) = -19.5 ± 0.9‰, δ¹⁵N(‰) = 11.1 ± 1.1 ‰, (n = 4). Stable carbon isotope values shows a mainly C₃ based diet such as rice and barley. Stable nitrogen isotope results implies the protein sources attributed to terrestrial animals. There are various age groups in this study, which are adult, child and infant. Two individuals within early childhood age ranges (< 3 years) shows more elevated δ¹⁵N values than that of adult and this result implies the continuation of breastfeeding in this group until the age of 3. The results provide new insight into the breastfeeding pattern of Goryeo people, where breastfeeding and weaning practices have important implication for fertility, population dynamics, migration pattern and disease.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.127-134
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• 2014

Organic carbon and nitrogen stable isotope ratios of particulate organic matter (POM) were determined at 7 stations (6 stations in Han river and Paldang dam outflow station) from May to October 2013, in order to understand the origin of POM at the Han river. ${\delta}^{13}C$ values of POM in four stations showed significant seasonal changes season, but ${\delta}^{15}N$ values were enriched in around Kyeongan stream (K). POC, PN and Chl-a concentration showed a similar seasonal pattern in Kyeongan stream, with an apparent decrease from July to August. POC and PN concentration has a higher correlation with Chl-a concentration in Kyeongan stream (K). ${\delta}^{13}C$ and ${\delta}^{15}N$ values of POM has a lighter value during lower Chl-a concentration peroid, compared to other seasons. Our results revealed that Kyeongan stream (K) seemed to be influenced by substantial amount of organic manure or fertilizer input in 2013, compared to the previous year (2012). These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of organic matter origin in aquatic environments.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.132-136
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• 2011

The Temporal variability in the food chain structure of bacteria in the sedimentary organic matter was investigated using stable isotope and fatty acid. Potential organic matter sources (Land plant, Marine POM, benthic microalgae, Riverine POM), sedimentary organic matter and bacteria were sampled in Gamo largoon and Nanakita estuary. The main objective of the present study was to determine food sources of bacteria along with temporal variability. Land plant (${\delta}^{13}C$ = -26.6‰ and ${\delta}^{15}N$ = 3.6‰) and Riverine POM (${\delta}^{13}C$ = -25.5‰ and ${\delta}^{15}N$ = 8.9‰) were isotopically distinct from benthic microalgae (${\delta}^{13}C$ = -16.3‰ and ${\delta}^{15}N$ = 6.2‰) and Marine POM (${\delta}^{13}C$ = -20.3‰ and ${\delta}^{15}N$ = 10.3‰). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -20.7‰ to -191‰. The stable carbon and nitrogen isotope values of bacteria in the study were -20.8‰ to -18.6‰ for ${\delta}^{13}C$ and 6.5‰ to 8.6‰ for ${\delta}^{15}N$. From this results based on stable isotope measurements showed that in the bacteria was found to be dominated by Marine POM and Benthicmicoralge during 0 to 20 day. Whereas, terrestrial plant and riverine POM showed little in fluence to bacteria during the experiment.

• The Korean Journal of Nuclear Medicine
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• v.9 no.1
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• pp.51-58
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• 1975

It is a great value to find an early detection of involvement of ureteric obstruction in the carcinoma of cervix. Little or no knowledge of the condition of the kidneys or the lower urinary tract are able to elucidate by the biochemical studies such as blood nitrogen or urine creatinine in carcinoma of cervix. Findings of urography delineates the condition of urinary tract stasis in the renal pelvis and ureters, however, slight stasis maybe difficult to demonstrate. On the other hand isotope nephrography is accepted as a sensitive method to observe renal function especially in regarding to the excretory function of kidney. It was attempted to analysis the findings of urography conjunction with isotope nephrography in 50 cases of unselected patients with invasive carcinoma of cervix through pre and post irradiation follow up studies. Urography was done as a routine procedure and.analysed emphasising changes of collecting systems and ureter condition. Isotope nephrography was carried out by means of $15{\mu}ci\;I^{131}$-Hippuran injected intravenously and the curves were analysed as follows. Parameter were; time of maximum amplitude ($T_{max}$), half time of maximum amplitude ($T\frac{1}{2}$), Kac and Kex value calculated from these two parameters in Tobe's method. The excretion index by Aurell defines the ratio between the maximum activity and the activity measured on the slope of the third phase ten minites after it has reached its maximum. Results: 1. 28.8% had an abnormal IVP suggestive of ureteric involvement before irradiation therapy and the patient of stage III and IV were the great part. 2. 21.7% had abnormal findings of per-irradiation renogram whom showed normal IVP. The other group showed normal IVP which group also showed normal renogram prior irradiation. 3. The more severe the ureteric involvement, the change of excretion index was greater. 4. Even in stage I and II patient, abnormal renogram was revealed in 12 cases (39.4%) among 31 cases. 5. All cases of TAH showed abnormal findings of IVP and renogram. 6. No. definite change of renogram was obtained just after the irradiation therapy (point $A:8000{\sim}9000rads,\;B:5000{\sim}6000rads,\;Co:11000{\sim}13000rads$). Each 3 month follow up study was performed and comparing with preirradiation study which showed significant changes of excretion index of renogram were 42.8% in $6{\sim}9$ month follow-up and 75% in $9{\sim}12$ month, respectively. 7. It seems to be important to observe the parameter Kex and excretion index of renogram to determine early abnormality of kidney excretory function by means of post-irradiation follow up study.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.459-469
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• 2017

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of denitrification bacteria method (Pseudomonas chlororaphis ssp. Aureofaciens ($ATCC^{(R)}$ 13985)), three reference (IAEA-NO-3 (Potassium nitrate $KNO_3$), USGS34 (Potassium nitrate $KNO_3$), USGS35 (Sodium nitrate $KNO_3$)) were analyzed 5 times repeatedly. Measured the ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values of IAEA-NO-3, USGS 34 and USGS35 were ${\delta}^{15}N:4.7{\pm}0.1$‰ ${\delta}^{18}O:25.6{\pm}0.5$‰, ${\delta}^{15}N:-1.8{\pm}0.1$‰ ${\delta}^{18}O:-27.8{\pm}0.4$‰, and ${\delta}^{15}N:2.7{\pm}0.2$‰ ${\delta}^{18}O:57.5{\pm}0.7$‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated isotope values of potential nitrogen source (soil, synthetic fertilizer and organic-animal manures) and temporal patterns of ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values in river samples during from May to December. ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values are enriched in December suggesting that organic-animal manures should be one of the main N sources in those areas. The current study clarifies the reliability of denitrification bacteria method and the usefulness of stable isotopic techniques to trace the anthropogenic nitrogen source in freshwater ecosystem.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.139-153
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• 2023

This study aimed to understand the spatiotemporal variations in nitrogen content in the Gyeongan stream along the main stream and at the discharge points of the sub-basins, and to identify the origin of the nitrogen. Field surveys and laboratory analyses, including chemical compositions and isotope ratios of nitrate and boron, were performed from November 2021 to November 2022. Based on the flow duration curve (FDC) derived for the Gyeongan stream, the dry season (mid-December 2021 to mid-June 2022) and wet season (mid-June to early November 2022) were established. In the dry season, most samples had the highest total nitrogen(T-N) concentrations, specifically in January and February, and the concentrations continued to decrease until May and June. However, after the flood season from July to September, the uppermost subbasin points (Group 1: MS-0, OS-0, GS-0) where T-N concentrations continually decreased were separated from the main stream and lower sub-basin points (Group 2: MS-1~8, OS-1, GS-1) where concentrations increased. Along the main stream, the T-N concentration showed an increasing trend from the upper to the lower reaches. However, it was affected by those of the Osan-cheon and Gonjiamcheon, the tributaries that flow into the main stream, resulting in respective increases or decreases in T-N concentration in the main stream. The nitrate and boron isotope ratios indicated that the nitrogen in all samples originated from manure. Mechanisms for nitrogen inflow from manure-related sources to the stream were suggested, including (1) manure from livestock wastes and rainfall runoff, (2) inflow through the discharge of wastewater treatment plants, and (3) inflow through the groundwater discharge (baseflow) of accumulated nitrogen during agricultural activities. Ultimately, water quality management of the Gyeongan stream basin requires pollution source management at the sub-basin level, including its tributaries, from a regional context. To manage the pollution load effectively, it is necessary to separate the hydrological components of the stream discharge and establish a monitoring system to track the flow and water quality of each component.