• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.50-64
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• 2019

Recently, quantitative analyses of food web structure based on carbon and nitrogen stable isotopes are widely applied to environmental assessments as well as ecological researches of various ecosystems, particularly rivers and streams. In the present study, we analyzed carbon and nitrogen stable isotope ratios of POM (both planktonic and attached forms), zooplankton, benthic macroinvertebrates and fish collected from 6 sites located at Nakdong River. Samples were collected from upstream areas of 5 weirs (Sangju, Gangjeong-Goryeong, Dalseong, Hapcheon-Changnyeong, and Changnyeong-Haman Weirs) and one downstream area of Hapcheon-Changnyeong Weir in dry season (June) and after rainy season (September). We suggested ranges of their carbon and nitrogen stable isotope ratios and calculated their trophic levels in the food web to compare their temporal and spatial variations. Trophic levels of organisms were relatively higher in Sangju Weir located at upper part of Nakdong River, and decreased thereafter. However, the trophic levels were recovered at the Changnyeong-Haman Weir, the lowest weir in the river. The trophic level calculated by nitrogen stable isotope ratios showed more reliable ranges when they were calculated based on zooplankton than POM used as baseline. The suggested quantitative ecological information of the majority of biological communities in Nakdong River would be helpful to understand the response of river food web to environmental disturbances and can be applied to various further researches regarding the quantitative approaches for the understanding food web structure and function of river ecosystems as well as restoration.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.242-251
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• 2012

To investigate foodweb of aquatic ecosystem in the Tamjin River, carbon and nitrogen stable isotopes ratios of aquatic organisms, as well as environmental indicators based on the water, were determined in this study. Various organisms such as fishes (Coreoperca kawamebari, Zacco platypus, Cobitis lutheri, and Pungtungia herzi) and periphyton (epilithon and epiphyte), and particulate- and coarse particulate organic matters (POM and CPOM) were collected in upper (Tamjin River, Yuchi Stream, and Omcheon Stream) and lower (TJ-1~TJ-5) reaches of Jangheung Dam. The nitrate concentration and ${\delta}^{15}N$ signature of POM and organisms (invertebrates and fish) were found to be more enriched toward the downstream section of the river. It was determined that allochthonous matter occurring from a tributary alters the chemical character of water, as well as the isotopic signature of organisms contained therein. Attached algae (ephilithon) were identified as a base component of the benthic foodchain further downstream.

• YAKHAK HOEJI
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• v.52 no.3
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• pp.172-175
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• 2008

Stable isotope ratio of carbon and nitrogen ($\delta^{13}C$ & $\delta^{15}N$), and $\Delta^{9}$-tetrahydrocannabinol (THC) contents were measured on 37 Korean cannabis and 10 commercial grade marijuana seized in Korea. Factors influencing on the measured values and their variations were investigated. $\delta^{13}C$ value of cannabis is specified mainly by water availability. Korean cannabis showed relatively low $\delta^{13}C$ values ranging -33.29$\sim$-27.01% (mean=-31.01%), which reflect geographic conditions of Korea where is rainy, especially during summer. $\delta^{15}N$ values, which reflect individual planting conditions, were relatively high up to -0.5$\sim$18.0% (mean=6.44%). It reflects characteristics of Korean cannabis growing wild in forest or cultivated in fertile soil. Tetrahydrocannabinol is the major hallucinogenic compound of cannabis. Ethanol extracts of cannabis leaves were derivatized by N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and the derivatives were analyzed by GC-MS in selected ion monitoring (SIM) mode. THC contents of Korean cannabis ranged 0.11$\sim$4.34% (mean=1.47%), which were relatively low compared with commercial grade marijuana.

• 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 Heritage: History & Science
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• v.39
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• pp.39-58
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• 2006

This study reviews recent shell midden studies in Korea. With more interest in biological materials, recent shell midden studies have attempted to reconstruct palaeoenvironment, and understand subsistence economy, the formation processes and function of sites and past culture. Especially, one of the major topics in prehistoric Korean shell midden studies is the transitional process from hunter-gatherer to farmer. To solve these questions related with shell middens, new sampling strategies and excavation techniques have been adopted. Analytical methods combined with scientifical technologies also have been introduced to shell middle studies. These methods indude stable isotope analyses(Oxygen isotope and Carbon and Nitrogen isotope analyses) and growth-line analysis, etc.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.358-365
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• 2019

We measured the body composition, including bone mineral density (BMD) and food resource availability using dual energy X-ray absorptiometry and the carbon and nitrogen stable isotope ratios of body condition of 4 anuran species(Hyla japonica, Glandirana rugosa, Pelophylax nigromaculatus, Lithobates catesbeianus) in South Korea. Additionally, the carbon and nitrogen stable isotope ratios were employed to determine the food resource availability of anurans. We figured out the relationship between the body composition, including BMDs and food resource availability. The body composition and BMDs did not differ between male and female while there was difference among the species. Food resource availability and BMDs were the highest in L. catesbeianus, the lowest in H. japonica. BMDs tended to increase with higher food resource availability. Body composition and BMDs, which represent the body condition of an individual, can be used as an ecological indicator to assess the stability of the habitat of anurans.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.4
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• pp.523-529
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• 2016

An isotope dilution method using $[U-^{13}C]glucose$ and $[1-^{13}C]leucine$ (Leu) was conducted to evaluate the effects of rice straw supplemented with urea and molasses (RSUM-diet) on plasma glucose and Leu turnover rates in sheep. Nitrogen (N) balance, rumen fermentation characteristics and blood metabolite concentrations were also determined. Four sheep were fed either mixed hay (MH-diet), or a RSUM-diet with a crossover design for two 21 days period. Feed allowance was computed on the basis of metabolizable energy at maintenance level. The isotope dilution method was performed as the primed-continuous infusion on day 21 of each dietary period. Nitrogen intake was lower (p = 0.01) for the RSUM-diet and N digestibility did not differ (p = 0.57) between diets. Concentrations of rumen total volatile fatty acids tended to be higher (p = 0.09) for the RSUM-diet than the MH-diet. Acetate concentration in the rumen did not differ (p = 0.38) between diets, whereas propionate concentration was higher (p = 0.01) for the RSUM-diet compared to the MH-diet. Turnover rates as well as concentrations of plasma glucose and Leu did not differ between diets. It can be concluded that kinetics of plasma glucose and Leu metabolism were comparable between the RSUM-diet and the MH-diet, and rumen fermentation characteristics were improved in sheep fed the RSUM-diet compared to the MH-diet.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.27-34
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• 2008

The vertical distribution and origin of particulate organic matter (POM) were investigated in Shingu reservoir on 4th July (pre-monsoon) and 7th August (post-monsoon) 2006. High turbid water (120 NTU) were found at 4.5 m water depth in postmonsoon period. The average C/N ratio of POM was about 5.70 and 6.96 in surface water and bottom water, respectively in pre-monsoon period, exhibiting the close values to its ratio in phytoplankton cell. However, the average C/N ratio was 7.10 in surface water and 12.81 in bottom water in post-monsoon period. In addition, the ${\delta}^{13}C$ values of POM in pre-monsoon period ranged from -25.1%o to -26.1%o in whole water column, but the ${\delta}^{13}C$ values of POM in post-monsoon period showed relatively wide range between -23.2%o and -27.5%o. The apparently lighter values (average -27.5%o) in near bottom water (4.5 m water depth) demonstrate that POM in high turbid water in post-monsoon period may be derived from the outside terrestrial plants through heavy rainfall during the summer monsoon period. The present study suggests that carbon and nitrogen stable isotope ratios as well as C/N ratios should be useful indexes to clarify the origin of POM.

• 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.