• Korean Journal of Heritage: History & Science
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• v.49 no.4
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• pp.38-51
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• 2016

This study reports on human dietary reconstruction of Joseon Dynasty using stable isotope analysis. The stable carbon and nitrogen isotope values were measured of bone collagen extracted from 25 human bones from archaeological site in Myeongam-ri, Asan. Average values of ${\delta}^{13}C$ and ${\delta}^{15}N$ are $-19.7{\pm}0.5$‰(n=23) and $9.6{\pm}1.1$‰(n=23), respectively. The isotopic data indicates that Myeongam-ri individuals consumed $C_3$ plants mainly and assumed of dietary resourced from a terrestrial animal protein. Previous isotopic studies of the Joseon era suggested that dietary composition of Joseon population was not influenced by region and burial type. Also comparison of the isotopic results of male and female from double burials showed sex-dependent dietary patterns among individuals living in the same circumstances.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.685-694
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• 2018

We measured ecological niche space (ENS) using carbon and nitrogen stable isotope ratios of benthic macroinvertebrates to estimate its applicability for large river assessment. In particular, we compared ENSs of selected macroinvertebrates between upper and lower area of Seungchon Weir in Yeongsan River to estimate the impact of weir on biological community. We also measured basic water quality and community indices including benthic macroinvertebrates index (BMI) to estimate their correlations with calculated ENS. ENS was calculated using the Bayesian Stable Isotope in R statistics (package "SIBER"). The results showed that seasonal variations in water quality and community indices were found, but there was no apparent tendency between upper and lower area of the Seungchon Weir in June (before rainy season) and August (after rainy season). However, ENS of benthic macroinvertebrates markedly decreased across the weir in both June and August regardless of changes in water quality. This means the physical change of the stream due to the weir cause decrease of ecological isotopic niche space of benthic macroinvertebrates regardless of water quality, suggesting physical modification by the weir can affect the interaction between habitat condition and macroinvertebrates. Therefore, the ecological isotopic niche space can be a useful supplementary indicator for the river ecosystem assessment.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.9-16
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• 2010

The purpose of this study is to clarify the origin of organic matters on sediment and the characteristics of seasonal variation at an estuarine tidal flat. Silt-clay content (<63 ${\mu}m$), chlorophyll a, TOC, C/N ratio and the stable isotope ratio of carbon and nitrogen were measured at tidal flat around the estuary of the Nanakita River. As a result, organic matters originating from marine organic matter and bethic microalgae greatly contributed to sedimentation of organic matters at Stn.A, sandy tidal flat, though terrigenous organic matters did at Stn.C, muddy tidal flat. Furthermore, it was revealed that the volume and origin of organic matters in the sediments depended on seasonal variation, and the factors were different from the Stns, i.e. bentic microalgae and event for Stn.A, and the eventual sedimentation of organic matters originating from terrestrial plants, respectively.

• 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.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.319-326
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• 2014

Fish community was investigated in eutrophic Jeondae agricultural reservoir from April to November 2012. The food web structure of major fish species of Jeondae reservoir showed that due to serious organic pollution, the hyper-eutrophic condition with high chemical oxygen demand (COD), chlorophyll-a (Chl-a), total nitrogen (TN) and total phosphorus (TP), as estimated by stable isotope analysis. Total of 679 individuals were collected from the reservoir, and 9 species were identified. Interestingly, Lepomis macrochirus and Hemiculter eigenmanni known as less sensitive to pollution and water quality deterioration, dominated the reservoir, and their relative abundances were 38% and 27%, respectively. Further, the analysis of the stomach contents revealed that main food source of dominant L. macrochirus was high amount of zooplankton, which includes copepoda and cladocera, while Cyprinidae species mainly consumed organic particles with zooplankton preys. Stable isotope analysis also suggested that L. macrochirus, Carassiusauratus, Pseudorasboraparva, and H. eigenmanni are major zooplantivorous group in the Jeondae Reservoir.

• Journal of Environmental Science International
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• v.29 no.11
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• pp.1089-1098
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• 2020

To assess the trophic function of an artificial macroalgal habitat, we compared the stable carbon and nitrogen isotope ratios of two amphipods (Caprella sp. and Ampithoe sp.) and their potential food sources in a transplanted macroalgal habitat (Grateloupia asiatica) with those in a natural habitat. There were no significant differences in the isotopic values of both consumers and their potential food sources between the transplanted and natural habitats. Such isotopic similarities between the two sites indicate a comparable resource consumer relationship. Additionally, our results showed similar isotopic niche areas and high dietary overlap (>65%) of the two amphipods between the transplanted and natural sites, suggesting that the transplanted habitat plays ecological roles similar to the natural habitat. Overall, isotopic assessment can provide information on the trophic function of diverse transplanted macroalgal habitats and improve post-monitoring efforts in the management of artificial ecosystems.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.348-353
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• 2008

Oxygen isotope has not been used actively in water mass studies because of difficulties on the analysis though it has advantages as a water mass tracer. The most popular method to analysis the oxygen isotope ratio in water samples is equilibration method: isotopic equilibrium of water with $CO_2$ at constant temperature. The precision of oxygen isotope analysis using commercial automatic $H_2O/CO_2$ equilibrator is ${\pm}0.1%o$. This value is not sufficient for studies in open ocean. The object of this study is to improve the analytical precision enough to apply open ocean studies by modification of the instrument. When sample gas is transferred by the pressure difference, the fractionation which is preferential transportation of light isotope can be occurred since the long transportation path between the equilibrator and mass spectrometer. And the The biggest source of error during the analysis is long distance and large volume of the pathway of sample gas between. Therefore, liquid nitrogen trap and high vacuum system are introduced to the system. The precisions of 14 time analysis of same seawater sample are ${\pm}0.081%o$ and ${\pm}0.021%o$ by built-in system and by modified system in this study, respectively.

• 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.

• Ocean Science Journal
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• v.40 no.3
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• pp.167-176
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• 2005

A time-series sediment trap was deployed at 1,034 m water depth in the eastern Bransfield Strait for a complete year from December 25, 1998 to December 24, 1999. About 99% of total mass flux was trapped during an austral summer, showing distinct seasonal variation. Biogenic particles (biogenic opal, particulate organic carbon, and calcium carbonate) account for about two thirds of annual total mass flux $(49.2\;g\;m^{-2})$, among which biogenic opal flux is the most dominant (42% of the total flux). A positive relationship (except January) between biogenic opal and total organic carbon fluxes suggests that these two variables were coupled, due to the surface-water production (mainly diatoms). The relatively low $\delta^{13}C$ values of settling particles result from effects on C-fixation processes at low temperature and the high $CO_2$ availability to phytoplankton. The correspondingly low $\delta^{l5}N$ values are due to intense and steady input of nitrates into surface waters, reflecting an unlikely nitrate isotope fractionation by degree of surface-water production. The $\delta^{l5}N$ and $\delta^{l3}C$ values of sinking particles increased from the beginning to the end of a presumed phytoplankton bloom, except for anomalous $\delta^{l5}N$ values. Krill and the zooplankton fecal pellets, the most important carriers of sinking particles, may have contributed gradually to the increasing $\delta^{l3}C$ values towards the unproductive period through the biomodification of the $\delta^{l3}C$ values in the food web, respiring preferentially and selectively $^{12}C$ atoms. Correspondingly, the increasing $\delta^{l5}N$ values in the intermediate-water trap are likely associated with a switch in source from diatom aggregates to some remains of zooplankton, because organic matter dominated by diatom may be more liable and prone to remineralization, leading to greater isotopic alteration. In particular, the tendency for abnormally high $\delta^{l5}N$ values in February seems to be enigmatic. A specific species dominancy during the production may be suggested as a possible and speculative reason.

• Journal of Conservation Science
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• v.29 no.4
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• pp.437-444
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• 2013

We studied for the chemical characterizations of the charred residues obtained from the ancient potteries in the Proto-Three Kingdom period from archaeological sites in Joong-do, Chuncheon. Organic components of the charred residues were extracted and analysed using mass spectrometry and infrared spectroscopy. Lipid profiles from these samples were not identified in gas chromatography-mass spectrometry. Bulk stable isotope analyses of charred residues was used to infer an average values of the foods prepared. The average carbon isotope values (${\delta}^{13}C$) of the residues are $-14.7{\pm}2.8$‰ (ranging from -8.7‰ to -18.4‰, n=9), and nitrogen isotope values (${\delta}^{15}N$) are $6.2{\pm}1.1$‰ (ranging from -4.4‰ to -7.6‰, n=9). This is the first approach to analyse charred residues using stable isotopic method in Korea. Charred food residues on the interior surface of archaeological pottery can provide valuable information about pottery use and dietary habits of its population.