• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.96-104
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• 2018

Stable isotope approach for aquatic ecology and environmental sciences has been introduced as very useful technique since 1980s and also has been applied to investigate various issues in aquatic ecology and environmental study last 10 years in Korea. Especially carbon and nitrogen isotope ratios have been mainly used to understand food web energy flow and ecosystem structure. In addition, nitrogen isotope ratio has been applied for nitrogen cycle and source identification as well as biomagnification studies. However, large temporal or spatial variations of nitrogen isotope ratio of primary producer have been found in many aquatic environments, and it is regarded as the critical problems to determine trophic level of aquatic animals. Recently, the compound specific isotope analysis of nitrogen within individual amino acids has been developed as an alternative method for trophic ecology. This article introduces the progress history of stable isotope application in aquatic ecology and environmental sciences, and also suggests new direction based on future prospects in stable isotope ecology and environmental study.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.61-73
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• 2022

Stable isotope analysis (SIA) is being used in various research fields including environmental science, ecology, biogeochemistry, forensics, and archeology. In this paper, for the purpose of enhancing applications and utilizations stable isotope analysis techniques to aquaculture research, we would like to introduce the background knowledge necessary to utilize stable isotope analysis techniques. In particular, with a focus on the approach using natural abundance, the principle of fractionation (change in isotope ratio) that occurs in the process of the integration of elements into biological tissues and how stable isotope ratios are determined by fractionation. This paper is intended to suggest whether SIA is used as a valuable tool in the fields of ecology and environmental science. With the understanding of the field of stable isotopes through this paper, various applications of stable isotope ratios are expected in fisheries science and aquaculture research in the future.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.699-703
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• 2007

Compound-specific isotope analysis (CSIA) by isotope ratio mass spectrometer (IRMS) interfaced with gas chromatography (GC) is a state of the art analytical technique for stable isotopes in earth sciences, environmental sciences and forensics. Since early 1990s, GC-IRMS has been widely used to investigate the authenticity of food in forensic science and to trace the sources of organic contaminants in environmental science. In Korea, a GC-IRMS was firstly installed at the Korea Basic Science Institute (KBSI) in early 2005. In this study, we introduce the GC-IRMS of the KBSI shortly to stimulate various isotope-related researches of Korea, and report preliminary CSIA results for BTEX of different manufacturers.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.432-440
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• 2017

Compound specific isotope analysis of amino acids (CSIA-AAs) is being highlighted as an alternative approach for overcoming some restrictions in application of stable isotope analysis of bulk tissue (SIA) for trophic position (TP) estimation. However, this approach has rarely been applied in Korea. The present study determines TP of two Polychaeta (Nephtyidae and Glyceridae) and two fish species(Platycephalus indicus and Lophius litulon) collected from the Geum River estuary using nitrogen isotope ratio of amino acid and compared with the TP values estimated by SIA. The Polychaeta species, sampled in two sites, showed similar TP between SIA(2.7 and 3.1) and CSIA-AAs (2.6 and 3.1). However, for both fish species, TP values displayed a large difference between SIA (3.1 and 2.3) and CSIA-AAs (3.8 and 3.7). In this study TP values estimated by CSIA-AAs showed more similar to the previously reported gut content analysis of both fishes compared with the results of SIA. Current study suggests the applicability of nitrogen isotope ratio of amino acid to understand coastal ecosystem structure and trophic ecology.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.3
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• pp.191-195
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• 2000

Quantitation of N7-methyldeoxyguanosine (N7-MedG) produced in the in vitro N-methly-N-nitrosuourea (NMU) action on thymus DNA has been achieved by enzymatic degradation, liquid chromatoraphic separaphic separation and desorption chemical ionization tandem mass spectrometry. In conjunction with the resolving power HPLC in the separation of isomers, desorprion chemical ionization tandem mass spectrometry has utilized in determining modified nucleosides at low levels using a stable-isotope labled compound as an internal reforence. The quantitative estimation of N7-methyldeoxyguanosine was previously established by an independent HPLC analysis of methylated calf thymus DNA. A sensitive and specific methodogy for the quantitation of N7-MedG at the picomole level using HPLC combined with tandem mass spectrometry without radioisotope labeling process is presented. The potential of the liquid chromatoraphic tandem mass exposure to methlation agents in vitro.

• Ocean and Polar Research
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• v.41 no.2
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• pp.89-97
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• 2019

Long chain plant waxes (n-alkanes, n-alkanoic acids, and n-alcohols) and their carbon isotopic compositions (${\delta}^{13}C$) in geologic archives are valuable tools for paleovegetation reconstruction. However, the sensitivity of different plant wax constituents to vegetation shift is not well understood. This study explores controls on the variation in ${\delta}^{13}C$ values of long-chain n-alkanes ($C_{27}$ to $C_{33}$) and n-alkanoic acids ($C_{26}-C_{30}$) in the Gulf of Mexico core sediments (ODP 625B) near the Mississippi River delta. n-Alkanoic acids' ${\delta}^{13}C$ values were higher than those of n-alkanes by 1-2‰ on average and such a pattern is the opposite from their isotope fractionation observed in living plants: 1-2‰ smaller in n-alkanes than n-alkanoic acids. We attribute this offset to contributions from aquatic plants or microbes that produce high concentrations of $^{13}C-enriched$ long-chain n-alkanoic acids. The sensitivity of n-alkanes and n-alkanoic acids to vegetation and climate varied among chain lengths. The $n-C_{33}$ alkanes were most sensitive to $C_4$ grassland expansion among n-alkane homologues, while no specific trend was observed in n-alkanoic acids. This is due to the similarity in n-alkanoic acid concentrations between $C_3$ and $C_4$ plants by homologues and low terrestrial plant-derived n-alkanoic acid contributions to the sediments. The results of this study suggest that long chain n-alkanoic acids' ${\delta}^{13}C$ values in sediments may be influenced by contributions from different sources such as aquatic plants or microbial inputs and therefore interpretations regarding this matter should be cautiously formulated. We suggest that there is a need for further studies on characterizing long-chain n-alkanoic acids ($C_{26}-C_{34}$) in aquatic plants and microbes from various climates and environments in order to investigate their production and integration into sedimentary archives.