• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.443-444
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• 2005

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.34-44
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• 2015

Fish fauna, difference of stable isotope ratio between freshwater and seawater, and trophic guilds of freshwater fishes were investigated in the lower Geum River. The study was conducted in 2011, and total study area was about 30 km of 20 km upstream and 10 km downstream from the Geum River estuary barrage. Only freshwater fishes were used for analyzing trophic guilds, and discriminant function analysis (DFA) was utilized to reclassify trophic guilds based on stable isotope ratio. Fish fauna in freshwater and seawater areas were entirely different each other, but small number of migratory species such as Coilia nasus and Chelon haematocheilus occurred both areas. Other species were not collected in the different areas because they did not have physiological ability to adapt different salinity concentrations. Stable isotope ration of two areas were different considerably due to food sources. Estuary and seawater fishes uptake food sources originated from marine, and freshwater fishes were from freshwater and terrestrial. Some migratory species showed reverse stable isotope ratio. Even though they collected in freshwater, they showed stable isotope ratio of seawater. This is because ecological characteristics of each species. Trophic guilds of freshwater fishes were reclassified by DFA, and showed slight difference with literatures. However, because this result is related with ontogenetic shift of species, more studies are needed to explain exact and correct trophic guilds. Stable isotope ratio can be changed among regions, seasons and ontogenetic stage, thus we always consider these aspects when analyzing results to get a right answer.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.371-381
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• 2006

New proteomic techniques have been pioneered extensively in recent years, enabling the high-throughput and systematic analyses of cellular proteins in combination with bioinformatic tools. Furthermore, the development of such novel proteomic techniques facilitates the elucidation of the functions of proteins under stress or disease conditions, resulting in the discovery of biomarkers for responses to environmental stimuli. The ultimate objective of proteomics is targeted toward the entire proteome of life, subcellular localization biochemical activities, and the regulation thereof. Comprehensive analysis strategies of proteomics can be classified into three categories: (i) protein separation via 2-dimensional gel electrophoresis (2-DE) or liquid chromatography (LC), (ii) protein identification via either Edman sequencing or mass spectrometry (MS), and (iii) proteome quantitation. Currently, MS-based proteomics techniques have shifted from qualitative proteome analysis via 2-DE or 2D-LC coupled with off-line matrix assisted laser desorption ionization (MALDI) and on-line electrospray ionization (ESI) MS, respectively, toward quantitative proteome analysis. In vitro quantitative proteomic techniques include differential gel electrophoresis with fluorescence dyes. protein-labeling tagging with isotope-coded affinity tags, and peptide-labeling tagging with isobaric tags for relative and absolute quantitation. In addition, stable isotope-labeled amino acids can be in vivo labeled into live culture cells via metabolic incorporation. MS-based proteomics techniques extend to the detection of the phosphopeptide mapping of biologically crucial proteins, which ale associated with post-translational modification. These complementary proteomic techniques contribute to our current understanding of the manner in which life responds to differing environment.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.159-165
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• 2015

The organic matter sources of phytoplankton and related environmental factors influencing algal bloom in Paldang reservoir were studied using nitrogen and carbon isotope ratio(${\delta}^{15}N$, ${\delta}^{13}C$). Phytoplankton samples for stable isotope analysis were collected from four points in reservoir using a plankton net. Physicochemical water quality, algal taxa and hydrological data were collected from published monitoring material. Phytoplankton samples were analyzed by IRMS. CN ratio of each sample was very similar to that of phytoplankton from literature cited. ${\delta}^{15}N$ of each sample was decreased during July. Mixing and dilution of nitrogen sources due to increment of influx by concentrated rainfall were considered as the main reason for the decline of ${\delta}^{15}N$. Based on analyzed ${\delta}^{15}N$ value of each sample, nitrogen source of Bughan river sample was presumed to come from soil. The nitrogen sources of Namhan river and Kyeongan stream samples seemed to be sewage or animal waste. Low ${\delta}^{15}N$ value in August (2012) seemed to be influenced by isotope fractionation due to the blooming of nitrogen-fixation blue-green algae (Anabaena spp.). Variation in ${\delta}^{15}N$ values particularly by blue-green algal bloom was considered the important factor for estimating the organic matter sources of phytoplankton.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.452-458
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• 2017

The nitrogen isotope value in both ammonium and nitrate ion were determined at 9 stations during both June and August 2016, in order to understand the origin of DIN at the Han river. ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in 8 stations (CP, SB, MHC, P4, SJ, SBC, P2, SC) were no significant variation. However ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in KK (Kyeongan stream) showed significant different in comparison with 8 stations, with an apparent increase of nitrogen isotope values. These results indicate that antropogenic nitrogen source influence on KK station. Also the ${\delta}^{13}C$ and ${\delta}^{15}N$ isotope ratio of phytoplankton (Diatom and Cyanobacteria) in KK (Kyeongan stream) showed heavier values, compared to other study stations. These results indicate that nitrogen isotope value in phytoplankton effects by different nitrogen source in study sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of dissolved inorganic nitrogen origin in aquatic environments.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.477-494
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• 2008

Stable isotope analyses on lake or wetland sediments are useful to reconstruct paleoclimate. Organic and inorganic carbonates obtained from lake sediment are isotopically analyzed to get oxygen and carbon isotopic ratios. Oxygen isotope ratios can be used to quantitatively and qualitatively reconstruct paleo-temperature or humidity while carbon isotope ratios be used to reveal environmental changes around the lake or human impacts on the area. Peat mosses in peat bogs are nice samples for the carbon isotope analysis, which derives paleo-temperature and paleo-atmospheric $CO_2$ changes. In coastal area, the reconstruction of past sea-level is possible because terrestrial originated organic matter is carbon isotopically different from marine originated organic matter. Also, scientists can do research on Asian Monsoon based on the fact that $\delta^{13}C$ of C3 plants and C4 plants are consistently different each other and that they are distributed differently with respect to salinity. In Korea, paleoenvironmental studies using stable isotopes are not popular yet because of low academic interests on the methodology and difficulties of obtaining proper sediment samples. Interesting results can be produced to answer paleoenvironmental questions of Korea if scientists isotopically analyze sediment cores from a paleo-lake such as Hanon in Jeju island, peat bogs such as Mujechi-Neup and Yong-Neup, and coastal wetlands.

• Economic and Environmental Geology
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• v.46 no.6
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• pp.495-508
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• 2013

Recently, stable isotopes (${\delta}^{18}O$ and ${\delta}D$) of water are increasingly analyzed using laser-based technologies. These methods have advantages over Isotope Ratio Mass Spectrometry (IRMS) in that they can be used for in-situ measurements and require much less maintenance and preparation work. Two types of laser-based methods are currently available, which have different analytical principles; OA-ICOS (off-axis integrated cavity output spectroscopy) and WS-CRDS (wavelength-scanned cavity ring-down spectroscopy). In the WS-CRDS instrument, water is vaporized at controlled environment and transferred to an optical cavity by nitrogen carrier gas, and stable isotopic compositions of water vapor are measured using the degree of absorbance of specific wavelengths and the ratios of attenuation time of the laser intensity with the sensitivity of ppb to tens of ppt level. In this study, we introduce the principle of the WS-CRDS technology and the performance results including stability and comparisons with Isotope Ratio Mass Spectrometry (IRMS) and suggest possible applications of various topics in isotope hydrology.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.279-284
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• 2009

In order to understand food sources-metabolism for the pacific oyster (Crassostrea gigas), the stable isotope ratios of carbon (${\delta}^{13}C$) and nitrogen (${\delta}^{15}N$) of its gut, gill, and muscle as well as potential food sources (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass detritus) were determined in Dongdae Bay. Average ${\delta}^{13}C$ and ${\delta}^{15}N$ values reflect that oysters primarily fed on sedimentary organic matter as opposed to suspended organic matter during summer and winter seasons. However, the relatively enriched $^{15}N$ values of particulate organic matter (>$250{\mu}m$) and sedimentary organic matter in the summer may be due to the photosynthetic incorporation of $^{15}N$-enriched nitrogen (DIN) or the spawning events of bivalves. Specific oyster tissues (gut, gill, and muscle) revealed different metabolic pathways, which were determined through analysis of ${\delta}^{13}C$ and ${\delta}^{15}N$ in each organ. The present results suggest the determination of carbon and nitrogen stable isotopes to be a useful approach in ecological research related to the food sources- metabolism of Crassostrea gigas.

• Journal of the korean society of oceanography
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• v.35 no.2
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• pp.124-127
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• 2000

The analysis of stable carbon isotope ratios for benthic fauna was applied to identify the source of carbon in benthic food webs in Youngil Bay, Korea. The ${\delta}^{13}$C values of 9 invertebrate species collected in this area showed a narrow range between -20.5 and -16.3%$_o$ with a mean of-18.1 (${\pm}$1.1)"%$_o$. The results suggest that the major source of organic carbon for the benthic fauna of the lower estuarine reaches and the oceanic sites is autochthonous marine particulate organic matter. The contribution of organic matter from terrestrial and riverine sources to the diet of the benthic fauna in this area appears to be minor, despite the considerable inflow of riverine waters.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.83-88
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• 2011

The bone density fractionation method is a potential palaeodietary tool in tracing lifetime dietary changes as well as separating diagenetically altered fractions. This paper presents a workable bone density fractionation method that uses a devised mathematical model and the particle size distribution. Different grinding methods, i.e., a Spex $LN_2$ mill, a Disc mill and a Micronising mill, were used to reduce archaeological bone particles to an appropriate size range, which was then analyzed by a Laser particle sizer. It was found that density profiles are in good agreement with the diagenetic parameters, and with their stable isotope results.