• Geosciences Journal
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• 제22권6호
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• pp.975-987
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• 2018

Stable isotope ratios of $^{18}O/^{16}O$ and $^{13}C/^{12}C$ and rare earth elements geochemistry of the Upper Triassic carbonates from the Baluti Formation in Kurdistan Region of Northern Iraq were studied in two areas, Sararu and Sarki. The aim of the study is to quantify the possible diagenetic processes that postdated deposition and the paleoenvironment of the Baluti Formation. The replacement products of the skeletal grains by selective dissolution and neomorphism probably by meteoric water preserved the original marine isotopic signatures possibly due to the closed system. The petrographic study revealed the existence of foraminifers, echinoderms, gastropods, crinoids, nodosaria and ostracods as major framework constituents. The carbonates have micritic matrix with microsparite and sparry calcite filling the pores and voids. The range and average values for twelve carbonate rocks of ${\delta}^{18}O$ and ${\delta}^{13}C$ in Sararu section were -5.3‰ to -3.16‰ (-4.12‰) and -2.94‰ to -0.96‰ (-1.75‰), respectively; while the corresponding values for the Sarki section were -3.69‰ to -0.39‰ (-2.08‰) and -5.34‰ to -2.70‰ (-4.02‰), respectively. The bivariate plot of ${\delta}^{18}O$ and ${\delta}^{13}C$ suggests that most of these carbonates are warm-water skeletons and have meteoric cement. The average ${\Sigma}REE$ content and Eu-anomaly of the carbonates of Sararu sections were 44.26 ppm and 1.03, respectively, corresponding to 22.30 ppm and 0.93 for the Sarki section. The normalized patterns for the carbonate rocks exhibit: (1) non-seawater-like REE patterns, (2) positive Gd anomalies (average = 1.112 for Sararu and 1.114 for Sarki), (3) super chondritic Y/Ho ratio is 31.48 for Sararu and 31.73 for Sarki which are less than the value of seawater. The presence of sparry calcite cement, negative $^{13}C$ and $^{18}O$ isotope values, the positive Eu anomaly in the REE patterns (particularly for Sararu), eliminated Ce anomaly ($Ce/Ce^{\ast}$: 0.916-1.167, average = 0.994 and 0.950-1.010, average = 0.964, respectively), and Er/Nd values propose that these carbonates have undergone meteoric diagenesis. The REE patterns suggest that the terrigenous materials of the Baluti were derived from felsic to intermediate rocks.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.178-179
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• 2003

Mesothermal, tellurium-bearing gold-silver vein mineralization of the Yuryang mine was formed in mineralogically complex quartz-sulfide veins that filled the fault fractures in Precambrian gneiss within Gyeonggi Massif. Ore grades average 179 g/ton gold with a gold/silver ratio of 1.5 : 1. Ore mineralization was deposited in single stage. Major ore mineralization can be divided into two mineralization phases with increasing paragenetic time: Fe-sulfide and base-metal mineralization phase $\rightarrow$ telluride mineralization phase. (omitted)

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권3호
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• pp.25-36
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• 2021

This study evaluated monthly, seasonal and altitudinal changes of oxygen and hydrogen isotope compositions of wet precipitation samples (n = 238) that were collected for last four years from 7 altitudes (from 265 to 1,500 m above sea level) in the Jeju Samdasoo watershed at the southeastern part of Jeju island, in order to examine the recharge characteristics of groundwater that is pumped out for the production of the Samdasoo drinking mineral water. Precipitation samples showed a clear seasonal change of O-H isotopic composition as follow, due to the different air masses and relative humidity: 𝛿D = 7.3𝛿¹⁸O + 11.3 (R² = 0.76) in the wet season (June to September), while 𝛿D = 7.9𝛿¹⁸O + 9.5 (R² = 0.91) in the dry season (October to May). In contrast, the stable isotope compositions of groundwater were nearly constant throughout the year and did not show a distinct monthly or seasonal change, implying the well-mixing of infiltrated water during and after its recharge. An altitudinal effect of the oxygen isotope compositions of precipitation was also remarkable with the decrease of -0.19‰ (R² = 0.91) with the elevation increase by 100 m. Based on the observed altitudinal change, the minimum altitude of groundwater recharge was estimated as 1,200 m above the sea level in the Jeju Samdasoo watershed.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제2권4호
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• pp.259-273
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• 2021

We conducted a study to investigate the characteristics of the carbon cycle of two streams (located in Shig a Prefecture, Japan), having similar size, namely, the Adokawa stream (length: 52 km, area: 305 km², watershed population: 8,000) and the Yasukawa stream (length: 62 km, area: 380 km², watershed population: 120,000), but with different degree of human activity. Samples were collected from these two streams at 14 (Adokawa stream) and 23 (Yasukawa stream) stations in the flowing direction. The dissolved inorganic carbon (DIC) concentration and the stable carbon isotope ratio of DIC (δ¹³C-DIC) were measured in addition to the watershed features and the chemical variables of the stream water. The δ¹³C-DIC (-9.50 ± 2.54‰), DIC concentration (249 ± 76 µM), and electric conductivity (52 ± 13 µS/cm) in Adokawa stream showed small variations from upstream to downstream. However, the δ¹³C-DIC (-8.68 ± 2.3‰) upstream of Yasukawa stream was similar to that of Adokawa stream and decreased downstream (-12.13 ± 0.43‰). DIC concentration (upstream: 272 ± 89 µM, downstream: 690 ± 37 µM) and electric conductivity (upstream: 69 ± 17 µS/cm, downstream: 193 ± 37 µS/cm) were higher downstream than upstream of Yasukawa stream. The DIC concentration of Yasukawa stream was significantly correlated with watershed environmental variables, such as, watershed population density (r = 0.8581, p<0.0001, n = 23), and forest area percentage of the watershed (r = -0.9188, p<0.0001, n = 23). δ¹³C-DIC showed significant negative correlation with the DIC concentration (r = -0.7734, p<0.0001, n = 23), electric conductivity (r = -0.5396, p = 0.0079, n = 23), and watershed population density (r = -0.6836, p = 0.0003, n = 23). Our approach using a stable carbon isotope ratio suggests that DIC concentration and δ¹³C-DIC could be used as indicators for monitoring the health of stream ecosystems with different watershed characteristics.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.218-221
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• 2001

양양 양수발전소 건설 지역 터널 내에서 동일 암상 내에 부존하는 단열 암반 대수층 지하수를 수평/수직적 관점에서 체계적으로 채취하고 수리지구화학 및 환경동위원소 특성 연구를 수행하고 있다. 현재까지 모아진 특성 자료를 공간적 변화와 관련하여 예비 고찰한 곁과, 연구 지역에는 두 가지 상이한 지하수 유통계를 이루고 있는 것으로 판단된다.

• 약학회지
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• 제52권3호
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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.

• 생태와환경
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• 제41권spc호
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• pp.27-34
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• 2008

본 연구는 부영양상태의 신구저수지에서 강우기 전 후의 수질 변화와 강우기 유입수의 영향을 평가하기 위해 이루어졌다. 강우기 전에는 수심에 따른 수온차가 $1^{\circ}C$이하였지만 강우기 후에는 $4^{\circ}C$차 이상까지 벌어져 수온 약층이 뚜렷하게 형성되었다. 탁도는 강우기 전보다 강우기 후에 표층에서 12NTU, 저층 120NTU로 크게 증가하였다. POC의 농도는 강우기 전의 조사에서 수심에 따라서 $4.96{\sim}6.68mg\;L^{-1}$의 범위를 나타내고 강우기 후의 조사에서는 $1.73{\sim}5.32mg\;L^{-1}$의 범위를 나타내고 있어 전체적으로 강우기 전보다 강우기 후의 POC의 농도가 낮았으나 수심에 따라서 크게 증가하는 경향을 보이고 있다. 또한, DOC의 농도는 강우기 전의 조사에서 $3.82{\sim}3.96mg\;L^{-1}$의 범위를 나타내고 있고, 강우기 후의 조사에서 $2.18{\sim}2.57mg\;L^{-1}$의 범위를 나타내고 있어 전체적으로 강우기 전보다 강우기 후의 DOC농도는 감소하고 있다. 또한 강우기 후 저층의 높은 탁도층에서 강우기 전보다 입자성유기물의 C/N비가 크게 증가하였고 입자성 유기물의 ${\delta}^{13}C$와 ${\delta}^{15}C$값이 뚜렷하게 가벼운 값을 보이는 것으로 볼 때 저수지 주변 유역에서 유입된 유기물의 영향을 크게 받았다는 것을 알 수 있다. 본 연구 결과로 볼 때 농업용 저수지인 신구저수지는 하계 강우기시 유입하천을 통해 외부로부터 유입된 육상식물 유기물이 저층에 부유된 상태로 존재하며 이는 저수지 내 저층 수생태계의 에너지 흐름에 영향을 줄 수 있는 것으로 사료된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권4호
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• pp.51-62
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• 2012

Effects of climate change on groundwater system requires understanding the groundwater system in temporal and spatial scales through the long-term monitoring. In this study, the spatio-temporal variations of groundwater were analyzed through the continuous observation of water level, electrical conductivity (EC) and water temperature with automatic data-loggers and sampling in a Gwangneung catchment, Korea, for the four years from 2008 to 2011. Groundwater monitoring were performed at the nest-type wells, MW1 and MW2, located in upsteam and downstream of the catchment, respectively. During the survey period, both the total amount of annual precipitation and the frequency of concentrated rainfall have increased resulting in the elevation of runoff. Water level of MW1 showed no significant fluctuations even during the rainy season, indicating the confined groundwater system. In contrast, that of MW2 showed clear seasonal changes, indicating the unconfined system. The lag-time of temperature at both wells ranged from one to three months depending on the screened depths. Results of chemical analyses indicated that major water compositions were maintained constantly, except for the EC decreases due to the dilution effect. Values of the stable-isotope ratios for oxygen and deuterium were higher at MW2 than MW1, implying the confined system at the upstream area could be locally developed.

• 생태와환경
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• 제45권2호
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• pp.242-251
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• 2012

본 연구는 탄소 및 질소 안정동위원소비를 이용하여 하천에서 환경변화의 지표로 활용할 수 있는 부착조류의 먹이원으로서 기여도를 파악하고자 하였다. 연구지역인 탐진강은 지류를 통해 유입되는 외래기원물질의 영향으로 상류에서 하류로 갈수록 높은 영양염의 농도를 나타냈으며 이와 더불어 상위섭식자인 어류의 질소 안정동위원소비의 증가가 관찰되었다. 또한 탐진강에서 채집된 저서성대형무척추동물과 어류의 ${\delta}^{13}C$ 값이 상류에서 하류로 이동하면서 무거워지는 경향을 나타내었다. 이는 탐진강 하류 수역에서 무거운 ${\delta}^{13}C$ 값을 보였던 암석 부착조류가 먹이원으로서의 기여도가 높아진 결과로 판단된다.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.45-54
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• 2016

Background: Macrophytes are commonly utilised as habitat by epiphytic species; thus, complex macrophyte structures can support high diversities and abundances of epiphytic species. We tested the hypothesis that the presence of aquatic macrophytes is an important factor determining Sida crystallina (O.F. Muller, 1776) distribution. Results: An ecological survey was conducted in 147 lentic freshwater bodies. S. crystallina was frequently observed, and its density was strongly associated with macrophyte abundance. S. crystallina was found on emergent plant species such as Phragmites australis and Paspalum distichum, attached to the stem surfaces by adhesive substances secreted by the nuchal organ. Thus, S. crystallina was more strongly attached to macrophytes than to other epiphytic cladoceran species. We found higher densities of S. crystallina in filtered water with increased macrophyte shaking effort (i.e. 10, 20, 40, or 80 times). S. crystallina attachment was not related to fish predation. Stable isotope analysis showed that S. crystallina utilises epiphytic organic matter (EOM) on macrophytes as a food source. Conclusions: Consequently, S. crystallina seems to have a strong association with species-specific macrophyte biomass than with other cladoceran species, which may contribute to this species' predominance in various freshwater ecosystems where macrophytes are abundant.