• 생태와환경
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• 제51권1호
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• pp.96-104
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• 2018

안정동위원소비는 전 세계적으로 수생태 환경 연구에서 매우 활발하게 적용되고 있는 분야로써, 국내에서도 2000년대 이후 담수 및 연안 생태계의 먹이망 구조 연구 등 다양한 연구에서 활용되고 있다. 최근에는 기존의 총 조직내의 안정동위원소 분석기법의 한계점을 인지하고 보완하기 위한 방안으로 아미노산의 질소 안정동위원소 분석 기법이 개발되었으며, 이를 활용한 다양한 연구 사례들이 보고됨에 따라 수생태 연구의 활용범위가 급격히 확대되고 있다. 아미노산의 질소 안정동위원소 분석기법의 기술적인 접근성의 한계에 의해 현재까지 국내에서 수생태계 연구를 위해 아미노산의 질소 안정동위원소비를 활용한 연구는 제한적인 실정이지만, 국내 다양한 하천 및 호수 그리고 연안의 환경 변화 특성을 고려할 때, 향후 수생태 환경연구에 있어 그 유용성과 활용 가치가 대단히 높을 것으로 전망된다.

• 한국해양생명과학회지
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• 제7권2호
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• pp.61-73
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• 2022

안정동위원소 분석 기법(Stable isotope analysis, SIA)은 환경과학, 생태학, 지구생물화학, 법의학, 고고학 등 다양한 연구 분야에 활용되고 있다. 본 총설에서는 수산 및 양식 연구에 안정동위원소 비 분석 기법을 활용하기 위해 필요한 배경 지식을 소개하고자 한다. 특히, 자연값(natural abundance)을 이용하는 연구에 초점을 두었고 원소가 생물의 조직으로 통합되는 과정에서 발생하는 분별작용(동위원소 비의 변화)에 대한 원리와 안정동위원소 비가 유용한 도구로서 어떤 목적으로 생태, 환경학 분야에 이용되는지, 나아가 수산 및 양식 분야에 활용 가능한 예들을 제시하고자 한다. 본 논문을 통한 안정동위원소 분야의 이해로 향후 수산학 및 양식 연구에서 안정 동위원소 비의 다양한 활용이 기대된다.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제3권3호
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• pp.165-171
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• 2022

The Chinese crested tern (Thalasseus bersteini) is one of the most globally endangered species, listed as "Critically Endangered (CE)" on the IUCN Red List, with only approximately 30-49 individuals surviving in the wild. Chinese crested terns were discovered to breed in South Korea for the first time in 2016 while conducting a census on uninhabited islands. The Ministry of Environment has declared the breeding habitat of the Chinese crested terns as "Specified Island" to protect this CE species. However, brown rats (Rattus norvegicus) inhabiting the breeding grounds of the Chinese crested terns and Black-tailed gulls may potentially pose a threat to the breeding of these avian species. Therefore, we conducted a study on the feeding behavior of brown rats involving stable isotope analysis to determine their food sources. Fecal analysis showed that brown rats mainly fed on plants, whereas they scarcely fed on animals, such as insects. In addition, the stable isotope analysis showed that the δ¹³C values of brown rats, insects, and Indian goosegrasses were approximately -16 to -11‰, whereas the δ¹³C value of Chinese crested terns that obtained their food from the marine ecosystem was approximately -22 to -18‰. Hence, we conclude that the source of carbon for brown rats on this island is the terrestrial ecosystem. We ruled out the possibility of any direct prey-predator interaction between the brown rat and the Chinese crested tern or Black-tailed gull.

• 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.

• 생태와환경
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• 제38권spc호
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• pp.8-11
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• 2005

Carbon stable isotope ratios of producers varied in lake ecosystems. In tile present study, we tried to estimate the seasonal variations of carbon isotope ratios of phytoplankton and benthic diatoms in a strongly acidic lake ecosystem. Lake Katanuma is a volcanic, strongly acidic lake (average pH of 2.2), located in Miyagi, Japan. Only two algal species dominate in Lake Katanuma; Pinnularia acidojaponica as a benthic diatom, and Chlamydomonas acidophila as a green alga. Carbon isotope values of P. acidojaponica varied seasonally, while those of particulate organic matter, which were mainly composed of C. acidophila remained fairly stable. The differences suggested that $CO_2$ gas was more frequently limited for P. acidojaponica than C. acidophila, since high density patches of benthic diatoms were sometimes observed on the lake sediment. Generally, carbon concentration mechanisms (CCMs)of microalgae can fix bicarbonate in lakes, and affect the carbon isotope values of microalgae. While, in Lake Katanuma, CCMs of the microalgae may scarcely function because of high $CO_2$ gas concentration and low pH. This is the reason for low seasonal amplitude of carbon isotope values of phytoplankton relative to those in other lakes.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.85-86
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• 2005

• Journal of Ecology and Environment
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• 제43권4호
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• pp.461-468
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• 2019

Background: This study aimed to identify NO₃^--N sources using the stable isotope δ¹⁵N in Chydorus sphaericus (OF Müller), to investigate hydrological characteristics and nutrient states in artificial wetlands near the Nakdong River. Chydorus sphaericus is dominant in wetlands where aquatic plants are abundant, occurring in high density, and is sensitive to wetland water pollution, making it suitable for identification of NO₃^--N sources. Results: NO₃^--N sources for each wetland were strongly dependent on hydrological characteristics. Wetlands with sewage or rainfall/groundwater as their main sources had high levels of NO₃^--N, whereas wetlands with surface water as their main input had comparatively lower levels. Since wetlands with sewage and rainfall/groundwater as their main water sources were mostly detention ponds, their inputs from tributaries or the main river stream were limited and nutrients such as NO₃^--N easily become concentrated. Changes in NO₃^--N levels at each wetland were closely associated with δ¹⁵N of C. sphaericus. Interestingly, regression analysis also showed positive correlation between δ¹⁵N of C. sphaericus and NO₃^--N level. Conclusions: We conclude that the nitrate stable isotope (δ¹⁵N) of C. sphaericus can be used to elucidate the hydrological characteristics of riverine wetlands. This information is important for maintenance and conservation of artificial wetlands at the Nakdong River.

• 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.

• 생태와환경
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• 제50권4호
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• pp.432-440
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• 2017

CSIA-AAs은 섭식 생물의 영양단계 산출 연구에서 SIA를 대체할 수 있는 연구 방법으로 크게 주목 받고 있지만, 최근까지 국내 연구 사례는 매우 부족하다. 본 연구에서는 금강 하구역에서 채집된 두 종의 다모류(Nephtyidae, Glyceridae)와 두 종의 어류 (Platycephalus indicus, Lophius litulon)에 대한 영양단계를 ${\delta}^{15}N_{AAs}$를 통해 산출하고 이를 ${\delta}^{15}N_{bulk}$를 이용해 산출한 영양단계와 비교하고자 하였다. 두 정점에서 채집된 다모류의 $TP_{bulk}$는 각각 2.6과 3.1로 다른 것으로 확인되었으며, 두 산출기법($TP_{base2}$, $TP_{base1}$)에 따른 차이는 작은 것으로 나타났다. 반면에, 본 연구에서 분석된 두 어종에 대한 $TP_{bulk}$는 각각 3.1과 2.3으로 어종 간 차이가 확인되었으나, $TP_{AAs}$는 3.8과 3.7로 어종 간 차이가 매우 작고 상대적으로 높은 영양단계가 확인되었다. 이는 두 어종이 어식성 어류임을 고려할 때 $TP_{AAs}$가 보다 더 신뢰할 수 있는 기법이라는 것을 확인할 수 있었으며, 본 연구는 한국 연안 생태계에서 CSIA-AAs의 활용 필요성과 그 유용성을 보여주고 있다.

• Journal of Ecology and Environment
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• 제44권1호
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• pp.1-7
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• 2020

Background: Fish body size is a major determinant of freshwater trophic interactions, yet only a few studies have explored the relationship between the fish body size and trophic interactions in river upstream. In this study, we investigated the relationship between the body size and trophic position (TP) of Coreoperca kawamebari (Temminck & Schlegel, 1843) in an upstream of the Geum River. Results: A stable isotope analysis (based on δ¹⁵N) was used to determine the TP based on the body size of C. kawamebari. The regression analysis (n = 33, f = 63.840, r² = 0.68) clearly showed the relationship between the body length and TP of C. kawamebari. The TP of C. kawamebari was clearly divided by body size into the following classes: individuals of size < 10 cm that feed on insects and individuals of size > 10 cm feed on juvenile fish. This selective feeding is an evolutionarily selective tendency to maximize energy intake per unit time. Furthermore, the diet shift of C. kawamebari was led by different spatial distributions. The littoral zone was occupied by individuals of size < 10 cm, and those of size > 10 cm were mainly in the central zone. The littoral zone can be assumed to be enriched with food items such as ephemeropterans and dipterans. Conclusion: The TP of C. kawamebari, as a carnivorous predator, will have a strong influence on biotic interactions in the upstream area of the Geum River, which can lead to food web implication.