• 생태와환경
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• 제33권2호통권90호
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• pp.152-161
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• 2000

1981년 5월부터 1999년 6월까지 남한의 97개 지소의 다양한 담수역에서 채집된 표본들에 근거하여 요술시모물벼룩(Simocephalus mixtus Sars)을 재기재하였으며, 한국에서의 시모물벼룩속 종들의 과거 기록들을 검토하였다. 이 종은 최근까지 극동아시아 지역에서 긴눈시모물벼룩(S. vetulus (O.F. Muller)) 및 S. vetuloides Sars와 분류학적으로 혼동되었거나 오동정되었던 종이다. 본 종은 갑각의 후배각이 낮고 넓게 돌출하였고, 갑각의 등쪽 가장자리의 뒷부분이 팽창하였으며, 머리의 부리에 가까운 배쪽 가장자리 부위가 깊게 함몰되어 있고, 길쭉한 모양의 단안을 가지며, 후복부 발톱의 기부에 빗모양의 가시군이 없다는 점에서 근연종들과 구별된다.

• 생태와환경
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• 제33권2호통권90호
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• pp.119-127
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• 2000

Miceocystis aeruginosa에 의한 심한 수화가 발생한 1996년 여름동안 공산호에서 식물플랑크톤의 일수직분포와 물리.화학적 요인을 조사하였다. 최대 현존량은 M. aeruginosa가 우점으로 나타난 표층에서 나타났으며, 수심에 따라 점차 감소하였다. M. aeruginosa개체군의 높은 밀도가 이른 아침과 저녁에 표층에 축척되었으나 일몰 후에 급격히 감소하였다. 현존량의 대부분은 수심 5m 내에 분포하였고, 현존량의 일변화가 표층에서 명확하게 나타났으나 수직이동은 나타나지 않았다. 표층에서 현존량의 일변화는 바람에 의한 수평적 이동의 결과로 추측되었다.

• 생태와환경
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• 제48권4호
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• pp.280-286
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• 2015

점봉산의 한 소하천에 서식하는 녹색강도래 Sweltsa illiesi와 S. lepnevae의 생활환이 추정되었다. 약충은 DNA barcode로 동정되었다. 이들의 약충은 성충으로 우화하기 몇 달 전부터 머리에 종 특이적 무늬가 나타났으며, 더듬이 셋째 마디의 모양이 서로 달랐다. 두 종은 거의 동일한 semivoltine 생활환을 가지며, 산란된 알은 6월에 부화하여 약 701일의 생육기간을 보내는 것으로 나타났다. 두 종의 통합된 연평균 생물량은 회분외질량 (AFDM)으로 $96mg\;AFDM\;m^{-2}$으로 추정되었다. 통합 2차생산력은 size frequency법으로는 373 mg, increment summation법으로는 $297mg\;AFDM\;m^{-2}\;yr^{-1}$인 것으로 추정되었다.

• 생태와환경
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• 제44권4호
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• pp.337-346
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• 2011

We investigated nutrient loading and trophic states in a coastal estuarine system in the Asan estuary by assessing phytoplankton biomass and using the trophic index (TRIX). The monthly and yearly nutrient loading (TN, TP) from freshwater discharge from the Asan and Sapgyo reservoirs into the estuary were estimated and analyzed with related factors. Monitoring data (physio-chemical and biological variables) collected at five estuary stations were used to assess trophic states. Descriptive statistics of total phytoplankton cells, chl a concentrations and primary productivity were also used to assess seasonal trophic status. N loading from freshwater ranged $1.0{\sim}1.3{\times}10^4$ ton yearly. The yearly P loading ranged between 350 and 400 ton during 2004~2006, increasing to 570 ton in 2007. Regression results suggest that DIN and DSi were correlated with freshwater discharge at the upper region. Based on phytoplankton biomass and total cell abundance, the trophic state of the estuary was found to be eutrophic during spring due to phytoplankton bloom. Primary productivity level was remarkably high, especially in summer coinciding with high nutrient loading. Pheopigments increased during warm seasons, i.e. summer and fall. Trophic index results indicate that the trophic state varied between mesotrophic and eutrophic in the estuary water body, especially in the upper region. The results suggest that phytoplankton production was regulated by nutrient loading from freshwater whereas biomass was affected by other properties than nutrient loading in the Asan Estuary ecosystem.

• 생태와환경
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• 제44권4호
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• pp.317-326
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• 2011

With its recent advances, nanotechnology is now being applied to various areas. Despite the benefits of nanoparticles, their risk in the environment has caused controversy, which is now becoming an international issue. Nanoparticles can easily infiltrate into cells, accumulate in biota, and may cause adverse effects in the levels of molecules, cells and organisms, and in the community. If nanoparticles are released into the environment, they can be transferred to organisms in the ecosystem, and eventually to the human body through the food chain. In this study, the research trend of the trophic transfer of nanoparticles in the food chain was investigated. Although a few investigations have been conducted regarding this topic, the trophic transfer of nanoparticles is becoming a significant issue in the area of nanotoxicology due to the potential risk to humans via the biomagnification process. While previous studies have demonstrated evidence of the trophic transfer of nanoparticles intensive future studies are needed to provide further information on the properties of nanomaterials, the exposure media, and the in vivo mechanisms such as uptake, accumulation, and depuration.

• 생태와환경
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• 제50권4호
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• pp.374-380
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• 2017

Pine wilt disease (PWD) is one of the hazardous pine tree diseases in whole world. In Korea, PWD has been spreading since it was first observed in Busan in 1988. Dispersion of PWD is mainly mediated by its vectors such as Japanese pine sawyer. In this study, we characterized environmental condition including meteorological factors, geographical factors, and land use factors influencing on the occurrence of PWD. The occurrence data of PWD were collected at 153 sites where were the initial occurrence sites of PWD in local government regions such as city, Gun, or Gu scale. We used Akaike Information Criterion (AIC) to evaluate the relative importance of environmental variables on the discrimination of occurrence or absence of PWD. The results showed that altitude, slope, and distance to road were the most influential factors on the occurrence of PWD, followed by distance to building. Finally, our study presented that human activities highly influenced on the long term dispersal of PWD.

• 생태와환경
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• 제53권1호
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• pp.22-30
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• 2020

In this study, we investigated the relationships between benthic macroinvertebrate assemblages and various environmental factors in Iancheon (NIA) and Bukcheon (NBC) streams, Korea. We collected benthic macroinvertebrates and 33 environmental factors in April 2017 at 9 sites (5 sites in NIA and 4 sites in NBC). We identified 93 species(5 phyla, 9 classes, 16 orders, and 53 families) and 69 species(5 phyla, 9 classes, 17 orders, and 47 families) in NIA and NBC streams, respectively. Considering benthic macroinvertebrate index (BMI), NIA (88.2) and NBC (80.2) streams were in "very good" status. Upstream areas showed the highest scores, 95.5 (NIA1) and 94.2 (NBC1), whereas BMI score was the lowest in downstream areas of both streams, especially in NBC4 (51.0 "bad" status). Cluster analysis and non-metric multidimensional scaling analysis represented the differences of benthic macroinvertebrate assemblages according to spatial and anthropogenic gradients. Our findings provide reference data and highlight the need for the continued monitoring to maintain the good status and manage macroinvertebrate diversity in these two streams, in Sangju-si, Korea.

• 생태와환경
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• 제53권1호
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• pp.80-90
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• 2020

In order to understand the stress responses, we measured the concentration of stress hormones by using the fresh feces of wild otters in the Gwangju stream and Seomjin river during summer and winter in 2018. We compared seasonal and regional number of spraints (=otters' feces), temperature, altitude, water width, land cover, and water quality with stress hormones. The stress hormone levels were higher in summer than in winter, and significantly different to season and region. In addition, the number of feces were different according to the season and region, and showed a negative correlation with stress hormone. This study suggested assessing stress hormones as another promising method for the analysis of status of wild otters and it will contribute to establish the management and conservation policy, especially in urban area.

• 생태와환경
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• 제33권1호통권89호
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• pp.1-8
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• 2000

실험실에서 배양을 하기 위해 담수에서 광범위하게 서식하는 4종류의 검물벼룩목 요각류를 실험하였다. 이 중 Eucyclops serrulatus만이 성공적으로 배양되었다. 다음으로 9가지 먹이 조건 중 어떤 것에서 유생발달이 정상적으로 이루어지는 지를 살펴보았다. 이렇게 선정된 실험실 배양 환경하에서 E. serrulatus의 생식과 성장을 관찰하였다. 배양 방법이 간단하여 짧은 시간 동안 많은 순수배양된 개체들을 얻을 수 있다는 점으로 볼 때 Eucyclops serrulatus는 담수 생태계의 오염을 측정하는데 bioindicator 생물로서 응용 가능성이 크다고 할 수 있겠다.

• 생태와환경
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• 제45권2호
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• pp.200-209
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• 2012

The current of the water body is very important information for the water quality management on reservoirs. It is applied to hydraulics and water quality model for simulation. In this regard, the current characteristic of water body is the basic information that can be used to predict various conditions. However, it is very slow flowing and is affected by the reservoir operations and external factors. As such, an accurate measurement of the current is a difficult problem. In order to measure the water current, we constructed a drifter. According to the result of flow survey at Yongdam reservoir, 5m and 10 m depth layer flow was investigated from the upstream to the downstream, during a flood period. Maximum flow rate of 5 m depth is 13.8 cm $sec^{-1}$ and 10 m depth shows 4 cm $sec^{-1}$, respectively. But 2m depth shows a backward flow and maximum flow rate is 4 cm $sec^{-1}$. Density currents flow plays the role of back flow in reservoirs. Flow velocity in the reservoir was measured in the range of 1~2 cm $sec^{-1}$, at normal flow season, and the flow direction were different for each survey. This phenomenon occurs because the reservoir volume is very large, compared to the inflow and outflow volume.