• Journal of Ecology and Environment
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• 제38권3호
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• pp.307-318
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• 2015

The objectives of this study were to identify multi-level stressors from blood biomarkers to community-level bioindicators and diagnose the stream ecosystem health in polluted streams. Blood chemistry such as total protein ($T_{Pro}$), blood urea nitrogen ($B_{UN}$), total cholesterol ($T_{Cho}$) and $A_{lb}$umin ($A_{lb}$) were analyzed from sentinel fish tissues; the functions of kidney, gill and liver were significantly decreased in the impacted zone ($I_z$), compared to the control zone ($C_z$). Histopathological analysis showed that fish liver tissues were normal in the $C_z$. Fish liver tissues in the $I_z$, however, showed large cell necrosis and degeneration and also had moderate lobular inflammation and inflammatory cell infiltration of lymphocytic histocytes. Species biotic index (SBI) at species level and stream health assessment (SHA) at community level indicated that chemical impacts were evident in the $I_z$ (ecological health; poor - very poor), and this was matched with the blood tissue analysis and histopathological analysis. The impairments of the streams were supported by water chemistry analysis (nitrogen, phosphorus). Tolerance guild analysis and trophic guild analysis of fish were showed significant differences (P < 0.01) between $C_z$ and $I_z$. Overall, multiple parameter analysis from biomarker level (blood tissues) to bioindicator level (community health) showed significantly greater impacts in the $I_z$ than $C_z$. This approach may be effective as a monitoring tool in identifying the multilateral and forthcoming problems related to chemical pollution and habitat degradation of stream ecosystems.

• Journal of Ecology and Environment
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• 제36권2호
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• pp.141-150
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• 2013

Natural zooplankton communities are composed of many different species at different trophic levels in the aquatic food web. Several researchers have reported that in mesocosm/enclosure experiments, larger cladocerans tend to be more sensitive to carbamate insecticides than smaller ones (Daphnia > Moina, Diaphanosoma > Bosmina). In contrast, results from individual-level laboratory tests have suggested that large cladoceran species are more tolerant than small species. To clarify this inconsistency, we conducted a microcosm experiment using model zooplankton communities with different species compositions, where animals were exposed to lethal (near to the 24 h LC50, concentration estimated to kill 50% of individuals within 24-h for the small cladoceran Bosmina) and lower, sublethal concentrations of carbaryl. In the experiment, population densities of the small cladocerans (Bosmina and Bosminopsis) decreased subsequent to the applications of chemical, but no impacts were observed on the large cladoceran Daphnia. Our results supported the reports of previous individual level toxicity tests, and indicated that the sensitivity of zooplankton to the insecticide was unchanged by biological interactions but the response of population can be modified by compensation of population through hatching from resting eggs and/or the persistence of insecticide in the systems.

• 생태와환경
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• 제55권4호
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• pp.360-367
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• 2022

본 연구에서는 이매패류 3종인 대칭이, 펄조개, 말조개의 위 내용물을 DNA metabarcoding으로 분석한 결과, 공식 전 먹이원은 22문, 35강, 51목, 71과, 87속으로 나타났다. 3종의 공식 전 공통 동식물플랑크톤은 좁쌀공말목, 유글레나목, 유영목, 스파이로플레아목, 고리돌기돌말목으로 조사되었다. 공식 후에는 대부분의 동식물플랑크톤이 검출되지 않아 소화 및 흡수, 배출된 것으로 보여진다. 먹이원 폭 분석 결과, 펄조개의 Bi 지수가 0.3으로 대칭이(0.14)와 말조개(0.21)에 비해 높아 다양한 먹이원을 섭식하는 것으로 확인되었다. 대칭이의 생태지위중첩(niche overlap)은 펄조개(0.78)와 말조개(0.7)와 다른 이매패류에서 높은 값을 보였다. 먹이원 정보를 바탕으로 계산된 대칭이, 말조개, 펄조개의 영양 단계는 각각 2.0, 2.0, 2.5로 조사되었다. 이러한 결과는 안전동위원소 문헌조사 연구에서도 이매패류의 영양 단계가 1.8~2.4로 나타나 유사하였다. 본 연구결과는 동식물플랑크톤을 주로 섭식하는 이매패류의 먹이원 분석에 DNA metabarcoding이 적용이 효과적이며 섭식생태 분석에도 활용할 수 있음을 시사한다.

• Nutritional Sciences
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• 제7권4호
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• pp.196-200
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• 2004

There are increasing evidences that prebiotics can modulate various properties of the immune system. This study was conducted to investigate effects of three kinds of fructans (chicory inulin, chicory inulin oligosaccharide and fructooligosaccharide) and a glucose oligomer(isomaltooligosaccharide) in large bowel mass and innnunoglobulin A (IgA) in rats. Forty five Sprague-Dawley male rats weighing about 1909 were randomly sorted to receive one of the five treatments, which were control diet, control diet+6% isomaltooligosaccharide (IMOS), control diet+6% fructooligosaccharide (FOS), control diet+6% chicory inulin oligosaccharide (CIOS), or control diet + 6% chicory inulin (CI). Rats were pair-fed and received the experimental diets for 5 weeks. Cecal and colonic wall weights were significantly higher in fructan (FOS, CIOS, CI)-fed groups compared with control and IMOS groups, and the length of colon was elevated in FOS and CIOS groups compared with control group. Fecal concentrations of acetic acid and total short-chain fatty acids (SCFAs) were significantly elevated in fructan-fed groups. Plasma and cecal levels and fecal excretion of immunogiobulin A (IgA) in rats were not significantly different among groups. However, fructooligosaccharide tended to increase IgA level in cecum. Cecal IgA level was significantly negatively correlated with pH of cecal content (r=-0.337), positively correlated with acetic acid level (r=0.310). Fecal IgA excretion was positively correlated with total SCFA (r=0.311) and propionic acid (r=0.400) level in feces. These results indicate that fructooligosaccharide and chicory inulin oligosaccharide exerted trophic effects in large bowel wall, increased production of SCFAs and decreased pH, which were conditions positively associated with cecal and colonic IgA secretion.

• Ocean Science Journal
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• 제40권3호
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• pp.127-143
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• 2005

The taxonomic sufficiency approach has been proposed as a surrogate for the typical analysis of species-abundance data, especially in conditions involving prominent pollution gradients. Here, we evaluate the use of taxonomic sufficiency with infralittoral macrobenthic data derived from samples taken in a moderate polluted subtropical environment in southeastern Brazil, analysing five taxonomic levels and including two functional levels throughout polychaete feeding guilds and trophic groups. The data were collected seasonally at nine stations and studied for two abundance data series (0.5 and 1.0 mm sieve mesh-size). The results showed a similar ordination pattern between the two sieve mesh-size, but with the 0.5 mm sieve data a different pattern was observed during austral summer. A slight loss of information was detected using genus, family, polychaete species and their feeding guilds as taxonomic/functional units. These results together with those of the cost! benefit ratio, suggested that the family level seemed to be sufficient to detect the impact caused by moderate pollution in this shallow-water, subtropical environment. In additional, through the use of feeding guilds, similar patterns are obtained. Correlation analysis showed that chlorophyll a, total organic matter, zinc, and chromium sediment content were the variables that best explained the biological pattern observed and not always the best correlation coefficient occurring at the species level. The feeding guild approach seems to be useful and generates interpretable results similar to those obtained with the species level of the whole macroinfauna. The results showed an important cost reduction in the sample processing, suggesting that it is possible to adopt a coarser taxonomic level monitoring program even in species-rich communities.

• 생태와환경
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• 제43권1호
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• pp.55-68
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• 2010

박테리아, HNF, 식물플랑크톤 그리고 섬모충류로 이어지는 미소생물군집의 계절적 변화를 2007년 5월에서 2008월 5월까지 부영양화된 기수호유역 시화호의 3개 정점에서 조사하였다. 배수갑문 주변의 두 정점과 비교하여 상류의 정점에서 염분농도가 낮게 나타났고, 영양염 농도와 더불어 Chl-$\alpha$가 현저하게 높게 기록되었다. 박테리아의 연 평균은 St. 1에서 $6.8{\times}10^6\;cells\;mL^{-1}$로, St. 2에서 $7.4{\times}10^6\;cells\;mL^{-1}$로, St. 3에서 $4.6{\times}10^6\;cells\;mL^{-1}$로 각각 관찰되었다. HNF의 연 평균은 St. 1에서 $19{\times}10^2\;cells\;mL^{-1}$로, St. 2에서 $6.7{\times}10^2\;cells\;mL^{-1}$로, St. 3에서 $5.9{\times}10^2\;cells\;mL^{-1}$로 각각 기록되었다. 최고치의 섬모충 개체수는 St. 1에서 2008년 4월 29 일에 관찰되었고, 전체의 99%가 자가영양성 섬모충 Mesodinium rubrum (=Myrionecta rubra) 이였다. Chl-$\alpha$농도는 박테리아와 높은 상관관계가 관찰되었으나, 박테리아는 HNF와 섬모충으로 이어지는 상위 포식자 간의 상관성이 높게 나타나지 않았다. 이것은 상위 포식자로 이어지는 에너지 흐름의 효율이 비교적 낮다는 것을 의미한다. 부영양화된 시화호에서 일차 생산자의 생물량이 높게 관찰되였음에도 불구하고, 미소생물군집의 상위 영양단계 생물과 하위 생물군과의 상관성이 나타나지 않았다는 것은 미소생물환의 먹이 연쇄는 고전적인 먹이망과 같은 간접적인 경로와 더불어 시간 지연의 영향을 받았을 것으로 사료되었다.

• 생태와환경
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• 제57권1호
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• pp.39-50
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• 2024

중상류 유수 하천의 경우, 빠른 유속의 특징을 가지기 때문에 서식지 내 어류의 섭식활동은 저서에서 집중적으로 일어나고 이에 따라 어류 종간 자원 경쟁이 발생하는데 이와 같은 생물 간 상호작용은 경쟁적 열위에 해당하는 종의 배제라는 결과를 유도한다. 따라서 멸종위기종인 여울마자의 개체수 감소 현상의 이해를 위해서는 서식지 특이적인 생물학적 요인에 의한 영향을 고려할 필요가 있다. 본 연구는 여울마자 및 여울마자와 생태적으로 유사한 종인 돌마자가 공통으로 출현하는 지점을 대상으로 먹이망 구성생물들을 채집하였고 안정동위원소를 기반으로 하여 서식지 내 어류들의 섭식특성 및 경쟁 정도를 정량적으로 분석하였다. 대상 종들의 영양 단계의 경우, 여울마자와 돌마자 각각 2.6, 2.4가 분석되어 잡식성향의 영양단계를 보였으나 타 어류에 비해 상대적으로 초식성향이 강한 것으로 나타났다. 안정동위원소 믹싱모델 분석 결과, 모든 어류가 부착성 유기물 기원의 먹이원에 대한 의존도가 높았고 생태지위면적의 경우 돌마자는 가장 넓은 생태지위면적을 보이는 동시에 타 어류 종의 생태지위면적에 중첩되는 정도가 가장 높게 나타났다. 반면, 여울마자는 조사지점에서 생태지위면적이 매우 좁은 것으로 분석되었다. 또한 돌마자, 참중고기와 비대칭적인 생태지위면적의 중첩 정도를 보여 해당 종들에 의해 섭식활동이 제한되는 것으로 분석되었다. 본 연구는 여울마자의 제한적인 분포를 결정하는 주요 요인들 중 생물학적 요인에 초점을 두어 평가한 것으로 향후 본 연구의 결과를 활용하여 서식지의 이화학적 요인과의 복합적인 분석이 수행된다면 여울마자의 개체수 감소에 대한 유추가 가능할 것으로 예상되며 여울마자의 보존 및 복원관리 방안 수립의 중요자료로 활용될 수 있을 것으로 예상된다.

• The Plant Pathology Journal
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• 제32권4호
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• pp.329-339
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• 2016

The short-term effects of low-level contamination by heavy metals (As, Cd, Cu, and Pb) on the soil health were examined by analyzing soil nematode community in soils planted with tomatoes. For this, the soils were irrigated with five metal concentrations ([1, 1/4, $1/4^2$, $1/4^3$, and 0] ${\times}$ maximum concentrations [MC] detected in irrigation waters near abandoned mine sites) for 18 weeks. Heavy metal concentrations were significantly increased in soils irrigated with MC of heavy metals, among which As and Cu exceeded the maximum heavy metal residue contents of soil approved in Korea. In no heavy metal treatment controls, nematode abundances for all trophic groups (except omnivorous-predatory nematodes [OP]) and colonizer-persister (cp) values (except cp-4-5) were significantly increased, and all maturity indices (except maturity index [MI] of plant-parasitic nematodes) and structure index (SI) were significantly decreased, suggesting the soil environments might have been disturbed during 18 weeks of tomato growth. There were no concentration-dependent significant decreases in richness, abundance, or MI for most heavy metals; however, their significant decreases occurred in abundance and richness of OP and cp-4, MI2-5 (excluding cp-1) and SI, indicating disturbed soil ecosystems, at the higher concentrations (MC and MC/4) of Pb that had the most significant negative correlation coefficients for heavy metal concentrations and nematode community among the heavy metals. Therefore, the short-term effects of low-level heavy metal contamination on soil health can be analyzed by nematode community structures before the appearance of plant damages caused by the abiotic agents, heavy metals.

• 환경정책연구
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• 제1권1호
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• pp.1-24
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• 2002

Due to the recent increase in greenhouse gases in atmosphere, world climate is rapidly changing and in turn, the earth ecosystem responds upon the climate changes. Comparing the ecosystem in the past, the present shapes of ecosystem is the result of the serious modification. Fishery resources in marine ecosystem, which usually occupy the upper trophic level, are also inevitable from such changes, because they always react to the natural environmental conditions. The northwestern Pacific is the most productive ocean in the world producing about 30% of world catch. From time to time, however, it has been notified that abundance, distribution and species composition of major fish species were altered by climate events. Furthermore, primary productivity of the ocean is not stable under the changing environments, so that carrying capacity of the ocean varies from one climate regime to another. Major climate events such as global warming, atmospheric circulation pattern, climate regime shift in the North Pacific, and El Nino event in the Pacific tropical waters were introduced in relation to fisheries aspects. The current status and future projection of fishery production was investigated, especially in the North Pacific including Korean waters. This new paradigm, ecosystem response to environmental variability, has become the main theme in marine ecology and fishery science, and the GLOBEC-type researches might provide a solution far cause-effect mechanism as well as prediction capability. Ecosystem management principles for multi-species should be adopted for better understanding and management of ecosystem.

• Journal of Microbiology
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• 제34권3호
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• pp.241-247
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• 1996

The stability of the genetically engineered microorganisms and their recombinant plasmids released in natural environments has been regarded as one of the molecular ecological topics. In this study, the recombinant plasmids pCU103 in which the pcbCD genes involved in biodegradation of biphenyl and 4-chlorobiphenyl were cloned in pBluescript SK(+) vector, were examined for their structural and functional stability in different waters at 15 $^{\circ}C$ by the methods of electrophoresis, Southern hybridization, quantification with fluorescent dye, and transformation. The recombinant plamids maintained their stabilities for about 30 days in sterilized distilled water (SDW), 15 days in autoclaved creek water (AW), 25 days in filtered and autoclaved non-sterile creek water (FAW), 4 days in Luria-Bertani (LB) broth, and less than one day in filtered non-sterile creek water (FW). The covalently closed circular (CCC) form of the plasmid was decreased and open circular (OC) form was increased as a function of incubation time, and then linear (L) form was produced to be ultimately degraded out. The degradation rates of the plasmid were proportionally correlated to trophic level of the water, and the biological factor such as DNases was found to be one of the most critical factors affecting structural and functional stability of the plasmid in non-sterile natural water.