• Ocean and Polar Research
• /
• 제23권4호
• /
• pp.389-394
• /
• 2001

During austral summer 1998 we examined the impacts of artificial UV-B and solar radiation on chlorophyll a content and fresh weight of four species of Antarctic red algae namely, Georgiella confluens, Iridaea cordata, Pantoneura plocamioides and Porphyra endiviifolium. These subject species were taken in consideration of clear demarcations of their vertical distribution and classified as shallow water group (Iridaea and Porphyra) and deep water group (Georgiella and Pantoneura). When irradiated with artificial UV-B at the irradiance of $2.0Wm^{-2}$ the shallow water inhabitants were much more resistant than the algae from deep water the fresh weight of which was reduced by 40-50% relative to control apart from loss of pigmentation. Direct solar radiation was lethal to the deep water group with a sign of complete bleaching whereas the shallow water group did not show any change in the physiological parameters. We were unable to discriminate difference in the algal sensitivity between UV-filtered and UV-transparent treatments since samples tested were either all unaffected or dead. Spectrophotometric measurements of methanolic extracts revealed a strong absorption peak in the UV range in the shallow water group of algae, Iridaea and Porphyra, but not in the deep water counterparts. Species difference in sensitivity to artificial UV-B and solar radiation is discussed in relation to biochemical and morphological characteristics and the role of the radiation in the algal vertical distribution is suggested from ecological perspective.

• Journal of Forest and Environmental Science
• /
• 제40권3호
• /
• pp.210-226
• /
• 2024

Old-growth mixed-conifer forests in Bhutan are characterized by remarkable tree species compositional heterogeneity. However, our knowledge of tree species assemblages and their structural attributes in these forests has been limited. Therefore, forest classification has been reliant on a single dominant species. This study aimed to distinguish tree species assemblages in an old-growth mixed conifer forest in Western Bhutan and to describe their natural compositional and stand structural characteristics. Furthermore, the regeneration status of species was investigated and the quantity and quality of accumulated coarse woody debris were assessed. Ninety simple random sampling plots were surveyed in the study site between 3,000 and 3,600 meters above sea level. Tree, standing deadwood, regeneration, and coarse woody debris data were collected. Seven tree species assemblages were distinguished by Hierarchical Cluster Analysis and Indicator Species Analysis, representing five previously undescribed tree species associations with unique set of consistent species. Principal Component Analysis revealed two transitional pathways of species dominance along an altitudinal gradient, highly determined by relative topographic position. The level of stand stratification varied within a very wide range, corresponding to physiognomic composition. Rotated-sigmoid and negative exponential diameter distributions were formed by overstorey species with modal, and understorey species with negative exponential distribution. Overstorey dominant species showed extreme nurse log dependence during regeneration, which supports the formation of their modal distribution by an early natural selection process. This allows the coexistence of overstorey and understorey dominant species, increasing the sensitivity of these primary ecosystems to forest management.

• Archives of Pharmacal Research
• /
• 제28권5호
• /
• pp.592-597
• /
• 2005

An HPLC/Esl/MS method has been developed to identify and quantify the spirostanol glycosides in the rhizomes of five Polygonatum species. The relative distribution of two steroidal saponins in each extract was established using the selective ion monitoring (SIM) mode via an electrospray ionization (ESI) source. It was found that there were significant differences in the amount of spirostanol glycosides among the Polygonatum Species. The results showed that this method could be used to identify the steroidal saponins in the extracts and differentiate Polygonatum species with high sensitivity and reproducibility in a short time. Fragmentation patterns of the two reference compounds were also discussed with the electrospray ionization multi-stage tandem mass spectroscopy (ESI-MS$^n$).

• 한국물환경학회지
• /
• 제28권1호
• /
• pp.26-37
• /
• 2012

Multi-dimensional hydrodynamic and water quality models are widely used to simulate the physical and biogeochemical processes in the surface water systems such as reservoirs and estuaries. Most of the models have adopted the Eulerian grid modeling framework, mainly because it can reasonably simulate physical dynamics and chemical species concentrations throughout the entire model domain. Determining the optimum grid cell size is important when using the Eulerian grid-based three-dimensional water quality models because the characteristics of species are assumed uniform in each of the grid cells and chemical species are represented by concentration (mass per volume). The objective of this study was to examine the effect of grid-size of a three dimensional hydrodynamic and water quality model (EFDC) on hydrodynamics and mass transport in the Saemangeum Reservoir. Three grid resolutions, respectively representing coarse (CG), medium (MG), and fine (FG) grid cell sizes, were used for a sensitivity analysis. The simulation results of numerical tracer showed that the grid resolution affects on the flow path, mass transport, and mixing zone of upstream inflow, and results in a bias of temporal and spatial distribution of the tracer. With the CG, in particular, the model overestimates diffusion in the mixing zone, and fails to identify the gradient of concentrations between the inflow and the ambient water.

• 한국물환경학회지
• /
• 제25권4호
• /
• pp.494-501
• /
• 2009

Probabilistic Ecological risk assessment (PERA) is extensive approach to qualify and quantify risk on the multi species based on species sensitivity distribution (SSD). As a while, deterministic ecological risk assessment (DERA) considers the comparison of predicted no-effect concentration (PNEC) and predicted exposure concentration (PEC). DERA is used to determine if there is potential risk or no risk, and it doesn't consider the nature variability and the species sensitivity. But PERA can be more realistic and reasonable approach to estimate likelihood or risk. In this study, we compared PERA used in developed countries, and proposed PERA applicable for the Korean water environment. Taxonomic groups were classified as "class" level including Actinopterygill, Branchiopoda, Chlorophyceae, Maxillapoda, Insects, Bivalvia, Gastropoda, Secernentea, Polychaeta, Monocotyldoneae, and Chanophyceae in this study. Statistical extrapolation method (SEM), statistical extrapolation method $_{acutechronicratio}$ ($SEM_{ACR}$) and assessment factor method (AFM) were used to calculate the ecological protective concentration based on qualitative and quantitative levels of taxonomic toxicity data. This study would be useful to establish the PERA for the protection of aquatic ecosystem in Korea.

• 한국식품영양학회지
• /
• 제14권6호
• /
• pp.548-561
• /
• 2001

본 연구에서는 이 지역에서 유통되고 있는 해수 및 어패류를 직접 채취하여 Listeria spp.를 분리 하였으며, 각각의 검체에 대한 균종별 분리율, 생화학적시험과 표준균주를 사용한 pH에 대한 시간별 균의 생육관계를 조사하였으며, L. monocytogenes에 대한 마늘, 향신료, 녹차 등의 농도에 따른 시판용 TSB(0.6%ye, pH 7.3)에서의 시간별 균의 생육관계를 조사하였고, 또한 항균제 10종에 대하여 감수성 시험을 하여 다음과 같은 결과를 얻었다. 1. 총 검 체 200건에서 Listeria spp.가 검출된 것은 32건으로 분리율 16%이었고, 검체별로는 전어(japanese gizzard shad)에서 37.5%(6/16)로 가장 높았으며, 병어(pomfret)와 새우(metapenaeus shell) 에서 각각 31.3%(5/16). 맛(sinonoracula constricta)과 조기 (yellow tailrunner)에서 각각 18.8% (3/16), 해수(sea water)에서 14.3%(8/56), 바지락(little neck clams)에서 12.5%(2/16)이었으며, 홍합(hard- shelled mussels) 소라(top shell), 꼬막(cockle clam)에서는 검출되지 않았고, 균종별로는 L. innocua가 14.0%(28/200), L. monocytogenes와 L. seeligeri는 각 각 1.0%(2/200)가 분리 되었다. 2. L. monocytogenes를 비롯한 4종의 표준균주 모두는 pH 3.0에서 균의 생육이 정지되었고, pH 10.0에서는 미약하지만 균의 생육이 진행되었으며, 산성보다는 알칼리성에서 균의 생육이 활발함을 알 수 있었으며, pH 7.0∼8.0에서는 균의 생육이 가장 왕성하였고,4종의 표준균주 중 L. seeligeri가 최대의 0.D값인 0.627로 가장 높았다. 3. 마늘, 겨자, 와사비, 녹차 등의 농도에 따른 시판용 TSB(0.6%ye 포함, pH 7.3)에서 1. monocytogenes의 생육은 마늘추출물에서 0.D값이 0.078에서 0.210으로 가장 저해를 받았으며, 겨자와 와사비는 균의 생육에 큰 저해를 주지 못하였으나, 녹차 추출물은 미약하지만 18시간 이후에 균의 생육저해에 관여하고 있음을 알 수 있었다 4. 10종의 항균제 감수성시험에서 L . innocua 16주는 ampicillin, kanamycin, penicillin, trimethopriml/sulfamethoxale, vancomycin에 대하여 모두 100%의 감수성을 보였고, ciprofloxacin과 gentamicin은 각각 43.7%, 97.7%로 감수성 이 나타난 반면, tetracycline (5주, 31.3%), cefotaxime(12주, 75%)은 내성을 나타내었고, 특히 nalidixic acid는 100%모두 내성을 나타내었다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제17권5호
• /
• pp.1-9
• /
• 2012

The purpose of ecological risk assessment in soil ecosystem is to protect ecological receptors and to provide a scheme of efficient management for soil contaminants. Developed countries have already prepared the methodologies of ecological risk assessment by considering their soil properties, land use, and ecological receptors. In this study, we compared the soil ecological risk assessment processes in the similarity and differences in methodology. Four countries, except for USA, adjusted the toxicological data for ecological risk assessment, based on their representative soil properties because the soil properties affect toxic effects to ecological receptors. The soil ecological risk assessment methodology of Netherlands and UK was based on 'Technical guidance document on risk assessment (TGD)' of European Chemical Bureau (ECB). Australia, USA, and Canada developed their autonomous methodology. In the Netherlands, UK, Australia, and Canada, they employed the species sensitivity distribution (SSD) approach if sufficient toxicity data are available. The USA determined the ecological soil screening level by obtaining the geometric mean of toxicological data for three species. Furthermore, all countries consider secondary poisoning in their soil ecological risk assessment. The latest risk assessment methodology of soil ecosystem that this study investigated can be used to explore what Korea needs to develop the Korean ecological risk assessment methodology of soil ecosystem in the future.

• 한국환경보건학회지
• /
• 제45권2호
• /
• pp.192-202
• /
• 2019

Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.

• 한국환경복원기술학회지
• /
• 제17권1호
• /
• pp.111-122
• /
• 2014

The provided habitat of many services from natural capital is important. But because most ecosystem services tools qualitatively evaluated biodiversity or habitat quality, this study quantitatively analyzed those aspects using the species distribution model (MaxEnt). This study used location point data of the goat(Naemorhedus caudatus), marten(Martes flavigula), leopard cat(Prionailurus bengalensis), flying squirrel(Pteromys volans aluco) and otter(Lutra lutra) from the 3rd National Ecosystem Survey. Input data utilized DEM, landcover classification maps, Forest-types map and digital topographic maps. This study generated the MaxEnt model, randomly setting 70% of the presences as training data, with the remaining 30% used as test data, and ran five cross-validated replicates for each model. The threshold indicating maximum training sensitivity plus specificity was considered as a more robust approach, so this study used it to conduct the distribution into presence(1)-absence(0) predictions and totalled up a value of 5 times for uncertainty reduction. The test data's ROC curve of endangered mammals was as follows: growing down goat(0.896), otter(0.857), flying squirrel(0.738), marten(0.725), and leopard cat(0.629). This study was divided into two groups based on habitat: the first group consisted of the goat, marten, leopard cat and flying squirrel in the forest; and the second group consisted of the otter in the river. More than 60 percent of endangered mammals' distribution probability were 56.9% in the forest and 12.7% in the river. A future study is needed to conduct other species' distribution modeling exclusive of mammals and to develop a collection method of field survey data.

• 대한의생명과학회지
• /
• 제19권2호
• /
• pp.132-141
• /
• 2013

Mycobacterium isolates were retrospectively identified, antibiotics susceptibility test results and basic clinical data were analyzed for the 715, excepted 308 in 1,023 specimens, from a mycobacterial laboratory at a tertiary care hospital from September 2002 to December 2008. Their male to female ratio was 1.12 to 1 (379 male, 336 female). The median age of study population was 47 years (range from 10 to 93 years). Distribution of Mycobacterium species was 90.1% of total were isolates Mycobacterium tuberculosis, and 9.9% of the total non-tuberculosis Mycobacterium isolated, and Among nontuberculosis Mycobacterium isolates, 60.6% were Mycobacterium avium complex, 14.1% were isolates Mycobacterium abscessus, and 12.7% were isolates Mycobacterium intracellulare. Among 526 Mycobacterium tuberculosis isolates, 81.7% isolates were susceptible to first line antibiotics, 18.3% were resistant to one or more antibiotics. Non-tuberculosis Mycobacterium isolates, all were resistant to two or more antibiotics. Multi-antibiotic resistant tuberculosis rate was show 10.2% of total specimens. Isolated Mycobacterium species, 19.2% were multi-antibiotic resistant tuberculosis, and the rate of nontuberculosis Mycobacterium resistant to isoniazid and rifampin was very highly 84.5%. Thus among acid fast bacilli culture positive cases, Mycobacterium tuberculosis and non-tuberculosis Mycobacterium were must exactly identification and antibiotic sensitivity test. It was considered to help to select of the antibiotic in preventive medicine.