• Journal of Ecology and Environment
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• 제30권3호
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• pp.209-223
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• 2007

Twenty-four wetlands located in Higashi-Hiroshima City in West Japan were selected for this study in order to investigate both the relationship between aquatic plant composition and environmental conditions; and the relationship between changing land use patterns in the catchments and the concentration of different forms of nitrogen in the wetlands. The dominant and subdominant species which comprised the principal vegetation were determined based on a vegetation census conducted in each wetland during the growing season from June to August, 2006. The seasonal variations of water quality factors (pH, electrical conductivity, turbidity, dissolved oxygen, total dissolved solid, and temperature) and different forms of nitrogen such as nitrite, nitrate, ammonium, total nitrogen, dissolved organic nitrogen and dissolved inorganic nitrogen concentrations were analyzed as important indicators of water quality for the surface water of the wetlands. The surveyed wetlands were classified into three types (non-disturbed wetlands, moderately-disturbed wetlands and highly-disturbed wetlands), based on the degree of human disturbance to their catchment areas. An analysis of variance indicated that there was a significant difference among the wetland groups in the annual mean values of electrical conductivity, total dissolved solids, total nitrogen, nitrite, dissolved inorganic nitrogen and dissolved organic nitrogen. Classification of the wetlands into three groups has revealed a pattern of changes in the composition of plant species in the wetlands and a pattern of changes in nitrogen concentrations. A majority of the non-disturbed wetlands were characterized by Brasenia schrebi and Trapa bispinosa as dominant; with Potamogeton fryeri and Iris pesudacorus as sub-dominant species. For most of the moderately-disturbed wetlands, Brasenia schrebi were shown to be a dominant species; Elocheriss kuriguwai and Phragmites australis were observed as sub-dominant species. For a majority of the highly-disturbed wetlands, Typha latifolia and T. angustifolia were observed as dominant species, and Nymphea tetragona as the sub-dominant species in the study area. An analysis of land use and water quality factors indicated that forest area played a considerable role in reducing the concentration of nutrients, and can act as a sink for surface/subsurface nutrient inputs flowing into wetland water, anchor the soil, and lower erosion rates into wetlands.

• 한국수산과학회지
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• 제57권3호
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• pp.262-277
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• 2024

The mid-eastern coast of Korea is located at the boundary between cold and warm currents, which causes changes in the distribution and composition of marine organisms in response to fluctuations in the marine environment. To understand the seasonal changes in the seaweed community, we investigated its species composition, biomass, coverage, and frequency from November 2022 to August 2023. A total of 45 species (7 green, 18 brown, and 20 red algae) were found in the study area. In the intertidal zone, the number of species decreased from autumn to summer; the biomass peaked during winter (471.94 g wet weight m^-2). Seaweed groups were the dominant functional groups, which were coarsely branched, filamentous, and sheet-like during autumn, winter, spring, and summer. The morpho-functional group was dominated by turf species. In the subtidal zone, the number of species increased during autumn to spring, whereas the biomass peaked during spring (655.27 g wet weight m^-2). The functional group was dominated by coarsely branched species throughout all four seasons, whereas the morpho-functional group was dominated by canopy species. Consequently, changes in the biomass of brown and red algae are recognized as key drivers of seasonal changes in seaweed communities.

• 수산해양교육연구
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• 제9권2호
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• pp.222-235
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• 1997

천엽현암화전(千葉縣岩和田)어업협동조합에 소속하는 1인승어선이 어획한 7어종항목에 대해서 어획금액이 높은 어종항목으로 어선을 분류하여, 다시 이들을 판별함수로 분류한 결과, 6그룹으로 분류할 수 있었다. 이들 그룹은, 방어류를 주어종으로 하는 G1그룹, 넙치류를 주어종으로 하는 G2그룹, 가다랭이 참치류를 주어종으로 하는 G3그룹, 오징어류를 주어종으로 하는 G4그룹, 저서어류를 주어종으로 하는 G5그룹, 기타어류를 주어종으로 하는 G6그룹이다. 1인승어선 총척수의 대부분의 평균어획금액은 10년동안 400만엔에 미치지 못하는 G1, G2 및 G6그룹에 속하고, 전업어업에 종사하지 않는 어선들이었다. 그리고, 7어종의 어획금액에 관해서 주성분분석을 행하여, 제1주성분에서 제4주성분의 주성분득점으로 각 그룹을 고찰한 결과, 끌낚시어업에 의한 방어류와 넙치류를 주어종으로 하는 G1 G2그룹, 가다랭이 참치류와 오징어류를 주어종으로 하는 G3 G4그룹과 저서어류를 포함하는 G5그룹, G1 G2그룹과 유사하지만 자망에 의한 어획이 주된 G6그룹의 3그룹으로 다시 크게 분류할 수 있었다. 그러나, G1 G2그룹과 G3 G4 G5그룹의 일부분이 중복된 것에 대해서의 해석은 앞으로의 연구과제라 할 수 있다.

• Fisheries and Aquatic Sciences
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• 제14권1호
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• pp.55-61
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• 2011

Fish larvae were collected monthly with an ichthyoplankton net from 18 stations (including four stations located in eelgrass beds) in Gamak Bay and Yeoja Bay, southern Korea, in 2007. In total, 33 species of fish larvae were collected, of which Engraulis japonicus (48.5%), Tridentiger trigonocephalus (21.5%), and Omobranchus elegans (9.2%) were dominant. Dominant species varied seasonally: Hexagrammos otakii during December and January, Pholis nebulosa during January and March, Acanthogobius flavimanus in April, T. trigonocephalus in May, E. japonicus during June, July, September, and November, and Sillago japonica in August. Dominant species also differed between sites inside and outside the bays. Leiognathus nuchalis, O. elegans, and T. trigonocephalus were more abundant inside, while H. otakii was more abundant outside. From cluster analysis, three groups were identified according to sampling months (January-April, May-September, and October-December) and two groups according to station (inside and outside bays). The occurrence of small larvae of almost all major fish species indicated that the bays were used as spawning and nursery grounds. An exception was Lateolabrax japonicus, whose specimens were relatively large (>19 mm TL), suggesting that this fish may spawn offshore, with its juveniles approaching the bays with growth.

• 한국물환경학회지
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• 제32권1호
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• pp.15-22
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• 2016

This study aims to analyze the changes in the benthic macroinvertebrate community before and after a restoration project in a eutrophic stream. Species diversity and species richness increased at the points where the channel changed from standing water to running water. However, species diversity and richness decreased at the points where only riparian restoration was implemented, and the concentration of suspended solids increased, while biochemical oxygen demand and total phosphorus decreased and the concentration of dissolved oxygen increased. In such reaches, functional feeding groups went from collector-filterers to collector-gatherers, and habitat orientation groups changed from clingers to burrowers.

• Ocean and Polar Research
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• 제41권4호
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• pp.251-263
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• 2019

We investigated the mesozooplankton community structure during autumn in the southern Yellow Sea. Mesozooplankton density generally ranged from 352 to 2,954 ind. m^-3 and varied according to different sampling stations. The copepod Paracalanus parvus s.l. and its copepodites dominated in the communities, corresponding to 57.3% in density of the total. Surface and water-column averaged salinity were positively correlated with density of total mesozooplankton, copepods and a few dominant species, and the tunicate Thalia rhomboides was negatively related to chlorophyll-a concentration. The mesozooplankton community of the study area was divided into three groups according to the cluster analysis using species composition and density: one in the northern coastal region, another in the northern offshore region, and the other in the south. The most significant indicator species for each of the groups were Labidocera euchaeta in the northern coastal region, T. rhomboides in the northern offshore region, and Themisto sp. juveniles in the south. This study provides recent data on the characteristics of the mesozooplankton community in the southern Yellow Sea, which may be valuable for gaining a better understanding of changes in the pelagic ecosystem of the Yellow Sea.

• 한국버섯학회지
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• 제8권2호
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• pp.41-50
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• 2010

Mycoviruses have been found in many fungal species including mushrooms. Double-stranded (ds) RNA genomes were common type in mycoviruses, but single-stranded (ss) RNA mycoviruses were also reported in some fungal species. Sequencing analysis using cDNA cloning experiments revealed that mycoviruses can be classified into several different virus families such as Totiviridae, Hypoviridae, Partitiviridae and Barnaviridae etc. Because the nucleotide sequence data that are available in these days are very limited in a number of mycoviruses, the existence of more diverse viral groups in fungi are currently expected. In this review, we selected four different fungal groups, which were considered as the model systems for mycovirus related studies in both plant pathogenic fungi and edible mushroom species, and discussed about their molecular characteristics of diverse mycoviruses. The plant pathogenic fungi introduced here were Cryphonectria parasitica and Helminthosporium victoriae and the edible mushroom species were Agaricus bisporus and Pleurotus ostreatus.

• 한국자기공명학회논문지
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• 제21권2호
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• pp.44-49
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• 2017

Coffee is one of the top selling products in the world. There are various coffee bean species around the world. Among them, Coffea Arabica is the most popular species. However, there are few studies on the metabolites of coffee beans so far. This study demonstrates effects of the planted regions on the metabolite concentrations of coffee beans. The metabolites of coffee beans can be affected by growing area even although same species are grown. Accordingly, we studied coffee bean metabolites extracted from the same species in different regions (The brand names, Kona from Hawaii, Mocha Matari from Yemen, and Blue Mountain from Jamaica) by using mixed solvent of methanol: water: chloroform. A comparative analysis by NMR spectroscopy was performed and the statistical techniques were used to figure out the differences. As a result, we found that chlorogenic acid, caffeine, citrate, and sucrose mainly contributed to the separation of the three groups. When compared with Kona and Blue Mountain, concentrations of chlorogenic acid, caffeine, and sucrose in Mocha Matari were observed to be relatively down-regulated. In addition, compared with the two other groups, concentration of citrate in Kona was observed to be up-regulated.

• 미생물학회지
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• 제14권3호
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• pp.105-116
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• 1976

410 strains which belong to the genus aspergillus were isolated from specimens collected throught South Korea, and 17 species nad 1 variety through the 13 species groups were identified according to Repaer-Fennell's classification key. Among them the species and variety unrecorded in Korea are as follows : A, giganiteus, A. pseudogloucus, A. spinulosus, A.ficuum, A.japonicus, A.flavus var. columnaris, A. flavipes.

• 한국패류학회지
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• 제9권2호
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• pp.44-56
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• 1993

These studies were conducted to compare the external morphologies of 15 species of land snails in 8 genera of family Bradybaenidae in Korea. Principal component analyses of 15 species can be divided into five groups based on the morphological characters and the result of cluster analyses were in accord with the principal component analyses. The morphological intraspecific similarity of Nesiohelix samarangae of Mitan and Cheju population(S=0.999) proved to be highest. The degree of interspecific similarity between Aegista(Plectotropis)divesa and Aegista(plectotropis)quelpartensis(S=0.970)were more similar than the other interspecies.