• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.579-592
• /
• 2020

This study was designed to assess the water quality and phytoplankton community including chlorophyll a in blood cockle (Tegillarca granosa) farms in May, August and November of 2017 in the northwestern Yeoja Bay, Korea. As a result, the seasonal characteristics of water types by water temperature and salinity were clear. Nutrients were abundant in silicate throughout the season, but phosphate was scarce in spring and summer, and nitrogen sources were scarce in autumn. The species composition of phytoplankton community was a very simple distribution, and the standing crop was also very low. The annual dominant species is dominated by the diatoms, with Skeletonema costatum-ls, Nitzschia longissima in spring, Pleurrosigma normanii, Coscinodiscus gigas in summer, and N. longissima, Pseudonitschia pungens, Chaetoceros curvisetus, Eucampia zodiacus in autumn. In summer the results were different from other coastal waters of Korea. The principal component analysis(PCA) and correlation analysis showed that the characteristics of water quality and biological environments differed according to the season. Furthermore, it was determined by the supply of materials through fresh water on land, seawater congestion caused by the refueling of surface sediments with lower depth, and the balance of biological production and mineralization of organic matters in blood cockle farms.

• Korean Journal of Environmental Biology
• /
• v.34 no.4
• /
• pp.292-303
• /
• 2016

This study described the spatial distributions of marine environmental factors such as water temperature, salinity, chlorophyll a concentration and turbidity, and characteristics of phytoplankton community such as species composition, standing crops and dominant species at 19 fishing ports around Jeju Island during the early summer of 2016. I analyzed bio-oceanographical characteristics using principal component analysis (PCA) of the environmental factors and biological parameters. Water temperature, salinity, chlorophyll a and turbidity ranged from 17.6 to $20.7^{\circ}C$, from 26.19 to 32.33 psu, from 0.76 to $7.13{\mu}g\;L^{-1}$, and from 0.51 to 14.49 FTU, respectively. A total of 51 species of phytoplankton belonging to 35 genera were identified. In particular, diatoms and dinoflagellates accounted for more than 56.8% and 27.4% of all the species, respectively. Moreover, the number of phytoplankton species was controlled by salinity. Phytoplankton cell density ranged from $2.9cells\;mL^{-1}$ to $185.9cells\;mL^{-1}$. The dominant species were Navicula spp. Stephanopyxis turris, Eutreptiella gymnastica and Mesodinium rubrum. Environmental factors and the phytoplankton community varied greatly between sampling sites. According to PCA, the biological oceanographic characteristics of the around Jeju Island were characterized by meteorological factors such as air temperature, precipitation and discharge of ground water during early summer.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.3
• /
• pp.869-877
• /
• 2017

The monthly variations of zooplankton community were investigated at 12 stations near Tongyeong and Namhaedo in the South Sea of Korea from April to July, 2012. Zooplankton samples were collected by a plankton net (RN80) from near the bottom to the surface. Zooplankton community consisted of 97 taxa, and the mean abundance ranged from $213inds.m^{-3}$ in July to $426inds.m^{-3}$ in April. Copepods constituted 38.98% of zooplankton abundance, and included 39 species. Calanus sinicus, Corycaeus affinis, Paracalanus parvus s.l., copepodids, Evadne nordmonni, Podon leuckarti, cirriped nauplii, Muggiacea sp., Diphyes sp., and Zonosagitta bedoti were dominant species. Of these, Calanus sinicus was the most abundant throughout the study period, being constituted 18.6% of total zooplankton abundance. The density variations of dominant species between stations and months were correlated with the environmental factors. Zooplankton community varied with by sampling months, being influenced by monthly oceanographic variations.

• The Korean Journal of Ecology
• /
• v.21 no.5_3
• /
• pp.665-673
• /
• 1998

This study was conducted to clarified the relationship between bird community and forest structure and present the counterplan for protection and management of bird community from February 1993 to July 1995 at deciduous and coniferous forest within Mt. Nam area, Seoul, Korea. DBH distribution has not significant differences in each study site. Deciduous forest had more foliage coverage in all layers than coniferous forest. Total 41 species of birds, which were 16 species of resident, 14 species of summer visitor, 4 species of winter visitor, and 7 species of passage migrant were recrded in two study sites. Leaf use rate of birds was increased the increase of coverage. The number of breeding species and pairs, breeding density, and diversity index were greater in deciduous forest than coniferous forest. The number of species and pairs on bush-nesting and foraging guild were greater than other guilds. And the nuber of species and pairs on hole nesting guild were the fewest in nesting guild. Use rate of artificial nests for improvement of habitat quality was greater in coniferous forest than deciduous forest. Maintenance of bush layer, increase of coverage and leaf layer diversity, supply of artificial nests, management of large trees, and control of natural enemy were necessary for protection and management of bird community in Mt. nam area.

• Animal cells and systems
• /
• v.14 no.3
• /
• pp.225-236
• /
• 2010

We compared the composition of phospholipid fatty acids (PLFA) to assess the microbial community structure in the soil and rhizosphere community of non-transgenic watermelons and transgenic watermelons in Miryang farmlands in Korea during the spring and summer of 2005. The PLFA data were seasonally examined for the number of PLFA to determine whether there is any difference in the microbial community in soils from two types of watermelons, non-transgenic and transgenic. We identified 78 PLFAs from the rhizosphere samples of the two types of watermelons. We found eight different PLFAs for the type of plants and sixteen PLFAs for the interaction of plant type and season. The PLFA data were analyzed by analysis of variance separated by plant type (P<0.0085), season (P<0.0154), and the plant type${\times}$season interaction (P<0.1595). Non-parametric multidimensional scaling (NMS showed a small apparent difference but multi-response permutation procedures (MRPP) confirmed that there was no difference in microbial community structure for soils of both plant types. Conclusively, there was no significant adverse effect of transgenic watermelon on bacterial and fungal relative abundance as measured by PLFA. We could reject our hypothesis that there might be an adverse effect from transgenic watermelon with our statistical results. Therefore, we can suggest the use of this PLFA methodology to examine the adverse effects of transgenic plants on the soil microbial community.

• Journal of Climate Change Research
• /
• v.5 no.3
• /
• pp.249-256
• /
• 2014

Permafrost is frozen soil below $0^{\circ}C$ for two or more years. Surface of permafrost is called as active layer that seasonally thaws during the summer. Although the thawing of permafrost may deepen the active layer and consequently increase the microbial activity, the microbial community structure in this habitat has not yet been well described. In this study, we presented bacterial and archaeal diversity in the active layer soil from Resolute, Canada using pyrosequencing analysis. The soil sample was collected from the surface of the marsh covered with moss and Carex. A total of 7,796 bacterial reads for 40 phyla and 245 archaeal reads for 4 phyla were collected, reflecting the high diversity of bacteria. Predominant bacterial groups were Proteobacteria (37.7%) and Bacteroidetes (30.0%) in this study. Major groups in Archaea were Euryarchaeota (51.4%) and Thaumarchaeota (46.1%). Both methane producing archaea and consuming bacteria were detected in this study. Although it might be difficult to characterize microbial community with only one sample, it could be used for the basis of assessing the relative importance of the specific groups with a high resolution on the bacterial and archaeal community in this habitat.

• Korean Journal of Ecology and Environment
• /
• v.52 no.4
• /
• pp.348-357
• /
• 2019

To investigate the changes of dominant species of benthic macroinvertebrates following summer precipitation variance, we surveyed twenty five sites of the main Seomjin River in May and September in 2014 and 2015. The temperature, precipitation, water quality factors and substrate composition, water depth and flow velocity, which are important factors in benthos habitat environment, were collected and measured. There is not much difference of the cumulative precipitation (CP) between 2014 (2,322.1 mm) and 2015 (2,371.0 mm) in May. However CP in september was decreased by more than half in 2015 (3,726.1 mm) than 2014 (7,678.2 mm). Due to washing effect by summer precipitation, total number of species and individuals for benthic macroinvertebrates were higher in May than in September. Chironomidae spp. and Choroterpes altioculus were dominated in May, Ecdyonurus levis, Ecdyonurus kibunensis were dominated in September. As a result of correlation analysis between community indices and environment factors, it was found that there is a significant correlation with flow velocity and substrate compositions. According to the results of cluster analysis and PCA based on environment fators and dominant species of benthic macroinvertebrates in Seomjin River, it was divided into four groups following CP and MT. Ecdyonurus levis and Ecdyonurus kibunensis reflect the effect of the decrease in summer precipitation.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.5
• /
• pp.545-552
• /
• 2018

In this study, we performed a mesocosm experiment to estimate the mass balance of Nutrients (DIN, DIP) in a phragmites australis community. We developed 4 mesocosm tanks which is available to circulate seawater with adjustable tide levels and flooding times. Each of the mesocosm tanks were filled with phragmites australis and sediment from Jinudo in Nakdong Estuary. We investigated DIN, DIP concentrations in three layers (seawater-phragmites australis-sediment) to estimate the mass balance of Nutrients and biomass. Growth rates were also investigated. The results can be summarized as follows. 1) In spring, rhizome biomass was higher than that of aerial stem by about 6.3~9.7%. In summer, aerial stem biomass was higher than that of rhizome about 19.2~21.2 %. 2) Th Growth rate of phragmites in Mesocosm Tank A was faster than in Mesocosm Tank D by about 2 to 3 times for aerial stem and rhizome. 3) The Concentration of nutrients (DIN, DIP) in each mesocosm Tank showed 2~3 % variance in spring and summer. 4) The biomass in each mesocosm varied by about 23 % which was higher than the concentration variance for each mesocosm tanks.

• Korean Journal of Environmental Biology
• /
• v.40 no.4
• /
• pp.510-524
• /
• 2022

For the assessment of the benthic community health of Jinhae Bay using the Benthic Pollution Index, macrobenthic fauna samples were seasonally collected from 23 different sites between February, 2011 and November, 2012. The macrobenthic community health status was classified as "Poor" or "Very Poor" except for the bay mouth part of Jinhae Bay at the northern part of Geoje Island. A large proportion of functional Group IV and even azoic conditions appeared due to summer hypoxia at sites in sheltered regions of Jinhae Bay. Some of the dominant species recruited after summer hypoxia were Paraprionospio patiens, Sigambra bassi, and Theora fragilis belong to typical opportunistic species. By comparing the BPI values of the macrobenthic communities from other special management areas of Korea, Jinhae Bay was considered to have the lowest condition that was heavily polluted among special management areas.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.60 no.2
• /
• pp.101-113
• /
• 2024

This study investigated the species composition and community structure of aquatic organisms captured using coastal beam trawling in Gomso Bay, Jeollabuk-do, from January to December 2022. Throughout the experimental period, a total of 20,246 individuals belonging to 94 marine species were captured, with a combined biomass of 602,828 g. Fish exhibited the highest abundance, comprising 56 species, followed by crustacea (21 species), bivalvia (8 species), cephalopoda (5 species), gastropoda (3 species), and holothuroidea (1 species). The dominant species was Leiognathus nuchalis, constituting 14.0% of the total individuals, followed by Portunus trituberculatus at 12.1%, Oratosquilla oratoria at 10.4%, Crangon hakodatei at 9.9%, and Metapenaeus joyneri at 7.9%. The diversity index ranged from 1.72 to 2.55, with the lowest diversity observed in March and the highest in July. Cluster analysis based on species composition of the 27 most common species showed that aquatic organisms were divided into three groups: spring and summer organisms (Group A) and summer organisms (Group B) and autumn and winter organisms (Group C).