• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.2
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• pp.87-102
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• 2022

To clarify the spatial distribution pattern of macrozoobenthos in Korean coastal waters in the summer season and investigate the relationship between community structure and benthic environmental factors, field surveys on community structure and benthic environmental factors were conducted at 117 stations in August 2017. A total of 613 macrobenthic species were identified, with the mean density of 1,228 ind./m² and the mean biomass (wet weight) of 110.9 g WW/m². Rich biodiversity was found at stations near Wando and along the coast of the East Sea, and there is a trend that stations with greater biodiversity also showed higher mean density as well. The dominant species in all the coastal areas in Korea was Heteromastus filiformis, which were found at most of the stations during the survey. The relatively deep areas in the East Sea were dominated by Magelona johnsoni and Maldane cristata, which were the third and ninth dominant species in the study areas, respectively. Pseudopolydora kempi and Rhynchospio sp. were observed only at the station located in the Nakdong River estuary. From the cluster analysis the stations could be clustered into three station groups with more similar faunal composition. Group A was located in the eastern coast, characterized with deep water depth and low levels of sand contents, while Group B was located in the southern coast, characterized by shallow depth of water and high content of mud and organic matter. Lastly, Group C was in the western coast, demonstrating low levels of mud content and organic matters. The biodiversity of macrobenthic species in the study area showed high positive correlation coefficients with benthic environmental factors such as sorting, clay, silt, and contents of organic matter in sediments, but negatively correlated with the sand contents. Major dominant species, Theora lata and Eriopisella sechellensis, both showed negative correlation coefficients with the sand contents, but a relatively high positive correlation with the levels of organic contents.It can be concluded that the spatial distribution patterns of macrobenthic organisms in Korean coastal waters are affected by depth, sediment type, and contents of organic matters.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.229-246
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• 2023

The bitterling (Cyprinidae, Acheilongnathinae) is a temperate freshwater fish with a unique spawning symbiosis with host mussels. Female bitterlings use their extended ovipositors to lay eggs on the gills of mussels through the mussel's exhalant siphon. In the present study, in April of 2020, we investigated spawning frequencies and patterns of three bitterling fish species in host mussel species in the Nakdong River basin (Hoecheon). During field surveys, a total of four bitterling and three mussel species were found. We observed bitterling's spawning eggs/larvae in the three mussel species: Anodonta arcaeformis(proportion spawned: 45.5%), Corbicula fluminea(12.1%), and Nodularia douglasiae (45.2%). The number of bitterlings' eggs/larvae per mussel ranged from 1 to 58. Using our developed genetic markers, we identified the eggs/larvae of each bitterling species in each mussel species (except for A. macropterus): A. arcaeformis (spawned by Acheilognathus yamatsutae), C. fluminea (A. yamatsutae and Tanakia latimarginata), and N. douglasiae (A. yamatsutae, Rhodeus uyekii, and T. latimarginata). Approximately 57.6% of N. douglasiae mussel individuals had eggs/larvae of more than one bitterling species, suggesting that interspecific competition for occupying spawning grounds is intense. This is the first report on bitterling's spawning events in the Asian clam C. fluminea from Korea; however, it should be ascertained whether bitterling's embryo undergoes successful development inside the small mussel and leaves as a free-swimming juvenile. In addition, the importance of its conservation as a new host mussel species for bitterling fishes needs to be studied further.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.1-19
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• 2013

This study was carried out to analyze distribution situation of alien plants and to propose management plan in the 3 Folk village in Gyeongsangbuk-do which is Cultural property designated by the State; Hahoe, Yangdong and Hangae. This research is for improve of sincerity of historical site and provide basic information which use about administration of preservation. The results are as follows. 1. Overall flora and alien plants appearance The total flora in the 3 folk villages were listed total 752 taxa including 127 families, 430 genera, 614 species, 5 subspecies, 100 varieties and 33 forms. Among them, woody plants take 263 taxa(35.0%) and herbaceous plants take 489 taxa (65.0%). Flora in the Hahoe, Yangdong and Hangae village were total 534, 479 taxa and 408 taxa and exotic plant index was 30.1%, 38.2% and 37.0% respectively. In types of exotic plants, ornamental exotic plants were 135 taxa, deciduous exotic plants were 21 taxa, cultivating exotic plants were 64 taxa, and naturalized exotic plants were 80 taxa and those result lead that the ornamental exotic plants is the highest ratio. According to the villages, Hahoe village had 161 taxa(30.1%), Yangdong Village had 183 taxa(38.2%), and Hangae village had 151 taxa(37.0%) that Yangdong village showed the most number of exotic plants. 2. Planting of landscape exotic plants in the unit cultural assets Meanwhile, Ornamental exotic plants in old house's gardens in Andong Hahoe village which is designated as a unit assets, those are total 30 taxa; followed by the Okyeon house(8 taxa) is highest and the Yangjindang(7), the Hadong house(6) and the Chunghyodang(5). Magnolia denudata appears the most as for 4 times and Campsis grandiflora etc. each took 2 times. Based on the Yangdong village, Gyeongju, that are found total 51 taxa; followed by the Dugok house(16 taxa) the Sujoldang(14), the Mucheondang(13), and the Sangchunheon (12). High appearance rate of ornamental exotic plants were Viburnum opulus for. hydrangeoides, Lycoris squamigera, Caragagna sinica and Magnolia denudata etc. Based on the Hangae village, Seongju, that are designated total 62 taxa; followed by the Jinsa house(35 taxa), the Gyori house(25), the Hanju head family house(20), and the Hahoe house(16). Taxa with high appearance rates were Caragana sinica, Juniperus chinensis var. horizontalis, Magnolia denudata, Viburnum opulus for. hydrangeoides, Chaenomeles speciosa etc. 3. Problems of exotic plant landscapes in the outer spaces of the folk villages Problems of exotic plant landscapes in the outer spaces of the Hahoe village are as follows. In lower of the Mansongjeong forest, Ambrosia artemisifolia, which are ecosystem disturbance plants designated by the Ministry of Environment, live with high dominance value. This should be have a remove with Sicyos angulatus immediately. In the Nakdong river bed around the Mansongjeong forest is covered with a riparian vegetation forest belt of Robinia pseudoacacia L. forest, Populus nigra var. italic community, and Populus x tomentiglandulosa community colony. Based on the Yangdong village, the planted or naturally distributed Ailanthus altissima colony, sporadically distributed Robinia pseudoacacia as well as Amorpha fruticosa are detected all over the village and ecotones. Based on the Hangae village, Ailanthus altissima and Robinia pseudoacacia are sporadically distributed around the village and there is a sign of spreading. similarity of exotic plantsis 47.0% to 48.6% and a reason why this happened is all of research site in Gyeongsanbuk-do and that is why growth norm of plant is similar, exotic plant which is sales for ornamental and it infer to require related countermeasure of each villages and joint related countermeasure.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.889-896
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• 2013

Advanced Oxidation Processes (AOP) have been interested for removing micropollutants in water. Most of water treatment plants (WTPs) located along the lower part of Nakdong River have adopted the $O_3/BAC$ process and have interesting in peroxone process a kind of AOP. This study evaluated the removal characteristics of residual hydrogen peroxide ($H_2O_2$) combining with the biofiltration process in the next BAC process when the hydrogen peroxide is applied for the WTP operating $O_3/BAC$ process. In the experiment, changing the temperature and the concentration of $H_2O_2$ of influent, the biofiltration process showed rapidly dropped the biodegradability when the $H_2O_2$ concentration was increased and lowered water temperature while BAC process maintained relatively stable efficiency. The influent fixed at $20^{\circ}C$ and the concentration of $H_2O_2$ at 300 mg/L was continuously input for 78 hours. Most of the $H_2O_2$ in the influent did not remove at the biofiltration process controlled 5 to 15 minutes EBCT condition after 24~71 hours operating time while BAC process controlled 5 to 15 minutes EBCT showed 38~91% removal efficiency condition after 78 hours operating time. Besides, after 78 hours continuously input experiment, the biomass and activity of attached bacterial on the biofilter and BAC were $6.0{\times}10^4CFU/g$, $0.54mg{\cdot}C/m^3{\cdot}hr$ and $0.4{\times}10^8CFU/g$, $1.42mg{\cdot}C/m^3{\cdot}hr$ respectively. These biomass and activity values were decreased 99% and 72% in biofilter and 68% and 53% in BAC compared with initial condition. The biodegradation rate constant ($k_{bio}$) and half-life ($t_{1/2}$) in BAC were decreased from $1.173min^{-1}$ to $0.183min^{-1}$ and 0.591 min to 3.787 min respectively according to increasing the $H_2O_2$ concentration from 10 mg/L to 300 mg/L at $5^{\circ}C$ water temperature and the $k_{bio}$ and $t_{1/2}$ were $1.510min^{-1}$ to $0.498min^{-1}$ and 0.459 min to 1.392 min at $25^{\circ}C$ water temperature. By increasing the water temperature from $5^{\circ}C$ to $15^{\circ}C$ or $25^{\circ}C$, the $k_{bio}$ were increased 1.1~2.1 times and 1.3~4.4 times. If a water treatment plant operating $O_3/BAC$ process is considering the hydrogen peroxide for the peroxone process, post BAC could effectively decrease the residual $H_2O_2$, moreover, in case of spilling the $H_2O_2$ into the water process line, these spilled $H_2O_2$ concentration can be able to decrease by increasing the EBCT at the BAC process.