• Journal of Ecology and Environment
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• v.42 no.4
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• pp.265-271
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• 2018

Background: Temperature-driven variation in pollinator assemblage and activity are important information, especially at high altitudes, where rising temperature trends exceed global levels. Temporal patterns of pollinators in a flowering season can be used as a proxy to predict the changes of high-altitude plants' mutualistic relationships. We observed a spring temperature change in one population of a high-altitude endemic species, Megaleranthis saniculifolia on Mt. Sobaeksan, and related it to pollinator assemblage and activity changes. Methods: This study was conducted at two sites, each facing different slopes (NE and NW), for two times in the spring of 2013 (early-flowering, April 27-28, vs. mid-flowering, May 7-8, 2013). We confirmed that the two sites were comparable in snowmelt regime, composition of flowering plants, and flower density, which could affect pollinator assemblage and activity. Pollinator assemblage and activity were investigated at three quadrats ($1m^2$ with 5-m distance) for each site, covering a total of 840 min observation for each site. We analyzed correlations between the temperature and visitation frequency. Results: Twelve pollinator species belonging to four orders were observed for M. saniculifolia at both sites during early- and mid-flowering times. Diptera (five species) and hymenopteran species (four species) were the most abundant pollinators. Pollinator richness increased at both sites toward the mid-flowering time [early vs. mid = 7 (NE) and 3 (NW) vs. 9 (NE) and 5 (NW)]. Compared to the early-flowering time, visitation frequency showed a fourfold increase in the mid-flowering time. With the progression of spring, major pollinators changed from flies to bees. Upon using data pooled over both sites and flowering times, hourly visitation frequency was strongly positively correlated with hourly mean air temperature. Conclusions: The spring temperature change over a relatively brief flowering period of M. saniculifolia at high altitudes can alter pollinator assemblages through pollinator dominance and visitation frequency changes. Thus, this study emphasizes information on intra- and inter-annual variations in the mutualistic relationship between pollinators and M. saniculifolia to further assess the warming impacts on M. saniculifolia's reproductive fitness.

• 한국해양학회지
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• v.27 no.1
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• pp.46-54
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• 1992

An investigation on the benthic polychaete community in Youngil Bay was conducted during four seasons of 1991. Polychaetes. the dominant macrofaunal group occupying 71.3% in total macro-faunal density, comprised a total of 72 species with a mean density of 1,485 indiv. m/SUP -2/. The highest species number of 54 spp. and density of 3,207 undiv. m/SUP -2/ was recorded in summer, while the lowest in autumn. The most abundant species was Spiophanes nombyx (37.5%), followed by Pseudopolydora sp.(8.4%), Lumbrineris longifolia(7.0%), Madden cristata(6.5%), Polydora ciliata(4.9%) and so on. Maldane cristata was dominated in winter, Polydora ciliata in spring and Spiophanes bombyx in summer and autumn. The density and species number of Polychaetes were high in the southeastern area of Youngil Bay, and poor near the mouth of Hyoungsan River. Based on the species composition, study area was divided into three regions. Each region sustained its specific benthic faunal assemblage; Maldane-Praxillella assemblage from the middle to the southeastern region of Youngil Bay, Spiophanes-Nephtys assemblage in the northwestern region, and Pseudopolydora-Polydora-Capitella assemblage from the mouth of Hyoungsan River to Pohang Hobour. Maldane Praxillella assemblage showed the highest species number of 55 spp.. and the highest species diversity and species richness indices. Spiophanes-Nephtys assemblage had the highest density of 2,675 indiv. m/SUP -2/ and the highest dominance index because of the predominance of Spiophanes bombyx with a density of 2,073 indiv. m/SUP -2/. Pseudopolydora-Polydora-Capitella assemblage was found in the polluted area and it was a specific assemblage mainly composed of the dominance of organic pollution indicator species. The dominant Polychaetes were Pseudopolydora sp., Polydora ciliata, Capitella capitata, and Dorvillea sp.

• 한국해양학회지
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• v.27 no.2
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• pp.164-172
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• 1992

This study was carried out to investigate the benthic polchaete community in the southern area of Kyeonggi Bay, Korea. The species composition was examined in Asan Bay in 1985, the coastal area near Yibug in 1987, the area between Daeranjido and Asan Bay for 1988-1989, and the offshore south of Deogjeogdo in 1992. Polychaetes, the dominant faunal group occupying 57.4% in total density, comprised a total of 124 species with a mean density of 211 indiv.m/SUP -2/. The dominant polychaete was Prionospio sp. (28.8%), followed by Nephtys polybranchia (6.0%), Tharyx sp. (4.8%) Stermaspis scutata (4.4%), Lumbrineris longifolia (3.9%). The Number of species and density were higher in the coastal area near Yibug, Asan Bay and the mouth of Namyang Bay, while lower in the channels of offshore region. The cluster analysis revealed that the study area could be divided into 5 regions, which were distributed serially along the coast from Asan Bay to open sea. Each region sustained its specific Bay, Stermaspis-Heteromastus assemblage from Asan Bay to Daeranjido, Hemipodus assemblage in the channels of offshore, Lumbrineris assemblage on the coastal area o Yibug and Prionospio assemblage in the coastal area south of Yibug. Tharyx-Chone assemblage had the highest species number of 75 spp. and Prionospio assemblage had the highest density of 3,695 indiv.m/SUP -2/ due to the predominance of prionospio sp.. Hemipodus assemblage with the lowest density occupied the largest area in offshore region. The southern Kyeonggi Bay showed higher species number and lower density than the northern Kyeonggi Bay. But the dominant Polychaetes were similar between the southern Bay and the channel regions of the northern Bay.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.119-124
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• 2015

The objective of this study was to genetically characterize isolates of Giardia duodenalis and to determine if zoonotic potential of G. duodenalis could be found in stray cats from urban and suburban environments in Guangzhou, China. Among 102 fresh fecal samples of stray cats, 30 samples were collected in Baiyun district (urban) and 72 in Conghua district (suburban). G. duodenalis specimens were examined using light microscopy, then the positive specimens were subjected to PCR amplification and subsequent sequencing at 4 loci such as glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), ${\beta}$-giardin (bg), and small subunit ribosomal RNA (18S rRNA) genes. The phylogenetic trees were constructed using obtained sequences by MEGA5.2 software. Results show that 9.8% (10/102) feline fecal samples were found to be positive by microscopy, 10% (3/30) in Baiyun district and 9.7% (7/72) in Conghua district. Among the 10 positive samples, 9 were single infection (8 isolates, assemblage A; 1 isolate, assemblage F) and 1 sample was mixed infection with assemblages A and C. Based on tpi, gdh, and bg genes, all sequences of assemblage A showed complete homology with AI except for 1 isolate (CHC83). These findings not only confirmed the occurrence of G. duodenalis in stray cats, but also showed that zoonotic assemblage A was found for the first time in stray cats living in urban and suburban environments in China.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.288-301
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• 2000

The species composition and seasonal variation of fish assemblage in the coastal water off Gadeok-do, Korea were studied using the monthly trawled samlpes through a year of 1998. During the study period, 110 species of fishes from 57 families were collected. Repomucenus valenciennei, Thryssa kammalensis, Leiognathus nuchalis and Zoarces gilli dominated the fish assemblage throughout the year, and were responsible for $ 57.6{\%}$ and $37.2{\%}$ in the number of individuals and biomass, respectively. Fish species of secondary importance in abundance were Sillago japonica, Apogon lineatus, Pholis fangi, Engraulis japonicus, Thryssa adelae, Pho;is nebulosa, Conger myriaster, Liparis tanakai, Acentrogobius pflaumii, Limanda yokohamae, Chaeturichthys hexanema, Erisphex pottii and Cunoglossus abbreviatus. Higher numbers of species were collected in spring and autumn than in summer and winter. Abundance was high in spring and autumn, and low in summer and winter, Species diversity indices showed that the fish assemblage was more diverse in autumn than any other seasons.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.366-379
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• 2002

The monthly collected fish samples by three sides tyke nets were analyzed in order to study species composition and seasonal variation of fish assemblage in the coastal water off Gadeok-do, Korea through a year of 1998, During the study period, a total of 136 fish species of 69 families were collected. Trachums japonicus, Konosims punctatus and Mugil cephaus were three dominant species in the fish assemblage and they accounted for $63.7\%$ and $83.1\%$ in the number of individuals and biomass, respectively. Fish species of secondary importance in abundance were Leiognathus nuchalis, Takifugu niphobles, Somber japonious, Trichiurus lepturus, Chelon affinis, Apogon lineatus, Nibea aibiflora and Acanthopagrus schlegeli. The highest number of species was collected in July and the lowest in february. Abundance was high in spring, and low in winter. Species diversity indices showed that the fish assemblage was less diverse in spring than any other seasons.

• Journal of the Korean earth science society
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• v.37 no.6
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• pp.325-331
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• 2016

Three diatom assemblage zones were erected from HMB-103 core sediment of the Heuksan Mud Belt. The paleoenvironmental changes were reconstructed basing on diatom analyses using indicator species, cold and warm water species, and salinity. Seventy-six species belonging to 41 genera were identified in the core sediments. The number of diatom valves per gram of dry sediment ranged from 0.1 to $15.4{\times}10^4g^{-1}$. As a result, diatom assemblage I in about 45,000 yr B.P showed a high abundance in cold species indicating a major influence by the Korea Coastal Current. Diatom assemblage II from 14,000 to 11,646 yr B.P is characterized by rare abundance and indicative of the cold periods at Younger Dryas with the lower sea-level. However, diatom assemblage III from 11,646 yr B.P to Holocene was more affected by the Yellow Sea Warm Current while the progressive sea level rise.

• Computers and Concrete
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• v.10 no.2
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• pp.173-196
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• 2012

Experimental results of cyclic reversed lateral force test on a two-story reinforced concrete shear wall sub-assemblage are simulated analytically by using the PERFORM-3D program. A comparison of experimental and analytical results leads to the following conclusions: (1) "Shear Wall" and "General Wall" models with "Concrete shear" cannot simulate the pinching phenomena due to shear and show larger amounts of inelastic energy absorption than those in the experiment. (2) Modeling a story-height wall by using two or more "General Wall" elements with "Diagonal shear" in the vertical direction induces the phenomenon of swelling-out at the belly, leading to the erroneous simulation of shear behaviors. In application to tall building structures, it is recommended to use one element of "General Wall" with "Diagonal shear" for the full height of a story. (3) In the plastic hinge area, concrete deformations of analytical models overestimate elongation and underestimate shortening when compared with experimental results.

• 한국해양학회지
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• v.23 no.4
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• pp.169-183
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• 1989

Polychaete assemblages and their responses to habitat conditions were investigated in the southeastern continental shelf of Korea. The result of cluster analysis revealed that the study area could be divided into two regions, one including the shallow coastal region and the other the offshore region. The shallow coastal region sustained 4 polychaete assemblages: Nothria holobranchiata assemblage in the most northern part of fine sediments off Pohang, Magelona-Maldane assemblage off Gampo, Ophelina acuminata assemblage in the middle coastal area off Ulsan, Nothria conchylega assemblage in the south part off Pusan. These coastal polychaete assemblages contained less than 10 species per station and showed very low species diversity (H' = 1.22-1.52). The offshore also contained 4 assemblages: Terebellides-Aglaophamus assemblage in the northern and deep area of very fine sediments, Myriochele oculata and Spiophanes kroyeri assemblages in the central area of sandy bottoms, and Ninoe palmata assemblage in the southern offshore of sandy bottom. The offshore assemblages showed rather more species and higher diversity than coastal assemblages (H' = 1.90-2.26). The offshore region consisting of sandy sediment showed very low population densities. Some dominant species showed specific preference to sediment types and this phenomenon could be detected through their feeding modes. Depth or bottom temperature seems to be related to the distribution of most dominant worms. Thus the polychaete assemblages of the study area are found to be under the control of both a gradient of sedimentary properties and that of bottom temperature.

• Journal of the Korean earth science society
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• v.37 no.1
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• pp.11-20
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• 2016

Diatoms were studied from the trench sediments around Bangudae petroglyphs in order to better understand the depositional environment before and after the construction of Sayeon dam in Ulsan. There were no diatoms produced from the sediments before the dam construction while the diatoms were produced from the sediments (depth of trench 228 cm) after the construction of the dam. Seventy-five species of diatoms of 27 genera were identified in the trench sediments. The number of diatom valves per gram of dry sediment ranged from $0.2-5.8{\times}10^5g^{-1}$. Four diatom assemblage zones were identified according to the frequency of critical taxa as follows: assemblage zone I, from 228 to 150 cm; assemblage zone II, from 150 to 122 cm; assemblage zone III, from 122 to 62 cm; and assemblage zone IV, from 62 to 0 cm. In addition, based on the environmental indicator species, an analysis was carried out to measure eutrophication, acidity and $Cl^-$ value. Results of the eutrophication and $Cl^-$ values were as follows. Based on the lower 74 cm horizons, the degree of eutrophication middle-high to $Cl^-$ values were lower, upper horizons appeared to eutrophication in the low, and $Cl^-$ values were high. Acidification from low horizons of 122 cm showed a neutral-alkaline degree whereas it exhibited acid in the upper part. In particular, regarding nutrients (TP and TN), the index taxa showed a higher TP value at 175 cm while higher TN value at 62 cm.