• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.48-65
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• 2009

In order to understand the local vegetation history and the origin of rice cultivation, a phytoliths analysis was performed with sediments collected from archaeological site at Ga-dong in Gijang, Busan. From the analysis with the sediments of three sampling sites, fan-shape phytoliths of Oryza sativa were detected: sediment 8 ~ sediment 29 of sampling site 1, sediment 6 ~ sediment 20 of sampling site 2 and sediment 7 ~ sediment 33 of sampling site 3. On the bottom layers or near the bottom layers from the three sampling sites, high densities of Arundinoideae and Andropogoneae were detected. It indicates that these layers were wet soil environment when they were sedimented. From near bottoms up to surfaces, the densities of Arundinoideae and Andropogoneae were abruptly decreased, while the density of Oryza sativa was sharply increased. With these results, it should be considered that the rice cultivation was started from the Bronze Age on this region.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.643-655
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• 2011

This study addresses the periphytons along the Bukhan river stream and examines the biological indices that represents the river and estimate water quality assessment. Bukhan river in 4 major watershed streams (Bukchon-Hangeychon, Narinchon, Inbukchon, and Soyang river) was selected in 9 points. Land use pattern along the streams showed marked differenced in agriculture areas and forest areas. Lower Soyang streams showed blue-green algae and green algae also appeared in evenly pattern. Thus, the pollution source, biomass and distribution are somewhat correlated, and BOD, SS, biodiversity, and evenness showed a similar pattern. This situation can lead to conclusion of oligotrophic lake with good condition. Therefore, current biological index and is not so desirable for stream degree standard water quality and nutrient level.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.7-18
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• 1999

Fauna and biological water quality using benthic macroinvertebrates were analysed and estimated macroinvertebrates. Samples were collected 5 times from the 7 sites in the river between April and December 1997, and the results are summarized as follows. The taxa of benthic macroinvertebrates was totally composed 81 species, 45 genus, 37 families, 15 orders, 8 classes in 3 phyla. Among them, aquatic insects were mostly abundant as 65 species, and also, there were a species of oligochaetes, 2 species of hirundinida, 6 species of gastropods, 5 species of polecypoda, and 2 species of crustaceans. Average individual numbers in the whole sampling sites was 815 per square meter, and insects were abundant (Approx. 80%). Among the insects, the major taxa were respectively ephemeroptera (Approx. 70%) and trichoptera (Approx. 18%). According to the average individual numbers in each site, Chung-do stream (site 1) showed the highest appearance rate as 262 individual/ $m^3$ (32.2%), and the lowest value was at the end of Miryang River (site 7) as 38 individual / $m^3$(4.7%). The dominant species among the whole samples was Ecdyomurus levis Navas, and dominance indices was 0.3. In each site, Ecdyomurus levis Navas was dominant species from site 1 to site 5, and dominant species at site 6 and 7 was respectively Hirudinidae sp. 1. Species diversity index in total average of samples was 2.66. Average of species diversity index according to each study site was the highest value at site 4 (H'=3.47), and site 2, 1, 3, 5, 6, and 7 in that order. According to the water quality as biotic indices, GPI value was 1.49 in total average of Miryang river, and the pollution indices evaluated secondary water quality criteria as $\beta$-mesosaprobics. In each site, the best water quality was at site 3, and it revealed the first water quality criteria as Oligosaprobic. It was then site 1, 2, 4 and 5 in the order of water quality, and was evaluated secondary water quality criteria as $\beta$-mesosaprobics, respectively. Site 6 was also revealed the third water quality criteria as $\beta$-mesosaprobics. The worst water quality was at site 7, which revealed the third water quality criteria as a-mesosaprobics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.437-443
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• 1994

Appearance characteristics based on the daily mean air temperature (DMAT) were evaluated to obtain the fundamental data for the safety of dry-seeded rice under the local climatic conditions. The climatic data of 56 meteorological stations throughout Korea were applied for determination of the effective standard temperature at the emergence. The first appearance date at the DMAT 1$0^{\circ}C$ was found to be 20~30 days (standard deviation: 5~7 days) for year fluctuation and 4\geq$30 days for regional change in Pusan and Taegwallyong. Mean appearance date of it, also, was 10 days earlier than that of its 80% chance. Seeding date at the early critical seedling emergence was April 11 for Suwon, March 31 for Kwangju, April 1 for Taegu and April 7 for Kangnung.

• Korean Journal of Heritage: History & Science
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• v.44 no.2
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• pp.46-57
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• 2011

The aim of this study was to examine the current situation of otter inhabitation and conservation and to collect basic information for establishing appropriate policies. We conducted the study around the Bukhan river from April to October 2009, mostly focusing on otter distribution, feeding habits, threats, and conservation measures. We divided the study area into 2 sectors: the dam area and the stream. We found 39 spraint sites in the dam area and 70 in the stream area. A significant difference was observed in the number of spraint sites between the upper stream and the lower stream. To evaluate the feeding habit, we collected and analyzed the frequency and bulk occurrence of the spraints. Among the prey items, fish were the most numerous (36.99%) followed by amphibians (17.22%). Fish showed the highest bulk occurrence in the dam area, and the bulk occurrence of amphibians and insects seemed to increase in the stream area. However, the bulk occurrence in the dam area seemed to be lower than that in the stream area (ANOVA, F = 3.99, p < 0.05). Fyke nets and abandoned fishing nets were found to be the most threatening factors. Further research on the systematic management of otters and the use of stop grids is required for better conservation of otters.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.401-410
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• 2001

개요 유무선 인터넷 망 연동 무선에서의 ISP (MISP: Mobile ISP) 의미 이동통신사 과점에서 경쟁 체제로 (nTop, magicN, ez-i) MIDC 사업자 출현 (KT, 데이콤, 하나로) WAP, 컨텐트 컨버팅, 과금 서비스 문제점 접속 지점 (IWF, G/W) 접속 대가 접속 대상(중략)

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.494-498
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• 2010

금강수계에서 2007년 10월부터 2009년 10월까지 17개 지점을 대상으로 어류 모니터링과 하상재료를 조사하였다. 하상재료는 사립자 크기에 따라 6단계(실트, 모래, 가는자갈, 굵은자갈, 호박돌 및 전석)로 나누었으며, 각각 3개 지점씩 선정하여 조사하였다. 조사결과 모든 지점에서 채집된 어류는 10과 49종 7,316개체였다. 하상재료 중 실트~굵은자갈에서 피라미(Zacco platypus)가 가장 높은 출현율을 보였으며, 호박돌~전석에서는 참갈겨니(Zacco koreanus)가 우점하는 것으로 나타났다. 생물다양도 및 우점도는 가는자갈~굵은자갈에서 최적 상태를 보였으며, 정량적서식지평가(QHEI)와 생물보전지수(IBI)는 하상재료가 커짐에 따라 점수가 증가하여 최적 상태를 나타내었다.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.154-164
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• 2018

We investigated the ichthyofauna and fish community structure of the Mudeungsan National Park, Korea from 2014 to 2016 to prepare a conservation plan. We collected 21 species of 6 families collected from 8 survey stations through skimming nets and cast nets during the period. The dominant and subdominant species were Zacco temminckii (43.0%) and Rhynchocypris oxycephalus (15.1%), respectively. The other abundant species were Z. platypus (11.2%), Pungtungia herzi (10.1%), Squalidus gracilis majimae (8.9%), and Z. koreanus (4.5%). Among the fish collection, 13 species (61.9%) were Korean endemic species, but, endangered species and exotic species were not found. Similarity indices based on species composition and abundance showed the clear division of the fish community into two river systems (Yongsan River drainage system (St. 1-7) and Seomjin River drainage system (St. 8)). The Youngsan River system was further divided into the uppermost (St. 1, 2, 4, 6, and 7) and the upper-middle (St. 3 and 5) regions. The number of species appearing in a year was similar at 19 to 20 throughout the survey period. However, the individual number of fish in 2015 (2,670) was 20% less than that of 2014 (3,366) and 2016 (3,429), respectively. The probable reason for this decline is the rapid decline of stream level in 2015 compared to the other years. During the survey period, river works were undergoing at 3 out of 8 stations, having created disturbance in fish habitat and especially impacted on benthic fishes.

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.56-61
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• 2012

The distribution status and population size of the endangered species, $Cobitis$ $choii$, were investigated in the Guem River, Korea. From 1984~2004, this species occurred at 20 survey stations; however, their numbers have but rapidly decreased in recent years (2006~2011), during which time they were only observed at six stations. The area of their habitat is narrow and occurs in primarily downstream, sandy zones. Using the mark-recapture method, populations were estimated at 9,106 and 34,717 individuals for the main habitats of Baekgok and Ji Stream, respectively.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.305-309
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• 1999

The occurrence of tetQ and aacC2 genes encoding tetracycline and gentamicin resistance determinant, respectively, was assessed in total bacterial community DNA isolated from Dongchon stream of Sunchon area. To examine the resistance potential of bacteria that were not cultured, total DNA from 1 liter of stream water was extracted by freeze-thaw method. The PCR technique was employed to determine the abundance of the target genes. The highest frequency of tetQ gene was obtained from site 1, located near the animal farms area, whereas the incidence of aacC2 was highest in site 5, the downstream area. These results showed that the occurrence of antibiotic resistance gene may be used as a convenient marker of water quality related to source.