• 환경생물
• /
• 제31권1호
• /
• pp.1-9
• /
• 2013

본 연구는 해양환경이 크게 교란을 받고 있는 4개 저서환경을 선택하여 연체동물 중 어떠한 종이 기회종의 특성을 보이는지를 조사하였다. 기회종의 특성을 보인 5종의 이매패류에 대한 분포특성을 파악하고자 하였다. 이매패류인 애기반투명조개 (Theora fragilis), 대양조개(Macoma incongrua), 종밋(Musculista senhousia) 등이 빈 산소 현상을 보이는 반폐쇄성 연안역이나 유기물 축적이 많은 퇴적물을 가진 항만해역에서 우점하여 서식하고 있었으며, 소형 개체인 말발굽조개 (Thyasira tokunagai)와 쇄개량조개 (Raetellops pulchella)는 외해역의 폐기물 해양투기장에서 우점하는 종으로 나타났다.

• 한국관개배수논문집
• /
• 제17권2호
• /
• pp.42-48
• /
• 2010

This study was carried out to investigate the changing of benthic macrobenthos community in Saemangeum subtidal area. The distribution of macrobenthic community is important to assume the benthic environment in study area. Macrobenthic community was investigated three times in 2007 (March, June and September) in the Saemangeum subtidal area. The mean density of macrobenthos was $345{\sim}838ind./m^2$ and the most dominant taxa was benthic polychaete. Opportunistic species such as E.cordatum, T.fragilis, H.filiformis, and Tharyx sp. were shown high appearance rate in study area. The dominance of these opportunistic species suggest that the benthic environment of study area was unstable due to environmental disturbance. But, there are only few point that these species were recorded high densities, and also equilibrium species was dominant, too. It means disturbance and un stability of benthic environment in Seamangeum was not serious yet. so the dynamics and trends of these opportunistic species should be concerned.

• 대한수의학회지
• /
• 제51권3호
• /
• pp.243-247
• /
• 2011

It is important to identify the bacteria in snakes because they can cause disease; importantly, bacteria such as Stenotrophomonas maltophilia, Escherichia coli, Proteus vulgaris etc. could be pathogens especially in hospitalized, debilitated hosts, and immunocompromised patients. To analyze the distribution of snakes' bacteria in petting zoo, samples from 20 snakes were collected from 2002 to 2008. Nine bacteria species were isolated from both oral and cloaca while four and six species were identified only from oral and cloaca, respectively. Except for Actinobacter sp., all of the identified strains are opportunistic pathogens, and most of them can cause nosocomial infections in humans. Present results indicate that prevalence of various zoonotic bacterial strains in snakes could be involved in potential transfer of these bacteria into caretakers and other animals. Therefore, it needs to examine the antibiotic resistance of these pathogens to prevent outbreaks.

• Journal of Ecology and Environment
• /
• 제35권4호
• /
• pp.279-289
• /
• 2012

This study conducted a comparative analysis of benthic macroinvertebrate communities in the Fosu and Benya lagoons in Ghana, based on the anthropogenic effect on the two lagoons. Salinity, oxygen, temperature, conductivity, turbidity and pH were measured, invertebrate richness and species densities were determined. The AZTI Marine Biotic Index (AMBI) and multivariate statistics were used to determine the different responses of fauna to pollution. The fauna were categorized into five ecological groups based on the degree of tolerance of the different species to pollution: disturbance-sensitive species; disturbance-indifferent species, disturbance-tolerant species, second-order opportunistic species; and first-order opportunistic species. The Fosu Lagoon supported more pollution tolerant species, whereas the Benya Lagoon had more species that were sensitive to organic enrichment under relatively unpolluted conditions. Chironomus sp., which is adapted to virtually anoxic conditions, was the most abundant in the Fosu Lagoon whereas Nemertea sp. was the most abundant in the Benya Lagoon. The numerical and relative abundance (%) of all 7 taxa in the Fosu Lagoon was 1,359 and 92.35%, respectively. The numerical and relative abundance (%) of all 34 taxa in the Benya Lagoon was 2,459 and 87.52%, respectively. Expectedly, the level of dissolved oxygen in the less saline Fosu Lagoon was higher than that in the more saline Benya Lagoon. The reduced photoperiod and photosynthetic activities of aquatic plants might account for this trend. There is a need to implement comprehensive monitoring and management initiatives for sustaining the ecological health of coastal lagoons in Ghana in order to support the many people that depend upon these ecosystems for their livelihood.

• Journal of Ecology and Environment
• /
• 제47권3호
• /
• pp.118-133
• /
• 2023

Background: Free-living amoebae (FLA) are widely distributed in freshwater, seawater, soil, and extreme environments, and play a critical role as feeders on diverse preys in the ecosystem. Also, some FLA can become opportunistic pathogens in animals including humans. The taxa Amoebozoa and Heterolobosea are important amoeboid groups associated with human pathogens. However, the identification and habitat of amoebae belonging to Amoebozoa and Heterolobosea remain poorly reported in the Republic of Korea. This study highlights the first record for identification and source of four amoebae including putative pathogens in the Republic of Korea. Results: In the present study, four previously reported FLA were isolated from freshwaters in Sangju Gonggeomji Reservoir (strain GO001), one of the largest reservoirs during the Joseon Dynasty period, and along the Nakdong River, the largest river in the Republic of Korea (strains NR5-2, NR12-1, and NR14-1) for the first time. Microscopic observations and 18S rDNA phylogenetic trees revealed the four isolated strains to be Acanthamoeba polyphaga (strains NR5-2 and NR12-1), Tetramitus waccamawensis (strain GO001), and Naegleria australiensis (strain NR14-1). Strains NR5-2 and NR12-1 might be the same species and belonged to the morphological Group 2 and the T4 genotype of Acanthamoeba. Strain GO001 formed a clade with T. waccamawensis in 18S rDNA phylogeny, and showed morphological characteristics similar to previously recorded strains, although the species' flagellate form was not observed. Strain NR14-1 had the typical morphology of Naegleria and formed a strongly supported clade with previously recorded strains of N. australiensis in phylogenetic analysis of 18S rDNA sequences. Conclusions: On the bases of morphological and molecular analyses, four strains of FLA were newly observed and classified in the Republic of Korea. Three strains belonging to the two species (A. polyphaga and N. australiensis) isolated from the Nakdong River have the potential to act as opportunistic pathogens that can cause fatal diseases (i.e. granulomatous amoebic encephalitis, Acanthamoeba Keratitis, and meningoencephalitis) in animals including humans. The Nakdong River in the Republic of Korea may provide a habitat for potentially pathogenic amoebae, but additional research is required to confirm the true pathogenicity of these FLA now known in the Republic of Korea.

• 한국해양학회지:바다
• /
• 제16권4호
• /
• pp.246-253
• /
• 2011

낙동강 하구역에서 홍수기 전후에 저서동물군집 영향을 알아보기 위한 조사에서, 저서환경은 대부분 지역에서 사질 퇴적상이 우세하였으며, 일부 수로 지역에서 복잡한 퇴적상을 나타냈다. 홍수기 방류에 의한 공간에 따른 퇴적상 변화는 관찰되지 않았으며, 홍수기 이후 하구역 상부에서 유기물이 소량 증가하였다. 저서생물 종조성은 공간적으로 차이를 보였는데, 홍수기 이후에 배수갑문 근처 지역에서 종조성이 감소하였다. 군집분석 결과는 3개 군집구조가 나타났으며, 하구역 하부에 위치한 사주를 기준으로 공간적 구배를 나타냈다. 사주 상부에는 Sinocorophium sinensis, Magelona japonica, Heteromastus filiformis 등 유기오염 기회종들이 우점하였다. 기회종이 디수 출현한 것은 낙동강 하구둑 주변에 서식하는 저서동물이 방류로 인한 유기물 유입 영향에 따른 것으로 해석되며, 방류로 인한 영향은 방조제 부근에서 사주지역까지 나타났고, 사주 바깥지역은 대량방류로 인한 저서동물의 종조성 변화는 관찰되지 않았다.

• 한국환경보건학회지
• /
• 제30권3호
• /
• pp.207-213
• /
• 2004

For investigation of the food safety and influence of biofilm on the bacterial quality of tap water, it was detected by selective media, and identified by API kit and MIDI system. Biofilm and effluent showed much more colonies than influent. Although there were many presumptive positive colonies, no pathogenic bacterium detected. However opportunistic pathogens, such as Pseudomonas aeruginosa and Aeromonas species, and members of family Enterobacteriaceae were detected. Compared to influent, biofilm and effluent showed more diverse bacteria. This study implies that there would be the negative influence of biofilm on the bacterial qualities of tap water.

• Ocean and Polar Research
• /
• 제30권4호
• /
• pp.419-426
• /
• 2008

Ciliate plankton samples were collected biweekly from July 2006 to June 2008 in Jangmok Bay of Geoje Island. Species composition and abundances were analyzed by quantitative protargol stain and environmental parameters were also examined. A total of 88 ciliate species occurred during the study period, consisting of 22 tintinnids, 51 oligotrichs, and 15 other species. Higher ciliate abundances appeared from June to October during the warm season ($<20^{\circ}C$) and the maximum ($4.0{\times}10^4\;cells\;L^1$) in August, while the lower abundances were found during the cold season. The minimun ciliate abundance was found in November when water temperature rapidly decreased. The temporal succession of dominant species was very clear and opportunistic. Pelagostrombidium sp., Tontonia simplicidens, Helicostomella subulata, and Myrionecta rubra were co-dominant in summer while Rimostrombidium orientale occurred abundantly in winter. Strombidium tressum and S. compressum, eurythermal species, were observed during all seasons. Based on the species-specific ecology of ciliate plankton, it is suggested that the indicative ciliate species can be applied as a biological tool to detect environmental change in the southern coastal waters of korea.

• 한국수산과학회지
• /
• 제42권2호
• /
• pp.151-156
• /
• 2009

The stomach contents of Lumpenella longirostris, Malacocottus gibber and Bothrocara hollandi from the East Sea were examined to determine their feeding ecology. Specimens were caught seasonally from 2004 to 2006. The primary prey items of each species included crustaceans and mollusks. L. longirostris is a benthophage that primarily consumes bottom crustaceans and bivalves. M. gibber and B. hollandi are meso-pelagicphages that primarily consume amphipods and cephalopods. However, the species are opportunistic feeders that exploit the available prey in their habitat. The empty stomach ratio of the species is larger than that of offshore species (e.g. hairtail fish and yellow goose fish), and the prey diversity of the species evaluated in this study was much smaller than that of offshore species.

• 한국수산과학회지
• /
• 제48권1호
• /
• pp.82-87
• /
• 2015

For the ecological evaluation of marine algal vegetation, flora and their communities were surveyed seasonally at Goseong, on the southern coast of Korea. A total of 102 algal species, comprising 17 green, 18 brown and 67 red algae, was identified. Representative dominant species were assessed as Ulva australis, Sargassum thunbergii, and Gelidium amansii. Of these, Ulva australis was remarkably dominant in all seasons. High biomass of the dominant species were recorded. The total seasonal biomass was highest in winter and lowest in summer. The mean biomass value was $1315.6g/m^2$ across the four seasons. Each species was classified into six functional groups, and two ecological state groups (ESG) were evaluated based on these groups. While ESG I, the late successional species group, formed only 18.6% of the algal community; ESG II, composed of opportunistic species, comprised 81.4%. This suggests that environmental stress has been continuously imposed on the marine algal vegetation of the present study area.