• 한국물환경학회지
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• 제35권2호
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• pp.99-104
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• 2019

The objective of this study was to investigate the relationship between the biomass of cyanobacteria and the concentration of 2-methylisoborneol (2-MIB) in the lower Gongji stream. The investigation was done using a field study that was conducted from 2015 to 2017. The 2-MIB concentration in the lower Gongji stream ranged from 0 to 153 ng/L, while the upper stream had 0 2-MIB concentration. 3 genera (Oscillatoria, Phormidium, Pseudanabaena) of cyanobacteria were detected in the lower Gongji stream with 2-MIB concentration. Among these 3 genera, an increase in Phormidium, Pseudanabaena biomass was associated with an increase in 2-MIB concentration. Accordingly, Phormidium, Pseudanabaena were regarded as the biological source of 2-MIB in that area. In October 2017, although planktonic cyanobacteria occurred less frequently, many benthic cyanobacteria mats were observed on the surface of the water body. Therefore, the high 2-MIB concentration, which exceeded 110 ng/L, can likely be attributed to the benthic cyanobacteria. In a laboratory experiment, individual Oscillatoria filaments were aggregated to form a colony with a higher density. This colony tended to float on the water surface. Cyanobacteria mats after floating aggregated mats were distributed in a net shape on the bottom.

• 한국물환경학회지
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• 제32권3호
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• pp.261-270
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• 2016

We analyzed cyanobacterial community including akinete, resting cell, and benthic cyanobacteria in sediment of Bukhan, Namhan-River, Paldang-Lake, and Kyeongan-Stream and compared the physicochemical factors for water and pore water. We also performed cyanobacteria growth potential test through incubating sediment. As a result of physicochemical analysis, the concentrations of nutrients were similar for each depth of Bukhan-River. For Namhan-River and Lake Paldang sites, the concentrations of TP and DTN in bottom and deep water had higher levels. DTN in water body composed of NO3-N(73%) while DTN in pore water composed of NH3-N(77.8%). Benthic cyanobacteria in the sediment such as Oscillatoria tenuis, O. limosa, Phormidium tenue, Pseudanabaena limnetica, and Lyngbya sp. were dominant (between 0.0∼243.3×10³ cells/g, w/w). Cell densities of cyanobacteria in sediment depth of 0∼2 cm in most sites were higher compared to those in other depths. The cell density of cyanobacteria in sediment correlated with pH, conductivity, BOD5, TP, DTP, and chl. a. Increased phytoplankton and organic matters were found to be able to inhibit the growth of benthic cyanobacteria. Results of cyanobacteria growth potential test after incubating sediment revealed that harmful cyanobacteria (Anabaena, Aphanizomenon, Microcystis, and Oscillatoria) appeared at 7 days post culturing. Base on these results, the methods used in this study are considered to be able to determine the appearance of harmful cyanobacteria.

• 환경생물
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• 제36권3호
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• pp.291-298
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• 2018

Samples were collected from benthic and subaerophytic habitats of fresh and brackish water in Korea from April 2017 to April 2018. Accordingly, three genera and seven species were newly recorded in Korea. Three unrecorded genera were Cephalothrix, Cyanophanon and Toxifilum, and seven species were Anagnostidinema pseudacutissimum, Calothrix elenkinii, Cephalothrix komarekiana, Cyanophanon mirabile, Cyanosarcina chroococcoides, Leptolyngbya ectocarpi and Toxifilum mysidocida. Anagnostidinema pseudacutissimum and Cephalothrix komarekiana had been previously reported to inhabit freshwater, but these were found to be present in brackish water during the period of the present study. Also, Cyanosarcina chroococcoides previously reported to inhabit moorland waters and swamps, were found to be present in subaerophytic habitat.

• Journal of Ecology and Environment
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• 제38권4호
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• pp.619-627
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• 2015

Cyanobacteria were sampled at five sites in the Han River, Nakdong River, and Geum River watershed from June 2014 to May 2015 and then cultivated. Two genera and five species of the cyanobacteria were newly recorded in Korea. The newly recorded species were Limnothrix redekei, Pseudanabaena galeata, Pseudanabaena amphigranulata, Sphaerospermopsis aphanizomenoides, and Calothrix parietina. As a result, the Korean flora of the cyanobacteria now include four orders, 22 families with 73 genera, 143 species, and two varieties, giving a total of 146 taxa.

• 한국물환경학회지
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• 제31권5호
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• pp.460-467
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• 2015

We analyzed the formation of phytoplankton community and the occurences of odorus compound from benthic cyanobacteria in North, South Han-River, Paldang-Lake and Kyeongan-Stream sediments. Sediments were incubated in different water temperature. Akinetes were found (0~500 cells/g) with the highest number on sediment in Yangsoo railroad bridge (YC). The result showed that Anabaena ranged between $0.02{\sim}0.53{\times}10^3cells/mL$ in Sambong (SB), YC, Mukhyen-Stream (MS), Paldang-Lake (P2) and Kyeongan-Stream (KK). The total 68 taxa of phytoplankton were observed during the incubation period. A standing crop of phytoplankton was in the range of $0.13{\sim}8.97{\times}10^3cells/mL$ and Microcystis appeared in SB, YC, P2 and KK sites with $20{\sim}25^{\circ}C$ temperature. In South Han-River (P3), Oscillatoria tenuis was dominant at $25^{\circ}C$ temperature. The concentration of geosmin was the highest in SB-$15^{\circ}C$ (25.5 ng/L), and the concentration of 2-MIB was the highest in P3-$25^{\circ}C$ (286.8 ng/L). Odorous compounds were detected in all the temperature conditions from each site. Our results indicate that the dominant benthic cyanobacteria (O. tenuis, O. limosa, Phormidium tenue and Pseudanabaena limnetica) have high correlation with the occurrence odorous compounds and 2-MIB.

• 한국물환경학회지
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• 제30권6호
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• pp.658-664
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• 2014

In this study, Uiam-sediment(US) and Gongji-sediment(GS) were incubated to analyze the formation of phytoplankton community and occurrences of odorous compounds from benthic cyanobacteria. For the phytoplankton, 45 and 40 taxa were found in GS and US, respectively. The phytoplankton species detected in the harmful algae included Microcystis, Anabaena and Oscillatoria. As a result, a standing crop of phytoplankton appeared to be in the range of $0.9{\sim}71.8{\times}10^3$ cells/mL in GS, $0.8{\sim}51.2{\times}10^3$ cells/mL in US, and as the incubation progressed, benthic cyanobacteria was increased. The highest number of akinetes was shown in the initial incubation, and akinetes was reduced by 10% on day 4 of incubation start. After reduction of akinetes incubated for 4 days in US and 15 days in GS, Anabaena appeared from the surface water. Benthic cyanobacteria such as Oscillatoria tenuis, O. limosa and Lyngbya hieronymusii was dominant in GS (max. $3.96{\times}10^6cells/cm^2$) and US (max. $5.77{\times}10^6cells/cm^2$), forming cyanobacterial mats in sediment surface. Cyanobacterial mats were suspended after 10~12 days incubation in GS and US. Before and after the suspension of cyanobacterial mats, the concentration of geosmin was the highest in GS(115 ng/L) and US(175 ng/L). In the second suspension of cyanobacterial mats in GS, the concentration of 2-MIB was increased to the range of 22~92 ng/L.

• ALGAE
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• 제33권4호
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• pp.291-304
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• 2018

Lyngbya C. Agardh ex Gomont is a nonheterocytous cyanobacterial genus whose evolutionary history is still poorly known. The traditionally defined Lyngbya has been demonstrated to be polyphyletic, including at least five distinct clades, some of which have been proposed as new genera. Intraspecific diversity is also clearly underestimated in Lyngbya due to the lack of unique morphological characters to differentiate species. In this study, we describe the new genus Capillus T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes from benthic marine environments, including two new Brazilian species (here described as C. salinus T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes, and C. tropicalis T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes), and two species yet to be described, one of them from India (Capillus sp. 2.1), and the other from United States of America, based on strain PCC 7419. Capillus species presented cross-wise diagonal fragmentation, assisted or not by necridic cells, which has not been previously mentioned for Lyngbya. Ultrastructural analyses showed that C. salinus and C. tropicalis have numerous gas vesicles, which are rarely described for benthic marine species. The new genus formed a well-supported clade, and the D1-D1' and Box B secondary structures of internal transcribed spacer also supported the proposal of its new species. These findings help to clarify the diversity of species in the Lyngbya complex and the taxonomy of the group, and highlight the need of further floristic surveys in tropical coastal environments, which remain poorly studied.

• ALGAE
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• 제21권2호
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• pp.235-243
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• 2006

Benthic sediment samples ranging from poorly aggregated sand to complex, stratified mats were collected from six hypersaline ponds from March and July 1995 in the British Virgin Islands. Assemblages were analyzed with respect to species composition and abundance within visibly distinct layers in each mat sample. In individual ponds there was no apparent association between changing depth and the development of the benthic mats. Some species were present in all samples (e.g. Oscillatoria sp.) while others were restricted to single sites (e.g. Johannesbaptistia pellucida). Primary species included Microcoleus chthonoplastes, Phormidium spp., Coccochloris stagnina, and purple sulfur bacteria. Quantitative analysis of community structure included cluster and principal component analysis. Samples from individual ponds were often clustered; however, this was subject to seasonal variation. Mats collected in March were generally thicker and contained more layers than those in July. Variation among sites was not explained by the measured variation in environmental factors such as average pond salinity, depth, and oxygen concentration (mg/L). This study provides a detailed analysis of mat communities in hypersaline ponds and compares them with similar mat communities from other areas.

• 대한환경공학회지
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• 제34권6호
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• pp.421-429
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• 2012

본 연구는 화포천 수질 현황을 제시하여 특성을 분석하고 향후 관련연구에 활용할 목적으로 수행되었다. 상류에서는 step-pool 형태의 14개의 보로 인해 하천수가 저류되었고 주거단지 및 농경지를 지나면서 생활하수와 관개용수 등의 오염물 유입이 있었다. 이러한 이유로 정체구역의 하상에서 사상성 남조류인 Oscillatoria 군락이 번무하였으며 하천의 중 하류에서는 고모천(T3), 용덕천(T8)과 같이 N, P가 높은 고농도 지류가 유입되는 등 본류 수질을 악화시켰다. 화포천은 하류로 갈수록 DO가 감소하고 SS가 증가한 것이 특징적이었다. 상관관계 분석결과 긴 체류시간과 SS, COD, $NH_4{^+}$가 화포천에서 중요한 수질인자임을 나타내었다. 또한, 습지에서 하상 유기물 농도가 높고 부착조류가 풍부한 점도 본류 수질에 영향을 줄 것으로 판단되었다. 화포천 수질은 공간적으로 보가 있는 구간에서 농도가 상승하였고 하류의 습지에서는 일정하거나 소폭 감소하였다. 계절적으로는 겨울에 영양염 농도가 높았으나 여름에는 유기물 농도가 높았다. 식물플랑크톤은 6월에 보와 습지 등 정체구간에서 높게 나타난 점을 제외하면 전 구간에서 $40{\mu}g\;chl-{\alpha}/L$ 이하로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.906-913
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• 2004

A culture-independent molecular phylogenetic survey was carried out on the bacterial community in cold-seep sediment at Edison Seamount, south of Lihir Island, Papua New Guinea. Small-subunit rRNA genes were amplified directly from the sediment DNA by PCR and cloned. The majority of the cloned 16S rRNA gene sequences were most closely related to as-yet-uncultivated microorganisms found in deep-sea sediments, and were primarily affiliated with one of four groups: the $\gamma$-, $\delta$-, and $\epsilon$-subdivisions of Proteobacteria, and Cytophaga-Flavobacterium-Bacteroides. We did not recover any sequences related to cyanobacteria, prochlorophytes, and $\alpha$-Proteobacteria, which are known to occur in great abundance within the surface mixed layer of the Atlantic and Pacific Oceans. The majority of the cloned $\gamma$-and $\epsilon$-Proteobacterial sequences were closely related to chemoautotrophic sulfur-oxidizing symbionts of marine benthic fauna, and the $\delta$-Proteobacterial sequences to sulfate- and sulfur-reducing bacteria, indicating that they might play an important role in chemoautotrophic primary production and the sulfur cycle in the cold-seep area. There results demonstrate the high diversity of the bacterial community in the cold-seep sediment, and substantially expand knowledge of the extent of bacterial diversity in this formidable and unique habitat.