• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.249-252
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• 2005

Microphytobenthos bloom from late January to early March in Korean tidal flats. KOMPSAT-2 will provide multi-spectral images with a spatial resolution of 4 m comparable with IKONOS. Using IKONOS and Landsat data, algal mat detection was tested in the Saemangeum area~ Micro-benthic diatoms are abundant and a major primary product in the tidal flats. A linear spectral unmixing (LSU) method was applied to the test data. LSU was effective to detect algal mat and the classified algal mat fraction well correlated with NDVI image. Fine grained upper tidal flats are generally known to be the best environment for algal mat. Algal mat thriving in coarse grained lower tidal flats as well as upper tidal flats were reported in this study. A high resolution multi-spectral sensor in KOMPSAT-2 will provide useful data for long-term monitoring of microphytobenthos in tidal flats.

• 한국환경과학회지
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• 제22권3호
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• pp.371-378
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• 2013

After identifying species by collecting the suspended and attached algae mat inhabiting in the slow sand-filter, Spirogyra sp., Mougeotia sp. and Closterium sp. were main green algae and Synedra sp. was diatom algae. Among them green algae Spirogyra sp. was dominant species. A result of observing the life mode of apple snail for a month after introducing into the slow sand-filter, apple snail eggs were discovered on the filter walls 2 weeks after introducing, 4 weeks later lots of eggs were observed all of the slow sand-filter walls, it means there is no problem for apple snail to live in the slow sand-filter. The observation result for algae removal potential by introduced apple snail after 2 months later, slow sand-filter where apple snail were introduced, a few algal mat were observed. On the other hand, no introduced apple snail into the slow sand-filter, lots of suspended algal mats were formed in the water and attached algal mats on the sand surface as well, these algal mat induced much of operating problems.

• 대한원격탐사학회지
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• 제21권5호
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• pp.405-415
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• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• 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.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.734-738
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• 2002

We present spectral characteristics of tidal flat sediments and algal mat that were tested in the Gomso and Saemangum tidal flats, Korea. The objective of this study is to investigate the spectral reflectance and the radar scattering modeling in the tidal flats. Ground truth data obtained in the tidal flats include grain size, soil moisture content and its variation with time, surface roughness, chlorophyll, ground leveling, and field spectral reflectance measurement. The concept of an effective exposed area (EEA) is introduced to accommodate the effect of remnant surface water, and it seriously affects the reflection of short wavelength infrared and microwave. The nin size of 0.0625 mm has been normally used as a critical size of mud and sand discrimination. But we propose here that 0.25 mm is more practical grain size criterion to discriminate by remote sensing. Algal mat is the primary product in tidal flats, and it is found to be very important to understand spectral characteristics for tidal flat remote sensing. We have also conducted radar scattering modeling, and showed L-band HV-polarization would be the most effective combination.

• 환경생물
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• 제17권3호
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• pp.345-358
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• 1999

본 연구는 온천 배수의 유입이 소형 하천의 부착조류군집에 미치는 영향을 조사하기 위하여, 전북 고창군 석정온천에 발원하는 하천과 그 주변의 소형 하천을 대상으로 1996년 2월부터 1998년 9월까지 계절별로 조사하였다. 온천 배수의 유입이 직접 일어나는 지점에서는 저온기에 남조의 Oscillatoria와 Phormidium이 중심이 된 독특한 남조피막이 형성되었다. 특히, 부착조류의 출현 및 군집구조는 온천 배수의 영향 하천과 비영향 하천간에 뚜렷한 차이를 보였는데, 전체적으로 조사시기에 상관없이 규조의 높은 종 출현(전체의 58%)과 남조강의 높은 생물량(전체의 67%)이 대조적이었으며, 전자는 하천의 하류에 주로 분포하고, 후자는 집중적으로 상류에 분포하였다. 이러한 현상은 동계에 뚜렷하였으나, 계절이 전환되면서 보이지 않았다. 녹조와 유글레나류 등은 계절 및 지점에 큰 영향을 보이지 않았다. 대부분의 환경요인들은 하천방향을 따라 강하게 감소하였으나, 질산성 질소는 하천방향에 따라 다소 증가하였다. 본 조사하천은 온천 이용이 저온기에 집중됨으로서, 배출지점에 남조피막과 같은 독특한 하천생태계가 형성되지만, 하천방향에 따라 비영향 하천의 유입, 남조피막과 하천퇴적물과의 상호작용 등에 의한 화학물질의 빠른 감소로 하천의 하류로 갈수록 심한 오염현상은 발견되지 않았으나, 온천배수의 지속적인 유입이 이루어진다면, 하천의 퇴행적 천이가 빠르게 진행될 것으로 예상되었다.

• 생태와환경
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• 제38권spc호
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• pp.8-11
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• 2005

Carbon stable isotope ratios of producers varied in lake ecosystems. In tile present study, we tried to estimate the seasonal variations of carbon isotope ratios of phytoplankton and benthic diatoms in a strongly acidic lake ecosystem. Lake Katanuma is a volcanic, strongly acidic lake (average pH of 2.2), located in Miyagi, Japan. Only two algal species dominate in Lake Katanuma; Pinnularia acidojaponica as a benthic diatom, and Chlamydomonas acidophila as a green alga. Carbon isotope values of P. acidojaponica varied seasonally, while those of particulate organic matter, which were mainly composed of C. acidophila remained fairly stable. The differences suggested that $CO_2$ gas was more frequently limited for P. acidojaponica than C. acidophila, since high density patches of benthic diatoms were sometimes observed on the lake sediment. Generally, carbon concentration mechanisms (CCMs)of microalgae can fix bicarbonate in lakes, and affect the carbon isotope values of microalgae. While, in Lake Katanuma, CCMs of the microalgae may scarcely function because of high $CO_2$ gas concentration and low pH. This is the reason for low seasonal amplitude of carbon isotope values of phytoplankton relative to those in other lakes.

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.31.1-31.7
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• 2018

Three economic marine algae that have been used as food and carrageenan sources were collected from Korea during a survey of marine algal flora. They share the generic features of Hypnea, and three major clades supported by the sectional features were confirmed in a phylogenetic tree based on rbcL sequences. The first species, which belongs to a species group corresponding to the sect. Spinuligerae, nests in the same clade with Hypnea yamadae in a genetic distance of 0%. It is morphologically characterized by an entangled base, subcompressed or subterete to terete axes, somewhat percurrent main axis, irregularly alternately branching with wide angle, and rarely hooked spinous branchlets. The second one is also referred to the sect. Spinuligerae and formed the same clade as Hypnea cenomyce. The genetic distance between both sequences was calculated as 0.0-0.1%, which is considered to be intraspecific. This species is distinct by somewhat entangled thallus at the basal part, percurrent axis, short spine-like branchlets densely covering the axis, and medullary lenticular thickenings. The third alga, which forms a species group corresponding to the sect. Pulvinatae, nests in the same clade as Hypnea nidulans (no intraspecific divergence). It shows occasionally epiphytic habitat rather than epilithic habitat of low mat-forming growth and percurrent erect main axes with dense lateral branchlets. Based on these morphological and molecular data, the three Korean species are identified as H. yamadae, H. cenomyce, and H. nidulans. This is the first record of the Hypnea species in Korea.

• 환경생물
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• 제42권1호
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• pp.127-134
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• 2024

2022년 11월 전남 해남 송지해변에서 녹조류의 대량발생이 일어났다. 해변에서는 악취가 발생하였고, 녹조류가 녹색의 두꺼운 매트처럼 해변을 넓게 덮고 있었다. 종동정 결과는 범세계분포종인 녹조류 참깃털말로 나타났다. 참깃털말의 대량발생이 일어난 송지해변과 인근 지역의 해수 중 영양염 농도를 비교한 결과, 용존무기질소와 용존무기인 농도는 각각 1.067 및 0.461 mg L^-1로 남서해안 평균 영양염에 비해 6배 및 19배 높게 나타났다. 이 연구에서는 국내에서 처음으로 나타난 참깃털말의 대량발생 양상에 대하여 보고하였으며, 이는 해수 중 영양염 농도와 밀접한 관계가 있는 것으로 나타났다. 따라서 참깃털말 등의 녹조류 대량발생을 제어하기 위해서는 연안으로 유입되는 육상의 영양염 농도에 대한 관리가 필요할 것으로 사료된다.

• 한국습지학회지
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• 제19권1호
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• pp.90-102
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• 2017

본 연구에서는 과거 2년에 걸쳐 강우유출수 처리목적의 인공습지로부터 수집된 수질자료를 바탕으로 지금까지 국외에서 개발된 다양한 형태의 영양소 모델의 적용성을 평가하였다. 검토결과 질소제거에 가장 큰 영향을 미치는 요인은 수온과 수리학적 부하율(HLR) 이었는데 습지의 수표면적이 습지의 용량에 비해 더 중요하게 작용했음을 시사해주고 있다. 질소제거는 미국 WEF(water environment federation)가 개발한 준경험적인 형태의 모델이 적합한 것으로 밝혀졌다. 한편 인 제거 모델은 수온과 제거속도상수의 관계를 Power Model로 보고 모의했을 때 실측치와 가장 가깝게 계산치를 산출할 수 있었으며 실측치의 증가와 감소경향을 비교적 정확하게 모의할 수 있었다($R^2=0.79$). 그러나 모든 시도에서 수온이 특정온도 이하로 감소했을 때 가장 심한 오차를 발생하여 취약한 예측성능을 보였다. 한편 인공습지에서 질소제거특성을 검토한 결과 질산화에 비하여 탈질이 저조한 것으로 나타났는데 그 이유는 탄소원의 부족과 높은 용존산소 농도로 인하여 Anoxic 조건의 미형성 때문으로 분석되었다. 질소제거 향상방안으로 용존산소의 제어와 탄소원의 확보차원에서 햇빛에 노출된 개방수역과 햇빛에 노출된 식생구역, 그리고 습지의 기능적 측면을 고려한 구성요소의 배분 및 부유 수생식물 및 무기성 여재를 이용하는 방안을 논의하였다.