• ALGAE
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• 제23권1호
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• pp.75-81
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• 2008

The epiphytic diatom flora living on leaf tissues of Zostera marina, Z. japonica and Z. caespitosa at three study sites (Dadae, Gabae, and Jangmok) located in Geoje Island has been examined from July 2001 to March 2002 bimonthly. Total 81 species in 26 genera of diatoms have been observed on leaf tissues of the 3 Zostera species throughout the present study. Cocconeis spp. were predominant on Z. japonica, whereas Navicula spp. and Nitzschia spp. were predominant on Z. marina and Z. caespitosa. The community structure of the diatom assemblages varied according to the seagrass species. Species compositions of epiphytic diatoms appear to be closely related to morphology and lifespan of seagrasses.

• 한국해양학회지:바다
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• 제15권4호
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• pp.184-191
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• 2010

부착규조류는 초기 부착 생물로서 부착 천이과정에서 부착성 박테리아 층 위 해초 잎 표면 맨 아래 층에 부착함으로써 잎 표면의 미세 지형을 결정하고 다른 부착 생물에게 알맞은 부착환경을 제공해 주는 중요 생물로 부착 기질과의 상호 작용에 대한 연구는 부착 생물 생태 연구에 기초적인 연구라고 할 수 있다. 부착규조류가 해초에 부착 서식하는 형태는 크게 3가지로 나눌 수 있으며 1) 해초 잎 세포에 평행하게 또는 세포 변형을 통한 부착 2) 해초 잎 끝부분에 주로 밀집하여 서식 3) 잎의 끝에서 2차 부착 규조류인 줄기를 이용한 규조류보다 1차 부착규조류인 타원형의 규조류 밀집 지역이 많은 것이었다. 또한, 해초의 종별 규조류의 부착 군집 변화를 살펴보면 우선 길이와 너비의 차이가 많으나 세포의 모양이나 크기가 비슷한 Z. marina와 Z. japonica는 규조류의 출현종수, 현존량, 우점종의 차이가 컸던 반면 길이와 너비는 비슷하나 세포의 모양과 크기가 다른 Z. marina와 Z. caespitosa의 경우에는 규조류의 출현종수, 현존량, 우점종이 유사한 것으로 나타났다. 따라서, 본 논문에서는 해초의 미세지형이 될 수 있는 세포의 모양보다 해초의 길이와 너비 등 외형의 차이가 부착규조류 군집 변화의 주요 원인인 것으로 나타났다.

• 생태와환경
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• 제43권1호
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• pp.91-102
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• 2010

상을 차지하는 갈대의 침수줄기에 형성된 부착규조 군집 빛 수질특성을 파악하고자, 결빙기를 제외한 2005년 3월부터 10월까지 유입수, 습지(고습지, 저습지), 배출구를 각각 조사하여 다음과 같은 결과를 얻었다. 1) 습지에 상관없이 높은 유기물 및 영양염 지수를 나타냈으며, 습지를 통과하면서 질소계열은 감소한 반면, 인계열은 오히려 증가하였다. 2) 부착규조는 저온기에 보다 다양하고 높은 생물량을 나타냈으며, 우점종은 습지에 관계없이 Nitzschia palea, Nitzschia amphibia 였으며, 조사 시기(강우)에 따라 다양한 범위를 나타냈다 3) 저습지 보다 고습지에서 높은 현존량은 영양염과 광투과율, 그리고 낮은 canopy와 관계가 있는 것으로 판단되었다. 따라서 동화습지는 풍부한 퇴적물과 갈대 쇄설물로부터 유출된 영양물질(특히 인)이 특정 규조류의 성장을 촉진하였으며, 특히 갈대식물 밀도가 적어 낮은 canopy를 보였던 고습지에서 높은 현존량을 나타났다.

• 생태와환경
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• 제42권1호
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• pp.95-106
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• 2009

The Shihwa constructed wetland was established for the treatment of severely poluted water from Banwoul, Donghwa and Samhwa streams. This study was focused on investigating the structure of epiphytic diatom communities on reed (Phragmites communis) planting area at Banwoul high wetland (3 stations) and low wetland (3 stations) from March to October 2005. The concentration of T-N of inlet stations from the streams were decreased by flowed through the wetland, but the concentration of T-P were increased at outflow part. Epiphytic diatoms on the reed were a total 109 taxa which were composed of 103 species, 5 varieties, 1 unidentified species. The standing crops were rapidly decreasing tendency from spring to autumn but chlorophyll-a concentration were showed a very irregulated changes. Dominant species were 6 taxa which were Achnanthes minutissima in the early investigation, and were changed to the genus Navicula and the genus Nitzschia in the summer. DAIpo were ranged the values of $20.2{\sim}51$, which were mesosaprobic states at the high wetland and ranged the values of $12.4{\sim}52$, which were polysaprobic to mesosaprobic states at the low wetland. TDI were ranged the values of $28.8{\sim}94.5$, which were oligotrophic to eutrophic state at the high wetland and ranged the values of $33.3{\sim}89.7$ which were mesotrophic to eutrophic states at the low wetland. The healthy assessment (DAIpo and TDI) of water ecosystem were showed clean-bad from spring to autumn. These epiphytic diatom communities were determinated by the biological factor such as the growth of reed and the physical factors such as water temperature, light penetration and SS and so on.

• ALGAE
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• 제29권4호
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• pp.249-265
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• 2014

As with land crops, cultivated algae are affected by various diseases ranging from large outbreaks of a disease to chronic epiphytes, which may downgrade the value of the final product. The recent development of intensive and dense mariculture practices has enabled some new diseases to spread much faster than before. A new disease is reported almost every year, and the impact of diseases is expected to increase with environmental change, such as global warming. We observed the incidence of diseases in two Pyropia sea farms in Korea from 2011 to 2014, and estimated the economic loss caused by each disease. Serious damage is caused by the oomycete pathogens, Pythium porphyrae and Olpidiopsis spp., which decreased the productivity of the Pyropia sea farms. In Seocheon sea farms, an outbreak of Olpidiopsis spp. disease resulted in approximately US $1.6 million in loss, representing approximately 24.5% of total sales during the 2012-2013 season. The damage caused by green-spot disease was almost as serious as oomycete diseases. An outbreak of green-spot disease in the Seocheon sea farms resulted in approximately US $1.1 million in loss, representing 10.7% of total sales in the 2013-2014 season in this area. However, the causative agent of green-spot disease is still not confirmed. "Diatom felt" is regarded as a minor nuisance that does not cause serious damage in Pyropia; however, our case study showed that the economic loss caused by "diatom felt" might be as serious as that of oomycete diseases. Bacteria and cyanobacteria are indigenous members of epiphytic microbial community on Pyropia blades, but can become opportunistic pathogens under suitable environmental conditions, especially when Pyropia suffers from other diseases. A regular acid wash of the Pyropia cultivation nets is the most common treatment for all of the above mentioned diseases, and represents approximately 30% of the total cost in Pyropia sea farming. However, the acid wash is ineffective for some diseases, especially for Olpidiopsis and bacterial diseases.