• Applied Microscopy
• /
• v.45 no.4
• /
• pp.249-253
• /
• 2015

Microorganisms specifically groups of bacteria exhibiting physiological activities of production of acids are a major cause of concern because of their ability to induce corrosion in oil field pipelines and metal systems involved in water handling. Water Injection Stations as a means of secondary recovery from existing oil producing reservoirs, are often employed in most upstream oil and gas industries to ensure replenishment of voidage, maintenance of reservoir pressure and optimization of crude emulsion throughput. In the present study, scanning electron microscopy of macroscopic orange coloured slime formations sampled from leaking valves on the flow-lines of a Water Injection Stations of Oil India Limited revealed the presence of filamentous bacterial mats in association with diatoms. The species composition of the acidic slime formations from the sampled locations reveal the possible role of acid producing iron oxidizing bacteria (IOB) like Acidithiobacillus ferrooxidans in association with Gomphonema sp. in creating conditions for bio-corrosion.

• Journal of Environmental Health Sciences
• /
• v.36 no.2
• /
• pp.148-154
• /
• 2010

In this study, a method for river water quality evaluation by algal examination was investigated. For development of this method, algae living in small rural streams in Gwangcheon-Cheon were collected and observed by microscope. Samples were collected at six stations from May 2008 to May 2009. To elucidate the relationship between pollution and the algal species, diatom grasps were collected from the streams and used to determine the water quality grade. The numerical EC value was compared with the value of DAIpo (Diatom Assemblage Index of Organic Water Pollution), and the results showed a tendency to a mutually inverse relationship. Further, the numerical BOD and COD values were compared to the DAIpo value. The results showed that, various diatoms reside in Gwangcheon-Cheon, and water quality was found to be second-grade at all the examined points. These results indicate pollution of streams by livestock wastewater; however continuous monitoring will be necessary to more definitely determine the reason for the Gwangcheon-Cheon pollution.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.2 no.1
• /
• pp.21-28
• /
• 1998

A total of 94 taxa were identified from the Southern Ocean, 140-148 $^{\circ}E$ and 40-53 $^{\circ}S$, as an early austral summer phytoplankton. They were 53 diatoms, 37 dinoflagellates, 2 silicoflagellates, 1 prymnesiophyte, and 1 coccolithophorid. Integrated cell numbers of nanoplankton dominated microphytoplankton from 8 stations, especially from Subantarctic zone, but integrated biomass was lower than microphytoplankton. Integrated cell numbers of diatoms dominated dinoflagellates, coccolithophorids, and prymnesiophyte, but integrated biomass of microphytoplankton were dependent to the biomass of dinoflagellates except north of the Subtropical convergence zone and south of the Antractic convergence zone. Phytoplankton community changed across the fronts and 3 different communities were observed. Fronts seem to influence on the phytoplankton community from the west Pacific Sector of the Southern Ocean.

• The Korean Journal of Ecology
• /
• v.27 no.2
• /
• pp.61-65
• /
• 2004

To elucidate the trophic relationships within a subtropical wetland, the profile of fatty acids in producers, consumers and sediments of the mangrove forest and intertidal mudflat was studied. Results indicated a close relationship in fatty acid profiles between the mangrove plants Aegiceras corniculatum and Avicennia marina and the sesarmid crab Sesarma bidens, and between the fiddler crab Uca arcuata and diatoms. The fatty acid profile of the mudskippers Boleophthalmus pectinirostris and Periophthalmus cantonensis, however, showed a mixed diet of diatoms, macroalgae, protozoa and crabs. Seasonal changes in fatty acid profiles in mangrove plants, sediments and sesarmid crabs were noted. The implication of using fatty acids as tracer of trophic relationships was discussed.

• ALGAE
• /
• v.20 no.3
• /
• pp.197-205
• /
• 2005

Temporal variability in lake phytoplankton is controlled by a complex between hydrological and chemical factors, and biological interactions. We explored annual change of phytoplankton in Lake Daecheong, using phytoplankton analysis data from 1997 to 2002 (except 2000). The standing crop of phytoplankton was ranged from 3.5 x 10 to 1.5 x 106 cells mL$^{-1}$ and the highest mean value was at site 1. The class composition ratios of phytoplankton standing crop were divided into three classes. From January to March, diatoms showed a dominance (68.1-77.7%). From April to June, diatoms were mixed with cryptomonad etc. or blue-green algae. From July to October, blue-green algae showed a dominance (54.7-84.0%). In the case of green algae, the class composition ratios were below 10%. But green algae appeared all the year round.

• ALGAE
• /
• v.26 no.4
• /
• pp.299-315
• /
• 2011

The morphology, taxonomy, and distribution of species belonging to the diatom family Rhizosoleniaceae were studied from the marine coastal waters of Korea. Rhizosolenid diatom taxa were collected at 30 sites from September 2008 to February 2010 and were analyzed by light and scanning electron microscopy. We identified 6 rhizosolenid genera, including Rhizosolenia, Proboscia, Pseudosolenia, Neocalyptrella, Guinardia, and Dactyliosolen. We describe 5 genera in this study, except Rhizosolenia. Five genera were compared in detail with congeneric species. Six genera within the family Rhizosoleniaceae were divided into two groups based on morphological diagnostic characters including valve shape, areolae pattern, the shape of external process, and girdle segments in the column. The first group had a conoidal valve and loculate areolae, which comprised Rhizosolenia, Proboscia, Pseudosolenia, and Neocalyptrella, and the second group of Guinardia and Dactyliosolen showed a flat or rounded valve and poroid areolae. Important key diagnostic characters were based on valve shape, areolae pattern on the segment, external process, position of the tube, and the valve margin. D. phuketensis was new to Korean coastal waters.

• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.186-191
• /
• 2015

Diatoms are a major component of the biological community, serving as the principal primary producers in the food web and sustaining oxygen levels in aquatic environments. Among marine planktonic diatoms, the cosmopolitan Skeletonema costatum is one of the most abundant and widespread species in the world's oceans. Here, we report the basic characteristics of a new diatom-infecting S. costatum virus (ScosV) isolated from Jaran Bay, Korea, in June 2008. ScosV is a polyhedral virus (45-50 nm in diameter) that propagates in the cytoplasm of host cells and causes lysis of S. costatum cultures. The infectivity of ScosV was determined to be strain- rather than species-specific, similar to other algal viruses. The burst size and latent period were roughly estimated at 90-250 infectious units/cell and <48 h, respectively.

• 한국해양학회지
• /
• v.22 no.3
• /
• pp.179-190
• /
• 1987

A study on the fine structure of the marine diatoms has been carried out for taxonomical purpose during the periods from September 1983 to March 1987 in Korean coastal waters. Fine structure of smallThalassiosira(Bacillariophyceae) was studied by means of light microscope and scanning electron nisroscopy. Secondarily, six species of Thalassiosira were identified and described. Of these Thalassiosia allenii, T. binata and T. conferta were new records for Korean coastal waters. Thalassiosira aestivalis, T.allenii, T.binata, T.conferta, and T. pacifica have a valve with a single labiate process and one central and one marginal ring of strutted processes, but T.rotula has many central strutted processes close together instead of one central strutted process.

• Environmental Engineering Research
• /
• v.18 no.4
• /
• pp.259-265
• /
• 2013

This study was conducted June 2011 at Gamo Lagoon, after tsunami of March 2011, to estimate food sources and utilization. The results show that the tsunami affected the sediment properties by changing the physical environmental alterations. The fatty acids of the gut content of Nuttallia olivacea mostly comprised the same organic matter found in the sediment. Fatty acids in the tissues showed mainly diatoms, bacteria, and dinoflagellates. That is, most of the food sources (i.e., diatoms, bacteria, dinoflagellates, macroalgae, and terrestrial organic matter) probably pass through the digestive system unharmed; however, terrestrial organic matter, which is refractory to biochemical degradation, indicated a different assimilation trend between the gut content and the tissue. This result suggests that input of labile organic matter from the sediment may control selective metabolism in N. olivacea. From these results, although the physical environment of sediment characteristics by tsunami changed, the food utilization of N. olivacea suggested a better assimilation of selected components from the gut content, irrespective of physical alteration.

• Journal of Environmental Science International
• /
• v.2 no.1
• /
• pp.21-28
• /
• 1993

A total of 94 taxa were identified from the Southern Ocean, 140-148 。E and 40-53。S, as an early austral summer phytoplankton. They were 53 diatoms, 37 dinoflagellates, 2 silicoflagellates, 1 prymnesiophyte, and 1 coccolithophorid. Integrated cell numbers of nanoplankton dominated microphytoplankton from 8 stations, especially from Subantarctic zone, but integrated biomass was lower than microphytoplankton. Integrated cell numbers of diatoms dominated dinoflagellates, coccolithophorids, and pnrnnesiophyte, but integrated biomass of microphytoplankton were dependent to the biomass of dinoflagellates except north of the Subtropical convergence zone and south of the Antractic convergence sone. Phytoplankton community changed across the fronts and 3 different communities were observed. Fronts seem to influence on the phytoplankton community from the west Pacific Sector of the Southern Ocean.