• Journal of Microbiology and Biotechnology
• /
• v.26 no.12
• /
• pp.2127-2137
• /
• 2016

A mangrove microbial community was analyzed at the gene and protein levels using metagenomic and proteomic methods with the green macroalgae Enteromorpha prolifera as the substrate. Total DNA was sequenced on the Illumina HiSeq 2000 PE-100 platform. Two-dimensional gel electrophoresis in combination with liquid chromatography tandem mass spectrometry was used for proteomic analysis. The metagenomic data revealed that the orders Pseudomonadales, Rhizobiales, and Sphingomonadales were the most prevalent in the mangrove microbial community. By monitoring changes at the functional level, proteomic analyses detected ATP synthase and transporter proteins, which were expressed mainly by members of the phyla Proteobacteria and Bacteroidetes. Members of the phylum Proteobacteria expressed a high number of sugar transporters and demonstrated specialized and efficient digestion of various glycans. A few glycoside hydrolases were detected in members of the phylum Firmicutes, which appeared to be the main cellulose-degrading bacteria. This is the first report of multiple "omics" analysis of E. prolifera degradation. These results support the fact that key enzymes of glycoside hydrolase family were expressed in large quantities, indicating the high metabolic activity of the community.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.19 no.2
• /
• pp.125-135
• /
• 2001

The research on Harmful Algal Blooms is generally in progress through field work, such as the naked eye and sampling. It was difficult to forecast exactly the course, from appearance of red tide to disappearance, with the established ways of investigation and analysis. Accordingly it is need to analyze environmental factors in time and space, the appearance of red tide and the path of its migration by more objective and scientific methods. In this study the remote sensing was used to diminish damage from the occurrence of red tide. Such as a temperature change of sea water and a change of tidal currents, the major cause for red tide. The probed data were utilized. The technique for forecast of red tide phenomenon on the south coast was researched by analyzing the cause of red tide, pollutant flowed from landand the possibility of application of the technique was showed.

• Journal of Navigation and Port Research
• /
• v.36 no.8
• /
• pp.631-635
• /
• 2012

Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes signal distortion and error floor. In this paper, in order to design an efficient packet structure, we employ channel coding scheme and phase recovery algorithm. For channel coding scheme, half rate LDPC channel coding scheme with N=1944 and K=972 was used. Also, decision directed phase recovery was used for correcting phase offset induced by multipath. Based on these algorithms, we propose length of data for optimal packet structure in the environment of oceanic experimentation.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.8
• /
• pp.755-760
• /
• 2009

In this paper, we apply a reverberation suppression method using difference of singular values to improve the short-distance underwater obstacle detection probability in reverberation environment induced by a linear frequency modulation signal. The reverberation suppression method using difference of singular values suppresses LFM reverberation based on subtracting the singular values for a reference beam, assumed to contain only the reverberation, from those for the current beam of interest, assumed to contain the reverberation and target echo. For the validation, the reverberation suppression method using difference of singular values is applied to real oceanic data, which are acquired using the cross type array.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.3
• /
• pp.149-153
• /
• 2008

General underwater target detection methods adopt short-time FFT for estimate target doppler. This paper proposes the efficient target detection method, instead of conventional FFT, using approximate FFT for distributed sensor network target detection, which requires lighter computations. In the proposed method, we decrease computational rate of FFT by the quantization of received signal. For validation of the proposed method, experiment result which is applied to FFT based active sonar detector and real oceanic data is presented.

• Journal of the Korean earth science society
• /
• v.35 no.4
• /
• pp.249-258
• /
• 2014

Despite the greenhouse gases like carbon dioxide have steadily increased in atmosphere, the overall trend of the global average surface air temperature has stalled during the last decade (2002-present). This phenomenon is often called hiatus or warming pause, which is challenging the prevailing view that anthropogenic forcing causes warming environment. Our study characterized the hiatus by analyzing the HadGEM2-AO (95 yrs) simulation data based on RCP8.5 scenario. The PC2 time series from the EOF of the zonal mean vertical ocean temperature has been defined as the index that represents the warming pause. The relationship between the hiatus, ENSO and the changes in climate system are identified by utilizing the newly defined PC2. Since the La Nina index (defined as the negative of NINO3 index) leads PC2 by about 11 months, it may be possible that the La Nina causes the warming to be interrupted. We also show that the cooling of the climate system closed tied to the heat penetration into the deep ocean, indicating the weakening the warming rate is due to the oceanic heat uptake. Finally, the global warming hiatus is characterized by the anomalous warming in Arctic region as well as the intensification of the trade wind in the equatorial Pacific.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.1
• /
• pp.75-83
• /
• 2020

This study investigated the effects of El Niño and La Niña on coastal upwelling in the East Sea of Korea using long-term (1967-2017) water temperature observation data and Oceanic Niño Index (ONI). As a result of time series analysis of water temperature, the occurrence frequency of summer coastal upwelling was the highest in the southeastern (Ulgi ~ Gimpo) coast. In 1987-1988 and 1997-1998, when the annual fluctuations of ONI plunged more than 2.5, the water temperature in whole coast areas of the East Sea (Busan ~ Goseung) rose by 4 ~ 7 ℃. The temperature structure of the East Sea coastal water was different when El Niño was strong with ONI above 1.5 and La Niña with strong ONI below -0.8. When El Niño is strong, the water temperature anomaly in coastal waters is negative. This is due to the strong baroclinic tilting and the formation of shallow temperature stratification in the coastal waters. The strong La Niña season is opposite to the strong El Niño season, whereas the water temperature anomaly is positive. In addition, the baroclinic tilting is weaker than the time of strong El Niño and the temperature stratification is formed deeper than the time of strong El Niño. The formation of temperature stratification at shallow depths when El Niño is strong can increase the probability of occurrence coastal upwelling caused by southerly winds in the summer season. On the contrary, when La Niña is strong, occurrence of coastal upwelling is less likely even if the southerly wind blows continuously. This is because the temperature stratification is formed at deeper than when El Niño is strong.

• Geophysics and Geophysical Exploration
• /
• v.6 no.1
• /
• pp.40-52
• /
• 2003

Despite the various opening models of the southwestern part of the East Sea (Japan Sea) between the Korean Peninsula and the Japan Arc, the continental margin of the Korean Peninsula remains unknown in crustal structure. As a result, continental rifting and subsequent seafloor spreading processes to explain the opening of the East Sea have not been adequately addressed. We investigated crustal and sedimentary velocity structures across the Korean margin into the adjacent Ulleung Basin from multichannel seismic reflection and ocean bottom seismometer data. The Ulleung Basin shows crustal velocity structure typical of oceanic although its crustal thickness of about 10 km is greater than normal. The continental margin documents rapid transition from continental to oceanic crust, exhibiting a remarkable decrease in crustal thickness accompanied by shallowing of Moho over a distance of about 50 km. The crustal model of the margin is characterized by a high-velocity (up to 7.4 km/s) lower crustal (HVLC) layer that is thicker than 10 km under the slope base and pinches out seawards. The HVLC layer is interpreted as magmatic underplating emplaced during continental rifting In response to high upper mantle temperature. The acoustic basement of the slope base shows an igneous stratigraphy developed by massive volcanic eruption. These features suggest that the evolution of the Korean margin can be explained by the processes occurring at volcanic rifted margins. Global earthquake tomography supports our interpretation by defining the abnormally hot upper mantle across the Korean margin and in the Ulleung Basin.

• Journal of Ecology and Environment
• /
• v.31 no.1
• /
• pp.45-67
• /
• 2008

Ocean climate variables ($1900{\sim}2005$), time series of catches ($1910{\sim}2005$) and body size data were used to assess the year-to-year and decadal scale fluctuations in abundance of the fish populations (Japanese sardine, anchovy, jack mackerel, chub mackerel, Pacific saury and common squid) that have spawning grounds in the East China Sea and its adjacent regions. A negative correlation between the abundance of pelagic fishes (e.g. jack mackerel) in the Tsushima Warm Current (TWC) region and the Kuroshio-Oyashio Current (KOC) region was attributed to the climatic modulation of larval transport and recruitment, which depends on the winter monsoon-induced drift, current systems, and spawning season and site. The changes in abundance and alternation of dominant fish populations in the two regions in the 1930s, 1970s, and late 1980s mirrored changes in the climate indices (ALPI, AOI and MOI). Oscillations in the decadal climate shifts between the two regions led to zonal differences in larval transport and recruitment, and hence differences in the abundance of the pelagic fish populations. During deep Aleutian Lows, as in the 1980s, larval transport from the East China Sea to the KOC region increases in association with the strong winter Asian monsoon, cool regime and increased volume transport of the Kuroshio Current systems, whereas during a weak Aleutian Low (as in the 1990s), larval transport to the TWC region increased in association with a weak winter Asian monsoon, a warm regime, and increased volume transport of the Tsushima current system. We postulate that the increased chub mackerel abundance in the TWC region and the decreased abundance in the KOC region in the 1990s are partly attributed to changes in recruitment and availability to the fishing fleets under the warm regime in the spawning and nursery grounds in the East China Sea in association with the quasi-steady state of mild winter monsoon in the 1990s. The fluctuations in chub mackerel and jack mackerel abundance are under the environment-dependant growth form, although the tropicalization was identified in the TWC region. The density-dependant growth form was found in Japanese sardine populations, but no tropicalization by fishing was identified in the long ($10{\sim}15$ year) periods of abundance despite their short ($3{\sim}4$ year) generation time, suggesting that the environment-dependant growth form drove the changes in abundance. Year-to-year and decadal scale variations in abundance and population structure of the Pacific saury responded to climate regime shifts (1976/1977, 1988/1989), suggesting that the fish is a key bio-indicators for changes in the ecosystem.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.90-93
• /
• 2006

The first Geostationary Ocean Color Imager (GOCI) onboard its Communication Ocean and Meteorological Satellite (COMS) is scheduled for launch in 2008. GOCI includes the eight visible-to-near-infrared (NIR) bands, 0.5km pixel resolution, and a coverage region of 2500 ${\times}$ 2500km centered at 36N and 130E. GOCI has had the scope of its objectives broadened to understand the role of the oceans and ocean productivity in the climate system, biogeochemical variables, geological and biological response to physical dynamics and to detect and monitor toxic algal blooms of notable extension through observations of ocean color. The special feature with GOCI is that like MODIS, MERIS and GLI, it will include the band triplets 660-680-745 for the measurements of sun-induced chlorophyll-a fluorescence signal from the ocean. The GOCI will provide SeaWiFS quality observations with frequencies of image acquisition 8 times during daytime and 2 times during nighttime. With all the above features, GOCI is considered to be a remote sensing tool with great potential to contribute to better understanding of coastal oceanic ecosystem dynamics and processes by addressing environmental features in a multidisciplinary way. To achieve the objectives of the GOCI mission, we develop the GOCI Data Processing System (GDPS) which integrates all necessary basic and advanced techniques to process the GOCI data and deliver the desired biological and geophysical products to its user community. Several useful ocean parameters estimated by in-water and other optical algorithms included in the GDPS will be used for monitoring the ocean environment of Korea and neighbouring countries and input into the models for climate change prediction.