• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.479-481
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• 2003

Large number of coral reefs in Thailand waters make the use of satellite imagery probably the only practical method for their monitoring. This paper reports the result of detecting small shallow-water coral reef by using maximum likelihood classification technique. Combination of blue/green and near-infrared band ratio are used as spectral signatures derived from a Landsat 7 imagery covering western portion of the Gulf of Thailand. Result assessment reveals accuracy significantly over 60 percent. The result is encouraging and would be a basis for further study to realize the full potential and limitation of this technique.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.687-698
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• 2021

We present quantitative estimations of changes in the areal extent of coral reef habitats at Weno Island, Micronesia, using high-spatial-resolution remote sensing images and field observations. Coral reef habitat maps were generated from Kompsat-2 satellite images for September 2008 and September 2010, yielding classifications with 78.6% and 72.4% accuracy, respectively, which is a relatively high level of agreement. The difference between the number of pixels occupied by each seabed type was calculated, revealing that the areal extent of living corals decreased by 8.2 percentage points between 2008 and 2010. This result is consistent with a comparison of the seabed types determined by field observations. This study can be used as a basis for remediation planning to diminish the impact of changes in coral reefs.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.3-8
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• 2003

• Proceedings of the KSRS Conference
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• v.2
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• pp.917-917
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• 2006

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.4
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• pp.378-385
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• 1998

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.1-8
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• 2014

In this study, a field monitoring on Namae beach erosion countermeasure in the east coast of Korea is conducted to verify its efficiency and effectiveness. The Namae Beach project has been carried out for six years with three years for planning and three years for actual construction. The planning phase of numerical model tests and investigations had been reported by Kim et al. (2008, 2011). The field monitoring confirms increase in the beach width after the submerged artificial reefs construction and is due to its wave energy dissipation effects. The field monitoring is performed at the seaward and landward of the countermeasures. The wave height reduction from the seaward side (depth h = 10.5 m) to the landward side (h = 3.7 m) of the reef is measured for wave transmission coefficient (Kt) analysis. The analysis shows 60% of deduction in wave energy due to the submerged artificial reefs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.93-102
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• 2020

This study investigated the dif usion characteristics of Ecklonia cava spores around marine forest reefs. For this purpose, a numerical analysis was conducted using field observations in the target area and an EFDC model. Based on the results of field observations and the EFDC model, Flow-3D was performed on three types of marine forest reefs, mamely triangular pyramid reef, double-dome reef, and ribbed reef, to monitor the movement direction and maximum movement distance for E. cava spores. As a result, the equilaterally triangular pyramid reef and double-domed reef were found to have a maximum settlement of spores of 10 m in the northwestern direction and 6 m in the western direction. The ribbed reef had a maximum settlement of spores at 4m. These results show that consideration of the diffusion characteristics of E. cava spores when the seaweeds are installed can increase the effectiveness of the algae as substrate of adhesion.

• ALGAE
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• v.31 no.4
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• pp.317-340
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• 2016

The Abrolhos Continental Shelf (ACS) encompasses the largest and richest coral reefs in the southern Atlantic Ocean. A taxonomic study of non-geniculate coralline algae (NGCA) from the region was undertaken using both morpho-anatomical and molecular data. Specimens of NGCA were collected in 2012 and 2014 from shallow reefs of the ACS. Phylogenetic analysis was performed using dataset of psbA DNA sequences from 16 specimens collected in the ACS and additional GenBank sequences of related NGCA species. Nine common tropical reef-building NGCA species were identified and described: Hydrolithon boergesenii, Lithophyllum kaiseri, Lithophyllum sp., Lithothamnion crispatum, Melyvonnea erubescens, Pneophyllum conicum, Porolithon onkodes, Sporolithon ptychoides, and Titanoderma prototypum. A key for species identification is also provided in this study. Our molecular phylogenetic analyses suggest that Lithophyllum sp. corresponds to a new species. Our study also confirms that Lithophyllum kaiseri is a new record in Brazil. The psbA sequences of Lithophyllum kaiseri and Melyvonnea erubescens matched with type specimens indirectly. The taxonomic identification of the remaining species was supported by morpho-anatomical evidences as DNA sequences of their types or topotypes remain unavailable.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.922-934
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• 2010

To arrange artificial reefs for marine afforestation effectively, tidal currents were analyzed by numerical experiments, and particle tracking based on tidal currents was carried out to clarify the path of algae spores. The experiments were conducted by the Environmental Fluid Dynamics Code (EFDC), and water column was vertically divided into five layers. Tidal current patterns were showed to be affected by main currents outside of the study area, and two circle currents were observed during the analysis of residual currents. Particle tracking lasted 15 days at three installation places where artificial reefs for marine afforestation could be deployed. According to the results of the particle tracking experiment, particle movements at the No.1 and No. 3 stations were belt types along the coastal line. The No. 2 station documented an ellipse type movement 300~500m from coast line. These results suggest that artificial reefs for marine afforestation should be installed in the belt zones at of the No. 1 and No. 3 stations, and in the ellipse zone at the No. 2 station.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.342-354
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• 2015

We suggested definition and classification scheme of uninhabited islands in Taeanhaean National Park for efficient management. Islands (seom) and reefs (yeo) were classified based on approximate HHW. Uninhabited islands were categorized into vegetated islands and rocky islands depending on presence of woody vegetation cover for physical geographic and ecological value and importance. Reefs were also divided into an underwater reef and a reef which covers and uncovers based on approximate LLW. We excluded those areas which are not separated from main land by waterbody even though it is in approx. HHW from islands. We considered several divided areas which adjoin geographically and ecologically one another under the condition of approx. LLW as an island. By using above schemes, we categorized 50 uninhabited islands in Taeanhaean National Park into three groups; 24 vegetated islands, 14 rocky islands, and 12 reefs. If the public institutions adopt these schemes as national standards, it will be useful in managing uninhabited islands nationwide.