• Title/Summary/Keyword: Sand Dune

Search Result 205, Processing Time 0.024 seconds

Halacaridae (Acari) from Thailand: One New and Two Known Species of the Genus Copidognathus Trouessart

  • Chatterjee, Tapas;Chang, Cheon-Young
    • Animal cells and systems
    • /
    • v.6 no.3
    • /
    • pp.201-206
    • /
    • 2002
  • Three halacarid species belonging to the genus Copidognathus are recorded from the shallow subtidal sands at Ko Taenae Islet (sand dune) off Ko Pha-Ngan Island, Thailand: Copidognathus thailandicus n. sp., C. euryalus Bartsch, 1997 and C. orarius Otto, 2001. Copidognathus thailandicus n. sp. comes close with C. cribrosoma (Police, 1909) and C. cribellus Bartsch, 1993 due to dorsal plates completely covered with rosette pores. Dissimilarities among them are discussed. Copidognathus euryalus and C. orarius are recorded hove for the first time from Thailand and away from its type locality. The present paper is also the first contribution on the taxonomy of Halacaridae (Acari) from Thailand.

Capillary Hysteresis Model in Unsaturated Flow : State of the Art

  • Park, Chan-Kun;Sonu, Jun-Ho
    • Korean Journal of Hydrosciences
    • /
    • v.4
    • /
    • pp.33-49
    • /
    • 1993
  • The Purpose of this study is to classify existing hysteresis models and to discuss a possibility of a new type of the hysteresis model. The existing hysteresis models are classified into three types: the interpolation model, the scaling model and the domain model, of which only domain model is to simulate hysteresis curves based on the theoretical approach, It is useful to develop a hysteresis model that requires only one branch of hysteresis curves for the model calibration because obtaining hysteresis curves by experiments is expensive and time-concept by many investigators, however their models are not successful to accurately simulate real data of Rubicon Sandy Loam and Dune Sand. There is a possibility that a new model is based on the dependent domain concept considering the weighting factor, $P_a$($\theta$), which accounts for the pore blockage effect against air entry. Conclusively, a new model where the weighting factor $P_a$($\theta$) in Model III-1 (Mualem, 1984) reduces to a known variable through an appropriate method is an alternative model which required only one branch of main curves for the model calibration.

  • PDF

Occurrence and Distribution of Cellular Slime Molds in Relation to the Coastal Plant Communities of Islands near Inch`on (仁川 近海 島嶼地域의 海岸植物 群落에 따른 細胞性 粘菌의 出現과 分布)

  • Hong, Jeong-Soo;Nam-Kee Chang
    • The Korean Journal of Ecology
    • /
    • v.14 no.4
    • /
    • pp.457-467
    • /
    • 1991
  • Occurrence and distribution of the celluar slime molds in relation to the coastal plant communities of svven islands near inch'on wereinvestigated. as a results, total seven species were isolated from the soils of the coastal plant communities. These are dictyostelium mucoroides, polysphodylium pallidum, dictystelium polycephalum. d. mucoroides was the most commonly found in the coastal plant communities investigated, and was dominant pecularly in the coastal mixed forests, the coastal broad-leaved forests and salt marshes. In the coastal coniferous forest and the coastal dune sand plants, hoeever, p. violaceum was the dominant species. species diversity was relatively was relatively high in the coastal coniferous ferests and the coastal mixed forests. However, agerage number of species isolated from all plant communities was very low,2.8.

  • PDF

A Status of Distributions and its Characteristics of the Geomorphological and Geological Landform Resources in Taeanhaean National Park (태안해안국립공원 해안지형과 지질 자원의 분포 현황과 특성)

  • Seo, Jong Cheol
    • Journal of The Geomorphological Association of Korea
    • /
    • v.26 no.4
    • /
    • pp.97-106
    • /
    • 2019
  • This study aims to investigate geomorphological and geological landscapes in the Taeanhaean National Park to ensure they are well-preserved. This study discovered 390 geomorphological and geological landform resources distributed in the coastal zone of Taeanhaean National Park. Representative geomorphological and geological landforms include : sea cliffs, sea caves, wave-cut platforms, sea-stacks, pebble beaches, sand beaches, tidal flats, coastal dunes, coastal dune wetlands and folds (or micro folds) landforms. Deposition landforms are developed more and erosion and weathering landforms are less on the land zone than island zone. These landform resources vary from district to district and can be developed for geo-tourism resources. Combined efforts from the Taeanhaean National Park authorities and residents are essential to manage ecological programs using geomorphological and geological resources.

Spatial Variations of Salt Marsh Plants Induced by Sandy Sediment in Hampyeong Tidal Flat (함평만 갯벌의 모래 퇴적물로 인한 염습지 식물의 공간적 변이)

  • Minki, Hong;Jaeyeon, Lee;Jeong-Soo, Park;Hyohyemi, Lee
    • Ecology and Resilient Infrastructure
    • /
    • v.9 no.4
    • /
    • pp.247-258
    • /
    • 2022
  • Hampyeong Bay has a narrow seawater channel and a complex topographical structure. The sand content of the tidal flat soil is increasing due to asymmetrical sedimentation. Through the investigation of the vegetation distribution and the use of the line-transect method, sand flats were observed to gradually change the vegetation distribution of salt marshes. Comparing the vegetation area between 2016 and 2022, the obligate halophyte Suaeda maritima decreased by 74% and Zoysia sinica increased by 75%. Z. sinica seems to support the robustness of the dune environment by trapping sediments such as sand in the colony, because the underground rhizomes and stems are highly developed. To establish an effective conservation management plan for tidal flats, an integrated study should be conducted to assess the impact of changes in tidal flat soil and the interaction of vegetation communities in Hampyeong Bay.

Geographic Genetic Contour of a Ground Beetle, Scarites aterrimus (Coleoptera: Carabidae) on the Basis of Mitochondrial DNA Sequence

  • Wang, Ah-Rha;Kim, Min-Jee;Cho, Young-Bok;Wan, Xinlong;Kim, Ik-Soo
    • International Journal of Industrial Entomology and Biomaterials
    • /
    • v.22 no.2
    • /
    • pp.65-74
    • /
    • 2011
  • The Scarites aterrimus (Coleoptera: Carabidae), is one of the carabid beetles dwelling exclusively on coastal sandy dunes. Habitat deterioration and equivalent activity have greatly concerned population declines in several species dwelling on the coastal sandy dunes. As a first step to establish long-term conservation strategy, we investigated the nation-wide magnitude and nature of genetic diversity of the species. As a first step, we sequenced a portion of mitochondrial COI gene, corresponding to "DNA Barcode" region (658 bp) from a total of 24 S. aterrimus individuals collected over nine sandy dunes belonging to four Korean provinces. The sequence analysis evidenced moderate to low magnitude of sequence diversity compared with other insect species distributed in Korean peninsula (0.152% to 0.912%). The presence of closely related haplotypes and relatively high gene flow estimate collectively suggest that there had been no historical barriers that bolster genetic subdivision. Population decline was postulated on the basis of several missing haplotypes that are well found in the species with a large population size. This interpretation is consistent with field observation of small population size in the coastal sandy dune habitats. The highest genetic diversity estimates were found in the coastal sand dune population of Seogwipo, Jeju Island, justifying a prior attention to the population, in order to sustain overall genetic diversity of the species. Further scrutinized study might be required for further robust conclusion.

A study on the halophyte vegetation and halophyte flora characteristics of coastal ecosystem in the West and South coasts in Korea (한국 서·남해안 연안생태계의 염생식물군락과 염생식물상의 특성에 관한 연구)

  • Ji Won Park;Eui Joo Kim;Jung Min Lee;Yoon Seo Kim;Yeo Bin Park;Jae Hoon Park;Se Hee Kim;Kyeong Mi Cho;Yoon Kyung Choi;Ji Hyun Seo;Joo Hyun Seo;Young Han You
    • Journal of Wetlands Research
    • /
    • v.26 no.1
    • /
    • pp.72-81
    • /
    • 2024
  • Korea is surrounded by the sea on three sides, salt marshes and coastal sand dunes adjacent to them are developed. This study attempted to reveal the characteristics of the coastal ecosystem by investigating and analyzing the characteristics of plant communities and flora of 571stands of 48 sites in the salt marshes and coastal sand dunes on the western and southern coasts of Korea. As a result, in the salt marshes, 39 vegetation units appeared, with Phragmites australis community having the widest area and Chenopodium virgatum community having the narrowest area. Suaeda glauca community was distributed closest to the coastline, while Suaeda maritima community extended the farthest seaward. In the coastal sand dunes, 29 vegetation units were distributed with Elymus mollis community having the widest area and Salsola komarovii community having the narrowest area. Calystegia soldanella community was showed closest to the coastline, while Rosa rugosa community extended the farthest landward. The flora of the salt marshes consisted of 6 families, 14 genera, 17 species, 1 variant, and 18 taxa (floristic regional indicator score; 16) and the coastal sand dunes consisted of 11 families, 18 genera, 20 species, 1 variant, and 21 taxa (floristic regional indicator score; 34) appeared slightly higher than that of salt marshes. This result is interpreted that halophyte that are sensitive to salinity can grow on the coast of the west-south coast of Korea because coastal sand dunes are more indirectly affected by sea than salt marshes.

Identifying Landscape Perceptions of Visitors' to the Taean Coast National Park Using Social Media Data - Focused on Kkotji Beach, Sinduri Coastal Sand Dune, and Manlipo Beach - (소셜미디어 데이터를 활용한 태안해안국립공원 방문객의 경관인식 파악 - 꽃지해수욕장·신두리해안사구·만리포해수욕장을 대상으로 -)

  • Lee, Sung-Hee;Son, Yong-Hoon
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.46 no.5
    • /
    • pp.10-21
    • /
    • 2018
  • This study used text mining methodology to focus on the perceptions of the landscape embedded in text that users spontaneously uploaded to the "Taean Travel"blogpost. The study area is the Taean Coast National Park. Most of the places that are searched by 'Taean Travel' on the blog were located in the Taean Coast National Park. We conducted a network analysis on the top three places and extracted keywords related to the landscape. Finally, using a centrality and cohesion analysis, we derived landscape perceptions and the major characteristics of those landscapes. As a result of the study, it was possible to identify the main tourist places in Taean, the individual landscape experience, and the landscape perception in specific places. There were three different types of landscape characteristics: atmosphere-related keywords, which appeared in Kkotji Beach, symbolic image-related keywords appeared in Sinduri Coastal Sand Dune, and landscape objects-related appeared in Manlipo Beach. It can be inferred that the characteristics of these three places are perceived differently. Kkotji Beach is recognized as a place to appreciate a view the sunset and is a base for the Taean Coast National Park's trekking course. Sinduri Coastal Sand Dune is recognized as a place with unusual scenery, and is an ecologically valuable space. Finally, Manlipo Beach is adjacent to the Chunlipo Arboretum, which is often visited by tourists, and the beach itself is recognized as a place with an impressive appearance. Social media data is very useful because it can enable analysis of various types of contents that are not from an expert's point of view. In this study, we used social media data to analyze various aspects of how people perceive and enjoy landscapes by integrating various content, such as landscape objects, images, and activities. However, because social media data may be amplified or distorted by users' memories and perceptions, field surveys are needed to verify the results of this study.

Comparison of the Total Phenolic and Flavonoid Contents and Antioxidant Activities of Four Kinds of Sand Dune Plants Living in Taean, Korea (태안에서 서식하는 사구식물 4종의 폴리페놀, 플라보노이드 함량과 항산화 활성 비교)

  • Kim, Soon-seok;Cha, Hyeon-cheol
    • Korean Journal of Plant Resources
    • /
    • v.30 no.1
    • /
    • pp.8-16
    • /
    • 2017
  • This study attempted to investigate the antioxidant properties of four different species of sand dune plants (Calystegia soldanella, Messerschmidia sibirica, Vitex rotundifolia and Rosa rugosa). In order to validate the antioxidant activity of these plants, we first determined the total amount of flavonoid versus phenolic contents (TFC/TPC) and extracted crude flavonoids for measuring antioxidant activities that were determined by DPPH, ABTS and FRAP assays with radical scavenging effects. We found that highest amounts of TPC were detected in R. rugose with values of 110.20 mg/g (leaves) and 65.71 mg/g (stems), while the highest amounts of TFC in V. rotundifolia with values of 38.07 mg/g (leaves) and 6.55 mg/g (stems). We further examined how closely related the amounts of TFC/TPC in antioxidant activities and found that R. rugose has the highest activities of radical scavenging with values of $63.4{\mu}g/ml$ and $51.2{\mu}g/ml$ determined by DPPH and ABTS assays compared with the value of $21.2{\mu}g/ml$ by FRAP assay. It is of note that there is a statistically significant correlation between the resulting antioxidant activities and the total ratio of TFC and TPC, suggesting that the different amounts of TFC/TPC may directly contribute to the various antioxidant activities.

Time Series Analysis of Area of Deltaic Barrier Island in Nakdong River Using Landsat Satellite Image (Landsat 위성영상을 활용한 낙동강 삼각주 연안사주의 면적 시계열 분석)

  • Lee, Seulki;Yang, Mihee;Lee, Changwook
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.34 no.5
    • /
    • pp.457-469
    • /
    • 2016
  • Nakdong river barrage was affected by artificial interference such as construction of port, industrial complex and estuary barrage. This change in Nadong river lead to environmental changes and affected the ability of barrier islands. Therefore, it is decided that the observation of changes in the Nakdong river estuary is very important. In this paper, the topographic change of the Nakdong river barrage observe based on Landsat TM, ETM+ images from 1984 to 2015. In addition, this study tried to conduct a comparative analysis on the area for change of sandy sediment according to tide level. This results could estimate height and volume about sandy sediment accumulated on the lower sand dune. Also, these results are expected to be the basis for prediction of the changing topography of the sand dune. The area of the average change in region 1,2,3 was calculated as 3,015m2, 167,550m2, 14,596m2. This result is expected to be very useful for the continuous observation for sediment changes of Nakdong river.