scholarly journals Comprehensive Study of the Sand Spit Evolution at Tidal Inlets in the Central Coast of Vietnam

2020 ◽  
Vol 8 (9) ◽  
pp. 722
Author(s):  
Nguyen Quang Duc Anh ◽  
Hitoshi Tanaka ◽  
Ho Sy Tam ◽  
Nguyen Xuan Tinh ◽  
Tran Thanh Tung ◽  
...  
Keyword(s):  
Remote Sensing Data ◽  
Conservation Equation ◽  
Tidal Inlets ◽  
Central Coast ◽  
Longshore Sediment Transport ◽  
Extreme Flood ◽  
Sand Spit ◽  
Order Of Magnitude ◽  
Coast Of Vietnam ◽  
Comprehensive Study

Tidal inlets along the central coast of Vietnam are located in a microtidal, wave-dominated coastal environment. In addition, the Vietnam coast is highly influenced by the seasonal monsoon regime, which is characterized by large northeast waves from October to March and calm southeast waves from April to September every year. Consequently, the tidal inlet entrance morphologies often suffer from a dynamic seasonal evolution due to distinct differences in the direction of wave-induced longshore sediment transport (LST) between the two monsoon seasons. The migration or closure of tidal inlets causes a lot of problems for socio-economic development in the region since these are the main reasons leading to an increase in the risk of coastal flooding and the obstruction of navigation. This paper presents a comprehensive study of the morphological evolutions of natural tidal inlets on the central coast of Vietnam using long-term remote sensing data sets and by the Delft3D numerical model. Surprisingly, the estimated LST rates from the former method are in an order of magnitude agreement with the results from the latter one for all of the areas in this study. Based on the conservation equation for sand and comprehensive data collection, a new simple empirical formula for predicting the sand spit elongation rate as a function of the sand spit width is developed. Although the breaching of sand spit might happen during an extreme flood event at some tidal inlets, the growth rate of the spit before and after the breaching is almost unchanged. These findings are very useful information for supporting the local coastal authorities to find better management solutions in terms of sustainable development.

Sand Spit Development at the Loc An River Mouth, Vietnam

2018 ◽  
Author(s):  
Nguyen Quang Duc Anh ◽  
Dinh Van Duy ◽  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Nguyen Trung Viet
Keyword(s):  
Developing Countries ◽  
Numerical Calculation ◽  
Satellite Images ◽  
River Mouth ◽  
Southern Coast ◽  
Longshore Sediment Transport ◽  
Sand Spit ◽  
Coast Of Vietnam ◽  
The One ◽  
Good Agreement

Elongation of the sand spit in Loc An River Mouth located in the Southern Coast of Vietnam was studied using a series of satellite images to overcome the problem associated with lacking data in developing countries like Vietnam. Characteristic changes of the sand spit have been figured out based on the waterlines extracted from the re-rectified satellite images. In addition, longshore sediment transport rate (LSTR) along the up-drift sand spit was calculated based on the idea of the one-line model and this value shows good agreement with the numerical calculation performed in another study of this area.

scholarly journals PHYLOGENETIC ANALYSIS AND SPECIES IDENTIFICATION OF 11 GORGONIAN CORALS (OCTOCORALLIA: ALCYONACEA) IN THE NORTH CENTRAL COAST OF VIETNAM BASED ON MSH1MTDNA AND 28S RDNA MARKERS

2021 ◽  
Vol 9 (08) ◽  
pp. 505-514
Author(s):  
Nguyen Chi Mai ◽  
◽  
NinhThi Ngoc ◽  
Nguyen Xuan Cuong ◽  
Nguyen Hoai Nam ◽  
...  
Keyword(s):  
Species Identification ◽  
Phylogenetic Analyses ◽  
28S Rdna ◽  
Central Coast ◽  
North Central ◽  
The North ◽  
Traditional Classification ◽  
Gorgonian Corals ◽  
Coast Of Vietnam

Vietnam contains diverse marine ecosystems with the high biodiversity of marine organisms, including gorgonian corals of Alcyonacea order. In order to support traditional classification of these corals, in this study mitochondrial barcoding markers msh1 and nuclear 28S rDNA were developed for analysis of 11 specimens collected in 2015 and 2016 from different islands and bays along the North Central coast of Vietnam. Phylogenetic analyses based on msh1 and 28S sequence polymorphism showed that all specimens belonged to Anthozoa class, Octocorallia sub-class and Alcyonacea order. At lower taxa levels, they were divided into 4 sub-orders, 7 families and 7 genera according to 7 distinct clades with bootstrap values from 99-100%.The identifications of 7 out of 11 specimens including Sinularia brassica (2 specimens)and Sinularialeptoclados, Dichotellagemmacea, Annella reticulata, S. conferta and S. nanolobata were in concordance between morphological and molecular methods. The other 4 specimens were only identified at genus levels of Astrogorgia sp., Melithaea sp. Scleronephthya sp. and Muricella sp. by either msh1-morphology or msh1-28S markers. These results highlight the importance of molecular markers to elucidate patterns of biodiversity and species identification of soft coral.

scholarly journals A Hybrid Approach Using GIS-Based Fuzzy AHP–TOPSIS Assessing Flood Hazards along the South-Central Coast of Vietnam

2020 ◽  
Vol 10 (20) ◽  
pp. 7142
Author(s):  
Huu Xuan Nguyen ◽  
An Thinh Nguyen ◽  
Anh Tu Ngo ◽  
Van Tho Phan ◽  
Trong Doi Nguyen ◽  
...  
Keyword(s):  
Fuzzy Ahp ◽  
High Tide ◽  
Hybrid Approach ◽  
Local Economy ◽  
Provincial Government ◽  
Flood Hazards ◽  
The South ◽  
Central Coast ◽  
South Central ◽  
Coast Of Vietnam

Flood hazards affect the local economy and the livelihood of residents along the South-Central Coast of Vietnam. Understanding the factors influencing floods’ occurrence potentially contributes to establish mitigation responses to the hazards. This paper deals with an empirical study on applying a combination of the fuzzy analytic hierarchy process (AHP), the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS), and a geographic information system (GIS) to assess flood hazards along the South-Central Coast of Vietnam. Data are collected from focus group discussions (FGDs) with five communal authorities; a questionnaire completed by eight hamlet heads in the Phuoc Thang commune (Binh Dinh province); and documents, reports, and thematic maps provided from official sources. A total of 12 maps of flood factors are prepared. The results show that terrain elevation, creek-bottom terrains, high tide-induced flooding area, and distance to water body are the main factors affecting flood hazards. The An Loi hamlet faces the highest risk for floods, followed by Lac Dien, Luong Binh, and Pho Dong. The map of flood hazards indicates the western part is assessed as low hazard, whereas the eastern part is a very high hazard area. The study findings show that the hybrid approach using GIS-based fuzzy AHP–TOPSIS allows connecting decision makers with the influencing factors of flooding. To mitigate floods, both the Vietnam national government and the Binh Dinh provincial government should integrate natural hazard mitigation into socio-economic development policies.

scholarly journals The trade routes from the Central Highlands to the Central Coast in the past

2015 ◽  
Vol 18 (1) ◽  
pp. 33-39
Author(s):  
Hoa Thi Nguyen
Keyword(s):  
The Other ◽  
Central Coast ◽  
Trade Routes ◽  
The Past ◽  
Central Highlands ◽  
Coast Of Vietnam

To exchange goods from the Central Highlands to the Central Coast of Vietnam, there must have been some trade routes in the past. Indeed, there were at least two trade routes that the Central Highlanders in Vietnam used to take to exchange goods with people on the Central Coast. One route went to the towns of Phan Ri and Phan Rang where the Cham people lived and the other route led to Khanh Hoa and Phu Yen provinces where the Kinh people lived. These were local man-made trails that started out from highlanders’ villages.

scholarly journals Coastal Processes and Longshore Sediment Transport along Zemmouri Bay, Central East Coast of Algeria

2019 ◽  
Vol 21 (1) ◽  
pp. 7-15
Author(s):  
Khoudir Mezouar ◽  
Romeo Ciortan
Keyword(s):  
Sediment Transport ◽  
Morphological Changes ◽  
Shoreline Change ◽  
Spatial And Temporal Scales ◽  
Wave Refraction ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Western Area ◽  
Waves And Currents ◽  
Comprehensive Study

Abstract The coastline of Zemmouri Bay on the northeast coast of Algeria with about 50 km of shoreline has been eroding since 1970. Changes of the sandy shoreline are continuous and occur at diverse spatial and temporal scales. This erosion is a major crisis and it potentially impacts the coastal population and natural environment. In order to understand and predict these morphological changes, an accurate description of sediment transport by waves and currents and shoreline change is important. This paper presents a comprehensive study of wave refraction, current-driven sediment transport and shoreline change. Results show that the study area exhibits a great variety of shoreline evolution trends, with erosion prevailing in the eastern and central sectors and stability or even accretion in the Western area.

scholarly journals Factors affecting offshore fishing households’ income in southern central coast of Vietnam

2020 ◽  
pp. 1369-1376 ◽  
Author(s):  
Hiep Hong Hoang ◽  
Tam Bang Vu ◽  
Hanh Viet Ho ◽  
Hung Tuan Vu ◽  
Quang Dai Nguyen
Keyword(s):  
Central Coast ◽  
Factors Affecting ◽  
Southern Central ◽  
Coast Of Vietnam

scholarly journals Barcoding ciliates: a comprehensive study of 75 isolates of the genus Tetrahymena

2007 ◽  
Vol 57 (10) ◽  
pp. 2412-2423 ◽  
Author(s):  
Chitchai Chantangsi ◽  
Denis H. Lynn ◽  
Maria T. Brandl ◽  
Jeffrey C. Cole ◽  
Neil Hetrick ◽  
...  
Keyword(s):  
Dna Barcode ◽  
Sequence Divergence ◽  
Tetrahymena Pyriformis ◽  
Order Of Magnitude ◽  
Nj Tree ◽  
The Mean ◽  
Taxonomic Marker ◽  
The One ◽  
Close Relatives ◽  
Comprehensive Study

The mitochondrial cytochrome-c oxidase subunit 1 (cox1) gene has been proposed as a DNA barcode to identify animal species. To test the applicability of the cox1 gene in identifying ciliates, 75 isolates of the genus Tetrahymena and three non-Tetrahymena ciliates that are close relatives of Tetrahymena, Colpidium campylum, Colpidium colpoda and Glaucoma chattoni, were selected. All tetrahymenines of unproblematic species could be identified to the species level using 689 bp of the cox1 sequence, with about 11 % interspecific sequence divergence. Intraspecific isolates of Tetrahymena borealis, Tetrahymena lwoffi, Tetrahymena patula and Tetrahymena thermophila could be identified by their cox1 sequences, showing <0.65 % intraspecific sequence divergence. In addition, isolates of these species were clustered together on a cox1 neighbour-joining (NJ) tree. However, strains identified as Tetrahymena pyriformis and Tetrahymena tropicalis showed high intraspecific sequence divergence values of 5.01 and 9.07 %, respectively, and did not cluster together on a cox1 NJ tree. This may indicate the presence of cryptic species. The mean interspecific sequence divergence of Tetrahymena was about 11 times greater than the mean intraspecific sequence divergence, and this increased to 58 times when all isolates of species with high intraspecific sequence divergence were excluded. This result is similar to DNA barcoding studies on animals, indicating that congeneric sequence divergences are an order of magnitude greater than conspecific sequence divergences. Our analysis also demonstrated low sequence divergences of <1.0 % between some isolates of T. pyriformis and Tetrahymena setosa on the one hand and some isolates of Tetrahymena furgasoni and T. lwoffi on the other, suggesting that the latter species in each pair is a junior synonym of the former. Overall, our study demonstrates the feasibility of using the mitochondrial cox1 gene as a taxonomic marker for ‘barcoding’ and identifying Tetrahymena species and some other ciliated protists.

scholarly journals Stability of a micro-tidal inlet using semi-numerical approach

2017 ◽  
Vol 8 (3) ◽  
pp. 113-125
Author(s):  
R Senthilkumar ◽  
K Murali ◽  
V Sundar
Keyword(s):  
East Coast ◽  
Wave Model ◽  
Numerical Approach ◽  
Wave Climate ◽  
Tidal Range ◽  
Tidal Inlets ◽  
Littoral Drift ◽  
East Coast Of India ◽  
Longshore Sediment Transport ◽  
The Stability

Tidal inlets get disconnected depending on the seasons due to the formation of sand bars near its mouth are termed as “seasonally open tidal inlets.” These inlets are usually small of width of about 100 m and occur in micro-tide (tidal range not exceeding 1 m). Since the east coast of India experiences a net littoral drift of up to about 0.8 Mm3/annum, which is one of the largest in magnitudes that needs to be considered in the analysis of modeling of the sand bar formation and the associated phenomena. Kondurpalem inlet situated along the South east coast of India is considered as a case study. A frequency domain wave model (STeady-state spectral WAVE) has been used to compute the nearshore wave climate. The wave-induced currents have been obtained, and the longshore sediment transport rate is obtained through empirical relations. The tidal prism is found from measured depth and tidal velocity by solving shallow water equations. The stability of the inlet is investigated by applying the criteria developed by Bruun (1986). The effect of a pair of training walls on maintaining the stability of the mouth is reassessed over the periods.

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