Andaman Coast Research Articles

Shoreline and land use–land cover changes along the 2004-tsunami-affected South Andaman coast: understanding changing hazard susceptibility

Abstract. The 2004 tsunami affected the South Andaman coast, causing it to experience dynamic changes in the coastal geomorphology and making the region vulnerable. We focus on pre-and post-tsunami shoreline and land use–land cover changes from 2004, 2005, and 2022 to analyze the dynamic change in hazard. We used General Bathymetric Chart of the Ocean (GEBCO) data to calculate run-up [m], arrival times [min], and inundation [m] at a few locations using three tsunamigenic earthquake source parameters, namely the 2004 Sumatra, 1941 North Andaman, and 1881 Car Nicobar earthquakes. The Digital Shoreline Analysis System is used for the shoreline change estimates. Landsat data are used to calculate shoreline and land use–land cover (LULC) change in five classes, namely built-up areas, forests, inundation areas, croplands, and water bodies during the above period. We examine the correlation between the LULC changes and the dynamic change in shoreline due to population flux, infrastructural growth, and gross state domestic product growth. The Indian industry estimates the Andaman and Nicobar Islands losses exceeded INR 10 billion during 2004, which would today see a 5-fold increase in economic loss due to a doubling of built-up area, a 3-fold increase in tourist inflow, and population density growth. The unsustainable decline in the forest cover, mangroves, and cropland would affect sustainability during a disaster despite coastal safety measures.

Insights into the physiology, biochemistry and ecological significance of the red seaweed Tricleocarpa fragilis in the Andaman Sea

The present study focused on the physiological and biochemical aspects of Tricleocarpa fragilis, red seaweed belonging to the phylum Rhodophyta, along the South Andaman coast, with particular attention given to its symbiotic relationships with associated flora and fauna. The physicochemical parameters of the seawater at the sampling station, such as its temperature, pH, and salinity, were meticulously analyzed to determine the optimal harvesting period for T. fragilis. Seaweeds attach to rocks, dead corals, and shells in shallow areas exposed to moderate wave action because of its habitat preferences. Temporal variations in biomass production were estimated, revealing the highest peak in March, which was correlated with optimal seawater conditions, including a temperature of 34 ± 1.1 °C, a pH of 8 ± 0.1, and a salinity of 32 ± 0.8 psu. GC‒MS analysis revealed n-hexadecanoic acid as the dominant compound among the 36 peaks, with major bioactive compounds identified as fatty acids, diterpenes, phenolic compounds, and hydrocarbons. This research not only enhances our understanding of ecological dynamics but also provides valuable insights into the intricate biochemical processes of T. fragilis. The established antimicrobial potential and characterization of bioactive compounds from T. fragilis lay a foundation for possible applications in the pharmaceutical industry and other industries.

Nutritional and bioactive compound analysis of mangosteen fruit in hill and flat land plantations, during both the season and off-season, in provinces along the Gulf of Thailand and the Andaman Sea

This study examined the nutritional, physicochemical, and bioactive compounds in mangosteen grown in southern Thailand from 2022 to 2024, encompassing hilly areas (Nakhon Si Thammarat range, Tenasserim range) and flat lands during both the fruit season and off-season. The influence of coastal regions (Gulf of Thailand and Andaman coast) on mangosteen nutrition was explored. The impact of high-level plantation and harvesting (during the fruit season) on mangosteen size and levels of bioactive compounds with high antioxidant capacity in mangosteen flesh was found to be greater than that of flat plantations (during the off-season). Mangosteens grown in flatlands during the fruit season exhibited brighter flesh color and faster ripening compared to those grown in hilly areas. Mangosteens from these results contained carbohydrates ranging from 10.3% to 16.9%. Mangosteens cultivated along the Andaman coast exhibited elevated levels of minerals (K 349 mg/100 g, Na 7.76 mg/100 g, and Mn 1.63 mg/100 g) and vitamins, especially B2 (0.10 mg/kg), B6 (0.20 mg/kg), B12 (0.03 mg/kg), and vitamin C (9.25 mg/kg). Conversely, the highest total phenolic content, flavonoids, and antioxidant activity were observed in hilly areas during the fruit season along the Gulf of Thailand (55 mg GAE/100 g, 32 mg QE/100 g, and ABTS values of 88%, respectively). However, mangosteens from hilly areas ripened faster than those from flatlands due to higher total soluble solids and lower fruit firmness. These findings provide valuable insights into the effects of the environment and location, enhancing understanding for year-round mangosteen plantation preparation.

Hydrogeochemical characterization and water quality evaluation for drinking and irrigation purposes of coastal aquifers of Middle Andaman

A comprehensive study to characterize the hydrogeochemistry of the region and the impact of saltwater intrusion on groundwater was conducted along the eastern coast of Middle Andaman of Andaman and Nicobar (A&N) Islands. The escalating population growth and intensified tourism activities have resulted in the over-extraction of groundwater. Seismic activities led to the opening of lineaments to the sea and the dissolution of limestone in the influence of seawater. 24 groundwater samples and 1 reference sample from sea were taken from various locations of middle Andaman. The analysis involved the determination of major cations, anions, and heavy metals using Inductively Coupled Plasma Optical Emission spectroscopy (ICP), spectrophotometry, and flame photometry. Furthermore, X-ray diffraction analysis, binary diagrams, Chloro-alkaline indices (CAI), Gibbs Plot, correlation matrix, Piper plot, Chadha’s plot and Principal Component Analysis (PCA) to the major ions data indicated rock-water interactions, strong correlations among alkali and alkaline earth metals, and interactions between seawater and carbonate minerals respectively. The water quality index indicated “very poor to unsuitable for drinking purposes” in 24% of the samples. Additionally, indices for irrigation suitability; total hardness (TH), residual sodium carbonate (RSC), and Magnesium adsorption ratio (MAR) were found to be detrimental for irrigation in 80%, 08%, and 12% of the water samples, respectively. These results highlight the importance of implementing effective water resource management techniques, such as groundwater extraction rates, adopting appropriate water treatment technologies to mitigate the adverse impacts of heavy metals, saltwater intrusion and maintain water quality for human consumption and agricultural use in the region.

Impact of bathymetry on Indian Ocean circulation in a nested regional ocean model

The Regional Indian Ocean model based on Modular Ocean Model (MOM4p1) was used to understand the importance of a realistic representation of bathymetry on Ocean General Circulation. The model has 1/4° uniform horizontal resolution and is forced with Coordinated Ocean-Ice Reference Experiments (CORE-II) inter-annual forcing with two simulations named BLND (realistic bathymetry) and OM3 (smoothed bathymetry), which only differ in the representation of bathymetry for the years 1992–2005. We also used recent reanalysis products from ORAS5 and SODA3 and ADCP observation to compare the subsurface currents. We show that by the inclusion of realistic bathymetry, there is a significant improvement in the upper ocean salinity, temperature, and currents, particularly near the coast. The salinity and temperature of the upper ocean are very close to the observed value near the coast. The bias in the salinity and temperature was reduced to half in BLND simulation compared to OM3, which led to a more realistic East India Coastal Current (EICC). We show the first evidence of a basin-wide cyclonic gyre over the Bay of Bengal at 1000 m depth during spring, which is just opposite to that of a basin-wide anti-cyclonic gyre at the surface. We found the presence of poleward EICC during spring at 1000 m and 2000 m depth, which is opposite to that of the surface. The presence of this deeper EICC structure is completely absent during fall. We show the presence of a boundary current along the coast of Andaman and Nicobar Island at a depth of 2000 m. The observed Wyrtki Jet (WJ) magnitude and spatial structure are most realistically reproduced in BLND simulation as compared to OM3 simulations. Both ORAS5 and SODA reanalysis products underestimate the WJ magnitude. The presence of the Maldives Islands is responsible for the westward extent of Equatorial Under Current (EUC). The presence of Maldives also creates wakes on the leeward side in the EUC zonal current. During fall, EUC is better defined in the eastern Equatorial Indian Ocean and lies at a depth of between 50 and 100 m, unlike its spring counterpart, in which its core is located slightly deeper, between 100 and 150 m depth. During peak summer months, June–July, a strong eastward zonal jet is present at 1000 m depth, similar to Wyrtki Jet (WJ). Inter-monsoon Jets, i.e., spring and fall jets, are also seen but are in the opposite direction, i.e., westward, unlike eastward in WJ.

Characterization of internal solitary waves in the Andaman Sea and Arabian Sea using EOS-04 and sentinel observations

ABSTRACT In this study, we synergistically used Synthetic Aperture Radar (SAR) and optical observations to characterize the Internal Solitary Waves (ISW) in the Andaman Sea and Arabian Sea region. Total 25 scenes combined from EOS-04, Sentinel-1&2 satellites are considered for the year 2022. Various approaches, including Fast Fourier Transform (FFT), Multiple Image Comparison (MIC), Tidal Time Period (TTP) and Korteweg-de Vries (KdV) equations, were employed to characterize the ISW, and its spatial and seasonal variations are also analysed. The dominant wavelength of ISW over the Andaman Sea in June 2022 is found to be 6500 m travelling towards the Andaman coast. The overall phase speed of ISW in the Andaman Sea lies in the range of 1.87–2.60 ms−1. It shows a seasonal variation of around 16% between winter and summer months, where a significant variation in the seasonal mixed layer depth was noticed. The phase speed also decreased as the ISW travelled from deep water to shallower regions. In contrast, the dominant wavelength of ISW in the continental shelf region of the west coast of India (near Goa) was much smaller (~400 m) compared to the Andaman Sea. Here, the ISW phase speed estimated using MIC and TTP methods was ~ 0.56 ms−1 in February 2022. The KdV equation yielded lower estimates of phase speed compared to the other two methods. The use of multiple satellite images and various approaches possess an advantage in comprehending the spatial and temporal variations in the characteristic features of ISW.

Cassidinidea andamanensis sp. nov., a new species of intertidal Sphaeromatidae (Crustacea: Isopoda) from the Andaman Islands, northern Indian Ocean.

Cassidinidea andamanensis sp. nov. was collected from intertidal habitats on the coast of South Andaman, Andaman Islands, India and is described and illustrated in detail. Cassidinidea andamanensis sp. nov. the second definitive record of the genus from India, is characterized by: smooth body surface, prominently convex epistome anterior margin, pleotelson dorsal smooth surface and the posterior margin is subtruncate and weakly convex with small setae, the appendix masculina posterior margin is narrowly rounded.

Assessing effects of landscape modifications and identifying priority areas for two Asian otters in coastal wetlands

Conserving species inhabiting areas overlapped with human settlements is more challenging than usual as anthropogenic impacts need to be accounted for when management plans are formulated. This study aims to identify conservation priority areas for two otter species and evaluate the impact of land-use changes on conservation management in the coastal wetlands of southern Thailand. We conducted camera-trap surveys across 283 grids of 25 km2 each between 2016 and 2020. A single-species occupancy model was applied to estimate the occupancy probability of two otter species in relation to landscape characteristics and human factors. Occupancy probabilities were then correlated with anthropogenic threat levels obtained from Bayesian Belief Network to identify conservation management hotspots and conservation importance areas under various scenarios. The Smooth-coated Otter shows a higher occupancy probability in the Andaman, where a larger proportion of less disturbed wetlands remains compared to the Gulf. The Small-clawed Otter, in contrast, has higher occupancy in the Gulf. In the Andaman, the Smooth-coated Otter appears to occupy areas associated with lower human impacts and a higher proportion of natural habitats, while in the Gulf, both otter species have higher occupancy in areas where modifications of natural habitats are more intensive. In total, 1350 km2 were identified as very high conservation management hotspots, with an additional 750 km2 identified as very high conservation importance. The majority of these areas were located along the Andaman coast. However, land-use changes expanded the management hotspot areas to 2025 km2 while reducing conservation importance areas to just 175 km2. Our results emphasize the importance of protecting natural habitats and the urgency of implementing management interventions for otters on the Andaman coast, for the long-term survival of these threatened species.

National assessment and variability of blue carbon in seagrass ecosystems in Thailand

Seagrass ecosystems are important organic carbon (Corg) sinks with great potential to contribute to climate change mitigation strategies. However, the high spatial and temporal variability is a barrier to the accurate assessment of national Corg stocks. This study provides a national assessment of Corg within seagrass meadows, including spatial and temporal variations. The highest Corg stocks were within mangrove-associated (44.3 ± 8.27 Mg ha−1), while near-surface sediments were highest in reef-associated meadows (10.20 ± 3.69 Mg ha−1). Regionally, the highest stocks were in the Upper Andaman coast in monospecific meadows (51.7 ± 7.14 Mg ha−1). Corg stocks in near-surface sediments were significantly different across historical trends (p < 0.001), with the highest stocks in stable meadows (9.28 ± 3.39 Mg ha−1). The national Corg stock within seagrass meadows sediment was 40.45 ± 11.59 Mg C ha−1. The results of this study highlighted the complexity of blue carbon in seagrass meadows and the associated impacts on national Corg assessments, carbon accounting, and conservation strategies.

A multi-proxy reconstruction of the late Holocene vegetation dynamics in Krabi mangroves, Thailand Andaman Sea

Pollen, charcoal, loss on ignition, geochemistry, and geophysical analyses were used to reveal the palaeoenvironment, vegetation, and sedimentary dynamics of the Krabi mangroves and the Andaman coast during the late Holocene. Two sediment cores, radiocarbon dated to ∼4400 cal BP, were collected from the Nai Nang mangroves in Krabi Province, the Thailand Andaman coast. This analysis documented how the area evolved from a tidal channel to a tidal area dominated by mangrove ecosystems. During the tidal channel phase (∼4400–2700 cal yr BP), the study site was characterized by a high-energy depositional environment, where sediment accumulated along tidal channels. Mangrove development began around 4400 cal yr BP and was influenced by varying contributions from tidal and freshwater inputs. Sea level during this period showed a slight rise until ∼4200 cal yr BP, followed by a subsequent fall. From ∼2700 to 1050 cal yr BP, the tidal channel was filled with finer sediments, forming intertidal flats that supported mangroves, back mangroves, and freshwater forest taxa, indicating a transition to mixed coastal vegetation. Sea levels remained relatively low during this period. From around 1050 cal yr BP to the present, mangroves replaced the previous mixed coastal vegetation, most likely driven by rising sea levels, particularly during the last 200 years. The observed sedimentation rates indicate that mangroves in Krabi will need to undergo continued future landward migration to adapt to changing coastal conditions, given the current and projected global sea-level rise.

Antibacterial and Anti-HIV Metabolites from Marine Streptomyces albus MAB56 Isolated from Andaman and Nicobar Islands, India.

Marine-derived actinobacteria have tremendous potential to produce novel metabolites with diverse biological activities. The Andaman coast of India has a lot of microbial diversity, but it is still a relatively unknown ecology for isolating novel actinobacteria with beneficial bioactive compounds. We have isolated 568 actinobacterial strains from mangrove rhizosphere sediments and sponge samples. Crude extracts from 75 distinct strains were produced by agar surface fermentation and extracted using ethyl acetate. In the disc diffusion method, 25 actinobacterial strains showed antimicrobial activity; notably, the strain MAB56 demonstrated promising broad-spectrum activity. Strain MAB56 was identified as Streptomyces albus by cultural, microscopic, and molecular methods. Conditions for bioactive metabolites from MAB56 were optimized and produced in a lab-scale fermenter. Three active metabolites (C1, C2, and C3) that showed promising broad-spectrum antimicrobial activity were isolated through HPLC-based purification. Based on the UV, FT-IR, NMR, and LC-MS analysis, the chemical nature of the active compounds was confirmed as 12-methyltetradecanoic acid (C1), palmitic acid (C2), and tridecanoic acid (C3) with molecular formulae C14H28O2, C16H32O2, and C13H26O2, respectively. Interestingly, palmitic acid (C2) also exhibited anti-HIV activity with an IC50 value of < 1µg/ml. Our findings reveal that the actinobacteria from the Andaman marine ecosystems are promising for isolating anti-infective metabolites.

Stakeholder perceptions on Community‐Based Ecological Mangrove Restoration (CBEMR): a case study in Thailand

Mangroves are a unique ecosystem that provides various benefits to people. In Thailand, Mangrove Action Project (MAP) has introduced Community‐Based Ecological Mangrove Restoration (CBEMR), a novel technique to restore degraded mangroves. Unlike conventional tree planting, CBEMR does not require a planting phase. It emphasizes preproject assessments of mangrove ecology and hydrology to facilitate natural regeneration. Therefore, this study aims to (1) investigate the perception of stakeholders on the value of mangroves; (2) examine the understanding of stakeholders on conventional mangrove planting and CBEMR as mangrove restoration techniques; (3) understand the challenges and motivations of the CBEMR efforts in the Andaman Coast of Southern Thailand. We use Q Methodology, a semi‐quantitative method that requires participants to rank a set of statements to analyze their perceptions according to the research questions. As a result, we can identify three clusters of perceptions; D1 demands more CBEMR and less conventional planting. D2 believes mangrove planting is good, given suitable conditions. D3 thinks restoring mangroves brings benefits, but most conventional planting often fails. This study highlighted that all CBEMR stakeholders believe inadequate technical knowledge is the root cause of mismatch restoration practices. Mangrove planting should be done with suitable species, conditions, and areas. Conventional planting of mangroves without considering ecological factors and local engagement should be avoided as it fails to achieve sustainable outcomes. Enhancing knowledge of mangrove ecology and restoration techniques is therefore a sustainable route to the long‐term success of mangrove restoration in Thailand.

The influence of key success factors on business growth for tourism business along Thailand’s Andaman coast: moderating role of location

Purpose – This research aimed to examine the influences of key success factors on business growth. Additionally, it aimed to examine the moderating role of the location of the tourism enterprise. Design – Multiple regression was used and a variable selection tool was employed to test a statistical model both for the aggregate and in the context of individual provinces. Methodology – Quantitative research methods were used in this research. Approach – The convenience sampling method was used. Data was collected from fourhundred and nineteen tourism enterprises along the Andaman Coast in Thailand using online and in-person questionnaires. Findings – The results showed a positive influence of some dimensions of key success factors on business growth during the pandemic crisis COVID -19. In addition, the results showed that business location played a positive moderating role. Originality of the research – Key success factors are important concepts for business models to improve and increase the growth of a company. However, there are few studies that attempt to find out the key success factors in the context of tourism businesses that have been significantly affected by the COVID -19 pandemic. Therefore, this research aims to fill a gap in academic and practical discussions and implications.

COMMUNITY BASED-TOURISM (CBT) MANAGEMENT DURING THE CORONAVIRUS PANDEMIC ALONG THE ANDAMAN COAST OF THAILAND

Community-based tourism (CBT) have been challenged in the Coronavirus 2019 era. This qualitative research aims to explain the CBT management during the Coronavirus 2019 pandemic in five communities of five provinces along the Andaman coast of Thailand. The data were collected via online in-depth interviews and online focus group discussions, from totally 10 key informants of CBT entrepreneurs (two from each province/community). The data were analyzed by using content analysis. The results revealed that the CBT management during the Coronavirus 2019 pandemic was based on the communities’ cultural and natural resources. The tourism operation was focused on building confidence and safety for tourists.

Community-Based Tourism Management during the Coronavirus Pandemic along the Andaman Coast of Thailand

The spread of the coronavirus pandemic from the end of 2019 until the present has drastically changed the trends in the tourism service industry around the world, also in community-based tourism in Thailand. This qualitative research article aimed to explain community-based tourism management during the coronavirus pandemic and includes multiple case studies in five communities of five provinces (Phangnga, Phuket, Krabi, Trang, and Satun provinces) along the Andaman coast of Thailand, which creates an understanding of the characteristics of community-based tourism management for application in specific situations. The data were collected from January to March 2022 via online in-depth interviews and online focus group discussions, with ten key informants and community-based tourism entrepreneurs (two representatives from each). Then, the data were verified using triangulation and analyzed by using content analysis. The results revealed that the community-based tourism management in the Andaman coastal area of Thailand was based on the communities’ cultural and natural resources. The tourism operation during the coronavirus 2019 pandemic was focused on building confidence and safety for tourists, namely: 1) characteristics of vaccinated tourists entering the communities and preferred quality tourists; 2) communities’ readiness for receiving tourists — service staff was regularly checked for coronavirus, renovations were done, and tourism activities were designed to be appropriate in a pandemic situation; 3) public relations and communication of the communities’ good image were pursued; 4) community development sought to achieve the standard of the Thailand Safety and Health Administration; 5) a surveillance system was established to monitor community situations. However, recommendations based on this research are that the government should support community-based tourism operations through tax measures, financial projects allocated to the communities, and technology to promote tourism on various platforms. Results from this research can be applied to community-based tourism entrepreneurs, especially in other areas of Thailand.

Spatial Planning and Systems Thinking Tools for Climate Risk Reduction: A Case Study of the Andaman Coast, Thailand

The impact of climate change and related hazards such as floods, heatwaves, and sea level rise on human lives, cities, and their hinterlands depends not only on the nature of the hazard, but also on urban development, adaptation, and other socioeconomic processes that determine vulnerability and exposure. Spatial planning can reduce climate risk not just by influencing the exposure, but also by addressing social vulnerability. This requires that relevant information is available to planners and that plans are implemented and coordinated between sectors. This article is based on a research project in Thailand, particularly on the results of multi-sectoral workshops in the case study region of the Andaman Coast in southern Thailand, and draws upon climate risk, spatial planning, and systems thinking discourses. The article formulates recommendations for planning in the context of Thailand that are relevant for other rapidly growing and urbanizing regions. Among other conclusions, it suggests that systems thinking approaches and cross-sectoral strategies are ways to grasp the interdependencies between and within climate risk and spatial development challenges.

Gracilaria khanjanapajiae sp. nov. (Gracilariales, Rhodophyta) from the Andaman coast of Thailand

ABSTRACT Taxonomy and diversity of the Gracilariaceae has been increasingly investigated by using integrated morphological and genetic approaches. The Indo-Pacific is likely a hotspot for diversity of these macroalgae. Collections of flattened Gracilaria samples from Natai beach, Andaman coast of Thailand, were morphologically and genetically analysed. Our results clearly indicated the presence of a new species, G. khanjanapajiae sp. nov., in Thailand. In comparison to other known Indo-Pacific flattened species, G. khanjanapajiae can be distinguished by its dentate blade margin, deep spermatangial conceptacles (verrucosa-type) and numerous lateral and basal nutritive filaments within mature cystocarps. This new species resembles G. srilankia in having similar branching pattern and male reproductive structures, but differs in blade margin features. Phylogenetically, G. khanjanapajiae was more closely related to G. spinulosa from Taiwan than other Thai and Indian Ocean species. This present study highlights the continuing discovery of Gracilaria diversity and distribution in the tropical Indo-Pacific.

Antibacterial activity of the released metabolites of sea anemone Stichodactyla gigantea (Forskal, 1775) from the coast of South Andaman, India

Marine sessile organisms produce unique bioactive metabolites, which render a defensive barrier against microbial threats and increase survivability in the middle of predators. The earlier studies focused on isolated metabolites from marine sources, composed to exhibit antibacterial, antiviral, and cytotoxic properties. The present study aims to evaluate the antibacterial property of the anemone-released metabolites. The crude and released mucoid metabolite obtained from the sea anemone Stichodactyla gigantea (Forskal, 1775) assayed against five human pathogens like Bacillus subtilis (MTCC 121), Listeria monocytogenes (MTCC 839), Staphylococcus aureus (MTCC839), Bacillus cereus (MTCC 443), and Salmonella enterica typhimurium (MTCC 1252). The assay exhibited positive activity against two pathogens, viz. B. subtilis (MTCC 121) and L. monocytogenes (MTCC 839). Based on the demonstrated activity, the released metabolites were purified using Open Column chromatography. The fractions collected were subjected to an antibacterial assay, which showed a high inhibition zone of 39 mm and 23 mm in diameter against B. subtilis and L. monocytogenes. Followingly, the characterization of purified fractions through GC-MS analysis confirmed the presence of 22 compounds. This study reveals the potential power of the released mucoid metabolites against antibiotic-resistive pathogens. Further studies are essential to elucidate the role of endosymbiont's contribution to mucoid production and their responsiveness towards tackling stressed conditions.

Mesoscale/Microscale and CFD Modeling for Wind Resource Assessment: Application to the Andaman Coast of Southern Thailand

Situated in the southern part and on the western coast of Thailand, the Andaman Coast covers the provinces of Ranong, Phangnga, Phuket, Krabi, Trang and Satun. Using a coupled mesoscale atmospheric model and a microscale wind flow model, along with computational fluid dynamics (CFD) modeling, this paper presents a detailed assessment of the wind energy potential for power generation along the Andaman Coast of Thailand. The climatic data are obtained from the Modern Era Retrospective analysis for Research and Applications (MERRA), along with a high-resolution topography database and Land Use Land Cover digital data. The results are compared to the equivalent wind speeds obtained with the Weather Research and Forecasting (WRF) atmospheric model. The results showed that, at 120 m above ground level (agl), the predicted wind speeds from the models proposed were 20% lower for the mesoscale model and 10% lower for the microscale model when compared to the equivalent wind speeds obtained from the WRF model. A CFD wind flow model was then used to investigate 3D wind fields at 120–125 m agl over five potential sites offering promising wind resources. The annual energy productions (AEP) and the capacity factors under three different wake loss models and for five wind turbine generator technologies were optimized for 10-MW wind power plants, as per Thailand’s energy policies. With capacity factors ranging from 20 to 40%, it was found that the AEPs of the best sites were in the range of 18–36 GWh/year, with a total AEP in the vicinity of 135 GWh/year when using a single wind turbine model for the five sites studied. The combined energy productions by these wind power plants, once operational, could avoid GHG emissions of more than 80 ktons of CO2eq/year.

Biogeography and Biodiversity of the Intertidal Barnacle Tetraclita Species in the Gulf of Thailand and Andaman Sea – Influences of Oceanographic Currents and Pleistocene Glaciations

The present study investigated the phylogeography of the intertidal barnacle Tetraclita in the Gulf of Thailand ecoregion (Sunda Shelf Province in the Pacific) and the Andaman Sea Coral Coast ecoregion (Andaman Province in the Indian Ocean) in Thailand’s waters. Tetraclita species were identified by a combined morphological and molecular approach using mitochondrial gene fragments (CO1 and 12S rRNA). Tetraclita singaporensis is a major occupiers on the Andaman coast but is sparse in the western Gulf of Thailand. Tetraclita squamosa inhabits almost all of our collection sites in the Gulf of Thailand but has a very low abundance in the Andaman Sea. Tetraclita kuroshioensis has two genetically distinct populations, one in the Andaman Sea and the other in the West Pacific region. S-DIVA analysis showed that the most recent common ancestor (MRCA) of T. kuroshioensis was distributed in both the Andaman Sea and West Pacific region, with a relative probability of 63%; the analysis further identified two molecular subclades, one on each side of the Sunda Shelf by vicariance about 0.53 million years ago, far before the Last Glacial Maximum (LGM). The MRCA of T. squamosa was based in the West Pacific region (relative probability: 90%), and dispersed into the Andaman Sea after the LGM. The MRCA of T. singaporensis was in the Andaman Sea (relative probability: 89.5%) and dispersed into the Gulf of Thailand via monsoonal currents through the Malacca Strait after the LGM. Presently, T. singaporensis is absent from the West Pacific region, further supporting its origin in the Andaman Sea. The distribution of intertidal barnacles in the Sunda Shelf and Andaman provinces is a result of the interplay between geological events and present day oceanographic currents.