Nicobar Islands Research Articles

A New Variety of <i>Jasminum multiflorum</i> (Burm. f.) Andr. from the Nicobar Islands

Jasminum multiflorum (Burm. f.) Andr. var. nicobarium Thoth. var. nov., collected from the Car Nicobar Island is described.

Internal solitary waves in the central Andaman sea observed by combining mooring data and satellite remote sensing

The behavioral characteristics of internal solitary waves (ISWs) in the central Andaman Sea were revealed by analyzing multisource satellite remote sensing images combined with synchronous mooring data. The relationship between the generation time and tides of ISWs in the central Andaman Sea was analyzed and discussed. The ISWs in the central Andaman Sea exhibit a notable semidiurnal tidal cycle, primarily occurring during the spring tide. Additionally, it was observed that larger currents can generate ISWs with larger amplitudes. The propagation velocity of the ISWs initially increases and then decreases from the source, with no significant overall change in the deep areas. Based on the analysis of satellite remote sensing images that cover the source of ISWs in the central Andaman Sea, the generation time of ISWs was estimated. A comparison was made between the estimated generation time and the tidal flow predicted from the TPXO 9 global tidal model at the location of the ISW source. It was found that ISWs are generated when the westward tidal flow reaches its maximum. The ISWs in the central Andaman Sea are generated between the islands of Car Nicobar and Teresa Island. They propagate eastward into the Andaman Sea, grow in amplitude, split into multiple waves, dissipate, and vanish in the waters near the Danao Islands. The entire life cycle of these waves lasts for approximately 3∼4 days.

SDUST2020MGCR: a global marine gravity change rate model determined from multi-satellite altimeter data

Abstract. Investigating the global time-varying gravity field mainly depends on GRACE/GRACE-FO gravity data. However, satellite gravity data exhibit low spatial resolution and signal distortion. Satellite altimetry is an important technique for observing the global ocean and provides many consecutive years of data, which enables the study of high-resolution marine gravity variations. This study aims to construct a high-resolution marine gravity change rate (MGCR) model using multi-satellite altimetry data. Initially, multi-satellite altimetry data and ocean temperature–salinity data from 1993 to 2019 are utilized to estimate the altimetry sea level change rate (SLCR) and steric SLCR, respectively. Subsequently, the mass-term SLCR is calculated. Finally, based on the mass-term SLCR, the global MGCR model on 5′ × 5′ grids (SDUST2020MGCR) is constructed by applying the spherical harmonic function method and mass load theory. Comparisons and analyses are conducted between SDUST2020MGCR and GRACE2020MGCR resolved from GRACE/GRACE-FO gravity data. The spatial distribution characteristics of SDUST2020MGCR and GRACE2020MGCR are similar in the sea areas where gravity changes significantly, such as the eastern seas of Japan, the western seas of the Nicobar Islands, and the southern seas of Greenland. The statistical mean values of SDUST2020MGCR and GRACE2020MGCR in global and local oceans are all positive, indicating that MGCR is rising. Nonetheless, differences in spatial distribution and statistical results exist between SDUST2020MGCR and GRACE2020MGCR, primarily attributable to spatial resolution disparities among altimetry data, ocean temperature–salinity data, and GRACE/GRACE-FO data. Compared with GRACE2020MGCR, SDUST2020MGCR has higher spatial resolution and excludes stripe noise and leakage errors. The high-resolution MGCR model constructed using altimetry data can reflect the long-term marine gravity change in more detail, which is helpful in studying seawater mass migration and its associated geophysical processes. The SDUST2020MGCR model data are available at https://doi.org/10.5281/zenodo.10701641 (Zhu et al., 2024).

Biodiversity of mosquitoes (Diptera: Culicidae) in phytotelmata from Car Nicobar Island, India.

The Culicidae mosquito family breeds in various natural and artificial water bodies. Phytotelmata are plant structures that hold water and are used by many mosquito species during their life cycle. Mosquitoes are disease vectors, and phytotelmata play an important role in harbouring them. Investigating these phytotelmata will facilitate to develop appropriate site specific vector control strategy. Approximately 750 phytotelmata in 16 locations on Car Nicobar Island was examined. Mosquito larvae were collected from different habitats such as tree holes, root holes, leaf axils, and bamboo stumps. On average, the number of larvae per 10 ml of water ranged from 0.003 to 3.833. Among the 16 mosquito species identified, there were vectors of malaria (Anopheles sundaicus), dengue (Aedes aegypti and Aedes albopictus) and filariasis (Culex quinquefasciatus), belonging to seven genera. The most common phytotelmata were coconut trees (17.5%) followed by Java apple trees (10.3%) and bamboo stumps (7.1%). The most widespread mosquito species was Aedes edwardsi, followed by Aedes malayensis and Ae. albopictus, and the per cent of phytotelmata that contained these species were 42.6, 22.0, and 16.8% respectively. Anopheles mosquitoes had the highest container index (6.1%) in root holes, while Aedes and Culex mosquitoes were more frequently found in bamboo stumps. The alpha biodiversity indices indicated that the mosquito population in Car Nicobar Island was highly diverse (S = 16; DMg = 36.9). Tree holes showed the highest diversity, as all 16 species were collected from them. Assessment of phytotelmata, there is a significant relationship observed between mosquito genus, village, habitat, and tree families, on the remote island of Car Nicobar. Considering the presence of disease-transmitting mosquito vectors in the phytotelmata, these habitats should be considered when implementing control measures to eliminate mosquito-borne infections.

HYPTISCAPITATA JACQ. (HYPTIDINAE: LAMIACEAE) NEW RECORD FOR FLORA OF MAHARASHTRA, INDIA

Hyptis capitata Jacq. reported here first time from the Southern Konkan region of Maharashtra. Previously, this species was recorded from Andaman and Nicobar Island, Kerala, Tripura, West Bengal and Goa. In the present article brief description, photographs, and relevant notes are provided to facilitate its easy identification.

Burden of hypertension and associated risk factors among the Nicobarese tribe of Car Nicobar Island, India

Background: Hypertension, a significant risk factor for various non-communicable diseases, poses a preventable threat to mortality and disease burden. However, there remains a lack of data on hypertension within Indian tribes, particularly those residing in impoverished areas. Determining the prevalence of hypertension and identifying associated risk factors among the Nicobarese tribes. A cross-sectional survey was conducted, involving 2600 tribal individuals aged 18 years and above from ten randomly selected villages on Car Nicobar Island. Methods: A structured questionnaire was utilized to gather data on blood pressure (BP), anthropometric measurements, and detailed participant characteristics. Prevalence of hypertension was determined and analyzed in relation to various identified risk factors using chi-square, Karl Pearson coefficient of correlation, and generalized linear models. Prevalence ratio and adjusted risk ratio calculated, along with their corresponding confidence intervals. Results: Prevalence of hypertension was 57.9%. Several factors, including age, male gender, illiteracy, diabetes, smoking, alcohol consumption, and higher body mass index (BMI), were significantly associated with hypertension. Systolic and diastolic BP levels increased significantly with age, socio-economic scores, BMI, and weight. Conclusions: The prevalence of hypertension among the Nicobarese tribes is significantly higher compared to the general population. Adapting preventive strategies based on an understanding of the tribe's specific culture and lifestyle is important for controlling hypertension. However, it is also crucial to consider genetic and environmental influences that may contribute to the high prevalence of hypertension in this tribe.

Human decomposition in the unique context of the Andaman and Nicobar Islands (India): a comparative analysis with reference data

ABSTRACT The understanding of the victim’s decomposition process is crucial in forensic science for establishing accurate time since death, and the overall timelines of criminal investigations. Global research, which primarily relies on non-human animal proxies, highlights a scarcity of facilities using human bodies and a lack of baseline data for some regions and remote locations. In cases such as the Andaman and Nicobar (A&N) Islands (India), forensic practitioners turn to literature-derived patterns developed at the closest locations (mostly mainland India). This study examines 51 human decomposition cases investigated in A&N in comparison with the existing literature, emphasizing distinctions and similarities in their decomposition relative to the current Indian literature. This study advocates for further research and potentially calls for the establishment of the first anthropology research facility in the Indo-Pacific region, encouraging the development of tailored methodologies for more accurate estimations in diverse environments.

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.

New distribution record of Alstonia sebusii (Van Heurck & Müll. Arg.) Monach. from Manipur, India

The genus Alstonia belonging to the Apocyanaceae family is represented by 44 species distributed worldwide. In India, the taxon is represented by eight species, reported from Andaman & Nicobar Islands, Western Ghats, Eastern Ghats, western Himalaya, and northeastern regions. The present study reported the occurrence of Alstonia sebusii from Pudunamei village, Mao, a new addition to the flora of Manipur. Detailed morphological descriptions and measurements were recorded based on living plant specimens. The plant is locally called ‘Topfiira Koso Pro’ having ethno-medicinal properties and widely been used by local people of the state to treat various ailments. The plant is rare and found to occur at specific location at Pudunamei village.

Children under attack: trends and patterns of sexual offences against children in India

Introduction: Recently, the United Nations declared November 18 as the World Day for the Prevention of and Healing from Child Sexual Exploitation, Abuse, and Violence. Despite sexua l offences against children being frequently reported in Indian media, scientific studies analysing the annual trends and re gional patterns of these crimes are scarce in India. Objectives: To describe annual trends and regional patterns of sexual crimes against children (CAC) in India Methods: National Crimes Record Bureau (NCRB) data on sexual c rimes for years 2014-2021 were analysed to describe annual trends and regional patterns of sexual offences against childr en in India. Results: An incremental trend in sexual offences was reported dur ing the 2014-2021 period. Sexual offences had the highest crime rate in 2021 (12.1%). There was a continuous increase in sexual offences in each succeeding year during the 2014-2021 period. The highest year-over-year increase was reported in 2017 (142%). The proportion of sexual offences in all CAC increased from 10% in 2014 to 36% in 2021. A higher num ber of cases were reported among girls (mean=25112; SD=5371) than boys (mean=241; SD=47). In 2021, Delhi had the highest crime rate for all CAC, while Andaman and Nicobar Islands had the highest crime rate for sexual offences. Conclusions & Recommendations: Despite the legal framework av ailable to protect children, there is still an increase in sexual offences against children in India. Regional patterns suggest a diverse distribution of sexual offences across India. A higher concentration of sexual offences was reported on remote, g eographically smaller Indian islands as well as on the densely populated mainland of India. Interventions aimed at providi ng knowledge about reporting sexual offences, altering community attitudes, and encouraging a safe and healthy childhood a re recommended.

SEATANI: hazards from seamounts in Southeast Asia, Taiwan, and Andaman and Nicobar Islands (eastern India)

Abstract. Submarine volcanism makes up approximately 85 % of volcanism that occurs on Earth, and its eruptions have the potential to cause several hazards including ash dispersal, pumice rafts, pyroclastic density currents, sector collapses, and tsunamis. Recent examples include the eruptions in Japan and in the Kingdom of Tonga in 2021 and 2022 respectively, but there has been little to no study of submarine volcanism in Southeast Asia and surroundings. Here we provide a compilation of 466 seamounts from the region, from different published sources, through the SEATANI dataset (Southeast Asia, Taiwan, and the Andaman and Nicobar Islands). We use this newly compiled dataset to assess on a regional level the seamount hazard potential and exposure potential as a springboard for future more quantitative hazard studies of the region. The hazard potential was assessed through seamount morphological and structural analyses, to determine the seamount evolution stage and grade of maturity. The exposure potential was evaluated with two different approaches: an areal analysis of the number of assets within a 100 km radius of each seamount and the development of a hazard-weighted seamount density map to highlight potential areas of interest for future more-in-depth studies. Our results show that there are several potentially hazardous seamounts in this region. Taiwan has the highest hazard and exposure potential, for all assets considered, while the Philippines, Indonesia, and Vietnam have relatively high exposure potential for submarine communication cables and ship traffic density. The results from this work serve as a first step towards Southeast Asia and neighbouring countries becoming more resilient against and prepared for submarine volcanic eruptions 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.

Perceived Utility of Jan Aushadhi Outlets and Awareness of Generic Medicines at the Andaman and Nicobar Islands: A Cross-Sectional Study.

Despite being the leading exporter of generic medicines to the world, affordable medicines are still beyond the reach of most patients in India.Analysis of the National Sample Survey data showed that in one year, more than 55 million Indians became poor only because they had to spend their own money to purchase medicines. The Jan Aushadhi Scheme launched by the Government of India is an ambitious step to make quality generic drugs affordable to the common man of the country. This study aimed to assess the knowledge, attitude, and perceptions of patients at a tertiary care teaching hospital in the Andaman and Nicobar Islands about Jan Aushadhi Kendras and generic medicines. The study was a questionnaire-based cross-sectional study. A prevalidated self-made questionnaire was distributed to 200 patients visiting the OPD of different clinical departments in the hospital. Participants' knowledge, attitude, and perception of Jan Aushadhi Kendras and generic medicines were evaluated. Analysis of collected data was done using descriptive statistical measures such as mean and percentages. It was found that most of the participants were not fully aware of the Jan Aushadhi Scheme and the facts about generic medicines. The majority of the participants were under the notion that generics were not similar in quality to the branded ones. The study observed that the patients had a very poor understanding of the Jan Aushadhi Scheme and generic medicines with the majority being ignorant and having incorrect information. To fill this gap, a more proactive approach by the healthcare workers and authorities is needed to disseminate the scheme-related facts, dispel the myths regarding generics, and accept the program wholeheartedly by the common man.

New records of soft corals, genus Sarcophyton (Octocorallia: Malacalcyonacea: Sarcophytidae) from the Andaman and Nicobar Islands, India

ABSTRACT This article reports three new records of soft corals, viz. Sarcophyton boletiforme Tixier-Durivault 1958; S. cinereum Tixier-Durivault 1946; and S. turschi Verseveldt 1976, from the Andaman and Nicobar Islands, India. The specimens were collected from coral reef regions, to a depth of 25 m. Species identification involved a detailed analysis of colony morphology, sclerite structures, and measurements taken from various parts of the colony. Sarcophyton boletifome features club-shaped sclerites (up to 0.38 mm) on capitulum and stalk surfaces, and spindle-shaped sclerites (up to 1.10 mm) in the stalk interior; S. cinereum exhibits warty club-shaped sclerites, in the capitulum surface layer (0.17–0.27 mm) and in the base surface layer (0.10–0.55 mm); and stalk interior features curved or straight spindles (up to 1.77 mm). The capitulum of S. turchi bears club-shaped surface sclerites, ranging in size from 0.09 to 0.38 mm, while the stalk interior contains spindle-shaped structures ranging from 0.35 to 0.75 mm. In a time when octocorals are threatened, it is refreshing to find octocoral species that are new to the Andaman and Nicobar Islands. These islands remain amongst the most ecologically significant in the Indo-Pacific region and should be protected.

An eco-epidemiological analysis of dengue outbreak in Port Blair, South Andaman Island, India.

In Port Blair, the capital of Andaman & Nicobar Islands, in the Bay of Bengal, India, there was a sudden increase in fever cases resembling the symptoms of dengue in the monsoon period of 2022. Hence, an investigation was carried out to find out epidemiological and entomological reasons behind the outbreak. An entomological survey was carried out in 24 wards of Port Blair Municipal Council (PBMC) area, epidemiological data of last six years (January-December 2017-2021 and January-October 2022) and patient details of the year 2022 were collected. Both the epidemiological and entomological data were analyzed concerning time and place. During this outbreak period tyres (22.4%) came out as a major breeding habitat followed by small discarded materials (17.5%), metal drums (15.3%), and plastic drums (11.7%). In rainy season, peri-domestic breeding (55%) was more than the domestic breeding (45%) habitat. Ae. aegypti had a high preference for indoor large containers (100-1000 L) like plastic tank, metal drum and cement tank whereasAe. albopictus prefers to breed in medium sized plastic container (20-100 L) and outdoor water receptacles like tyres, flower pots, and domestic discarded materials. By source reduction, indoor space spray and outdoor fogging, vector density was controlled which curtailed the transmission and within eight weeks a decreasing trend of dengue cases was noticed. A regular entomological survey is crucial to know the seasonality and key breeding habitats of the vector for proper planning of vector control.

Seagrass ecosystems of Ritche’s Archipelago in the Andaman Sea harbor ‘Endangered’ Holothuria scabra Jaeger, 1833 and ‘Vulnerable’ Actinopyga mauritiana (Quoy & Gaimard, 1834) sea cucumber species (Echinodermata: Holothuroidea)

This study reports the presence of ‘Endangered’ sea cucumber Holothuria scabra for the first time from the mixed seagrasses of Havelock Island, and the ‘Vulnerable’ Actinopyga mauritiana from the monospecific Thalassia hemprichii meadows from Neil Island of Ritche’s Archipelago of Andaman & Nicobar Islands (ANI). Both species were found during field survey of intertidal seagrass ecosystems of Ritche’s Archipelago. Morphometric measurements were carried out in the field using a vernier caliper, and identification was confirmed using the identification guide for sea cucumbers of ANI provided by the Zoological Survey of India. The total body length of the H. scabra specimen was 15.7 cm, mouth width of 3.2 cm and body circumference of 5.7 cm. The specimen was a juvenile, grey in color with a total of 17 black and yellow transverse stripes along the body. The average body length of A. mauritiana specimens examined differed between those from seagrass meadows (20.4 cm) non-seagrass areas (15.7 cm) as did mouth width and total circumference. Mono and mixed seagrass meadows of ANI are critical habitats for sea cucumbers and require monitoring and protection for conservation of declining populations.

Analysis of long-term trends of rainfall and extreme rainfall events over Andaman & Nicobar and Lakshadweep Islands of India

The two major archipelagos of India, the Andaman & Nicobar Islands and the Lakshadweep situated in the climate-hazardous areas of the Bay of Bengal and Arabian Sea respectively are largely affected by weather systems developing over the sea and heavy rainfall activities. The recent two daily gridded rainfall data sets published by IMD; Rajeevan et al. (2010) at 1° × 1° spatial resolution and Pai et al. (2014) at 0.25° × 0.25° spatial resolution extending for a period of more than 100 years have been extensively used by researchers to study the rainfall characteristics at various spatiotemporal scales over the Indian mainland. However, these data sets do not include the grids over these two island meteorological subdivisions of India mainly because of the absence of daily rainfall observation for this long period. In this study, an attempt has been made to develop daily gridded rainfall data over these island subdivisions for the recent 70 years (1951 to 2020) in two spatial resolutions, viz., 1° × 1° and 0.25° × 0.25° using all the available islands station data during the period and carry out statistical analyses of various rainfall characteristics over these islands. The 0.25° × 0.25° data set was observed to be more comparable with the official rainfall time series of IMD for both these two Island subdivisions, and hence this data set has been used to carry out the trend analysis of Daily events of rainfall DER (> = 5 mm) for these two island subdivisions for the whole data period of 1951-2020 and the climate regime shift period of 1971-2020. DER was classified into two categories DMR (5-100 mm), daily moderate rainfall events and DHR (100 mm and above) daily heavy rainfall events. Signs and magnitude of the long-term trends in the frequency of DER (with DMR & DHR) showed significant changes during the recent period 1971-2020.

New Species of Eupelte (Crustacea, Copepoda, Harpacticoida) from the East Sea, with Notes on the Zoogeography of the Genus

A new species of the genus Eupelte Claus, 1860, was obtained from the algal bed bottom in Dokdo Island, East Sea of Korea, using a light trap. Specimens of both sexes of the Korean new species are described in detail and compared with its congeners. The present species, Eupelte dokdoensis sp. nov., is closely similar to E. aurulenta Wells and Rao, 1987, found in algal sands from the Andaman and Nicobar Islands, and E. setacauda Monk, 1941, collected from seaweeds in the Californian coast of the USA. These species share the body length (0.5–07 mm), the nine-segmented A1, the setation of the first and second endopodal segments of P1 (one and four setae), P4 exp-3 with three inner setae, and enp-3 of P2–P4 with five setae in both sexes. The new species can be readily discernable from the previous two species by the short rostrum with a serrate distal margin, the shape of the maxillipedal basis, the setation and surface ornamentation of P1 enp-2 (covered with long setules), the exp-3 of P3 and P4 with thicker middle inner seta, and the setation of female and male P5 exopod and baseoendopod (six and six, four and two setae, respectively). In addition, the zoogeography of the valid species of the genus Eupelte is briefly discussed, and a diagnostic key to the females of the species is provided. Eupelte dokdoensis sp. nov. described herein is the first report of the genus from Korean waters and is the fourteenth member of the genus.

A reconnaissance-level characterization of wave energy resource in the exclusive economic zones of Bay-of-Bengal

Bordering the Bay-of-Bengal, Bangladesh, India, Sri Lanka, Indonesia, and Myanmar possess significant potential for harnessing wave energy to address their growing energy crisis. This study aims to comprehensively characterize wave energy resources in the exclusive economic zones of the Bay-of-Bengal's littoral countries. The study utilizes 13 years of wave hindcasts obtained from WAVEWATCH-III, a widely used third-generation numerical wave model. Various approaches for characterizing wave energy resources were employed, including site accessibility analysis and extreme event analysis, which were overlooked in prior studies on Bay-of-Bengal. The research revealed that the mean wave energy flux in the Bay-of-Bengal is higher (16–39 kW/m) during the summer-monsoon season (July–October) and lower (2–12.5 kW/m) during the post-monsoon season (November–February). Consequently, the summer-monsoon season is deemed appropriate for energy harvesting, while the post-monsoon season is ideal for wave energy converter installation, servicing, or maintenance. The sea-state analysis demonstrated that the significant wave height and energy period of the most frequent and energetic sea-states in the Bay-of-Bengal range from 0.5 to 3.5 m and 4–16 s, respectively. Based on considerations of annual energy storage, resource stability, and wave energy converter survivability, the locations in the exclusive economic zones of Sri Lanka, Indonesia, and India's Andaman and Nicobar Islands were identified as the most suitable for constructing wave power plants. The research findings presented herein can assist local authorities and stakeholders in the energy sector by facilitating a comparison of wave energy resources across different locations and determining the most suitable sites for wave power plant construction that align with their energy needs and goals. Additionally, the results can aid wave energy converter developers in planning tests in the Bay-of-Bengal, maintaining their devices, and evaluating potential sites for opportunities and risks.

Assessment of coastal and mangrove vulnerability in the Andaman Island, Indian Ocean

Coastal regions are highly susceptible to the effects of global warming, including rising atmospheric and sea surface temperatures, increased cyclone frequency, and sea level rise. Thus, it is imperative to examine coastal vulnerability to minimize the impact of multiple hazards and protect coastal resources, such as mangroves. Particularly in India studying the vulnerability of coastal zones of Andaman and Nicobar Islands which fall in seismic zone V is critical for conservation efforts. We conducted a vulnerability analysis of coastal zones impacted by the 2004 earthquake, causing varying degrees of ground upliftment and subsidence. We compared coastal vulnerability among sites that experienced uplift, no change, and subsidence (the southern portion). Our analysis utilized the Coastal and Mangrove Vulnerability Index (CVI and MVI) to measure and compare vulnerability in six zones distributed along uplift and subsidence gradient. High-resolution satellite imagery including WorldView-2, 3, and GeoEye-1 from year 2022 are utilized on this study. The CVI and MVI offers a good way to measure and compare vulnerabilities across sites and offer insights for better management. The CVI and MVI results indicate that approximately 34% of coastal grids and over 23% of mangrove grids across all zones are highly to extremely highly vulnerable. Subsided zones were found to be more vulnerable than uplifted zones. These findings suggest that large-scale natural disturbances such as tectonic displacement have the potential to impact coastal vegetation and mangrove cover can become even more vulnerable. In conclusion, our study emphasizes the importance of vulnerability analyses in coastal regions, especially in areas prone to seismic activity. Our findings have direct implications for conservation and restoration efforts and underscore the need for continued monitoring and mitigation efforts to safeguard coastal resources for long-term sustainability.