Analyzing the potential for Padina gymnospora cultivation in the coastal waters of St. Martin’s Island, Bay of Bengal, Bangladesh: Determining the fluctuations of physicochemical property across seasons and locations

Occurrence, spatial distribution and ecological risk assessment of trace elements in surface sediments of rivers and coastal areas of the East Coast of Bangladesh, North-East Bay of Bengal

Public health risk assessment and possible contamination with heavy metals in Saint Martin's Island, Bay of Bengal

The present study investigated microplastic (MP) contamination in surface seawater, intertidal sediments, and commercially important fish and shellfish from Cox's Bazar and Saint Martin's Island, two of the most popular tourist destinations in Bangladesh. Seawater and sediment samples were collected from three locations per site, with each site having three replicates. Additionally, seven fish and four crustacean species were obtained from local markets and barbecue shops. MPs were morphologically identified under a stereomicroscope and chemically characterized using Fourier transform infrared spectroscopy (FTIR). The average MP concentrations in surface water were higher at Saint Martin's Island (35.1 ± 29.5 particles L-1) than at Cox's Bazar (10.45 ± 7.65 particles L-1). In sediments, concentrations averaged 0.211 ± 0.05 items g-1 at Cox's Bazar and 0.2055 ± 0.1 at St. Martin's Islands. MP abundance in fish and shellfish was tissue-dependent and varied by location, generally following the order: gut > dorsal muscle > ventral muscle. Overall, mean MP concentrations in the corresponding tissues were higher in samples from Cox's Bazar than in those from St. Martin's Island. Fibers, predominantly black and red (0.1-0.5 mm), were the most dominant form of MPs across all samples. FTIR analysis identified polyethylene terephthalate (53.33%), polyethylene (26.67%), and polypropylene (20%) as major polymer types. The estimated daily MP intake via seafood consumption was highest in adults (74.99 items day-1) and children (49.99 items day-1), primarily through the ingestion of Awaous grammepomus. These findings revealed widespread MP contamination in the Bay of Bengal region, underscoring the potential ecological and human health risks associated with it.

Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

The study aimed to determine eight hazardous heavy metals in surface water and sediment samples collected from the Naf River, Shah Porir Dwip (estuary), and mostly around Saint Martin's Island in the Bay of Bengal. The results of heavy metals in water samples were ranged as Pb 14.7-313.0, Cd 33.0-70.0, Cr < 11.0-37.0, Cu 38.0-57.0, Zn 26.8-69.2, Ni 102.0-285.0, and Hg 0.3-1.6μgL-1. The concentrations of metals in sediment samples were ranged as Pb < 10.0-37.5, Cd 0.2-1.0, Cr < 5.0-30.1, Cu < 3.0-30.9, Zn 24.1-88.0, Ni < 4.0-48.3, As 0.1-7.3, and Hg < 0.01-0.08mgkg-1 dw. Ni and Cr were strongly correlated, suggesting that this pair of metals might diffuse from a common origin. The contamination factor (Cif) demonstrated that sediment samples were mostly contaminated by Cd and slightly contaminated by Pb and Zn. The geoaccumulation index (Igeo) revealed considerable values for Cd on Saint Martin's Island. Cd as a single regulator posed moderate to considerable risk frequently among the sampling stations. Pollution load index (PLI) values remained below 1 (< 1), which indicated a decrease from baseline pollution value among all stations. However, potential ecological risk (PER) was graded for two stations (St1 and St13) with a moderate-risk zone due to the Cd contribution. However, shipping emission and lithogenic sources were the most predominant for heavy metals in the sediment, which were determined by applying the principal component analysis-absolute principal component score (PCA-APCS). Graphical abstract.

Nutrient and heavy metal dynamics in the coastal waters of St. Martin’s island in the Bay of Bengal

This paper is based on my fieldwork on St. Martin Island in 1962, as a member of an expedition sponsored by the Society of Natural Sciences, East Pakistan. St. Martin is a coral island in the Bay of Bengal, about twenty-five miles southwest of Teknaf, at the southernmost point of the Chittagong district in East Pakistan, and forty miles west of Akyab in Burma. The island's area is nine square miles; it has a population of 927. My research approach was primarily ethnographic. I tried to tap the documentary sources such as collective administrative reports of the District Magistrates on different sections of the district population to the Governor of Bengal and the reports of Subdivisional Officers to the District Collector; and then I correlated my fieldwork findings with them. At the outset I had to learn to understand the island dialect which is a curious mixture of Arakanese (a Burmese dialect) and Chittagonian (a Bengali dialect). I selected five informants on the basis of their individual reputation of being honest, straight-forward persons. I recorded their life histories and then randomly interviewed a cross-section of the island population in order to cross-verify the information provided by the informants. St. Martin Island, first located and named by the Portuguese traders in the sixteenth century, is locally called Jingira. It was settled in 1880 by fourteen families. The men of these families were from the Chittagong hill tracts in the southern part of East Pakistan, while their wives were from the Kachin area of highland Burma. The Gazeteer of the District Magistrates does not say how this came about. Originally, fourteen men from the Chittagong hill tracts banded together and went to highland Burma in search of fortune. They married girls of the Kachin tribe, which was against the Kachin tribal rules. Consequently, the couples were ousted from the Kachin area. Travelling home by boat, they took shelter on an island to escape a bad cyclone. They named the island Jingira, which literally means chained from harm, and liked it so much that they never cared to leave for the mainland.

Examining the socio-ecohydrological status of St. Martin's Island in Bangladesh

The current research paper focuses on the geopolitical and strategic significance of Saint Martin’s Island, situated in the Bay of Bengal within the Indian subcontinent. This study employs secondary data, drawing from prior research papers, newspapers, geographical analyses, expert opinions, and other credible communication sources as required. The nature of this research is Descriptive. It investigates the potential strategic applications of Saint Martin’s Island by global powers and assesses Indian security issues. The findings and recommendations of this research underscore the possible challenges associated with Saint Martin's Island and the implications that may arise.

What water color parameters could be mapped using MODIS land reflectance products: A global evaluation over coastal and inland waters

Trace metal (Fe, Co, Ni, Cu, Zn, Cd, and Pb) concentrations in zooplankton from the mixed layer were investigated at 8 coastal and 20 offshore stations in the western Bay of Bengal during the summer monsoon of 2003. The ecotoxicological importance of trace metal uptake was apparent within the Bay of Bengal zooplankton. There was a distinct spatial heterogeneity of metals, with highest concentrations in the upwelling zones of the southeast coast, moderate concentrations in the cyclonic eddy of the northeast coast, and lowest concentrations in the open ocean warm gyre regions. The average trace metal concentrations (μg g⁻¹) in coastal zooplankton (Fe, 44894.1 ± 12198.2; Co, 46.2 ± 4.6; Ni, 62.8 ± 6.5; Cu, 84.9 ± 6.7; Zn, 7546.8 ± 1051.7; Cd, 46.2 ± 5.6; Pb, 19.2 ± 2.6) were higher than in offshore zooplankton (Fe, 3423.4 ± 681.6; Co, 19.5 ± 3.81; Ni, 25.3 ± 7.3; Cu, 29.4 ± 4.2; Zn, 502.3 ± 124.3; Cd, 14.3 ± 2.9; Pb, 3.2 ± 2.0). A comparison of average trace metal concentrations in zooplankton from the Bay of Bengal showed enrichment of Fe, Co, Ni, Cu, Zn, Cd, and Pb in coastal zooplankton may be related to metal absorption from primary producers, and differences in metal concentrations in phytoplankton from coastal waters (upwelling zone and cyclonic eddy) compared with offshore waters (warm gyre). Zooplankton showed a great capacity for accumulations of trace metals, with average concentration factors of 4 867 929 ± 569 971, 246 757 ± 51 321, 337 180 ± 125 725, 43 480 ± 11 212, 1 046 371 ± 110 286, 601 679 ± 213 949, and 15 420 ± 9201 for Fe, Co, Ni, Cu, Zn, Cd, and Pb with respect to dissolved concentrations in coastal and offshore waters of the Bay of Bengal. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2009.

Comparison of bacterial community structure in coastal and offshore waters of the Bay of Bengal, India

The assessment of water clarity of any regional water body is particularly important from ecological and water quality perspectives, especially in the regions which are highly influenced by sediment run-off and seasonal fluctuations in turbidity. The ocean colour remote sensing has played a significant role in monitoring the turbidity level in marine and inland water bodies. However, algorithms to accurately estimate the turbidity in such optically complex waters are scarce or limited by high level of uncertainty due to various issues. The present study proposes a simple, two band algorithm to estimate turbidity in both turbid and clear waters. It was found that the band ratio of remote sensing reflectance (Rrs(670)/Rrs(670)+Rrs(555)) represents the proxy of TSS (Total suspended sediment) and therefore, positively correlates to turbidity. The new algorithm is based on the assumption that light reflected in these two vital bands contains the essential information regarding the total suspended matter in the water column. The statistical results showed that the percent mean relative error between the predicted turbidity and the measured turbidity was within ±20%. To further demonstrate the robustness of the present algorithm, the spatial grid contours for the measured and the predicted turbidity was generated for the month of January 2014, August 2013 and May 2012 for the coastal waters in Bay of Bengal (Point Calimere, located in the southeast coast of India). The close consistency between the predicted and measured turbidity spatial patterns revealed that the present algorithm can be applied with high confidence to predict turbidity in both coastal and inland waters.

Research communication dealt here, a digital application on a species migration &amp; conservation of Hilsa (Tenulosa ilisha), Ray-fish of Ganges and others using the digital technique and described. Application comes in Hilsa, Ray fish and few others are described based on one of the most important water quality parameters, fisheries for migration and conservation. Known that Hilsa has got an immense importance among the fish lovers and to the fish-eating people because of taste and nutrition. Hilsa is one of the most popular among the fishes found in Bay, Estuary or Rivers of Indian Continent. A single matured Hilsa can be weighing around 6 kg. When get matured. Distribution of Hilsa fish are found in Bays, in and around the great Sundarbans and migrates to adjacent waters across the upward of river stretches mainly Ganges, Padma and Godavari rivers while to breed. As like most other fish species this Hilsa species migrates in search of a suitable Total Dissolved Solids (TDS), and in this communication, the study area from coastal Bay of Bengal to the upward fresh-waters of river Ganges. The extent of migration may depend on the fact that till this species gets suitable minimum total dissolved solids on the way to migration while to perform the course of natural breeding. During the breeding period, like every other fish species, this Hilsa fish tries to find a minimum TDS to breed naturally. The threshold value of TDS can easily be detectable computer and electronics devices or simply a TDS meter. This research-study found that a Hilsa fish can breed naturally when the TDS value may become closer to 95-105 ppm, found near up-to the middle stretch of river Ganges regions. Species Hilsa, can migrate mere a 100-300 km or even more in search of mentioned suitable TDS and after the course of natural breeding, the species re-migrate to Bay along with all juveniles unless being caught. For growth and maturity of Hilsa fish like to prefer TDS of a range, 120 to 260 ppm, usually at the Sundarban Estuary and coastal regions of Bay of Bengal.

Mischaracterization of sedimentary rocky reef as a coral reef in the economic valuation of St. Martin's Island, Bangladesh: A comment on Rani et al. (2020)