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Protected areas (PA) co-management can offer equitable benefits from global to local level. Therefore, social equity has come out as a vital goal in PA co-management for ethical and instrumental reasons. In the Bangladesh context, however, social equity issues have been less studied in PA co-management. This study was conducted in the Sundarbans of Bangladesh, and we evaluated social equity as multidimensional concepts of recognitional, procedural and distributional equity. We employed mixed approaches, including 122 structured interviews using a 5-point Likert scale, 15 key informants interview and 4 focus group discussions to collect data on equity perception. Mean and frequency (percent) were calculated and generalized linear models were performed to analyze the predictor's influence on equity perception. The results showed that recognitional equity was perceived high, while procedural and distributional equity perceived moderate and low. Findings would be useful for policy makers in framing policies towards equitable PA co-management. [ABSTRACT FROM AUTHOR]

Situating in the lap of the Bay of Bengal, the world's largest mangrove forest, the Sundarbans, plays a significant role in the livelihood of more than three million people and provides shelter to an undetermined number of species. Unfortunately, this United Nations Educational, Scientific and Cultural Organization (UNESCO) declared world heritage site faces various threats to wildlife and biodiversity due to human interventions in the forest and animal habitats. The present study finds that despite having 150 forest policies to conserve the forest, the forest size is gradually shrinking across the country, particularly in the Sundarbans. However, National Forestry Policy 1979 (amended 2016) aims to protect forests and forest resources, and Wildlife (Conservation and Security) Act, 2012 (hereafter the Wildlife Act 2012) protects against wildlife crimes. Although National Forestry Policy 2016 endeavours to engage the local communities in the conservation process, no significant improvement was seen in the life of local communities and forest management. This paper assesses the role of international institutions that often support and cooperate with other countries for sustainable forest management and biodiversity conservation, like the Sundarbans of Bangladesh. [ABSTRACT FROM AUTHOR]

Small-scale fisheries are affected by both local and external pressures, despite the contribution to poverty alleviation, employment, and food and nutritional security. Diverse social and ecological pressures make small-scale fishing communities trapped in persistent cycles of a particular fisheries resource dependence. Consequently, the overall sustainability of that particular species, especially biological, economic and social aspects, becomes vulnerable. This study investigates the biological, economic, and social aspects of a commercially important fish species, i.e., mud crab (Scylla sp.) and explores its link to social-ecological traps. The findings show how the social-ecological traps are forming based on mud crab resource utilization, poverty, overcapitalization and seasonality of crab availability, coupled with weak institutions and governance. Apart from ongoing environmental risks (e.g., extreme climate events), negative feedback comes from poor enforcement of rules and regulations, illegal and destructive fishing, inadequate income, social conflicts, and declining stock. In response to crises, fishers are increasingly dependent on middlemen, leading to the unfair price of their products compared to the market. To escape from the social-ecological traps, strong local institutions, alternative income opportunities, compliance of fishing laws (e.g., gear selectivity, harvest, and trade prohibition of undersize crabs), strong collaboration between management authority and local stakeholders are important toward ensuring the sustainability of the mud crab fishery in the Bangladesh Sundarbans. [ABSTRACT FROM AUTHOR]

Co-management has been adopted in the Sundarbans of Bangladesh since 2008 toward biodiversity conservation and livelihood improvement of local communities. However, we have limited research on how good governance was maintained and practiced in co-managed mangrove protected areas (PA). Drawing on a case study, this research assessed stakeholders' perception on good governance in PA co-management in the Sundarbans of Bangladesh. We adopted a 'good governance framework' consisting of six governance principles (stakeholders' participation, transparency, responsiveness, legitimacy, fairness and organizational capacity) and deployed both qualitative (11 key-informants' interviews and 4 focus group discussions) and quantitative methods (135 structured interviews) for data collection. Median, frequencies (percent), contingency table chi-square tests were performed for quantitative data. About 30–35% of the respondents perceived neutral in their responses to good governance principles (stakeholders' participation, transparency, responsiveness, legitimacy, fairness and organizational capacity) indicating moderate level of governance in PA co-management in the Sundarbans. This study has demonstrated a wider implementation gap between the ambitious intent enshrined in the new policy framework and actual rollout of PA governance on the ground. These results would be useful to policy-makers, development agencies and PA managers in formulating and implementing effective policies for PA co-management in Bangladesh and elsewhere. [ABSTRACT FROM AUTHOR]

Excoecaria agallocha is a dioecious mangrove species, reported to have various medicinal properties. This study compares the gender-related biological activities between the sexes of E. agallocha in accordance with morpho-biochemical parameters which indicate their fitness over various environmental stresses as well as some information about the investment of their resources over defence and growth. For this investigation, mature sun leaves of E. agallocha were collected from each sex from three different ecological regions like Bokkhali, Jharkhali, and Kolkata, West Bengal. The comparative study found that leaf of female plants yielded more compounds than males and also resulted in higher anti-bacterial, reducing power, total antioxidant, and lipid peroxidation activities. Female leaves also showed higher concentrations of biochemical constituents like chlorophyll a, chlorophyll b, total carotenoids, total phenolic compounds and total protein content than male leaves. However, leaf area of all-male leaves in all sites was found to be greater than female leaves. The differences in growth rate and secondary metabolite content-based defences between sexes suggest that females invest resources in defences or resistance (Relative electrolytic leakages and TBARS content), whereas male invests their resources in growth (Leaf area) or tolerance. The present study strongly suggests that the female plant's yields are more beneficial in terms of medicinal properties as compared to the male plant. [ABSTRACT FROM AUTHOR]

Abstract Background Endophytic fungi play a vital role in plant defense system by secreting various antimicrobial agents. To evaluate the antimicrobial activity of the endophytic fungi of the mangrove plant Heritiera fomes (Buch. -Ham), plants were collected from the Sundarbans, Bangladesh. The endophytic fungi were subsequently isolated and identified. Results Fifty-five endophytic fungi were isolated from the leaves, root, and bark of H. fomes (Buch. -Ham). Genomic DNA was extracted for PCR (polymerase chain reaction) by specific primers to multiply ITS region and sequences were determined. Nucleotide sequence data were submitted to the Genbank and accession number for each fungal strain was obtained. Antimicrobial activity of the ethyl acetate (EtOAc) and methanolic extracts of eleven species from both fermentation and mycelium, respectively, were analyzed by microtiter plate-based antimicrobial assay incorporating resazurin as an indicator of cell growth against two Gram-positive bacteria namely Staphylococcus aureus NCTC 12981 and Micrococcus luteus NCTC 7508, two Gram-negative bacteria namely Escherichia coli NCTC 12241 and Pseudomonas aeruginosa NCTC 12903, and a fungus Candida albicans ATCC 90028. All the endophytic fungal extracts exhibited antimicrobial activities against more than one-tested pathogenic microbial strains. Overall, methanolic extracts showed greater activity than EtOAc extracts. Pseudopestalotiopsis camelliae-sinensis, Pestalotiopsis microspora, and Penicillium copticola were the most active endophytic fungal strains and exhibited strong inhibitory activity against the microorganisms under investigation and their MIC values ranged from 0.0024 to 5.0 mg/mL. Methanolic extracts of both P. camelliae-sinensis and P. microspora showed the highest antibacterial activity (MIC value of 0.0024 mg/mL) against P. aeruginosa NCTC 12903. Conclusion This study showed that the isolated and identified endophytic fungi from H. fomes (Buch. -Ham) could be potential sources of antimicrobial agents.

Mud crab (Scylla spp.) aquaculture has become an important livelihood option for the coastal fisher-folks in Bangladesh. Mud crabs harvested from wild sources are traditionally fattened in pens installed in tidal rivers, ghers, and earthen ponds in Bangladesh. The study was aimed at understanding the practice and production economics of mud crab farming in the South-West Sundarbans region of Bangladesh, and was conducted in the areas namely Bagerhat, Satkhira and Khulna districts where mud crab fattening are predominately ventured. Most of the farmers fatten both male (lean) and female (gonadally immature) crabs of 100 - 180 g. The crabs are stocked at varying rate (12 - 641 g/m2), and fed at the rate of 8-10% of body weight with trash live fishes, dried fishes, snails, mollusks, and cattle viscera. The fattening for a mean cycle of 22 ± 14.34 days has the survival rate of 55 - 90%, and has the production of 0.065 ± 0.26, 0.084 ± 1.33, and 0.17 ± 3.76 kg/m2 in Bagerhat, Satkhira, and Khulna, respectively. After harvesting (mostly partial), crabs are sold at average price rate of 4.35 ± 0.45 US$/kg. The lowest production cost (3.14 US$/kg) and the better economic return (US$ 147.77) per cycle was recorded in the district of Satkhira. The mud crab fattening has hitherto been evaluated economically feasible in and around the Sundarbans region, but the production and economic efficiency can be scaled up adopting scientifically demonstrated regime of stocking, feeding, and health management. The development of crab seed hatchery, artificial feed for crab, and strongest marketing network are addressed as crux issues for the sustainability of mud crab aquaculture in Bangladesh.

Livelihood management is a severe challenge in the coastal area near the Sundarbans mangrove forests of Bangladesh. Human-tiger conflict in the area further complicates the situation and generates a group of women known as tiger widows who have lost their husbands because of attacks by tigers. They are therefore socially stigmatized as cursed and harbingers of bad luck. As a result, the lives of these widows in rural and geographically remote locations are full of suffering and hardships, especially with respect to their being able to manage livelihoods. This article discusses their vulnerabilities and difficult lives in this antagonistic eco-social setting. It also reveals their adoption of different livelihood strategies backed by some NGOs' development assistance, whereby they become able to secure the survival and well-being of their families. Furthermore, our findings show how the widows have developed capacities to transform their own lives from utter misery to gain socioeconomic stability by fighting patriarchal constraints and also influencing other women to become self-reliant. [ABSTRACT FROM AUTHOR]

The Sundarbans, the largest mangrove forest in the world and a UNESCO world heritage site has been facing increasing pressure of habitat destruction. Yet, no study has been conducted to test how human disturbances are affecting plant-pollinator interactions in this unique ecosystem. Hence, we aimed to provide the first insight into the impact of habitat loss and human disturbances on the pollinator communities in the Sundarbans. We selected 12 sites in the North-Western region of the Sundarbans, along a gradient of decreasing habitat loss and human activities from forest fragments near human settlements to continuous pristine forest, where we studied insect pollinators of two mangrove plant species, Acanthus ilicifolius and Avicennia officinalis. Our results show that different pollinator groups responded to the disturbance gradient differently. For example, the abundance of Apis dorsata, one of the three local species of honey bees, increased gradually from the village area towards the deep pristine forest. On the other hand, A. cerana and A. florea were found in the village sites and completely absent in the deep forest. Although pollinator community composition changed along the disturbance gradient, their efficacy in pollination did not seem to be significantly affected. However, lower plant diversity and low understory plant cover in the forest patches nearby the village indicated that human disturbances not only affected pollinator community composition but also played a major negative role in the regeneration of the forest. Our study provides first insights into plant-pollinator interactions in the Sundarbans and demonstrates that more research is needed to imply conservation strategies for this unique habitat.

Mangrove forests provide a variety of ecosystem services, and among them, the ability to sequester large quantities of below-ground carbon reservoirs is considered the most critical service for mitigating climate change. Therefore, most mangrove studies are highly concerned with estimating ecosystem carbon stocks, while only a few studies have focused on the factors driving these carbon stocks. Thus, we examined the role of stand structure, species diversity, and functional traits on above-ground, below-ground, and total carbon stocks using data from 28 sample plots from the low salinity zone of the Sundarbans mangrove forest of Bangladesh. We also aimed to understand the distribution patterns of carbon stocks among different components of the ecosystem, such as above-ground, below-ground soil, and roots. The study results revealed that tree height, diameter at breast height (DBH), and basal area were highly correlated with both above-ground (AGC) and below-ground carbon (BGC, incuding soil carbon at 0–50 cm depth) stocks. Multiple regression models indicated that tree height and basal area were two significant positive predictors for AGC, BGC and total carbon stocks (TCS) (p < 0.05). Species richness and community-weighted mean wood density were significant positive predictors for BGC and TCS. In contrast, Simpson diversity and community-weighted mean specific leaf area negatively influenced BGC. Furthermore, we observed that the above-ground tree carbon (AGTC = 80.4 ± 32.0 Mg ha−1) was significantly higher than below-ground soil carbon to 50 cm depth (BGSC-50 cm = 41.0 ± 5.4 Mg ha−1), followed by below-ground root carbon (BGRC = 37.1 ± 10.1 Mg ha−1), pneumatophore (Pneu_C = 28.8 ± 18.8 Mg ha-1), and downed wood (DW = 0.03 ± 0.02 Mg ha−1) (p < 0.05). In terms of specific species contribution, Heritiera fomes contributed the most to AGTC and BGRC, followed by other species such as Avicennia officinalis > Excoecaria agallocha > Sonneratia apetala > Xylocarpus mekongensis > Bruguiera sexangula. Our findings indicate that maintaining dominant trees (H. fomes) and a diverse stand can be an effective way to enhance carbon stocks in a mangrove ecosystem. • The role of stand structure, species diversity and functional traits on mangrove carbon stocks were investigated. • Above-ground tree carbon was significantly higher than other components to a soil depth of 50 cm. • Both tree height and basal area are significant predictors of both above- and below-ground carbon stocks. • Heritiera fomes contributed the highest ecosystem carbon stocks. [ABSTRACT FROM AUTHOR]

Spillage of furnace oil is a more frequent event in recent times. In this study, environmental samples from furnace oil spillage sites of the Shela River, the Sundarbans, Bangladesh, were collected after three weeks of spillage. Serial dilution was applied and total seven bacterial isolates were separated as pure cultures. The oil-degrading potentiality of all seven isolates was further assessed, confirmed and compared with the growth pattern in furnace oil supplemented media, 2, 6-dichlorophenolindophenol test, and gravimetric analysis. After 7 days of incubation, isolates SS3, RW2, and SB degraded 56%, 43%, and 52% of supplemented furnace oil, respectively. The top three hydrocarbonoclastic bacterial isolates were selected as potential and identified as Pseudomonas aeruginosa (SS3), Bacillus sp. (RW2), and Serratia sp. (SB). All three isolates showed significant oil-degrading capacity compared to negative control, when incubated in sterile pond water supplemented with 2% furnace oil, suggesting them as potential bioremediation agents.

The Sundarbans is a deltaic mangrove forest, formed about 7000 years ago by the deposition of sediments from the foothills of the Himalayas through the Ganges river system, and is situated southwest of Bangladesh and south of West Bengal, India. However, for the last 40 years, the discharge of sediment-laden freshwater into the Bay of Bengal through the Bangladesh part of the Sundarbans Mangrove Forests (BSMF) has been reduced due to a withdrawal of water during the dry period from the Farakka Barrage in India. The result is two extremes of freshwater discharge at Gorai, the feeding River of the BSMF: a mean minimum monthly discharge varies from 0.00 to 170 m3·s−1 during the dry period with a mean maximum of about 4000 to 8880 m3·s−1 during the wet period. In the BSMF, about 180 km downstream, an additional low discharge results in the creation of a polyhaline environment (a minimum of 194.4 m3·s−1 freshwater discharge is needed to maintain an oligohaline condition) during the dry period. The Ganges water carries 262 million ton sediments/year and only 7% is diverted in to southern distributaries. The low discharge retards sediment deposition in the forestlands’ base as well as the formation of forestlands. The increase in water flow during monsoon on some occasions results in erosion of the fragile forestlands. Landsat Satellite data from the 1970s to 2000s revealed a non-significant decrease in the forestlands of total Sundarbans by 1.1% which for the 6017 km2 BSMF is equivalent to 66 km2. In another report from around the same time, the estimated total forestland loss was approximately 127 km2. The Sundarbans has had great influence on local freshwater environments, facilitating profuse growth of Heritiera fomes (sundri), the tallest (at over 15 m) and most commercially important plant, but now has more polyhaline areas threatening the sundri, affecting growth and distribution of other mangroves and biota. Landsat images and GIS data from 1989 to 2010 at the extreme northern part of Khulna and Chandpai Ranges revealed the formation of a large number of small rivers and creeks some time before 2000 that reduce the 443 km2 forestland by 3.61%, approximately 16 km2, and decreasing H. fomes by 28.75% and total tree cover by over 3.0%. The number of the relatively low-priced plants Bruguiera sexangula, Excoecaria agallocha and Sonneratia apetala, has, on the other hand, increased. Similar degradation could be occurring in other ranges, thereby putting the survivability of the Bangladesh Sundarbans at risk. The growing stock of 296 plants per ha in 1959 had been reduced to 144 by 1996. Trend analysis using “Table Curve 2D Programme,” reveals a decreased number of 109 plants by the year 2020. The degradation of the Bangladesh Sundarbans has been attributed to reduced sediment-laden freshwater discharge through the BSMF river system since commissioning the Farakka Barrage on 21 April 1975 in India. To reduce salinity and forestland erosion, the maintenance of sediment-laden freshwater discharge through its river system has been suggested to re-create its pre-1975 environment for the growth of H. fomes, a true mangrove and the highest carbon-storing plant of the Sundarbans. This may possibly be achieved by proper sharing of the Ganges water from the Farakka Barrage, forming a consortium of India, Nepal, Bhutan and China, and converting parts or whole of the Ganges River into water reservoir(s). The idea is to implement the Ganges Barrage project about 33 km downstream, dredging sediments of the entire Gorai River and distributaries in the Ganges floodplain, thus allowing uniform sediment-laden freshwater flow to maintain an oligohaline environment for the healthy growth of mangroves. The system will also create healthy hinterlands of the Ganges floodplain with increased crop production and revenue. The expenditure may be met through carbon trading, as Bangladesh is a signatory of the Copenhagen Accord, UN Framework Convention on Climate Change. The total carbon reserve in the BSMF in 2010 was measured at about 56 million metric tons, valued at a minimum of US$ 280 million per year. The forest is rich in biodiversity, where over 65 species of mangroves and about 1136 wildlife species occur. The BSMF acts as a natural wall, saving property as well as millions of lives from natural disasters, the value of which is between 273 and 714 million US$. A 15 to 20 km band impact zone exists to the north and east of the BSMF, with a human settlement of about 3.5 million that is partly dependent on the forests. Three wildlife sanctuaries are to the south of the BSMF, the home of the great royal Bengal tigers, covering a total area of about 1397 km2. Construction of a coal-fired power plant at Rampal will be the largest threat to the Sundarbans. It is a reserve forest, declared as a Ramsar site of international importance and a UNESCO natural world heritage site.

Iron overload results in oxidative damage to various biomolecules including DNA, proteins and lipids which ultimately leads to cell death. The Sonneratia apetala fruit contains a high content of antioxidants and displays several bioactive properties. Therefore, the powder of the S. apetala fruit was successively fractionated into n -hexane (Hex), chloroform (Chl), and methanol (Met) fractions to evaluate their efficiency in ameliorating iron overload. In vitro , a colorimetric method was used to assess the Fe-chelating activity of the fractions using ferrozine. The fractions were also used in vivo to examine their efficacy in ameliorating iron overload and iron-induced oxidative stress in mice induced by intraperitoneal injection of ferric carboxymaltose at 100 mg/kg body weight (bw). Among the fractions, Met showed the highest Fe-chelation ability with an inhibitory concentration 50 of 165 μg/mL followed by Hex (270 μg/mL), and Chl (418 μg/mL). In vivo , the results showed a significantly ( P <0.05) lower iron profile (iron and ferritin concentrations in serum and liver tissue and total iron-binding capacity of serum) in the Met and the Hex treated mice groups than in the iron-overloaded group. Met at 1,000 μg/kg bw completely ameliorated iron overload in the blood and the liver tissue of mice. At this concentration, Met also prevented iron-induced oxidative stress in the liver tissue of iron-overloaded mice by restoring reducing power, total antioxidant capacity, and total protein. Thus, the S. apetala fruit, especially its Met fraction can be used in treating iron overload and associated toxicity., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest., (Copyright © 2023 by The Korean Society of Food Science and Nutrition.)

This paper examines Amitav Ghosh's novel The Hungry Tide (2004) to explore Ghosh's dramatization of the affective impacts of a specific environment on local subjects, and the role cosmopolitan subjects play in translating those affects into knowable forms through their embodied and affective encounters with the local. My investigation draws upon recent theories of affect--negotiating between constructive and deconstructive views--and places the discussion in a framework of eco-cosmopolitan connections. By invoking the coexistence of the affects of fear and love, I seek to move beyond the concept of the uncanny, exploring affect both as emotions and intensity generated by the socio-ecological conditions of the wetlands. I take the affective encounters between the locals and the cosmopolitans as a relational medium through which modes of feeling and knowing on the part of cosmopolitan subjects can be transformed. The uncanny of the environment experienced by the local can also be translated into accessible forms through this medium, bringing into our sensory ken the slow violence that is far away and out of sight and thereby enabling ethical actions. [ABSTRACT FROM AUTHOR]

Heavy metals are one of the hazardous contaminants in the total environment. The present study shows that the Sundarbans soil is contaminated with sludge and moderately contaminated with Cd and Co according to Contamination factor (CF), Enrichment factor (EF), Index of geo-accumulation (Igeo), and Ecological risk factor (ERF). The correlation, principle component analysis and factor analysis showed that Mn and Fe might have lithogenic origin whereas Cu, Pb, Co and Cd have anthropogenic inputs. The screening quick reference table (SQuiRT) shows that Cu and Cd may exert a possible toxic effect on the sediment dwelling biota. The phytoremediation study revealed that the endangered Heritiera fomes leaves can accumulate 80% of cadmium from the soil, which is highest based on this study as compared to other mangroves. The study also indicated that threatened date palm Phoenix paludosa leaves can accumulate 74% and 73% of Cu and Fe, respectively, from the soil. Now a day, there has been a spurt in mangrove plantations worldwide for the conservation of mangrove ecosystem using ecological engineering approaches. The present study is very much useful to choose a proper plant to decontaminate the soil from various heavy metal pollutants for effective management of mangrove wetlands. [ABSTRACT FROM AUTHOR]

Spillage of furnace oil is a more frequent event in recent times. In this study, environmental samples from furnace oil spillage sites of the Shela River, the Sundarbans, Bangladesh, were collected after three weeks of spillage. Serial dilution was applied and total seven bacterial isolates were separated as pure cultures. The oil-degrading potentiality of all seven isolates was further assessed, confirmed and compared with the growth pattern in furnace oil supplemented media, 2, 6-dichlorophenolindophenol test, and gravimetric analysis. After 7 days of incubation, isolates SS 3 , RW 2 , and SB degraded 56%, 43%, and 52% of supplemented furnace oil, respectively. The top three hydrocarbonoclastic bacterial isolates were selected as potential and identified as Pseudomonas aeruginosa (SS 3 ), Bacillus sp. (RW 2 ), and Serratia sp. (SB). All three isolates showed significant oil-degrading capacity compared to negative control, when incubated in sterile pond water supplemented with 2% furnace oil, suggesting them as potential bioremediation agents. [ABSTRACT FROM AUTHOR]

This paper explores the local perspective of community engagement in restoring the natural ecological balance and sustain the eco-tourism opportunities on the backdrop of the recent oil spillage in the Sundarbans. Drawing from community discourse and the community resilience model (Akamani 2012), and national and international media releases in relevance to the oil spillage incident, this study explores community views of the post-Spillage-Sundarbans. A number of suggestions are made for restoring the balance as a platform to build a tourist-friendly resilient community. The study calls for the sustainable public supported community resilience ingenuity. It emphasizes on a harmonised and balanced interrelationship between the private and public parties, stakeholders and beneficiaries to undertake community resilience initiatives for survival. [ABSTRACT FROM AUTHOR]

The Sundarbans is a deltaic mangrove forest, formed about 7000 years ago by the deposition of sediments from the foothills of the Himalayas through the Ganges river system, and is situated southwest of Bangladesh and south of West Bengal, India. However, for the last 40 years, the discharge of sediment-laden freshwater into the Bay of Bengal through the Bangladesh part of the Sundarbans Mangrove Forests (BSMF) has been reduced due to a withdrawal of water during the dry period from the Farakka Barrage in India. The result is two extremes of freshwater discharge at Gorai, the feeding River of the BSMF: a mean minimum monthly discharge varies from 0.00 to 170 m³⋅s-1 during the dry period with a mean maximum of about 4000 to 8880 m³⋅s-1 during the wet period. In the BSMF, about 180 km downstream, an additional low discharge results in the creation of a polyhaline environment (a minimum of 194.4 m³⋅s-1 freshwater discharge is needed to maintain an oligohaline condition) during the dry period. The Ganges water carries 262 million ton sediments/year and only 7% is diverted in to southern distributaries. The low discharge retards sediment deposition in the forestlands' base as well as the formation of forestlands. The increase in water flow during monsoon on some occasions results in erosion of the fragile forestlands. Landsat Satellite data from the 1970s to 2000s revealed a non-significant decrease in the forestlands of total Sundarbans by 1.1% which for the 6017 km² BSMF is equivalent to 66 km². In another report from around the same time, the estimated total forestland loss was approximately 127 km². The Sundarbans has had great influence on local freshwater environments, facilitating profuse growth of Heritiera fomes (sundri), the tallest (at over 15 m) and most commercially important plant, but now has more polyhaline areas threatening the sundri, affecting growth and distribution of other mangroves and biota. Landsat images and GIS data from 1989 to 2010 at the extreme northern part of Khulna and Chandpai Ranges revealed the formation of a large number of small rivers and creeks some time before 2000 that reduce the 443 km²forestland by 3.61%, approximately 16 km², and decreasing H. fomes by 28.75% and total tree cover by over 3.0%. The number of the relatively low-priced plants Bruguiera sexangula, Excoecaria agallocha and Sonneratia apetala, has, on the other hand, increased. Similar degradation could be occurring in other ranges, thereby putting the survivability of the Bangladesh Sundarbans at risk. The growing stock of 296 plants per ha in 1959 had been reduced to 144 by 1996. Trend analysis using "Table Curve 2D Programme," reveals a decreased number of 109 plants by the year 2020. The degradation of the Bangladesh Sundarbans has been attributed to reduced sediment-laden freshwater discharge through the BSMF river system since commissioning the Farakka Barrage on 21 April 1975 in India. To reduce salinity and forestland erosion, the maintenance of sediment-laden freshwater discharge through its river system has been suggested to re-create its pre-1975 environment for the growth of H. fomes, a true mangrove and the highest carbon-storing plant of the Sundarbans. This may possibly be achieved by proper sharing of the Ganges water from the Farakka Barrage, forming a consortium of India, Nepal, Bhutan and China, and converting parts or whole of the Ganges River into water reservoir(s). The idea is to implement the Ganges Barrage project about 33 km downstream, dredging sediments of the entire Gorai River and distributaries in the Ganges floodplain, thus allowing uniform sediment-laden freshwater flow to maintain an oligohaline environment for the healthy growth of mangroves. The system will also create healthy hinterlands of the Ganges floodplain with increased crop production and revenue. The expenditure may be met through carbon trading, as Bangladesh is a signatory of the Copenhagen Accord, UN Framework Convention on Climate Change. The total carbon reserve in the BSMF in 2010 was measured at about 56 million metric tons, valued at a minimum of US$ 280 million per year. The forest is rich in biodiversity, where over 65 species of mangroves and about 1136 wildlife species occur. The BSMF acts as a natural wall, saving property as well as millions of lives from natural disasters, the value of which is between 273 and 714 million US$. A 15 to 20 km band impact zone exists to the north and east of the BSMF, with a human settlement of about 3.5 million that is partly dependent on the forests. Three wildlife sanctuaries are to the south of the BSMF, the home of the great royal Bengal tigers, covering a total area of about 1397 km². Construction of a coal-fired power plant at Rampal will be the largest threat to the Sundarbans. It is a reserve forest, declared as a Ramsar site of international importance and a UNESCO natural world heritage site. [ABSTRACT FROM AUTHOR]

The paper reports the observations of the aerosol studies carried-out for three years (2004-2007) during the summers and winters at Kaikhali (22.0220 N & 88.6140E) lying in the east coast of India inside a special mangrove ecosystem: 'The Sundarbans'. Aerosol optical depths were measured using a five filter channel sunphotometer with wavelengths at 340, 500,870, 936 and 1020 nm respectively. The sampling site enjoys a tropical climate and is under the strong influence of the southwest or summer monsoon and weak northeast or winter monsoon. The mean aerosol optical depth (AOD) during the winters (2004-2007) for the filter channels 340, 500, 870, 936 and 1020 nm have been found to be 1.478, 1.014, 0.579, 0.541 and 0.523 respectively whereas for the summer periods, they have been found to be 1.173, 0.859, 0.603, 0.564 and 0.597 respectively. The mean values of the angstrom exponent calculated for the winter and summer months over the years 2004-2007 have been found to be 1.283, 0.999, 1.285 and 1.094, 1.167 and 1.91 respectively. Generally the higher angstrom exponent values during the winter periods over the years from 2004-2007 except for the year 2005-2006 indicate high ratio of smaller fractions to larger fractions. The values of Angstrom exponents observed at the site suggest that the aerosol comprise mostly of the small size particles. An attempt has been made in the paper to compare the aerosol optical depth and angstrom exponent values with another study conducted in a different coastal zone in India. [ABSTRACT FROM AUTHOR]

Cyclone Sidr, a Category IV storm, struck the southwestern coast of Bangladesh on November 15, 2007 killing 3,406 people. Despite a similar magnitude, Sidr claimed far fewer lives than Cyclone Gorky, also a Category IV storm, which struck Bangladesh in 1991 causing an estimated 140,000 fatalities. The relatively low number of deaths experienced with Sidr is widely considered the result of Bangladesh government’s efforts to provide timely cyclone forecasting and early warnings, and successful evacuation of coastal residents from the projected path of Cyclone Sidr. Using information collected from both primary and secondary sources, this study identified several other reasons for the unexpectedly lower mortality associated with Cyclone Sidr relative to Cyclone Gorky. Fewer casualties may be attributed to a number of physical characteristics of Cyclone Sidr, such as duration of the storm and storm surge, landfall time and site, varied coastal ecology, and coastal embankment. This article recommends improvements to the cyclone warning systems, establishment of more public cyclone shelters, and implementation of an education campaign in coastal areas to increase the utilization of public shelters for future cyclone events. [ABSTRACT FROM AUTHOR]

• The mean soil organic carbon (SOC) is lower in the Sundarbans than most mangroves. • Both salinity zone and forest type had a significant effect on SOC. • Irrespective of salinity zonation, the top 10 cm contained the highest SOC density. • Salinity, C:N and tree diameter were the best predictors of SOC variability. Globally, mangroves sequester a large amount of carbon into the sediments, although spatial heterogeneity exists owing to a wide variety of local, regional, and global controls. Rapid environmental and climate change, including increasing sea-level rise, global warming, reduced upstream discharge and anthropogenic activities, are predicted to increase salinity in the mangroves, especially in the Bangladesh Sundarbans, thereby disrupting this blue carbon reservoir. Nevertheless, it remains unclear how salinity affects the belowground soil carbon despite the recognised effect on above ground productivity. To address this gap, research was undertaken in the Bangladesh Sundarbans to compare total soil organic carbon (SOC) across three salinity zones and to explore any potential predictive relationships with other physical, chemical properties and vegetation characteristics. Total SOC was significantly higher in the oligohaline zone (74.8 ± 14.9 Mg ha−1), followed by the mesohaline (59.3 ± 15.8 Mg ha−1), and polyhaline zone (48.3 ± 10.3 Mg ha−1) (ANOVA, F 2, 500 = 118.9, p < 0.001). At all sites, the topmost 10 cm of soil contained higher SOC density than the bottom depths (ANOVA, F 3, 500 = 30.1, p < 0.001). On average, Bruguiera sp. stand holds the maximum SOC measured, followed by two pioneer species Sonneratia apetala and Avicennia sp. Multiple regression results indicated that soil salinity, organic C:N and tree diameter were the best predictor for the variability of the SOC in the Sundarbans (R 2 = 0.62). Despite lower carbon in the soil, the study highlights that the conservation priorities and low deforestation rate have led to less CO 2 emissions than most sediment carbon-rich mangroves in the world. The study also emphasised the importance of spatial conservation planning to safeguard the soil carbon-rich zones in the Bangladesh Sundarbans from anthropogenic tourism and development activities to support climate change adaptation and mitigation strategies. [ABSTRACT FROM AUTHOR]

This study evaluated anti-bacterial, anti-diarrheal, and cytotoxic activities of ten edible fruits ( Aegiceras corniculatum , Avicennia officinalis , Bruguiera gymnorrhiza , Ceriops decandra , Heritiera fomes , Nypa fruticans , Phoenix paludosa , Sarcolobus globosus , Sonneratia caseolaris ) in the Sundarbans mangrove forest of Bangladesh. Highest antibacterial activity was shown for ethanol:methanol (1:1) extracts of Xylocarpus mekongensis ) in the Sundarbans mangrove forest of Bangladesh. Highest antibacterial activity was shown for ethanol:methanol (1:1) extracts of S. caseolaris (2 mg/disc), which demonstrated inhibition zones of 16.7, 17.0, 14.7, 15.7, and 15.7 mm against Escherichia coli , Klebsiella sp., Shigella boydii , Shigella sonnei , and Staphylococcus aureus , respectively. In mice with castor oil-induced diarrhea, S. caseolaris extract (250 mg/kg body weight) showed the highest inhibition (87.7%) and delayed the onset time (273 min) of diarrheal episodes, followed by A. corniculatum extract (inhibition, 83.6%; delayed onset time, 187.4 min). S. caseolaris and A. corniculatum fruit powders were successively fractionated into n -hexane, diethyl ether, chloroform, ethanol, and methanol. Antidiarrheal activity significantly increased with increasing polarity of these fractions. In brine shrimp lethality assay, S. globosus extract demonstrated the highest cytotoxicity (59.2 μg/mL), followed by H. fomes (74.1 μg/mL) and C. decandra (116.7 μg/mL); however, lowest cytotoxicity was shown for A. corniculatum , A. officinalis , and S. caseolaris extracts. Mice treated with A. corniculatum extract did not experience any acute toxicity. These results demonstrate that S. caseolaris and A. corniculatum fruits have potential to treat diarrhea and may act as useful nutraceuticals., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest., (Copyright © 2021 by The Korean Society of Food Science and Nutrition. All rights Reserved.)

• Sonneratia apetala forms distinct annual growth rings marked by radially flattened fibres. • Intra-annual cambial activity is not restricted within monsoon. • Lower growth rate in high salinity zone suggests a high sensitivity to salinity. • All standard chronologies are significantly correlated with the river discharge rate. Mangroves throughout the world are threatened by environmental changes apart from anthropogenic disturbances. Many of these changes may inhibit the growth and survival of mangrove species. To understand and predict the effects of global change on mangrove forests, it is necessary to obtain insights on the growth dynamics of mangroves in relation to environmental factors. This study was conducted on Sonneratia apetala , a mangrove species which grows under a range of salinity conditions across the Sundarbans in Bangladesh. We studied trees growing under respectively high, medium, and low salinity conditions based on the influence of freshwater discharge. First, the periodicity of radial growth across the year was detected by applying cambial analyses. Based on tree-ring analyses, we calculated the growth response of S. apetala to monthly variation in precipitation and temperature as well as river discharge, as a proxy for salinity. We found the cambium of S. apetala being active during the monsoon and post-monsoon period whereas it was dormant in the pre-monsoon. This periodicity in radial growth leads to the formation of distinct annual rings with ring boundaries being marked by radially flattened fibres. S. apetala trees growing under low salinity conditions generally show higher growth rates indicating the positive impact of river discharge, i.e. freshwater input on mangrove growth. Wet and warm conditions during the monsoon period positively affected S. apetala growth, especially in the low salinity zone. Our results show that salinity is the primary driver of growth dynamics of S. apetala in the Sundarbans. A gradual or seasonal increase in salinity, e.g. as a consequence of sea-level rise may therefore importantly alter the growth of this species, possibly leading to changes in mangrove forest dynamics and zonation. [ABSTRACT FROM AUTHOR]

This study evaluated the antidiarrheal, analgesic, and anthelmintic activities of honey samples from the Sundarbans mangrove forest of Bangladesh. Composite raw honey (RH), and its diethyl ether (DEH), ethanol (ETH), methanol (MEH), and distilled water (DWH) fractions were investigated. RH and its fractions strongly inhibited castor oil-induced diarrheal episodes in mice at a concentration of 250 mg/kg body weight (b.w.) ( P <0.05). At this concentration, RH, DEH, ETH, MEH, and DWH showed inhibitory activity on diarrheal episodes at 43.8, 47.4, 29.8, 12.3, and 38.5%, respectively, whereas for the inhibitory activity for the positive control (PC, 3 mg loperamide/kg b.w.) was 47.4%. Similarly, DEH (250 mg/kg b.w.) showed strongest inhibition (63.5%) of acetic acid-induced writhing in mice, followed by RH (55.7%), ETH (46.2%), MEH (37.6%), and DWH (32.9%). In a hot plate test, mice treated with DEH at a concentration 250 mg/kg b.w. showed the greatest increase in response time, followed by treatment with RH. RH was further used in an anthelmintic test, where it showed a strong dose-dependent reduction in both the paralysis time and the time until death of the parasite, Paramphistomum cervi . Honeys in the Sundarbans could therefore be of great use as nutraceuticals., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest.

This study evaluated the physicochemical, nutritional, antioxidant, and phenolic properties of ten honey samples from the Sundarbans mangrove forest, Bangladesh. The average pH, electrical conductivity, total dissolved solid, ash, moisture, hydroxymethyl furfural, titrable acidity, and absorbance were 4.3, 0.38 mS/cm, 187.5 ppm, 0.14%, 17.88%, 4.4 mg/kg, 37.7 meq/kg, and 483 mAU, respectively. In the honeys, the average contents of Ca, Cu, Fe, K, Mg, Mn, and Na were 95.5, 0.19, 6.4, 302, 39.9, 3.4, and 597 ppm, respectively, whereas Cd, Cr, Pb, and Ni were not found. The average contents of total sugar, protein, lipid, vitamin C, polyphenols, flavonoids, and anthocyanins in the honeys were 69.3%, 0.8%, 0.29%, 107.3 mg/kg, 757.2 mg gallic acid equivalent/kg, 43.1 mg chatechin equivalent/kg, and 5.4 mg/kg, respectively. The honeys had strong 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, reducing power and total antioxidant capacity. High-performance liquid chromatography analysis of the honey fractions revealed the quantification of six polyphenols namely, (+)-catechin, (-)-epicatechin, p -caumeric acid, syringic acid, trans -cinnamic acid, and vanillic acid at 194.98, 330.34, 74.64, 218.97, 49.55, and 118.84 mg/kg, respectively. Therefore, the honeys in the Sundarbans are of excellent quality and a prospective source of polyphenols, and antioxidants., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest.