Search

Metal pollution is a subject of growing concern as it affects the whole food chain of an ecosystem by bioaccumulation. Growing industrialization and anthropogenic intervention have put tremendous pressure on self-sustaining ecosystems worldwide. Sundarbans mangrove estuary, being a UNESCO World Heritage site, suffers severely from anthropogenic stress, urbanization, ecotourism, overexploitation of natural resources and discharges of industrial as well as municipal waste products. Our study unfolds the extent of metal pollution in the sediment of this estuarine mangrove ecosystem and also investigates the source and distribution of these metals. Extensive samplings were performed during three major seasons, namely pre-monsoon, monsoon, and post-monsoon for two consecutive years at ten sampling stations along the major river networks of the mangrove estuary. Seasonal variations of these metals, physicochemical properties, and soil texture studies were performed to explore the sediment quality of the study area. Positive correlation was observed between the pollutants and siltation. Several environmental indices were investigated to explore the degree of metal pollution which revealed contamination of Cd, Cr, and Pb to cross the permitted safe index in the study area. Pollution load index indicates the spatial as well as seasonal variation of eco toxic metal load along the course of the rivers. Statistical analyses such as principal component analysis and correlation matrix identified different sources for metal contamination. Almost 700 tannery industries are located in the upstream region of the rivers, and several small- and large-scale battery industries seem to be the main possible source for Cd, Cr, and Pb pollution. Analysis of the results indicates the alarming condition of this heritage site. The metal concentrations beyond toxicity thresholds are responsible for gradual deterioration of this estuarine mangrove which may only be protected by developing sustainable management planning.

Mangrove ecosystems are a major biodiversity hotspot of the world. The world heritage site Sundarbans is an archipelago with an estuarine mangrove ecosystem. It is assumed that each individual Island of the Sundarbans possess a unique biodiversity due to the seasonal variation of physicochemical parameters, along with tidal dynamics of Bay of Bengal. This study unfolds a time series analysis of microbial diversity using high-resolution 16S rRNA tag pyrosequencing. Eight soil samples were collected over three years at a pristine temperate estuarine site located at the sea mangrove interface at the island of Kalash. Apart from the predominant phyla such as Proteobacteria [31.6%], Chloroflexi [10.7%], Firmicutes [7%] Bacteroidetes [7%] and Actinobacteria [1.2%], soil from Kalash also contained a significant amount of rare phyla NC10 and WS3 categorized as microbial dark matter (MDM). Variation in bacterial community composition occurs mainly as a result of the seasonal changes and consequent alterations of physicochemical parameters leading to microbial adaptations. Further we performed functional metagenomics to estimate the possibility of the synthesis of new natural compounds by diverse Polyketide Synthase (PKS). The data indicated diverse microbial origins of keto synthase sequences from polyketide synthase genes. Presence of this unique keto synthases confirmed the existence of a potential microbiome which may be capable of producing novel small molecules. This is the pioneering report to correlate the microbial community structure of Sundarbans with their potential to produce essential bioactive compounds.

Indian retail sector has seen a drastic transformation and rapid growth since the last decade. Till date it is being dominated by small and unorganized entrepreneurs like Khirana shops, standalone stores, boutiques, traditional family business stores, etc. In this present study, researchers concentrate on three selective questions: predictive modeling, dimension reduction, and visualization modeling. The population consisted of random shoppers who have visited shopping centers. The survey was conducted in year 2015, and all of the surveys were conducted in person. The questionnaire consisted of 150 items. The majority of participants completed the survey between 10 and 12 min. This present study indicates that the atmosphere of a retail setup has a major impact in the minds of mall consumers reflecting their behavioral response and the role of experiential value in determining these behavioral responses.

The global knowledge of microbial diversity and function in Sundarbans ecosystem is still scarce, despite global advancement in understanding the microbial diversity. In the present study, we have analyzed the diversity and distribution of bacteria in the tropical mangrove sediments of Sundarbans using 16S rRNA gene amplicon sequencing. Metagenome is comprised of 1,53,926 sequences with 108.8 Mbp data and with 55 ± 2% G + C content. Metagenome sequence data are available at NCBI under the Bioproject database with accession no. PRJNA245459. Bacterial community metagenome sequences were analyzed by MG-RAST software representing the presence of 56,547 species belonging to 44 different phyla. The taxonomic analysis revealed the dominance of phyla Proteobacteria within our dataset. Further taxonomic analysis revealed abundance of Bacteroidetes, Acidobactreia, Firmicutes, Actinobacteria, Nitrospirae, Cyanobacteria, Planctomycetes and Fusobacteria group as the predominant bacterial assemblages in this largely pristine mangrove habitat. The distribution of different community datasets obtained from four sediment samples originated from one sampling station at two different depths providing better understanding of the sediment bacterial diversity and its relationship to the ecosystem dynamics of this pristine mangrove sediment of Dhulibhashani in, Sundarbans. Keywords: Mangrove sediment, Dhulibhashani, Metagenome, Pyrosequencing, Bacterial diversity

Mangroves are among the most diverse and productive coastal ecosystems in the tropical and subtropical regions. Environmental conditions particular to this biome make mangroves hotspots for microbial diversity, and the resident microbial communities play essential roles in maintenance of the ecosystem. Recently, there has been increasing interest to understand the composition and contribution of microorganisms in mangroves. In the present study, we have analyzed the diversity and distribution of archaea in the tropical mangrove sediments of Sundarbans using 16S rRNA gene amplicon sequencing. The extraction of DNA from sediment samples and the direct application of 16S rRNA gene amplicon sequencing resulted in approximately 142 Mb of data from three distinct mangrove areas (Godkhali, Bonnie camp, and Dhulibhashani). The taxonomic analysis revealed the dominance of phyla Euryarchaeota and Thaumarchaeota (Marine Group I) within our dataset. The distribution of different archaeal taxa and respective statistical analysis (SIMPER, NMDS) revealed a clear community shift along the sampling stations. The sampling stations (Godkhali and Bonnie camp) with history of higher hydrocarbon/oil pollution showed different archaeal community pattern (dominated by haloarchaea) compared to station (Dhulibhashani) with nearly pristine environment (dominated by methanogens). It is indicated that sediment archaeal community patterns were influenced by environmental conditions.

Mangrove microbial communities and their associated activities have profound impact on biogeochemical cycles. Although microbial composition and structure are known to be influenced by biotic and abiotic factors in the mangrove sediments, finding direct correlations between them remains a challenge. In this study we have explored sediment bacterial diversity of the Sundarbans, a world heritage site using a culture-independent molecular approach. Bacterial diversity was analyzed from three different locations with a history of exposure to differential anthropogenic activities. 16S rRNA gene libraries were constructed and partial sequencing of the clones was performed to identify the microbial strains. We identified bacterial strains known to be involved in a variety of biodegradation/biotransformation processes including hydrocarbon degradation, and heavy metal resistance. Canonical Correspondence Analysis of the environmental and exploratory datasets revealed correlations between the ecological indices associated with pollutant levels and bacterial diversity across the sites. Our results indicate that sites with similar exposure of anthropogenic intervention reflect similar patterns of microbial diversity besides spatial commonalities.