Mangrove Region Research Articles

The dynamic mechanism of rapid sediment deposition in the mangrove region of the Guangxi Beibu Gulf

The dynamic mechanism of rapid sediment deposition in the mangrove region of the Guangxi Beibu Gulf

The Sustainable Tourism Potential of Tongke-Tongke Mangrove Forest in Sinjai Regency

This research investigates whether or not the Tongke-Tongke mangrove forest in Sinjai Regency has the potential to become an eco-friendly tourism destination. In accordance with the tenets of sustainable tourism, the study looks at the effects that this natural marvel has on many aspects of society and the natural environment. The Tongke-Tongke mangrove region has received a lot of attention from the local government and many stakeholders, which has helped it evolve into a model for collaborative sustainable tourism projects. This research sheds light on the many ways in which the mangrove forest contributes to the local economy, such as the creation of jobs and the maintenance of a wide variety of animal species. In addition to this, it investigates the accessibility, tourist facilities, and public amenities in Sinjai Regency that contribute to positive visitor experiences there. The Tongke-Tongke mangrove forest is a potential contribution to both the economic growth of the local community and the protection of the natural environment, especially as the area works toward more responsible management of tourism.

Microplastic pollution in surface waters and sediments matrices of the Sundarbans – The largest single block of tidal halophytic mangrove forest in the world

The Sundarbans, which is the largest mangrove forest in the world, are immensely threatened by plastic waste. For Sundarbans, plastic pollution is a relatively recent and serious issue. We investigated the quantitative assessment of microplastics (MPs) in surface waters, and sediments in the Sundarbans mangrove region of the northern Bay of Bengal, Bangladesh coast. The average concentrations of MPs observed during the pre-monsoon sampling period (surface water: 81,056 ± 8085 items/km2, sediments: 47 ± 11 items/kg) were higher than the post-monsoon (surface water: 73,722 ± 9096 items/km2, sediments: 41 ± 7 items/kg). MPs abundance was significantly higher in the downstream sampling station compared to the upstream. MPs were dominated by fibers in type, smaller dimensions (301–500 µm) in shape, black in color, and polyethylene terephthalate (surface water: 30%, sediments: 24%) in composition. Comprehensive research is strongly urged for plastic contamination controls and management of this crucial ecosystem.

Malacofaunal diversity (Gastropods and Bivalves) along the mangrove forest area of the Gulf of Mannar marine biosphere region, South India

The mangrove ecosystem is one of the most distinctive biospheres, and it is under threat from habitat loss, aquaculture expansion, overharvesting, and pollution, all of which impact the malacofaunal diversity. This study aimed to investigate the malacofaunal diversity along the mangrove region of the Gulf of Mannar (GoM) and Physico-chemical properties of the sediments were measured to correlate the malacofaunal diversity. The diversity of the molluscs along the Thoothukudi coast was investigated from December 2020 to September 2021, documenting 84 mollusc species, represented by 45 gastropods and 39 bivalves. The class Gastropoda represented 7 orders, 15 families, and 30 genera, with Caenogastropoda having the highest species (19), followed by Neogastropoda with 7 species, while in bivalves, Venerida had the most species (14 species), followed by Cardiida (9 species). Palayakayal had the greatest number of species (68), followed by Punnakayal (63), Karapad Bay (32), and Machoda Bridge (33). Palayakayal has the highest Shannon–Wiener diversity index (H’) and Margalef species richness (d) at 4.11 and 10.81, followed by Punnakayal at 4.05 and 10.16; Karapad at 3.39 and 5.65; and Machoda Bridge at 3.55 and 3.55 respectively. The BC (Bray–Curtis)​ similarity index identified the most similarity (86.91%) between Palayakayal and Punnakayal. Palayakayal has the greatest (H’) and (d) values due to its pristine mangrove habitat and low anthropogenic activity. The Physico-chemical results showed that salinity and diversity were positively correlated, while hydrogen sulfide, organic matter, and molluscan diversity were negatively correlated. The malacofaunal diversity has been documented to provide useful baseline data for conservation management. Additionally, the findings showed that salinity is a crucial factor in favoring diversity. The anthropogenic activities in the ecosystem first alter the salinity of the soil, directly impacting malacofaunal diversity. Such studies might increase knowledge among the public and policy-makers, enabling them to develop legislation adequately.

Molecular Changes in the Brain of the Wintering Calidris pusilla in the Mangroves of the Amazon River Estuary.

Migrant birds prepare differently to fly north for breeding in the spring and for the flight to lower latitudes during autumn, avoiding the cold and food shortages of the Northern Hemisphere's harsh winter. The molecular events associated with these fundamental stages in the life history of migrants include the differential gene expression in different tissues. Semipalmated sandpipers (Calidris pusilla) are Arctic-breeding shorebirds that migrate to the coast of South America during the non-breeding season. In a previous study, we demonstrated that between the beginning and the end of the wintering period, substantial glial changes and neurogenesis occur in the brain of C. pusilla. These changes follow the epic journey of the autumn migration when a 5-day non-stop transatlantic flight towards the coast of South America and the subsequent preparation for the long-distance flight of the spring migration takes place. Here, we tested the hypothesis that the differential gene expressions observed in the brains of individuals captured in the autumn and spring windows are consistent with the previously described cellular changes. We searched for differential gene expressions in the brain of the semipalmated sandpiper, of recently arrived birds (RA) from the autumnal migration, and that of individuals in the premigratory period (PM) in the spring. All individuals were collected in the tropical coastal of northern Brazil in the mangrove region of the Amazon River estuary. We generated a de novo neurotranscriptome for C. pusilla individuals and compared the gene expressions across libraries. To that end, we mapped an RNA-Seq that reads to the C. pusilla neurotranscriptome in four brain samples of each group and found that the differential gene expressions in newly arrived and premigratory birds were related with neurogenesis, metabolic pathways (ketone body biosynthetic and the catabolic and lipid biosynthetic processes), and glial changes (astrocyte-dopaminergic neuron signaling, astrocyte differentiation, astrocyte cell migration, and astrocyte activation involved in immune response), as well as genes related to the immune response to virus infections (Type I Interferons), inflammatory cytokines (IL-6, IL-1β, TNF, and NF-κB), NLRP3 inflammasome, anti-inflammatory cytokines (IL-10), and cell death pathways (pyroptosis- and caspase-related changes).

An Improved Framework for Estimating Organic Carbon Content of Mangrove Soils Using loss-on-ignition and Coastal Environmental Setting

The use of loss on ignition (LOI) measurements of soil organic matter (SOM) to estimate soil organic carbon (OC) content is a decades-old practice. While there are limitations and uncertainties to this approach, it continues to be necessary for many coastal wetlands researchers and conservation practitioners without access to an elemental analyzer. Multiple measurement, reporting, and verification (MRV) standards recognize the need (and uncertainty) for using this method. However, no framework exists to explain the substantial differences among equations that relate SOM to OC; consequently, equation selection can be a haphazard process leading to widely divergent and inaccurate estimates. To address this lack of clarity, we used a dataset of 1,246 soil samples from 17 mangrove regions in North, Central, and South America, and calculated SOM to OC conversion equations for six unique types of coastal environmental setting. A framework is provided for understanding differences and selecting an equation based on a study region’s SOM content and whether mineral sediments are primarily terrigenous or carbonate in origin. This approach identifies the positive dependence of conversion equation slopes on regional mean SOM content and indicates a distinction between carbonate settings with mean (± 1 S.E.) OC:SOM of 0.47 (0.002) and terrigenous settings with mean OC:SOM of 0.32 (0.018). This framework, focusing on unique coastal environmental settings, is a reminder of the global variability in mangrove soil OC content and encourages continued investigation of broadscale factors that contribute to soil formation and change in blue carbon settings.

Determination and evaluation of the ecological risk of mercury in different granulometric fractions of sediments from a public supply river in Brazil

This work reports the quantification of total mercury in sediments collected in periods with and without rain from the Joanes River, Bahia, Brazil. Determinations were made using Direct Mercury Analysis (DMA), the accuracy of which was confirmed with two certified reference materials. The highest total mercury concentrations were found at the sampling point close to commercial areas and large residential condominiums. On the other hand, the lowest levels were found in the site close to a mangrove region. The geoaccumulation index was applied to the total mercury results, evidencing low contamination in the region studied. The contamination factor showed that of the seven stations investigated, four samples collected in the rainy season showed moderate contamination. The results of the ecological risk assessment were utterly consistent with the contamination factor data. This study showed that the smaller sediment particles concentrate more mercury, corroborating what has been predicted by the adsorption processes.

Isolation and characterization of halotolerant plant growth promoting rhizobacteria from mangrove region of Sundarbans, India for enhanced crop productivity.

Halotolerant plant growth promoting rhizobacteria (PGPR) are beneficial microorganisms utilized to mitigate the biotic and abiotic stresses in plants. The areas of Sundarban mangroves of West Bengal, India have been reported to be rich in halotolerant microflora, yet major area remains unexplored. The present study, therefore, aims to map down the region-specific native microbial community potent of salt tolerance, plant growth promoting (PGP) activity and antagonistic activity against fungal pathogens. Bacterial samples were isolated from the saline soil of the Sundarban mangroves. A total of 156 bacterial samples were isolated and 20 were screened for their salt tolerance potential. These isolates were characterised using morphological, biochemical, and molecular approaches. Based on 16s rRNA sequencing, they were classified into 4 different genera, including Arthrobacter sp. (01 isolate), Pseudomonas plecoglossicida (01 isolate), Kocuria rosea (01 isolate), and Bacillus (17 isolates). The halotolerant isolates which possessed plant growth promoting traits including phosphate, and zinc solubilization, indole acetic acid production, siderophore, and ammonia generation were selected. Further, the effect of two halotolerant isolates GN-5 and JR-12 which showed most prominent PGP activities was evaluated in pea plant under high salinity conditions. The isolates improved survival by promoting germination (36 to 43%) and root-shoot growth and weight of pea plant in comparison to non-inoculated control plants. In a subsequent dual culture confrontation experiment, both these halo-tolerant isolates showed antagonistic activities against the aggressive root rot disease-causing Macrophomina phaseolina (Tassi) Goid NAIMCC-F-02902. The identified isolates could be used as potential bioagents for saline soils, with potential antagonistic effect on root rot disease. However, further studies at the physiological and molecular level would help to delineate a detail mechanistic understanding of broad-spectrum defence against salinity and potential biotic pathogen.

Climate vs. nutrient control: A global analysis of driving environmental factors of wetland plant biomass allocation strategy

Wetland plant biomass and its allocation are sensitive to environmental changes, and they make up a significant part of the carbon pool in wetlands. Here, we collected global data on wetland plant biomass from 1980 to 2021. Based on an analysis of 1134 observations from 182 published papers on wetland ecosystems, we generated spatially explicit global maps of belowground biomass (BGB) to aboveground biomass (AGB) ratio of wetland plants. Our study found that AGB is higher in tropical mangrove regions while BGB is higher in cold regions at high latitudes. AGB did not show a significant response to any individual environmental factors (p > 0.05). In the contrast, plant BGB is influenced by total phosphorus (p < 0.05) but not total nitrogen, and extreme temperatures are the main driver of plant BGB (p < 0.05). Compared to climate factors, soil nutrients were the main factor affecting plant biomass allocation in different wetland types. The relationships between the wetland plant biomass and their environmental conditions are discussed, which provided a basis for further understanding the conservation of wetland plants under environmental change.

A distributed land cover classification of FP and CP SAR observation using MapReduce-based multi-layer perceptron algorithm over the Mumbai mangrove region of India

ABSTRACT Globally, the rapid loss of mangrove forests often creates long-lasting environmental damage alongside coastlines, mudflats, and river banks. All-weather, physical monitoring of such areas is almost impossible because of inaccessibility to swampy areas and a hostile substrate. Subsequently, conventional field surveys are relatively unavailable to monitor human encroachment in coastal areas like the Mumbai mangrove region of India. In this context, the polarimetric synthetic aperture radar (PolSAR) remote sensing tool becomes a potential candidate for mangrove conservation and management. Since the Mumbai mangrove region of India exists over the extensive land cover, the large-scale classification can articulate the continuous encroachment because of the location of human settlements or activities across this metropolitan coastal city. For this, the traditional algorithms need the essential improvisation to apply for large-scale data analysis, aiming simultaneously at getting the highest decisive and time efficiency. Here, we introduce a shallow learning model of MapReduce-based Multi-Layer Perception (MLP) algorithm to classify the hybrid compact polarimetric (CP) and fully polarimetric (FP) feature space. Even though a shallow learning model of the automated method is easily scalable, it requires a distinctive shallow learnable feature set for better land cover classification. In this effort, this paper investigates the efficacy of derived feature space compared to direct polarimetric measurements of sensors and shows that the shallow learnable feature set is more effective with both CP & FP observations. Simultaneously, the relevancy of the proposed distributed model of MLP is also justified compared to distributed extreme learning machine (DELM) algorithm and provides a practically implementable scaled-MLP algorithm of shallow learning model. Ultimately, this paper comes up with a better polarimetric signature of land types for both the CP and FP datasets, which can be used in an alternative manner as per data availability for a multi-sensor data analysis.

Mangrove reforestation provides greater blue carbon benefit than afforestation for mitigating global climate change

Significant efforts have been invested to restore mangrove forests worldwide through reforestation and afforestation. However, blue carbon benefit has not been compared between these two silvicultural pathways at the global scale. Here, we integrated results from direct field measurements of over 370 restoration sites around the world to show that mangrove reforestation (reestablishing mangroves where they previously colonized) had a greater carbon storage potential per hectare than afforestation (establishing mangroves where not previously mangrove). Greater carbon accumulation was mainly attributed to favorable intertidal positioning, higher nitrogen availability, and lower salinity at most reforestation sites. Reforestation of all physically feasible areas in the deforested mangrove regions of the world could promote the uptake of 671.5–688.8 Tg CO2-eq globally over a 40-year period, 60% more than afforesting the same global area on tidal flats (more marginal sites). Along with avoiding conflicts of habitat conversion, mangrove reforestation should be given priority when designing nature-based solutions for mitigating global climate change.

SYSTEMATIC STUDY OF CARBON SEQUESTRATION OF MANGROVE FORESTS AT RAIGAD DISTRICT COAST, MAHARASHTRA, INDIA

Mangrove forests are highly productive ecosystems with carbon sequestration rate almost equivalent to tropical green forests. Mangroves distribute proportionally more carbon below ground and possess higher below to above ground carbon mass ratio as compared to any other forests (Kathiresen, 2004). Mangrove is amongst the most carbon rich biomes containing more than 950 tC/H. The said study overlooks destructive and non-destructive methods of the carbon sequestration. It is conducted as a comparative assessment of the carbon sequestration potential of mangrove and non-mangrove regions. By means of methodology of calculating Soil Bulk Density (gcm -3) and Total Organic Carbon (TOC) in mangroves soils (El Wakeel and Riley, 1956) and Carbon Sequestration Rate (CSR) is estimated based on the sediment rates and TOC content of the soil (Duan Xiaonan et al (2008). The systematic assessment conducted at West Coast of Maharashtra; shows mangrove region with Avicinnia marina species and in non–mangrove region total carbon in soil (%) recorded 17.15% and 4.52 percent respectively. Total Soil Carbon Stock recorded is 431 million g / Ha at mangrove region and 105.7 million g / Ha at non mangrove region. After methodical estimation of biomass and carbon stock of mangroves (English et.al, 1997 and Kaufman and Donato, 2012), total carbon stock of mangrove stand was recorded 393.14 mg/Ha and that of non-mangrove stand was recorded to be 91.7 mg/Ha. It shows that mangroves absorb almost 315.14 percent more carbon than non-mangrove region. In other words, carbon stock in Avicinnia marina stand found to be almost 3 times more than non-mangrove zone.

Watershed Management and Classification in Thailand

Based on a study of research and experiences in Thailand, this paper provides an overview of the implementation and challenges of watershed management, as well as potential solutions. The review found hierarchical ambiguity, inconsistency, and asynchrony across rules, as well as a lack of (participation, synchronization, and coordination) among watershed management stakeholders. Deficitsin the planning phase include a lack of integration between sectors, a lack of community participation, and a limited willingness to integrate watershed planning into regional planning. Stakeholder participation is also essential for the successful implementation of degraded watershed rehabilitation, including in terrestrial forest and mangrove regions. Failure should be minimized by providing adequateknowledge about degraded watershed characteristics, selecting appropriate plant species, and employing good mechanical construction techniques for soil and water conservation. Increase public understanding of the importance of a sustainable watershed and provide opportunities for community involvement in each phase of watershed management to achieve community participation as the majordriver of watershed management. Another issue is data gaps, which must be addressed from the designthrough the evaluation stages. The gaps can be filled using remotely sensed data and hydrologically based modeling models. Simplified watershed assessment criteria may also be required, depending on site-specific challenges and the extent of the watershed.

A Strategy for preventing coastal degradation due to mangrove logging on the coast of Bintan Island, Indonesia to prevent shallowing of the strait by applying international principles: The common heritage of mankind

Mangroves are important as a green belt for coastal areas. Mangrove logging is causing coastal degradation due to logging mangroves for land clearing. This study employs a qualitative and empirical legal method to analyze the issues that need addressing in this study on law enforcement in preventing coastal degradation caused by mangrove cutting in coastal Bintan, Indonesia, to prevent siltation of waters and straits through the application of the principle of the common heritage of mankind, so that marine and coastal sustainability can be realised. From the national data, the distribution of mangrove forests in Riau Islands Province is 68,417 ha, 37.000 hectares have been damaged, and at least 37 thousand ha have been destroyed. In addition, mangrove degradation, including logging, leads to problems of sea silt, which can negatively impact upstream agriculture and estuarine agriculture. The principle of shared heritage of mankid must be implemented in the mangrove region. Therefore, coastal mangrove must be conserved in order to prevent destruction and the shallowing of the sea or strait.

Nutrients and trace elements of semi-arid dwarf and fully developed mangrove soils, northwestern Venezuela

Mangrove forests are characterized by a high carbon storage capacity. Anthropogenic activities and the climate change are threatening the stability of these ecosystems, specially those that are surviving on extreme environmental conditions, representing the most susceptible groups. This study aims to understand the geochemical differences of soils of mangrove forest with diverse degree of development of Rhizophora mangle and Avicennia germinans, located in two semi-arid regions from the Falcon state, Venezuela. The soil samples were collected in Punta Caimán region (dwarf mangroves of less than 2 meters height) and Boca de caño lagoon (fully developed mangroves of up to 8 meters height). The trace elements and macronutrients were determined in two sequential extraction, first with 1M HCl followed by an extraction with ultrapure grade HNO_{3}. Results showed that, in general, dwarf mangroves have limited capability to accumulate organic matter in the soil (average TOC of 0.6 pm 0.2%) and that the sampled surface soils from the dwarf mangrove region had no differences with deeper material. On the other hand, the TOC of soils dominated by developed mangroves is 6 pm 2 %, representative of semi-arid conditions. Moreover, the soils dominated by dwarf mangroves are characterized high concentrations of trace elements related to the chalcophile group. The difference in soil chemistry between Rhizophora mangle and Avicennia germinans becomes significant when mangroves are fully developed. Finally, soils of dwarf mangrove forests presented a greater concentration of trace elements than soils of fully developed mangroves, which might be due to a different sediment source, to an anthropogenic influence or to the difference in organic matter.

Multigene Phylogenies of the Estuarine Sesarmid Parasesarma bidens Species Complex (Decapoda: Brachyura: Sesarmidae), with Description of Three New Species.

S Parasesarma bidens (De Haan, 1835) is a common intertidal sesarmid crab that inhabits the estuarine and mangrove regions of East Asia, as well as Vietnam and the Philippines. Previous studies have suggested that P. bidens is a species complex composed of several species. Our findings indicated that the P. bidens species complex is monophyletic with six clades, as shown by reconstructed phylogenies based on mitochondrial 16S rDNA and cytochrome c oxidase subunit I, as well as nuclear 28S rDNA. Specimens of each clade exhibited different characters, including the morphology of the cheliped, anterior carapace, male gonopod 1, and female vulvae, as well as the coloration. Three species in this complex have been previously described: P. bidens (De Haan, 1835), P. cricotum (Rahayu & Davie, 2002), and P. sanguimanus Li, Shih & Ng, 2019. Here, we describe three additional species: P. continentale n. sp., P. insulare n. sp., and P. chiahsiang n. sp. Biogeographically, the range of P. bidens includes the southern margin of Korea, the main islands of Japan, and the Ryukyus, with a comparatively northern distribution. P. continentale is widely distributed from the continental coasts of southeastern and southern China (including northern Hainan Island) to southern Vietnam and is occasionally found in Penghu, Taiwan. Parasesarma insulare is an insular species distributed from Taiwan main island, the central Philippines, to northern Borneo. Finally, P. chiahsiang is mainly limited to the Penghu Islands (Pescadores) but is also sometimes found in Taiwan main island and the offshore Gueishan Island.

Modelling of sediment plume associated with the capital dredging for sustainable mangrove ecosystem in the Old Mangalore Port, Karnataka, India

Old Mangalore port is located at the Confluence of River Gurpur and Netravathi in the Mangalore District, Karnataka. The Ministry of Shipping has promoted the modernisation of ports, including the Old Mangalore port, under the Sagarmala Project. The Old Mangalore port’s navigational channel is approximately 3.2 km long and 80 m wide. It is proposed to deepen the existing approach channel to 7 m to allow medium-capacity vessels access to the port. The expected quantity of dredging is estimated to be 1160000 m3. We investigated the sediment spill plume movement of the dredging/dumping operations at Old Mangalore port using FVCOM (Finite Volume Community Ocean Model). Analysis showed that the spill plume was moved towards the offshore direction during the wet season and is primarily dictated by the prevailing currents and freshwater influx from the rivers. During the dry season (minimal discharge), the plume spreads approximately 8 km to the upstream regions and is mainly controlled by tidal currents. The study also revealed that the dumping point at a distance of 18–20 km offshore (depth > 20 m) is ideal for the optimum settling of the sediments for both seasons. The capital dredging of a navigational channel and construction of a new coastal berth is a one-time operation. Any siltation of the river mouth during the dry season will likely be flushed out in the subsequent wet season. We identified 12 types of mangrove species in the vicinity of the dredging area, and mangroves near the Old Mangalore port may be more exposed to the dredging activities impacts. Spillage during the dredging produces the sediment plume, and its transport to the mangrove region may choke the root system, thereby reducing oxygen availability. Hence, the study recommends that dredging operations can be carried out at any season but restricted to the ebb tide, thereby preventing the movement of sediment plumes to the mangrove region and thus conserving the mangrove ecosystem.

Are the Sundarbans, the World's largest mangroves region under threat?—An ecosystem‐based geospatial approach to assess changes past, present, and future in relation to natural and human‐induced factors

AbstractThe World's most extensive mangrove region, the Sundarbans ecosystem, is highly biodiverse but severely stressed. Past, present, and future potential changes in Sundarbans mangroves have been assessed from multi‐temporal satellite data of 1980, 2000, and 2020, elevation data, and topographical maps using geospatial techniques, digital shoreline analysis system, land change modelling, and ground truth verification. The mangrove loss was 16,025 ha between 1980 and 2020 and is predicted to be 22,286 ha between 2020 and 2050. Major changes were observed in mangroves, waterbodies, mudflats, agriculture, and aquaculture. The shoreline change by endpoint rate indicated the erosion rate by 5.81 m yr−1 in 2000–2020 compared to −0.90 m yr−1 in 1980–2000. The weighted linear regression indicated the average erosion and accretion rate of −5.96 m‐yr −1 and 4.92 m yr−1, respectively, with erosion in 76% of transects and accretion in the remaining 24% between 1980 and 2020. A sea‐level rise by 1 m will inundate 17,486 ha of mangroves. The finding revealed the dynamic nature of mangroves, past and expected future loss, the severely eroding transects, hotspots, and the consequences of mangrove loss on depending the population. As fringe mangroves will be at greater risk, speedy measures are needed to stabilize the highly eroding regions.

16S rRNA genes developed a baseline of the microbial community associated with soil, water, fish and shellfishes in the sundarbans of Bangladesh

The microbial environment of the Sundarbans mangrove forest contains sediments and water usually more diverse than the other aquatic environment, and pathogenic for finfish and shellfishes will be revealed by phylogenetic tree analysis of the positive controls PCR product. Approximately, 21 samples of the soil, 21 samples of water, 21 samples of fish, and shellfishes are dominated by typical mangrove habitats surrounded by Sathkhira, Khulna, and Bagherhat have been covered. The bio-physiochemical test was carried out after isolation and culture of the microorganisms from soil, water, fish &amp; shellfishes. Initially, the bio-physiochemical and molecular survey tools were used to finally screen 63 samples, which were used for the genomic DNA extraction, and the accurate quantitative and qualitative estimation of the extracted DNA was confirmed by Nano-drop. Finally, 12 samples were confirmed using Nano-drop calibration for PCR amplification and UV-translumination. The allelic and loci variation, genetic diversity, heterozygosity, PIC, genetic distance, and similarity within the genotypes (samples) were examined. This research technique is a rapid and effective tool for diversity assessment; this result might be helpful to the development of a genetic baseline of the pathogenic bacterial and viral community in the Sundarbans of Bangladesh to control the diseases of fish and shellfishes in mangrove regions.

MOLECULAR PROFILING, IN-VITRO ANTIMICROBIAL AND ANTIOXIDANT ASSAYS OF ANTAGONISTIC FUNGUS ASCOTRICHA SINUOSA VJCH-18 FROM MANGROVES OF ANDHRA PRADESH, INDIA

The fungi from mangrove habitats are the immense source for biologically active secondary metabolites with therapeutic potential. The objective of the present study is to screen the potent fungi from mangrove sediments that could produce secondary metabolites active against pathogenic microbes. Soil samples collected from mangrove regions of Adavuladeevi, South coast of Andhra Pradesh, India were employed for isolation of fungi using serial dilution plate technique. To isolate fungi, three media viz. Czapek-Dox agar, potato-dextrose agar and Sabouraud-dextrose agar media supplemented with 2% sodium chloride were used. 18 fungal strains isolated from the samples were designated as VJCH-1 to VJCH-18 and evaluated for antimicrobial and antioxidant activities. Among them, VJCH-18 showed broad spectrum of antimicrobial and antioxidant activities. The strain was cultured in Sabouraud-dextrose broth to record growth phases. Ethyl acetate extract of culture broth was active against bacteria (Escherichia coli, Proteus vulgaris) and fungi (Candida albicans). The strain exhibited significant antioxidant activity against DPPH free radicals. Characterization of the strain was performed based on cultural, morphological and genomic characteristics using 18s r RNA sequencing and identified as Ascotricha sinuosa VJCH-18 (GenBank accession number: MK463994). The study suggested that fungi from unexplored mangrove habitats of South coast of Andhra Pradesh serve as a source for antimicrobial and antioxidant compounds.