Abhra Chanda

Jadavpur University | JU · School of Oceanographic Studies

Particulate matter (PM2.5) has long been recognized as a lethal air pollutant. Multifarious anthropogenic activities, especially in the urbanized belts, lead to this pollution, and the humans and other life forms thriving in these regions suffer the worst. In this regard, the present study collated the PM2.5 data for seven years (2017–2023) across...

This study characterized India's Kolkata and Howrah Municipal Corporations' air quality during three prominent waves of the coronavirus pandemic (25 March–14 April 2020; 15 May–30 May 2021; and 1 January–15 January 2022). The primary aim was to examine the role of these COVID-19 pandemic-induced lockdowns and their stringency and meteorological fac...

The study characterized the temporal and spatial variability in greenhouse gas (GHG) fluxes (CO2, CH4, and N2O) between December 2020 and November 2021 and their regulating drivers in the subtropical wetland of the Indian Himalayan foothill. Five distinct habitats (M1—sloppy surface at swamp forest, M2—plain surface at swamp forest, M3—swamp surfac...

The present study reports on a transient diatom bloom of Palmerina hardmaniana (Greville) Hasle 1996 encountered accidentally in May 2018 in the world's largest mangrove forest of Sundarbans, India. This bloom was the sixth record of diatom blooms from Indian coastal waters and the fourth from Sundarbans waters. The diatom cell count ranged from 2....

Small estuaries often remain neglected while characterizing air-water CO2 flux dynamics. This study reports the seasonal, spatial, and multi-annual variability of carbon biogeochemistry, emphasizing air-water CO2 flux from a small tropical mangrove-dominated estuary (Dhamra Estuary) of the Bay of Bengal, based on the 9-year-long sampling survey (20...

The seasonal and interannual variation in the partial pressure of carbon dioxide in water [pCO2(water)] and air-water CO2 exchange in the Mahanadi estuary situated on the east coast of India was studied between March 2013 and March 2021. The principal aim of the study was to analyze the spatiotemporal variability and future trend of pCO2 and air-wa...

Phytoplankton forms the base of the ecological food chain in any aquatic ecosystem and plays a crucial role in several biogeochemical processes in the marine waters that regulate the atmospheric gaseous composition. The Indian Ocean, especially the two flanks of this basin adjoining Indian landmass, the Bay of Bengal and the Arabian Sea, exhibits a...

The Sundarban is the world’s largest contiguous mangrove forest and stores around 26.62 Tg of blue carbon. The present study reviewed the factors causing a decline in its blue carbon content and poses a challenge in enhancing the carbon stock of this region. This review emphasized that recurrent tropical cyclones, soil erosion, freshwater scarcity,...

The present study assessed the micro-litter load in Bakkhali and Fraserganj Beaches, two tourist destinations on the West Bengal coast in the northern Bay of Bengal periphery. This study aimed to develop first-hand baseline information about the micro-litter load in the beach sediments, considering the essentiality of monitoring these pollutants an...

In towns and cities in developing countries, negligence in consistently regulating the growth of urban sprawl is commonplace. The purpose of the study was to analyze spatiotemporal changes in land use land cover (LULC) and their impact on land surface temperature (LST) in Balurghat, Dakshin Dinajpur district, West Bengal, India. The results reveale...

The Indian Sundarban has witnessed consecutive major cyclones (Cyclone Bulbul, Super Cyclone Amphan and Cyclone Yaas) in the 18 months between November 2019 and May 2021. Following Cyclone Yaas, the region also faced an extreme rainfall event. These extreme events have been compounded by the Covid-19 pandemic. This consecutive (and compound) hazard...

In the Indian Sundarban, multiple attributes and interactions of natural hazards, exposure, and vulnerability pose severe threats to lives and livelihoods. Understanding the cause-and-effect relationships contributing to the risk of loss of sustainable livelihoods has become imperative but has not yet been holistically explored in a single study th...

The present study reviewed the carbon-biogeochemistry-related observations concerning CO2 and CH4 dynamics in the estuaries adjoining the Indian Sundarbans mangrove ecosystem. The review focused on the partial pressure of CO2 and CH4 [pCO2(water) and pCH4(water)] and air–water CO2 and CH4 fluxes and their physical, biogeochemical, and hydrological...

Unlabelled: River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exploited landforms. The Global Delta Risk Index (GDRI) was developed to assess multi-hazard risk in river deltas and support decision-making in risk reduction interventions in delta regions. Disasters have significant impacts on the progress...

Sub-tropic Himalayan wetlands play a critical role in regional greenhouse gas (GHG) fluxes and budgets, consequently influencing climate change. Nevertheless, the magnitude, trends, and drivers regulating GHGs fluxes in the sub-tropic wetlands of the Indian Himalayan foothill remain uncertain. Herein, we characterized temporal and spatial GHGs flux...

All the oceans of planet Earth are inter-connected and comprise one huge water body. Due to wind-driven forces and thermohaline circulation, all the water molecules get circulated to every nook and corner of this giant water body. However, based on several physical and chemical properties, as well as geomorphological features, marine water bodies c...

Oceanic water columns, their overall health, and the ongoing biogeochemical processes in these oceanic masses are integral in regulating several global phenomena and providing ecosystem services to humankind. Ever since the potential of oceanic water bodies and the significance of all the biotic life forms in this hydrosphere have been realized by...

Excessive addition of nutrients causes nutrient over-enrichment, while nutrient bleaching creates a nutrient deficit in the aquatic ecosystems leading to the degradation of the natural ecology. The input of some elements.

The term "marine pollution" has several definitions. The ocean-scientific community universally accepts the one framed by a joint panel of experts formed by the United Nations in 1982 on the Scientific Issues of Marine Pollution.

Oceanic domains and their vast resources have been long used by humankind for their benefit.

Global plastic production crosses over 300 million tonnes every year. Plastics having varying properties like cheap, lightweight.

Technology has developed tremendously in the last few decades and the quality of lifestyle is improving day by day. Most of the gadgets, we are using nowadays, runs on electric power which are unique just because of its easy transmission through a pair of thin wires. On the other hand, 1.5 billion people in the world have no access to electricity (...

With the onset of globalization and increased anthropogenic activities over the seas, the number of cases of marine oil spillage has increased.

Oceanography (also referred to as oceanology) is a scientific study that focuses on the oceanic realms of the world. The gradual advent of several Earth science disciplines led to the emergence of oceanography as a subject. Since our elementary days, we have known that oceans comprise almost 71% of the Earth’s surface.

Organic compounds produced intentionally/unintentionally that can withstand environmental degradation and remain intact for a prolonged time are termed Persistent Organic Pollutants (POPs).

Several laboratory tests are used as the standardized parameters to detect the quality of the disposed wastewater. These are known as wastewater quality indicators.

A geomorphic hazard is a process or event in the physical environment that has the potential to negatively affect humans, their activities or the environment.

Our climate is changing in a rapid pace. Rapid industrialisation and dependence on fossil fuel increase the atmospheric carbon.

Heavy metals are found naturally in the earth’s crust; however, humankind has put these metals into use ever since the industrial revolution for multifarious purposes.

The NOAA defines Ocean Acidification as the reduction in the pH of the ocean over an extended time, caused primarily by the uptake of carbon dioxide (CO2) from the atmosphere.

Mining activities play an important role for the development of civilisation. Palaeolithic man first mined rock to create their weapon for hunting. Since then, the mining industries are engaged in exploiting the earth resource to cater to different other industries including metallurgy and chemical industry. The mineral resources are basically high...

Development in coastal area was started from the historic past with the development of port and ocean navigation.

The incidence of droughts and their intensity in recent times are affected by climatic variability and change, consequently affecting the agro-based economy of red and laterite zone (RLZ) India. In the present study, changing characteristics of meteorological droughts have been investigated over the sub-humid RLZ of West Bengal, India, using the St...

Inland aquaculture practice is becoming popular throughout the world to suffice the increasing protein demand of the growing population. Aquaculture ponds in general emit methane (CH4) towards the atmosphere. However, available data are scarce from India, where the number of aquaculture plots is growing at a fast pace. We measured the partial press...

Blue carbon means the organic form of carbon locked in the marine ecosystems, and the major repositories of such carbon are the mangroves, seagrasses, and salt marshes throughout the world. Pieces of evidence show that these ecosystems can store substantial quantities of carbon and have the potential to offset the anthropogenic carbon emissions. Al...

Recurrent droughts, particularly in the monsoon seasons, often severely affect the agricultural yield. Such short-lived yet acute droughts lead to crop failure, affecting the livelihood of small and marginal farmers of the sub-humid red and laterite zones (RLZs). The present paper analyses the monthly agricultural droughts during the monsoon season...

Blue carbon and its storage for a long time in the coasts and estuaries are one of the most important natural ways to combat and mitigate ongoing threats of climate change. Hence, measurement and estimation of blue carbon storage and burial became extremely crucial for researchers throughout the globe. In the last few decades, many cut-of-the-age t...

Assessment of land suitability for rain-fed cultivation in undulating terrains of red and lateritic zones (RLZ) is essential to enhancing agricultural productivity, given the recurrent droughts that are taking place due to the ongoing climate change. In this study, a GIS-based multi-criterion decision-making approach characterized the agricultural...

The present study collated data on the Indian blue carbon repository (mangroves, seagrasses, and salt marshes) from peer-reviewed literature on carbon stock assessment. This meta-analysis indicated that the blue carbon ecosystems of India could have a collective carbon stock of 67.35 Tg C (mangroves, seagrass, and salt marsh accounting for 67 Tg C,...

The climate of India reflects the instability and variability of the monsoon in the tropical regions of the country. Monsoon in India occurs annually, with variations in rainfall that adversely affect water resources, agriculture, and other regional conditions. The perception of the variability of the monsoon season is one of the critical problems...

Constant monitoring of the mangroves is important for understanding their health species assemblage and undertaking policies to rehabilitate or restore them. In this study, an attempt was made to classify and detect health and carbon stock in mangroves through a Remote Sensing perspective. The AVIRIS-NG dataset with high spectral (5nm) and spatial...

Darjeeling tea is one of the world's famous agro-products of India, which earned its' huge mercantile prospect in the global agricultural world. Darjeeling Tea serves as an ecological indicator, and it is India's first GI tagged product. The geographical features like altitude, rainfall, sunshine, and mist, coupled with the exquisite processing tec...

Estuaries and coastal waters are generally significant emitters of CO2 to the atmosphere. Globally, submarine groundwater discharge (SGD) is a significant driver of inorganic carbon dynamics and the partial pressure of CO2 in water [pCO2(water)] in estuaries and coastal waters. However, there are few studies of CO2 emission and SGD in large tropica...

Field Traverse on Sundarban Delta System, approved by 36th IGC Society, has been planned to be taken up during February 25-March 01, 2020. The trip will encompass visit to geo-tourism sites of the Ramsar wetland. Processes of delta building, erosional and accretional landforms, endangered flora and fauna including variety of mangroves, archaeologic...

The sub-humid regions of India have become vulnerable to recurrent drought in recent times due to climate change. Rainwater harvesting (RWH) has a promising potential to overcome water scarcity under a warming climate. The present study emphasizes a pragmatic methodology for evaluating potential sites for RWH structures (RWHSs) implementing multipl...

This book gives an overview of various aspects of blue carbon dynamics from each country bordering the Indian Ocean. Given the importance of the topic of blue carbon, it can be assumed that in near future, more and more researchers from the Indian Ocean countries will pursue environmental research in this domain. This book is a ready reference to a...

Expansion of aquaculture in the Sundarbans Biosphere Reserve (SBR) is irreversibly replacing agricultural land and the drivers of this change are disputed. Based on in-depth interviews with 67 aquaculture farmers, this paper characterizes major aquaculture types in the SBR, their impacts, and identifies drivers of conversion from agricultural land....

Indian Sundarbans Biosphere Reserve (SBR) comprising over 100 estuarine islands and shared by human habitation and mangrove forests is considered to be a potential area for coastal aquaculture. This study, using LANDSAT imageries of the last two decades (1999–2019), delineated the spatiotemporal expansion of aquaculture at the expense of agricultur...

Oceans have long been realized as a sink for CO2. Though this nature of oceans has changed many times in the glacial and interstadial phases that this planet has witnessed in the past. These vast water reservoirs play a crucial role in regulating the biogeochemical cycles of several important elements and gases that are integral to life, and carbon...

Anecdotal information indicates that salt marshes and tidal flats are prevalent in almost all the countries on the Indian Ocean rim. However, this region has received very little attention compared to the stretch and potential that coastal habitats can offer to mitigate climate change. The present chapter collated the existing information on the co...

Estuaries and coastal margins are one of the dynamic lotic ecosystems of this planet. The admixture of terrestrial inputs with the marine volume of seawater gives rise to a unique regime that leaves a signature on the global carbon dynamics. The blue carbon ecosystems grow and interact continuously with these shallow waters. The exchange of carbon...

The global scientific community unequivocally accepts the significance of mangroves in offsetting anthropogenic carbon emissions. This unique vegetation sequesters disproportionately high carbon than many other natural ecosystems, and the countries bordering the Indian Ocean host varying extents of mangrove cover in their coastlines. Small countrie...

Despite the debate that continues to go on, at present, corals do not qualify to be a part of the conventional blue carbon ecosystems. Nonetheless, these marine ecosystems are crucial as they provide a plethora of ecosystem services not only to humans but also to several blue carbon ecosystems. These ecosystems provide shelter to the adjacent seagr...

Seagrasses are flowering plants that thrive in marine environments. The high productivity of the seagrass meadows enables these vegetative covers to act as a net repository of blue carbon. In this context, this ecosystem has received substantial attention in the last decade. However, information is mostly available from the seagrasses of the Medite...

The blue carbon ecosystems like mangroves, seagrasses, and salt marshes are facing severe threats throughout the globe due to several natural and anthropogenic factors. The persistence of such imminent threats has led to a dire need for conservation and management plans for these crucial marine habitats. The present chapter reviewed the overall con...

Human beings have been on earth for almost six million years. Through this long journey, we have evolved physiologically and mentally and brought ourselves up as social animals. We learned to utilize the earth's valuable resources to meet daily life activities. However, in the past three centuries, the consumption of fossil fuels to meet the energy...

The scientific community and the common mass have unequivocally realized the significance of blue carbon habitats in mitigating climate change and providing livelihood options to the marginalized section of coastal people. Even then, these ecosystems witnessed a rapid decline in the last few decades, and several natural and anthropogenic factors po...

Coastal areas have become more susceptible and vulnerable to natural and human‐made hazards. The rise in sea level and associated erosion are slow onset hazards. It usually takes months or even years to observe the consequences of erosion; thus, it is generally known as a ‘Slow onset Coastal Hazard’. This work addresses the threats from rising sea...

Tide and lunar phases often influence the behaviour and life cycle of different fishes, especially migratory species. In the Hooghly River estuary, Hilsa shad is an anadromous fish species that migrates from the adjacent sea to the estuary and rivers for spawning. After spawning, the juveniles remain in the rivers and estuary for few months then st...

Wetlands are emitters of greenhouse gases. However, many of the wetlands remain understudied (like temperate, boreal, and high-altitude wetlands), which constrains the global budgets. Himalayan foothill is one such data-deficient area. The present study reported (for the first time) the greenhouse gas fluxes (CO2, CH4, N2O, and H2O vapor) from the...

The aquaculture ponds have been recognized as significant sources of greenhouse gases like CO2 and CH4 as a substantial amount of organic matter remains unspent during fish culture, which eventually mineralizes into inorganic form and escapes the water bodies as CO2 or the methanogens act upon these organic substrates to form CH4. The Indian Sundar...

The Indian Sundarbans, together with Bangladesh, comprise the largest mangrove forest in the world. Reclamation of the mangroves in this region ceased in the 1930s. However, they are still subject to adverse environmental influences, such as sediment starvation due to migration of the main river channels in the Ganges–Brahmaputra delta over the las...

The Indian part of Sundarbans hosts a population of more than 4.4 million people and the land-use-land-cover dynamics of this region has witnessed significant changes in the recent past due to multifarious anthropogenic interventions. Though several pieces of research characterized the land-use-land-cover dynamics of this region, exclusive focus on...

Ponds are small lentic bodies that are abundant throughout the world. In the rural setup of many Asian countries, especially in the deltaic regions (where adjacent waters are mostly saline), ponds serve as an essential source of freshwater. The Sundarbans is renowned for being the largest mangrove forest on Earth. India and Bangladesh share this un...

Small aquatic ecosystems like ponds and lakes have been found to emit a significant amount of CH4 towards the atmosphere and their role is worth inclusion in delineating the global CH4 budget. The Sundarbans Biosphere Reserve (SBR) of India, besides being the abode of the world’s largest mangrove forest, shelters almost 4.4 million people with a su...

Though agriculture continues to be the predominant livelihood option for the millions residing within the Indian Sundarban Biosphere Reserve (SBR), inland fishing has lately emerged as a promising and viable option to alleviate the financial status of the grossly impoverished population of this region. Ponds and rearing of fishes in those ponds are...

Numerous fresh and saline-water tropical aquaculture ponds that often can be significant sources super-saturation of CO2 towards the atmosphere are gradually increasing throughout the world. The role of salinity in regulating the chlorophyll-a and dissolved pCO2 in a freshwater aquaculture pond, situated in East Kolkata Wetlands, Eastern India, was...

Lentic ecosystems though encompass a much smaller area compared to the lotic water bodies of the world, are found to emit substantial quantities of greenhouse gases like CO2, towards the atmosphere. The Sundarbans Biosphere Reserve (SBR) of India, besides being the abode of the world’s largest mangrove forest, shelters almost 4.4 million people wit...

The present study characterized the difference in air pollution levels between Diwali celebrations amidst the Covid-19 pandemic (14 November 2020) and the previous year (27 October 2019). The concentration of seven principal air pollutants, namely PM2.5, PM10, NO2, NH3, SO2, CO, and O3, was substantially higher in 2020 Diwali than in 2019 Diwali. P...

This book aims to give a holistic overview of the pond ecosystem of Indian Sundarbans. Due to climate change, the Indian Sundarbans faces several challenges. With rising sea levels, islands are disappearing and the increasing salinity in the water and soil has severely threatened the health of mangrove forests and the quality of fresh water, soil a...

data were integrated into GIS-based modeling by a multi-criteria decision-making technique (analytical hierarchy process) to generate the habitat suitability maps of juvenile Hilsa. The model-derived information was verified with the indigenous knowledge of the fishers regarding the suitable habitat of juvenile Hilsa by conducting group discussions...

The seasonal variability of the lateral flux of total alkalinity (TAlk) and dissolved inorganic carbon (DIC) of the tropical Hooghly estuary is analyzed in this work. In situ observations of water temperature, salinity, dissolved oxygen, TAlk, and pH were measured in four different stations of the Hooghly estuary. It was measured once every month d...

Reduction in riverine freshwater supply due to climate change as well as anthropogenic activities are documented throughout the globe. How river discontinuity in upstream reaches and the subsequent reduction in freshwater influx alter inorganic and organic carbon dynamics in downstream estuaries adjacent to mangroves has been rarely reported. We in...

Estuarine sediments, especially the mangrove-dominated ones, are prone to accumulate several trace metals. The Hooghly-Matla estuary is such a unique ecosystem where anthropogenic influences pollute the pristine mangroves and the adjacent estuarine sediments. The present review collated all data acquired so far in the last two decades (2000 to 2021...

COVID-19 pandemic compelled many countries in the world to go for a nationwide lockdown to prevent the spread of the coronavirus. India started the lockdown on 24 March 2020. We analyzed the air quality of three megacities of India, namely Mumbai, Delhi, and Kolkata, during the lockdown phase and compared it with the pre-lockdown and post-lockdown...

Persistent organic pollutants (POPs) comprise an array of organic pollutants, renowned for their toxicity and bioaccumulation potential. These POPs exist in abundance in the coastal and estuarine sediments, water column, and biotas, which are impacted by city sewage, agricultural runoffs, aquaculture practices, and others. This chapter summarized t...

Salinity, pH, dissolved oxygen (DO), dissolved inorganic nitrate (DIN), dissolved inorganic phosphate (DIP), and reactive silicate (DSi) concentrations were measured in three tidal creeks in the Sagar Island (situated within the Sundarban Biosphere Reserve, India) during 2016–17, once in a month throughout an annual cycle. The present observations...

The northeastern flank of the Indian ocean, i.e., the Bay of Bengal (BoB), is considered to be one of the most dynamic oceanic regions of the world. A significant amount of river discharge from several perennial estuaries vis-à-vis the effect of monsoon and frequent depression and tropical cyclones makes the estuarine and coastal waters of the BoB...