Vertical current structure in a macro-tidal, well mixed Sundarban ecosystem, India

Pitchaikani, J. Selvin

doi:10.1007/s11852-020-00782-4

Cited by 12 publications

(3 citation statements)

References 22 publications

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“…These are interconnected by a complex network of east-to-west flowing channels. The tidal amplitude is between 3.5 m and 4 m, with seasonal variation between 1 and 6 m and a strong lunar 18.6-year nodal cycle [46]. The region is characterized by a tropical climate with a dry season between November and April and a wet monsoonal period over the rest of the year.…”

Section: The Sundarban Biosphere Reserve Indiamentioning

confidence: 99%

Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020

et al. 2021

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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 last few centuries, cyclone landfall, wave action from the Bay of Bengal—changing hydrology due to upstream water diversion—and the pervasive effects of relative sea-level rise. This study builds on earlier work to assess changes from 2000 to 2020 in mangrove extent, genus composition, and mangrove ‘health’ indicators, using various vegetation indices derived from Landsat and MODIS satellite imagery by performing maximum likelihood supervised classification. We show that about 110 km2 of mangroves disappeared within the reserve forest due to erosion, and 81 km2 were gained within the inhabited part of Sundarbans Biosphere Reserve (SBR) through plantation and regeneration. The gains are all outside the contiguous mangroves. However, they partially compensate for the losses of the contiguous mangroves in terms of carbon. Genus composition, analyzed by amalgamating data from published literature and ground-truthing surveys, shows change towards more salt-tolerant genus accompanied by a reduction in the prevalence of freshwater-loving Heiritiera, Nypa, and Sonneratia assemblages. Health indicators, such as the enhanced vegetation index (EVI) and normalized differential vegetation index (NDVI), show a monotonic trend of deterioration over the last two decades, which is more pronounced in the sea-facing parts of the mangrove forests. An increase in salinity, a temperature rise, and rainfall reduction in the pre-monsoon and the post-monsoon periods appear to have led to such degradation. Collectively, these results show a decline in mangrove area and health, which poses an existential threat to the Indian Sundarbans in the long term, especially under scenarios of climate change and sea-level rise. Given its unique values, the policy process should acknowledge and address these threats.

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Section: The Sundarban Biosphere Reserve Indiamentioning

confidence: 99%

Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020

et al. 2021

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“…However, many estuaries lost their connection with the perennial flow of the Ganges and are on the verge of losing their estuarine character, especially during the dry seasons [ 57 ]. This region experiences semi-diurnal tides of varying amplitudes and strong tidal currents [ 58 ]. Oceanographers classify the Sundarban estuaries as meso–macro tidal ones.…”

Section: Introductionmentioning

confidence: 99%

Challenges towards the Sustainability and Enhancement of the Indian Sundarban Mangrove’s Blue Carbon Stock

Chanda,

Akhand

2023

Life

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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, reduced sediment load into the delta, nutrient deficiency, salt-stress-induced changes in species composition, mangrove clearing, and anthropogenic pollution are the fundamental drivers which can potentially reduce the total blue carbon stock of this region. The southern end of the Ganges–Brahmaputra–Meghna Delta that shelters this forest has stopped its natural progradation due to inadequate sediment flow from the upper reaches. Growing population pressure from the north of the Sundarban Biosphere Reserve and severe erosion in the southern end accentuated by regional sea-level rise has left minimal options to enhance the blue carbon stock by extending the forest premises. This study collated the scholarly observations of the past decades from this region, indicating a carbon sequestration potential deterioration. By collecting the existing knowledge base, this review indicated the aspects that require immediate attention to stop this ecosystem’s draining of the valuable carbon sequestered and, at the same time, enhance the carbon stock, if possible. This review provided some key recommendations that can help sustain the blue carbon stock of the Indian Sundarban. This review stressed that characterizing the spatial variability of blue carbon with more sampling points, catering to the damaged trees after tropical cyclones, estuarine rejuvenation in the upper reaches, maintaining species diversity through afforestation programs, arresting coastal erosion through increasing sediment flow, and combating marine pollution have become urgent needs of the hour. The observations synthesized in this study can be helpful for academics, policy managers, and decision makers willing to uphold the sustainability of the blue carbon stock of this crucial ecosystem.

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“…There is an urgent need for the assessment of the change in climate over the region on a short and long-term basis. This has become difficult because of the absence of precise regional weather data of the Sundarbans on a short and long-term basis (Pitchaikani et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Past and future freshwater availability scenarios and their impact on the Indian Sundarbans ecosystem and fisheries

Das,

Bhowmick,

Goswami

et al. 2023

Aquatic Ecosystem Health &Amp; Management

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The Indian Sundarbans is considered one of the zones of highest vulnerability in the world in terms of climate change. About 4.43 million people living in the Indian Sundarbans face a lack of freshwater availability due to the erratic behaviour of monsoon rains, frequent cyclonic storms, intrusion of saline water, and other factors, all of which affect the fisheries and agriculture activities of this area. In this study, estimates of freshwater availability through past and predicted future rainfall and evapotranspiration change scenarios in the Sundarbans are presented. Due to the lack of high-quality in-situ data, various sources of gridded rainfall and evapotranspiration data were used. Between 1948 and 2010, half of the 19 administrative blocks showed a decreasing trend of monsoonal rainfall while the rest showed an increasing trend. Freshwater availability showed a decreasing trend during the monsoon season over different blocks of the Sundarbans, which is a matter of great concern for fisheries and agricultural activities. Statistical downscaling was used to generate future rainfall and evapotranspiration scenarios, using coarse resolution Global Climate Models from the Coupled Model Intercomparison Project phase five for a smaller area like the Sundarbans. Downscaled Global Climate Models project an increasing trend in future monsoon rainfall in both RCP 4.5 and RCP 8.5 emission scenarios. The increasing rainfall can trigger excessive run-off and flooding, which would in turn affect aquaculture infrastructure and damage lentic aquaculture productions across the Sundarbans. However, increased rainfall may expand the flood plain area and extend the feeding grounds of fish. Hence, the impact of rainfall change is quite unpredictable. Proper adaptation techniques may be required to harness the positive impacts while preventing negative effects.

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Vertical current structure in a macro-tidal, well mixed Sundarban ecosystem, India

Cited by 12 publications

References 22 publications

Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020

Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020

Challenges towards the Sustainability and Enhancement of the Indian Sundarban Mangrove’s Blue Carbon Stock

Past and future freshwater availability scenarios and their impact on the Indian Sundarbans ecosystem and fisheries

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