Sandip Mukhopadhyay

Bio: Sandip Mukhopadhyay is an academic researcher from University of Calcutta. The author has contributed to research in topics: Mangrove & Biogeochemical cycle. The author has an hindex of 17, co-authored 57 publications receiving 1258 citations.

Karyomorphological analysis of different species and varieties of Calathea, Maranta and Stromanthe of Marantaceae.

Abstract: Extensive analysis of morphological, anatomical and cytological characters was carried out on 14 different species and varieties of Calathea, Maranta and Stromanthe of Marantaceae. The morphological and anatomical features of these species vary between species to species and are correlated with chromosome number. These characters may serve as identifying parameters.Chromosome analysis has indicated the chromosome number to range from 2n=24 to 28 in Calathea, 2n=48 and 52 in Maranta and 2n=44 in only species of Stromanthe. The polyploid forms do not show an exact multiplication of the basic set. Duplication alongwith the minute structural alteration of chromosomes has played a role in speciation of these genera.A conspicuous variation was recorded amongst these species in length and volume of chromosomes. The length and volume did not show any direct correlation with chromosome number and a consistency in difference of these two characters was recorded as well. Differential coiling and uncoiling of the arm and ratios of different chemical components in the chromosome structure, have been suggested as responsible for this difference. The similarities in gross karyotype and morphological characters indicate a close relationship between these genera.

Interactions of Cu (II) and Fe (III) with mangal humic substances studied by synchronous fluorescence spectroscopy and potentiometric titration

Abstract: Humic (HA) and fulvic (FA) acids isolated from mangrove sediments of Sundarban, the largest delta on earth in the estuarine phase of the river Ganges, were studied and attempts were made to characterize their binding sites by quenching of Synchronous fluorescence (SyF) bands with Fe (III) and Cu (II) A modified Stern-Volmer relationship applicable for static quenching was applied for the determination of conditional stability constants and the data were compared with those determined by potentiometric titration In the excited state HA and FA showed different acidity constant compared to the ground state Values of the conditional stability constant (log Kc) for Fe (III) and Cu (II) indicated that binding sites were bidentate in nature FA were better chelators than the HA fractions High energy binding sites of both FA & HA were occupied by Fe(III) and the low energy binding sites, mainly responsible for mobilization and immobilization of metal, were occupied by Cu(II)

Diurnal carbon dynamics in a mangrove-dominated tropical estuary (Sundarbans, India)

Abstract: Based on a 24h of time-series study, we report the effects of a tidal cycle on carbon biogeochemistry of a mangrove dominated tropical estuary (the Sundarbans) located in the eastern part of India. Salinity, dissolved oxygen, and pH showed clear tidal variability with relatively higher values during high tide than low tide. Dissolved inorganic carbon (DIC) concentrations varied over a narrow range (1.92–2.19 mM) with relatively higher values during low tide; reverse trend, however, was noticed for δ13CDIC with significant variability (– 4.28 to – 2.21‰). During low tide, along with estuarine mixing, preliminary evidences for influences of biogeochemical (such as organic carbon mineralization, sulfate reduction, and denitrification) and hydrological processes (porewater exchange) were found on DIC dynamics. The δ13CDIC - DIC relationship suggested respiration of marine plankton to be one of the possible sources for DIC. Dissolved organic carbon showed tidal influence during high tide with a signal of porewater mediated addition during low tide. Both particulate organic carbon and particulate nitrogen concentrations reached the maximum during low tide with stable isotopic compositions showing predominantly marine signature along with the possibility of biogeochemical modifications within the estuary. Marine water contribution together with organic carbon mineralization and possible porewater influx resulted in ~214 μatm higher pCO2 and 1.13 times higher FCO2 during low tide than high tide. On diurnal basis, the estuary released ~1348 mg CO2 per m2 of surface area to the regional atmosphere.

Feulgen microspectrophotometric estimation of nuclear DNA of species and varieties of three different genera of Marantaceae

Abstract: Karyological analysis including determination of somatic chromosome number, total chromosome length, volume and karyotype formula andin situ estimation of 4C-nuclear DNA amount were carried out on 14 different species and varieties of the generaCalathea, Maranta andStromanthe. The 4C nuclear DNA amount was estimated through Feulgen microspectrophotometry following single wavelength method and expressed in arbitrary units of relative absorbances. The variation in 4C DNA amounts between the species ofCalathea was not distinct but in two species ofMaranta, a notable variation in nuclear DNA amount was recorded. In addition, the amount of nuclear DNA did not show direct correlation with the total chromosome length and volume. The absence of wide difference in nuclear DNA content at an interspecific level might have some adaptive value.

Assessing the Dynamics of Dissolved Organic Matter (DOM) in the Coastal Environments Dominated by Mangroves, Indian Sundarbans

Abstract: Tidal transport from coastal wetlands (“outwelling”) together with riverine fluxes provide most important sources of terrigenous organic matter (OM) to the ocean. The flux of dissolved organic carbon (DOC) from the mangrove swamps accounts for 10% of the terrestrial DOC flux to the coastal water. This study examines the sources, distribution, and export of dissolved OM at inter-annual, seasonal and diurnal basis along the estuaries located at the Sundarbans, world’s largest deltaic mangrove and heritage site. Sampling was carried out from riverine (Hooghly) and mangrove-dominated tidal estuaries (Saptamukhi, Thakuran, Matla) covering all three seasons (pre-monsoon, monsoon and post-monsoon) during 2012-2017. DOC varied at a broad range from 109 to 462 µM (n = 146) with higher concentration observed in the Hooghly (383±120 µM, n = 35) than the mangrove estuaries (246±82 to 266±120 µM, n = 111). Nonconservative mixing of DOC along the salinity gradient attested to mangrove input, particularly in the polyhaline waters. Upper and mid estuarine zones of the mangrove estuaries showed slightly higher DOC concentration (270±92 µM, n = 84, salinity range 18-25) than the mouth (250±85 µM, n = 27, salinity range 26-27) because of the dilution with marine waters having low DOC concentration and shorter water residence time downstream. Seasonally, higher DOC concentration during the post-monsoon might be linked to higher litterfall promoting leaching of organic compounds to the water. In that connection, colored dissolved organic matter (CDOM) could be the by-product of mangrove litter leaching, and its absorption coefficient (at 350 nm) exhibited non conservative mixing pattern at wide ranges from 2.5 to 7.6 m-1 (n = 40). CDOM enrichment was observed in the surface water during the low tide when outwelling maximized. Overall, central and eastern part of the Indian Sundarbans showed enrichment of more terrigenous type CDOM (evident from optical proxies e.g. S275-295 and SUVA254) than the western part, probably due to greater mangrove productivity in the eastern side. Flux estimates of DOM resulted in higher yield and export of mangrove-derived DOC but lower export of CDOM to the Bay of Bengal as compared to their riverine transport.

Mangrove Production and Carbon sinks: A revision of global budget estimates

Abstract: results in a conservative estimate of 218 ± 72 Tg C a 1 . When using the best available estimates of various carbon sinks (organic carbon export, sediment burial, and mineralization), it appears that >50% of the carbon fixed by mangrove vegetation is unaccounted for. This unaccounted carbon sink is conservatively estimated at 112 ± 85 Tg C a 1 , equivalent in magnitude to 30–40% of the global riverine organic carbon input to the coastal zone. Our analysis suggests that mineralization is severely underestimated, and that the majority of carbon export from mangroves to adjacent waters occurs as dissolved inorganic carbon (DIC). CO2 efflux from sediments and creek waters and tidal export of DIC appear to be the major sinks. These processes are quantitatively comparable in magnitude to the unaccounted carbon sink in current budgets, but are not yet adequately constrained with the limited published data available so far.

Carbon Cycling and Storage in Mangrove Forests

Abstract: Mangroves are ecologically and economically important forests of the tropics. They are highly productive ecosystems with rates of primary production equal to those of tropical humid evergreen forests and coral reefs. Although mangroves occupy only 0.5% of the global coastal area, they contribute 10–15% (24 Tg C y−1) to coastal sediment carbon storage and export 10–11% of the particulate terrestrial carbon to the ocean. Their disproportionate contribution to carbon sequestration is now perceived as a means for conservation and restoration and a way to help ameliorate greenhouse gas emissions. Of immediate concern are potential carbon losses to deforestation (90–970 Tg C y−1) that are greater than these ecosystems' rates of carbon storage. Large reservoirs of dissolved inorganic carbon in deep soils, pumped via subsurface pathways to adjacent waterways, are a large loss of carbon, at a potential rate up to 40% of annual primary production. Patterns of carbon allocation and rates of carbon flux in mangrove f...

Mangrove production and carbon sinks : a revision of global budget estimates - art. no. GB2013

Abstract: results in a conservative estimate of 218 ± 72 Tg C a 1 . When using the best available estimates of various carbon sinks (organic carbon export, sediment burial, and mineralization), it appears that >50% of the carbon fixed by mangrove vegetation is unaccounted for. This unaccounted carbon sink is conservatively estimated at 112 ± 85 Tg C a 1 , equivalent in magnitude to 30–40% of the global riverine organic carbon input to the coastal zone. Our analysis suggests that mineralization is severely underestimated, and that the majority of carbon export from mangroves to adjacent waters occurs as dissolved inorganic carbon (DIC). CO2 efflux from sediments and creek waters and tidal export of DIC appear to be the major sinks. These processes are quantitatively comparable in magnitude to the unaccounted carbon sink in current budgets, but are not yet adequately constrained with the limited published data available so far.

Budgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts

Abstract: [1] Air-water CO2 fluxes were up-scaled to take into account the latitudinal and ecosystem diversity of the coastal ocean, based on an exhaustive literature survey. Marginal seas at high and temperate latitudes act as sinks of CO2 from the atmosphere, in contrast to subtropical and tropical marginal seas that act as sources of CO2 to the atmosphere. Overall, marginal seas act as a strong sink of CO2 of about −0.45 Pg C yr−1. This sink could be almost fully compensated by the emission of CO2 from the ensemble of near-shore coastal ecosystems of about 0.40 Pg C yr−1. Although this value is subject to large uncertainty, it stresses the importance of the diversity of ecosystems, in particular near-shore systems, when integrating CO2 fluxes at global scale in the coastal ocean.