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The present investigation is conducted to study the year wise (2011 to 2018) changes of water hyacinth (Eichhornia crassipes) cover at Santragachi Lake a Wetland under National Wetland Conservation Programme of India. Further the relationship between water hyacinth cover and the most abundant migratory waterbirds of Satragachi, Lesser Whistling Teal (LWT; Dendrocygna javanica) is assessed because this bird species is fully depended on water hyacinth mat for their roosting. The study comprises of eight satellite images procured from Google earth (2011 to 2018) to explore this relationship. A marked decline in the number of LWT at Santragachi wetland is observed in the year of 2017 and 2018. It is very interesting fact that from 2017-2018, the water hyacinth mat of this wetland is almost cleared before winter and the result of cluster analysis supports this fact. Significant positive correlation is also observed within LWT number and water hyacinth cover area (r = 0.7481 at p< 0.05) along with the total perimeter (r = 0.8648 at p< 0.05) of the water hyacinth islands at Santragachi wetland. However, open water area is also needed for diving, swimming, food searching for the LWT and other waterbirds. Therefore, more study is needed to optimize the clearing operations, focused on optimizing the shape and size of water hyacinth islands for proper management of the waterbirds habitat.

East Calcutta Wetlands (ECW) located at the eastern fringe of Kolkata metropolitan, India designated as a Ramsar Site (No. 1208). ECW receives municipal solid wastes and composite wastewater from the city and local artisans use this for horticulture, agriculture and pisciculture practices. Horticulture designated as ‘green industry’ sequester significant amount of carbon (C) in plant biomass and in soil, therefore, helps to mitigate greenhouse gases and combat against global climate change. Six horticultural plant species commonly cultivated in ECW ecosystems were selected for present study. C sequestration potential of horticultural plants depends on plant biomass and plant density in cultivation fields. Highest amount of C was sequestered (40.76±6.73 ton ha-1) by ixora, a perennial plant in plant biomass. In case of basil, also a perennial plant, significant portion of the living plant biomass was exported from ECW as economically important parts which constitute 5.79±0.96 ton ha-1 C. Highest amount of soil organic carbon (SOC) was recorded from marigold fields (50.36±24.88 ton ha-1) which also constitute highest amount of C (34.37±5.67 ton ha-1) in residual parts (RP). Horticulture practices can sequester more amount of C in the ecosystem either by residual parts or remaining living plant biomass than agricultural practices.

The waterbird community structures of two sub-Himalayan wetlands (Nararthali and Rasomati) situated in forested areas were compared during the wintering period. These wetlands had similar geophysical features but were subject to different conservation efforts. Sixty species of waterbirds, including four globally threatened species, were recorded during the study. Nararthali was found to be more densely inhabited (116.05±22.69 ind./ha) by birds than Rasomati (76.55±26.47 ind./ha). Density increased by 44.6% at Nararthali and by 59% at Rasomati over the years of the study, from 2008 to 2015. Winter visitors increased considerably at Nararthali (66.2%), while a 71.1% decrease at Rasomati clearly indicated degradation of habitat quality at that site during the later years. Luxuriant growth of Eichhornia crassipes, siltation, poor maintenance and unregulated tourist activities were the key factors leading to the rapid degradation of Rasomati. Nararthali, on the other hand, a well-managed wetland habitat, showed an increasing trend in bird densities. Therefore, poor habitat management and rapid habitat alterations were observed to be the main reasons for depletion of bird density in the wetlands of eastern sub-Himalayan forest regions.

The present study aimed at recording the time-activity budget and feeding techniques of red-crested pochards (RCPs) to test the hypotheses that feeding techniques were influenced by the sexes and contrasting physical conditions of the habitat. The time-activity budget was quantified using the scanned sample approach. In this study, the mean sex ratio of the RCPs was recorded as 0.655. Dominant behavior was sleeping or resting (42.8% in February to 47.0% in January), followed by swimming (27.1% in February to 29.8% in December), feeding (10.9% in December to 16.6% in February), and preening (9.0% in January to 12.1% in February). During the diurnal hours, resting was highest in the morning, while swimming and feeding were both highest midday. Climatic factors, such as the maximum and minimum air temperatures, maximum and minimum air temperature differences, and day length, were considered to be influential on the diurnal time activities of the RCPs. Male birds were more frequent divers than the females and the duration of diving was greater in males than in females. However, in shallow water, beak dipping and upending were major foraging techniques in both sexes. The depth of the water played a significant role in the selection of the feeding techniques.

In this study, the heavy metal exposure risk model was employed to assess the exposure risk to a predominantly herbivore waterfowl, Northern Pintail, wintering in two wetland habitats in the Purulia district of West Bengal, located on overlapping Central Asian Flyway (CAF) and East Asian-Australasian Flyway (EAAF). Both wetlands were important staging and roosting grounds for migratory waterfowl for ages. The exposure model was used to quantify the risk of exposure to metals through oral ingestion. Exposure doses of Cu, Zn, Pb, and Cr through food plants ingestion and food-associated sediment consumption pathways were two potent sources of heavy metal exposure in the waterfowl under study. Exposure through water intake was ignored as metals were either of negligible concentrations or below the detection limit in water samples. Heavy metal concentrations showed significant positive correlations between bottom sediment and plant at both sites. At Purulia Sahebbandh (Site 1), the total exposure dose of all four metals was much higher than their conforming tolerable daily intake (TDI), and thereby, the metals might pose threats to the migratory wintering herbivorous waterfowl populations. However, in Adra Sahebbandh (Site 2), total exposure doses of Pb, Zn and Cu were much below their corresponding TDI. The Hazard Quotient (HQ) of Cr was highest followed by nonessential toxic Pb and these two elements could be considered as priority pollutants at Site 1. Prioritize threats were decreased in the following sequence: CrPbCuZn at Site 1 and CrZnPbCu at Site 2. Hazard Index was found to be5 at Site 1 and for much higher metal loads a significant correlation between metal concentrations in plants, bottom sediment and exposure doses were also recorded. Therefore, the peri-urban Purulia Sahebbandh wetland could immediately be considered for risk control and demanded holistic management of important waterfowl habitats.

The present limnological investigation is conducted to study the relationship between phytoplankton abundance and five important physicochemical factors in urban wastewater-fed seven fish ponds of Chota Nagpur Plateau area. A total number of 43 phytoplankton taxa representing four classes, namely Cyanophyceae (7), Chlorophyceae (29), Bacillariophyceae (5) and Euglenophyceae (2), are thriving in these ponds which may suggest that different nutrient-rich wastewater supports the diversity and abundance of the phytoplankton. Different values of diversity indices, results of post hoc analysis and rarefaction curve are depicted spatial variations of phytoplankton abundance and physicochemical factors. From the Principal Component Analysis, out of 43 phytoplankton species, 23 important species are extracted. The canonical correspondence analysis presents that most of the phytoplankton species densities are associated with higher values of the physicochemical variables in these ponds. Correspondingly, in the present study, Algal Genus Pollution Index (AGPI) is employed to study the water quality of seven sites. From the AGPI score, it is revealed that Site 4 has probable high organic pollution and Site 2 and Site 3 have moderate organic pollution. Therefore, long-term intensive studies and proper management are necessary to protect these ponds toward eutrophication and degradation, because these ponds not only act as a safeguard of livelihoods but also contribute significantly at local level food and water security and economic prosperity.

Everyday nearly 1.1 million m3 d−1 composite wastewaters from different source points, both municipal and industrial, pass through the East Kolkata Wetlands (EKW) via a web of canals which is productively used as irrigation water and in pisciculture. These composite wastewaters carry huge amount of total organic carbon (TOC) and total inorganic carbon (TIC), which have profound effect on wetland biogeochemistry and point out wetland carbon sequestration potential. However, at EKW (Ramsar Site; Group A; Criterion 1), which has been designated as a unique waste dependent resource recovery ecosystem for the past several decades, no comprehensive work has been done on the ecosystem service with special reference to carbon sequestration. Therefore, the aim of the present investigation is to estimate the TOC and TIC contents in composite wastewater and wastewater-fed fish ponds at EKW ecosystem at spatio-temporal scales. Different physico-chemical factors of these waters are also estimated in the same scales to record their influence on TOC and TIC contents in EKW. ANOVA results point out significant spatial and temporal variations of TOC and TIC besides other physico-chemical factors. Most of the measured factors including TOC and TIC contents are higher during pre-monsoon than in monsoon and post-monsoon periods. It is apparent from the correlation matrix that there are significant positive correlation between TOC and TIC and factors like TSS, TDS, conductivity, salinity, total hardness, F, Cl, SO4, Na, K, Ca and Mg. Principle component analysis (PCA) also suggests the significant influence of these physico-chemical factors that changed seasonally. Despite the mean level of TOC (348.05 ± 154.98 mg L−1) in composite wastewaters at the EKW areas are higher than the USEPA safe limit (2–4 mg L−1), a significant amount of carbon is sequestered in the wetland ecosystem. Between source point and final discharge site nearly 63% of carbon of TOC and 71% carbon of TIC in wastewater have been reduced. Interestingly, comparable level of reductions, i.e., 61% for TOC and 62% for TIC have also been noted between the source point and the wastewater-fed fish ponds. Efficient partitioning of carbon in bottom sediments and in aquatic biota has been possible for the quintessential flow-rate of wastewater in the carrying canals, long residence time in the wastewater-fed fish ponds and repeated use of wastewater in irrigating agricultural fields at the EKW ecosystem.

Wetland is the largest sink of C among entire terrestrial C pool, however, species specific efficiency of wetland macrophytes for sequestering C is not studied well. This study reports seasonal variations of the C sequestration efficiency of twelve abundantly grown wetland macrophytes in East Kolkata Wetland ecosystem (EKW) of India. The total amount of dry biomass and in sequel with the C content were higher in monsoon than postmonsoon and premonsoon periods. Considering all plants the C content of the leaf was the highest followed by the stem and root. Among the twelve plants studied, the C in total dry biomass of Phragmites karka was recorded as the highest followed by Eichhornia crassipes, Typha angustifolia. It was estimated that 1.17 kg C m−2 yr.−1 was captured by marginal aquatic plants, while 0.74 kg C m−2 yr.−1 was captured by the three floating macrophytes in EKW areas. To execute sustainable EKW conservation plans this study would provide an opportunity to refine our understanding about the role of macrophytes in C sequestration and gives a way to claim carbon credit from this service.

Guild structure and niche characteristics are important indicators of quantitative niche partitioning of a community. In the present study the niche structure was analyzed to determine whether resource partitioning reflected coexistence or exclusion of different waterbird species in relevant guilds at sub-Himalayan terai-dooars wetlands. Trophic guild structure and niche organization in wintering waterbirds were studied to understand why some species were rare and some were abundant and what possibly determined the diversity and abundance of multi-species waterbird communities. Two trophic components of niche partitioning, namely foraging habitat and foraging techniques, were considered in the present study. Cluster analyses based on foraging habitats and foraging techniques (i.e., two dimensions) provided bi-dimensional foraging guilds. Waterbirds precisely formed five distinct guilds, namely, medium and shallow water generalists, stalking waders, pecking waders, mud picking wader and divers. Further, a much higher diversity of waterbirds was observed from shallow and medium water habitats than deep waters which could be the outcome of higher net available trophic energy. Potential competitive interactions within intra-guild members were possibly minimized by using varied feeding techniques. The present study pointed out that the specialist guild members showed comparatively higher intra-guild niche overlap, whereas generalist guild members showed much lower niche overlap. Results indicated that waterbird communities were influenced mostly by trophic resources at a site and the birds' ability to exploit them. Waterbird guild structures and niche characteristics thus provide important ecological indicators of the ability of wetlands to support a range of species. Further, information on guild structures and niche characteristics are surely important for monitoring the biotic health of sub-Himalayan wetlands that would be important to work out effective wetland conservation strategies.

The present study focus the variation of carbon concentrations within three trophic level i.e., primary producer (phytoplankton), primary consumers (zooplankton) and secondary consumers (fish) in three selected ponds at East Kolkata Wetland area. Depending on the amount and frequency of wastewater input, physico-chemical characteristics of pond, species richness, predator-prey interactions and pond wise different piscicultural practices, the amount of carbon sequestration varied spatially. Significant temporal variations were also observed in each trophic level of these three selected East Kolkata Wetland pond ecosystems. On average primary producers were sequestered 2038.6 ± 244.8mg C m-3 d-1 whereas 307 ± 19.3 mg C m-3 and 11531.4 ± 318.2mg C m-3 was sequestered by primary and secondary consumers, respectively. In Kolkata and its nearby districts over 90% of the production was marked from the East Kolkata Wetland area. Consequently, a significant amount of sequestered carbon was exported from the East Kolkata Wetland ecosystem in the form of fish and this continuous system might increase the carbon sequestration efficiency of the aquatic ecosystem.

The present investigation was made to characterize spatial and temporal variations in soil properties and to evaluate possible differences that could be dependent on the tannery effluent discharges, municipal sewage discharges, vegetation cover, soil settlement rate, crop rotation, etc. Soil total organic matter (TOM), cations like, Sodium (Na), Ammonium (NH4), Potassium (K), Calcium (Ca) and Magnesium (Mg) contents in the bank soils and bottom sediments were recorded from seven different characteristic sites in East Kolkata wetland ecosystem, a Ramsar site (Ramsar site No. 1208). The profile maps were constructed by geostatistical methods to describe the spatial distribution as well as temporal variations of all the factors to identify the influences of composite wastewaters. The work was initiated to identify causes and consequences of the waste dumping in the concerned region for the past hundred years and thereby to suggest necessary precautionary measures to prevent further loss of soil quality.

The municipal sewage of Calcutta city together with industrial effluents traversed the East Calcutta Wetlands (ECW) (Ramsar Site No. 1208) for nearly a century. The composite wastewater at the ECW, was used for pisciculture and agriculture after natural stabilization. Such uses have always been thought to be a source of contamination to biota and humans. Some water-borne pollutants generate reactive oxygen species including superoxide radical anion (O2−.), hydrogen peroxide (H2O2), and hydroxyl radical (.OH), which are highly reactive and potentially deleterious to biological systems. The present study was initiated to examine the antioxidant activities against oxidative stress during different seasons in body fluids of two zooplankters, Moina micrura and Mesocyclops leuckarti thriving in wastewater-fed ponds of ECW. Results showed significantly higher electrical conductivity, chloride and metal (Cr, Cu, and Pb) concentrations in contaminated wastewater-fed pond (CP) at ECW compared to the uncontaminated ...

Determination of different environmental factors and their spatio-temporal variations is sparingly important theme in ecological science because the productivity of an ecosystem is regulated by these factors. Here in East Kolkata Wetland (EKW) through a web of canal the composite tannery effluent is discharged and these are productively used in the piscicultural and agricultural farming of this area. So, in concern of agro-piscicultural productivity it is very essential to know the present soil profile of EKW. Soil organic carbon (SOC) and some essential anions/nutrients like F, Cl, NO3, PO4 and SO4 in the agricultural/bank surface soils and bottom sediments are recorded from the seven different characteristic regions in EKW area. To describe precisely the variations of all these factors in spatio-temporal scale, the profile maps are constructed by using geostatistics. 1.03–2.25 % SOC in marginal bank soil and 1.26–2.42 % SOC in bottom soil are present in EKW area. Except NO3 all other measured anions are present higher concentration than normal level in EKW area and these have both positive and negative impact especially on the SOC concentration i.e. in carbon sequestration, anion-cation balance, ecotoxicity, nutrient availability of that area. Results of this study indicate that under proper management strategies of site specific use of tannery effluent will reduce the fertilizer/manure cost of farmers. These will surely increase the contribution of leather industry in ecologically and ecological productivity of EKW Ecosystem.

Objective To investigate the antibacterial activity of the extracts of Alternanthera philoxeroides (A. philoxeroides), Plumeria obtusa (P. obtusa), Polyalthia cerasoides (P. cerasoides) and Ixora acuminate (I. acuminate) against human pathogens. Methods Aqueous and chloroform: methanol (1:1) extracts of the dried leaf of A. philoxeroides, flowers of P. obtusa, fruits of P. cerasoides and flowers of I. acuminate were tested in vitro by the disk diffusion method against four bacterial strains, namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Susceptibility of four reference bacterial strains to some antibiotics in nutrient agar was also tested. Minimal inhibitory concentration (MIC) values were determined and qualitative phytochemical analysis of the crude extract of the tested plant parts was done. Results Both the aqueous and the chloroform: methanol (1:1) extracts of P. cerasoides showed the strongest activity, followed by flowers of P. obtusa, leaves of A. philoxeroides and flowers of I. acuminate. Aqueous extracts of all the plant parts appeared to have less antibacterial activity than the chloroform: methanol (1:1) extracts. The result of phytochemical analysis of the crude extract of the tested plants showed that flavonoid was absent from all plant parts whereas steroid was present in all tested plant parts. Conclusions The results support that these plant extracts can be used for the treatment of bacterial diseases.

The tannery effluent and composite municipal sewage water drained to the East Kolkata wetland (EKW), a Ramsar Site (1208), is used for agriculture and pisciculture after natural stabilization. Such composite wastewater is characterized by exceedingly high total dissolved solids, total hardness, chloride and heavy metals concentrations. These water born pollutants generate reactive oxygen species which are potentially toxic to the biological system. These reactive oxygen species are normally detoxified by some enzymes, such as superoxide dismutase (SOD) and catalase (CAT). The present study was commenced to find out the SOD and CAT activities against the oxidative stress, if any, in four macrophytes namely, Eichhornia crassipes, Pistia stratiotes, Alternanthera sessilis and Sagittarria montevidensis of contaminated ponds (Site 1 and Site 2) of EKW and an uncontaminated site (Control site). During the course of sampling the physico-chemical factors were found significantly higher in the EKW ponds compared to the control site. In the EKW sites, higher rate of evaporation during summer months caused higher elemental concentration in the premonsoon than in other seasons. This led to high activity of both SOD and CAT enzymes. In contrast, heavy rain fall in monsoon lowers the elemental concentration - mainly due to dilution effect. Present experiment indicated that in a stressed ecosystem like EKW, the wetland plants overcome the stress by altering their stress enzyme activities, hence suggesting an evidence of adaptive mechanism to thrive in a stressful environment.