CO fluxes from aquaculture ponds of a tropical wetland: Potential of multiple lime treatment in reduction of CO emission.

Partial pressure of CO in water [pCO(water)] and air-water CO flux were estimated in two aquaculture ponds (one received no lime treatment (NTP) and in the other lime treatment was performed (LTP) four times a year) every month throughout an annual cycle, situated in East Kolkata Wetlands, a Ramsar Site in eastern India. It was hypothesized that lime treatment can potentially lower the pCO(water) in aquaculture ponds and hence make these aquatic bodies sinks for CO. The results portrayed that NTP acted as a source of CO throughout the year (annual mean: 1929 ± 1397 μmol m h), whereas, LTP acted as CO sinks post lime addition (monthly mean ranged from -366 ± 16 to -449 ± 32 μmol m h), though the effect of lime addition was found to diminish by the next month and it acted as source for CO in the months when no lime treatment was done (LTP annual mean: 1010 ± 1617 μmol m h).

Nitrogen dynamics of the aquatic system is an important driving force for efficient sewage purification in single pond natural treatment wetlands at East Kolkata Wetland.

At East Kolkata Wetlands, though the domestic city sewage is purified very rapidly, the mechanisms of treatment remains inadequately explored. In this context, the present study investigated nitrogen dynamics of the single pond treatment systems during purification and explored its potential role in sewage treatment. For this purpose the concentrations of different forms of nitrogen present both in water and soil at different time points of purification were measured.

Nutrients and phytoplankton dynamics in the fishing grounds off Tiruchendur coastal waters, Gulf of Mannar, India.

Nutrients and phytoplankton dynamics in the traditional fishing grounds off Tiruchendur coast, Gulf of Mannar, India revealed a clear seasonal trend influenced by prevailing monsoon system in east coast of India. A total of 73 species of phytoplankton were identified from the fishing grounds, revealed higher abundance in summer months compared to other seasons. Among the three stations, maximum phytoplankton abundance was recorded in station 2 followed by stations 1 and 3.

Current status of seawater quality in Digha (India), northwestern coast of the Bay of Bengal.

The present investigation was intended to assess the seawater quality of Digha (India) in the northwestern coast of the Bay of Bengal. Digha is a meso-tidal coastal plain located between two major estuarine systems, i.e.

Physicochemical and biological factors controlling water column metabolism in Sundarbans estuary, India.

Background: Sundarbans is the single largest deltaic mangrove forest in the world, formed at estuarine phase of the Ganges - Brahmaputra river system. Primary productivity of marine and coastal phytoplankton contributes to 15% of global oceanic production. But unfortunately estuarine dynamics of tropical and subtropical estuaries have not yet received proper attention in spite of the fact that they experience considerable anthropogenic interventions and a baseline data is required for any future comparison.

Heavy metal accumulation in agricultural soils around a coal fired thermal power plant (Farakka) in India.

Agricultural soils around the ash dumping sites of one of the largest thermal power plant (TPP) in India located at Farakka, West Bengal were assessed for some heavy metal (Pb, Cd, Cr, As, Cu, Zn, Ni and Fe) distribution in association with other physicochemical components and compared with the control soils collected from far away of TPP. The toxic group metals (Pb, Cd, Cr and As) were well differentiated by their higher values of variability and non-normal distribution from the biologically essential metals (Cu, Zn, Ni and Fe). The statistical analysis of the heavy metals revealed that the two probable sources (Eigen values) in affected soils are responsible for their distribution; the more dominant one contributed the toxic metals and less dominating source contributed the essential heavy metals.

Dynamics of Sundarban estuarine ecosystem: eutrophication induced threat to mangroves.

Background: Sundarbans is the largest chunk of mangrove forest and only tiger mangrove land in the world. Compared to the rich species diversity and uniqueness, very few studies have so far been conducted here, mainly due to its inaccessibility. This study explores water quality, density of biomass, species diversity, phytoplankton abundance and bacterial population of a tidal creek in Sunderban estuary during the post and pre monsoon period of 2008-09.

Sewage treatment in a single pond system at East Kolkata Wetland, India.

East Kolkata Wetland (EKW), a Ramsar site, greatly contributes towards purification of city sewage employing single pond system. However, the underlying mechanism remains unknown. Therefore to gain an insight, in this study efforts have been made to understand the rate of biodegradation and the time dependent changes of different physicochemical factors and their interactions that are involved in the process.

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India.

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), beta-glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils.

Pesticide residue level in tea ecosystems of Hill and Dooars regions of West Bengal, India.

In the present study we quantified the residues of organophosphorus (e.g. ethion and chlorpyrifos), organochlorine (e.