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An intense bloom of Asterionellopsis glacialis (Family: Flagilariaceae; Class: Bacillariophyceae; Phylum: Ochrophyta) was observed in the near-shore waters at Kalpakkam, Tamil Nadu. Proliferation was supported by the favorable temperature, salinity, and nutrient levels in the coastal waters prevailing in the post-northeast monsoon period. BIOENV analysis and PCA confirmed salinity and nitrate as the key environmental factors responsible for the A. glacialis abundance. Cluster analysis further supported the distinct state of coastal water during the bloom with respect to physicochemical properties. The bloom period was floristically and faunistically richer than the pre- and post-bloom periods. The cluster and nMDS analysis confirmed the effects of bloom on plankton dynamics in the near-shore waters at Kalpakkam. The dominance of meroplankters especially, Cirripedia nauplii and Bivalvia larvae over Copepoda during the peak bloom period, was a significant result of the study. PCA ordination plot for the quantitative aspects of phytoplankton and zooplankton groups further supported the above observation. Among Copepoda, Cyclopoida and Poecilostomatoida (mostly carnivorous) exceeded the Calanoida (mostly herbivorous) during the peak bloom period unlike the reverse trend observed during other periods. Fish eggs and larvae were available in substantial numbers during the bloom which indicated their proliferation in the presence of the blooming diatom standing stock as the food material.

The spatiotemporal distribution, diversity and biomass of the choreotrich ciliate tintinnid, the ubiquitous planktonic protist, were analysed from nine sampling sites ( n = 252 ) of diverse environmental stresses along the Hooghly Estuary, eastern part of India during March 2012 to August 2014. Among 32 identified tintinnid species, the agglomerated genera Tintinnopsis (20 sp), dominated the community (∼62%) followed by Tintinnidium (2 sp), Leprotintinnus (2 sp), Codonellopsis, Stenosemella, Helicostomella, Favella, Eutintinnus, Metacylis, Dadayiellaand Wangiella (each comprising single species). A wide range of seasonal variations in tintinnid abundance was recorded maximum (2067±893 ind. l−1) for Tintinnopsis beroidea and minimum (11±4 ind. l−1) for Metacylis sp. during the investigation period. The biomass and daily production rate of tintinnid ranged from 0.004–2.764 μg C l−1 and 0.04–3.54 μg C l−1 day−1 respectively. An overall dominance and diversity of the small-sized tintinnid (lorica length k , showed species dominance over the investigated sites. The multidimensional scaling (MDS) Canonical Analysis of Principal coordinates (CAP) highlighting a significantly different spatial distribution of tintinnid. Principal Component Analysis (PCA) map showed clustering of core species with chl a and nitrate and could be considered as the crucial factors controlling the distribution and seasonal patterns of tintinnid. Biota-environment (BIOENV) analyses also reveal that these two parameters were the significant causative factors, suggesting that tintinnid may be used as a bioindicator for discriminating water quality in this estuarine system. The study provided detailed information of microzooplankton which enhances our understanding regarding its crucial role in marine ecosystem and complex biotic interactions for maintaining the ecological and economic stability.

Kalpakkam, located on the southeast coast of India, has witnessed intense nuclear power plant activities resulting in a substantial increase in social and industrial development. This has prompted the study of the concentrations of heavy metals in water, sediment, zooplankton and fish in the coastal waters of Kalpakkam to understand their pattern of distribution and bioaccumulation. The concentrations of metals were in the order Fe > Zn > Pb > Cr > Mn > Ni > Cu > Cd > Co in water, Fe > Zn > Mn > Pb > Cr > Cu > Ni > Cd > Co in zooplankton, Fe > Zn > Cu > Mn > Cr > Pb in fish and Fe > Cu > Zn > Pb > Cr > Ni > Cd in sediment. Metal concentrations in plankton were much higher than those in water, sediment and fish. The results showed wide variations in heavy metal concentrations in four food web components. The major sources of metals on the Kalpakkam coast are land-based anthropogenic ones. The coastal sediment is moderately polluted with Cu & Cd. Relatively low dissolved metal concentrations were observed when compared to other coastal waters. However, the results indicated that dermal absorption (CDIdermal) of Fe might be a matter of concern due to its carcinogenicity. The summer season had higher Metal Pollution Index (MPI) values, than the rest of the year. Metal pollution indices indicated that southwest monsoon (SWM) and northeast monsoon (NEM) periods had lower contamination (MPI: 1.0–2.0; Class-III) than the summer season (MPI: 2.0–4.0; Class-IV). The bioaccumulation of metal is faster and the content is much higher in zooplankton than in fish. Bioconcentration factors (BCF) were significantly different for different metals. Amongst the toxic metals the BCF was highest for Cr for both zooplankton and fish tissue. The metal concentrations in the fish species studied were sufficiently low that the fish tissue was safe for human consumption.

The study first investigated the spatial distribution, diversity, and biomass of the planktonic choreotrich ciliate tintinnids inhabiting the biosphere reserve, the core region of Indian Sundarban mangrove wetland. A total of 21 species (eight genera and six families) were recorded including agglomerated and non-agglomerated or hyaline forms from these intricate estuarine network systems. Maximum mean abundance (2747 ± 111 individuals L−1) and species diversity (H′ = 2.32) of tintinnid ciliate were recorded at the sampling site located towards the Bay of Bengal whereas lower abundance (666 ± 56 individuals L−1) and diversity (H′ = 1.55) were encountered towards inner part of the estuary. Tintinnopsis represented the most dominant agglutinated genus comprising of Tintinnopsis beroidea, Tintinnopsis fimbriata, Tintinnopsis cylindrica, Tintinnopsis tocantinensis, and Tintinnopsis radix, accounting ∼52% of total tintinnid community. The agglomerated forms Amphorellopsis tetragona, Eutintinnus apertus, Codonellopsis lusitanica, and T. fimbriata were recorded for the first time in this region. The biomass value exhibited wide range of variations (0.03 ± 0.09 to 12.4 ± 1.1 μg C L−1), accounting maximum value towards seaward region. The small-sized tintinnid (lorica length

Dissolved trace metal (Cd, Ce, Co, Cr, Cu, Fe, La, Mn, Ni, Pb, U and Zn) concentration in the surface water of Kalpakkam coast was investigated for two consecutive years (2012–14) to understand their seasonal fluctuations, source apportionment and risk assessments. Concentration of metal was determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Significant seasonal distribution in metal concentrations was noticed and most metals showed relatively high concentrations during summer season. During the study period metals follow the concentration levels Fe>Zn>Cu>Pb>U>Cr>Mn>Ni>La>Cd>Ce>Co. Principal Component Analysis (PCA) explained 70.12% of the total variance by the first three factors indicating the role of internal and anthropogenic activities in the metal contents in the coastal waters of Kalpakkam. The bioavailability of the metals in dissolved form suggested that the non-cancer and cancer risks posed by them are minimal. The overall hazard index (HQdermal) and cancer risk levels were within the safe limits recommended by WHO. However, the carcinogenic risks of the metals revealed that dermal absorption (CDIdermal) of Fe might be a matter of concern. Summer season has higher Metal Pollution Index (MPI) values, than the remaining period. Metal pollution indices indicated that southwest monsoon (SWM) and northeast monsoon (NEM) periods were less contaminated (MPI: 1.0–2.0; Class-III) as compared to the summer season (MPI: 2.0–4.0; Class-IV).

A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3 × 10 3 cells l −1 to 11.4 × 10 5 cells l −1 ) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity ( H′ = 2.86), richness ( R ′ = 6.38) and evenness ( E ′ = 0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5 × 10 3 to 50 × 10 3 ind m −3 ). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted.

The composition, species richness and diversity of a coastal fish assemblage from the Kalpakkam coast of south-east India are described along with temporal distribution patterns related to seasonal fluctuations in dissolved oxygen, salinity, pH, chlorophyll-a, phytoplankton and zooplankton species richness and density. A total of 244 fish species belonging to 21 orders, 87 families and 163 genera were recorded. The fish assemblage was dominated by reef-associated species, followed by demersal species. The majority of the species (63%) are widely distributed in the western Indo-Pacific as well as in the central Indo-Pacific. Jaccard's coefficient analysis showed three distinct seasonal patterns of fish occurrence: pre-monsoon (PrM), monsoon (M) and post-monsoon (PoM). The maximum number of species was during the PrM period, followed by the PoM and M periods. Species occurrence analysis showed Sardinella longiceps to be dominant during PrM and M periods, Leiognathus dussumieri during the M period and Secutor insidiator and Secutor ruconius during the M and PoM periods. Canonical correspondence analysis indicated that salinity and rainfall were the two most influential environmental factors strongly correlated with temporal variation in the fish assemblage. The physico-chemical conditions, in combination with factors such as greater food availability and shelter, might control the seasonal local distribution of the ichthyofauna in these Indian coastal waters.

In order to understand the phytoplankton community structure and its relationship with the envi- ronmental variables in the near shore waters of Kalpakkam, east coast of India, observations were car- ried out during 2008-2009. Phytoplankton population was comprised of 219 species, and the density was higher during the southwest monsoon (SWM) and inter-monsoon seasons than that of north east monsoon (NEM) season. The nutrient status on a temporal and spatial scale indicated the impact of point sources car- rying anthropogenic runoff. Comparison of ambient nutrient ratios with the Redfield ratio (N/P/Si= 16:1:16) showeda clear temporalvariation inthe factors that regulatethe phytoplankton growth. SWM and inter- monsoon season was evident to have an acute N- limitation of algal growth (~76 %) whereas P- limitation was encountered during the NEM season (~75 %). Interestingly, a sizable population of cyanobacteria (Trichodesmium erythraeum) were no- ticed during NEM season when there was an exponential increaseinnitrogenconcentration,probably due to nitrogen fixation. No significant impact of tem- perature on phytoplankton proliferation was observedin situ during the study period.

The feasibility of a potential bioindicator based on functional groups of microzooplankton tintinnids for bioassessments of water quality status was studied during southwest monsoon (June to September) along the coastal waters of Kalpakkam, India during 2012-2015. The work highlights the following features (1) tintinnid community composed of 28 species belonging to 11 genera and 9 families, revealed significant differences among the four study sites (2) maximum numerical abundance (2224±90ind. l-1) and species diversity (H'=2.66) of tintinnid were recorded towards Bay of Bengal whereas minimum abundance (720±35ind. l-1) and diversity (H'=1.74) were encountered in the backwater sites, (3) multivariate analyses [RELATE, Biota-environment (BIOENV) and canonical analysis of principal coordinates (CAP)] reveal that chl a, nitrate and phosphate were the potential causative factors for tintinnid distribution. Based on the results, we suggest that tintinnids may be used as a potential bioindicator of water quality status in marine ecosystem.

Seasonal population trends of butterflies inhabiting the campus of Department of Atomic Energy (DAE) at Kalpakkam were recorded by setting a permanent line transect of 300m and recording all species of butterflies observed within a 5m distance. The survey yielded 2177 individuals of 56 butterfly species, belonging to the families Nymphalidae, Pieridae, Lycaenidae, Papilionidae and Hesperiidae. Nymphalidae were found to be the dominant family during all seasons. Species richness and abundance were highest during the northeast monsoon and winter periods, indicating that in the southern plains of India butterflies prefer cool seasons for breeding and emergence. The taxonomic structure of the butterflies sampled resembles that of the Western Ghats and other regions of India in two ways: (a) dominance of nymphalids and (b) peak abundance during wet seasons. A detailed study of ecologically important local butterfly fauna and their host plants is in progress, to construct a butterfly garden in Kalpakkam to attract and support butterflies.

This article reports on the concentration of selected trace elements (Mn, Zn, Cr, Cu, Ba, As, B, V, and Hg) and major elements (Fe and Al) from the intertidal sediment cores from Sundarban wetland, India. This is a typical meso-macrotidal estuarine area affected by domestic and industrial activities located upstream. The overall concentrations range is low to moderate, indicating the environmental conditions in the outfall zone (grain size, hydrodynamic regime, and confinement), which favors the in situ accumulation of pollutants. The extent of contamination from trace elements in Sundarban core sediments is evaluated through a two-pronged approach: (i) by determining the metal enrichment in the sediments through the calculation of Pollution Load Index (PLI), Enrichment Factor (EF) and Index of Geoaccumulation (I geo), and (ii) by defining a potential level of biological risk by the use of quality criteria such as Threshold Effect Level (TEL) and Effects Range-Low (ERL) benchmarks. On the basis of the calculated indices, sediments are particularly enriched with Cr, Cu, B, V, and As. Those enrichments seem to be due to the fine granulometry of the regions with Fe and Mn oxi-hydroxides being the main metal carriers. Trace Elements input to the Sundarban wetland need to be kept under strict control in future specially with reference to As since, according to TEL and ERL benchmarks, it already appears to be associated with a potential biological risk.

The paper presents the first comprehensive account of congener profiles of polycyclic aromatic hydrocarbons (PAHs) in intertidal bivalve mollusks [Meretrix meretrix, Macoma birmanica, and Sanguilonaria (Soletellina) acuminata] of Sunderban mangrove wetland (India). The main aim of this work was to use the bivalves as bioindicators of the contamination of the 16 USEPA PAH. The PAH profile in bivalves is largely dominated by a petrogenic fingerprint, with over-imposition of pyrolytic PAH sources, as evidenced by diagnostic molecular ratios. Bioaccumulation factors (BAF) of individual compounds from the sediments were calculated, and it reveals overall higher values in the visceral mass of the bivalves. S acuminata showed significantly higher levels of PAHs, especially the high molecular weight (HMW) PAHs, compared to the other two species as a sensitive indicator of trace organic stress in future monitoring programs.

Organochlorine pesticides (OCPs) are an important potential component of chemical pollutants used extensively for agriculture and sanitation purposes in India as these are comparatively cheap and effective. These persistent organic compounds such as HCH isomers, DDT and its metabolites are the predominant chemical contaminants found along the Indian coast and thus constitute both alluring and grave areas of scientific research. Our objective in the paper is to provide a comprehensive account of the distribution of organochlorine pesticides in biotic and abiotic compartments of the Indian coastal environment, make some comments on their environmental sources, their movement through the food chain and possible ecotoxicological risk of health in biota including humans.The prevalent HCH, DDT and HCB concentrations differ markedly in eastern and western coast of India reflecting differing agricultural and other usage and their ultimate input into the coastal environment by several rivers and the bioturbation activities of macrozoobenthos (bivalve mollusks, polychaetous annelids, etc.). In several cases, the DDT levels exceeded the effects range-low (ER-L) and could thus cause acute biological impairments, in comparison with the sediment quality guidelines. Contributions of DDT metabolites (DDT, DDD and DDE residues) vary in different Indian coastal regions predominated by pp′-DDT and pp′-DDD. Measured concentrations of HCHs were lower than DDTs that might be due to higher water solubility, vapor pressure and biodegradability of the latter. HCH and DDT residues in fish in India were lower than those in the temperate countries indicating a lower accumulation in tropical fish, which might be related to rapid volatilization of this insecticide in the tropical environment. The concentrations of other chlorinated pesticides (aldrin, dieldrin, eldrin, methoxychlor, endosulfan sulphate) were lower and not generally of great concern. Keywords: Organochlorine pesticides, Tropical coast of India, Intertidal sediments, Ecotoxicological risk

The paper presents the first comprehensive survey of congener profiles of polychlorinated biphenyls (PCBs) in core sediment samples (63 microm particle size) covering seven sites in Sunderban mangrove Wetland, north-eastern part of the Bay of Bengal. Results pointed out a non-homogenous contamination of the wetland with Sigma23PCB values ranging from 0.5 to 26.9 ng g(-1) dry weight, reflecting very low to moderate contamination closely in conformity to other Asian coastal environment. The general decreasing order of the dominant congeners to the total load was: CB138153149101, indicating the predominance of hexa-chlorinated congeners. The spatial distribution revealed significant differences in concentration related to local urbanization with industrial and land-based sources. No uniform temporal trend on PCB levels was recorded probably due to particular hydrological characteristics of the wetland and/or non-homogenous inputs from point sources. Strong positive correlations between the seven dominant congeners suggest their common sources and similar environmental behaviors. These results were also used for a risk assessment evaluation in the Sunderban wetland, showing that the present PCB levels were exceeding in few cases the lower limit of sediment quality guidelines of Environmental Protection Agency and Canadian Council of Ministers of the Environment.

The suitability of using four bivalve molluscs (Sanguinolaria acuminata, Anadara granosa, Meretrix meretrix, and Pelecyora trigona) in biomonitoring of heavy metals (Cu, Pb, Cd, Zn, and Hg) collected from intertidal regions of the Sunderban mangrove wetland, northeastern part of the Bay of Bengal, were evaluated. Both speciesdependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs while shells represent very poor accumulation. Elevated values of Zn and Cu reflect high potential for biomagnification through marine food chain. Metal concentrations in different body size groups of the bivalves do not follow uniform trend. Correlation coefficient between different metal couplings as tested statistically revealed significant coupling for Pb-Zn, Pb-Cu, Zn-Cu, and Hg-Cu. Concentrations of all the metals in specific organs (visceral mass, mantle and gill) of the bivalves exceeded the safe levels according to the international standards for metals compiled by Food and Agricultural Organization of the United Nations and would be of great risk for human consumption. It is concluded that the mussel and clam are suitable biomonitors to employ in programs designed to assess changes in metal pollution in the Sunderban mangrove wetland.

This paper presents the first comprehensive report of the organochlorine pesticide residues (OCs) such as hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and its six metabolites (DDTs), and hexachlorobenzene (HCB) in core sediments (63-microm particle size) from the Indian Sunderban wetland. The pooled mean values of the mass fraction of SigmaHCHs, HCB, and SigmaDDTs in the sediments were 0.05-12, 0.05-1.4, and 0.05-11.5 ng g(-1) dry weight, respectively. The vertical distribution of pesticides reveals an erratic pattern. The concentration of four isomers of HCHs reveals a heterogenic distribution where gamma-HCH (lindane) and beta-HCH shared the dominant part. The mass fraction of HCB did not show any sharp spatial variation. The prevailing sequence of DDT metabolites indicates an active degradation of the parent compound in the sediments and/or inputs of already degraded pp'DDT to the region. Peak concentrations of HCH isomers and DDT metabolites have the potential to induce ecotoxicological impact as per the sediment quality guidelines.

The paper presents the first comprehensive survey of congener profiles (12 congeners) of polybrominated diphenyl ethers (PBDEs) in core sediment samples (63 microm) covering seven sites in Sundarban mangrove wetland (India). Gas-chromatographic analyses were carried out in GC-Ms/Ms for tri- to hepta- brominated congeners. Results pointed out a non-homogenous contamination of the wetland with summation operator(12) PBDE values ranging from 0.08 to 29.03 ngg(-1), reflecting moderate to low contamination closely in conformity to other Asian aquatic environments. The general order of decreasing congener contribution to the total load was: BDE 4799100154, similar to the distribution pattern worldwide. Although tetrabromodiphenyl ether BDE 47 was found in all samples followed by hexabromodiphenyl ether BDE-154, they were not necessarily the dominant congeners. No uniform temporal trend on PBDE levels was recorded probably due to particular hydrological characteristics of the wetland and/on non-homologous inputs from point sources (untreated municipal wastewater and local industries, electronic wastes from the dump sites, etc.) of these compounds. Because of the propensity of PBDEs to accumulate in various compartments of wildlife and human food webs, evaluation of biological tissues should be undertaken as a high priority.

The study is the first documentation of seasonal variations in species composition, abundance and diversity of tintinnid (Ciliata: Protozoa), in relation to water quality parameters along the stretch of the Hooghly (Ganges) River Estuary (HRE), eastern coastal part of India. A total of 26 species (22 agglomerated and 4 non-agglomerated) belonging to 8 genera has been identified from 8 study sites where Tintinnopsis (17 species) represented the most dominant genera, contributing up to 65 % of total tintinnid community followed by Tintinnidium (2 species), Leprotintinnus (2 species) and Dadayiella, Favella, Metacylis, Eutintinnus and Helicostomella (each with solitary species). The maximum (1,666 ind. l(-1)) and minimum (62 ind. l(-1)) abundance of tintinnids was recorded during post-monsoon and monsoon, respectively. A distinct seasonal dynamics in terms of biomass (0.005-2.465 μg C l(-1)) and daily production rate (0.04-3.13 μg C l(-1) day(-1)) was also noticed, accounting highest value during pre-monsoon. Chlorophyll a and nitrate were found to be potential causative factors for the seasonal variations of tintinnids as revealed by a stepwise multiple regression model. The result of ANOVA showed a significant variation between species abundance and months (F = 2.36, P ≤ 0.05). k-dominance curves were plotted to determine the comparison of tintinnid dominance between the investigated stations. Based on a principal component analysis (PCA), three main groups were delineated with tintinnid ciliates and environmental parameters. The changes in lorica morphology in terms of temperature and salinity, recorded for three dominant species, provided information on the ecological characteristics of the species assemblage in this estuarine system.