Commonness and rarity in the marine biosphere.

Explaining patterns of commonness and rarity is fundamental for understanding and managing biodiversity. Consequently, a key test of biodiversity theory has been how well ecological models reproduce empirical distributions of species abundances. However, ecological models with very different assumptions can predict similar species abundance distributions, whereas models with similar assumptions may generate very different predictions. This complicates inferring processes driving community structure from model fits to data. Here, we use an approximation that captures common features of "neutral" biodiversity models--which assume ecological equivalence of species--to test whether neutrality is consistent with patterns of commonness and rarity in the marine biosphere. We do this by analyzing 1,185 species abundance distributions from 14 marine ecosystems ranging from intertidal habitats to abyssal depths, and from the tropics to polar regions. Neutrality performs substantially worse than a classical nonneutral alternative: empirical data consistently show greater heterogeneity of species abundances than expected under neutrality. Poor performance of neutral theory is driven by its consistent inability to capture the dominance of the communities' most-abundant species. Previous tests showing poor performance of a neutral model for a particular system often have been followed by controversy about whether an alternative formulation of neutral theory could explain the data after all. However, our approach focuses on common features of neutral models, revealing discrepancies with a broad range of empirical abundance distributions. These findings highlight the need for biodiversity theory in which ecological differences among species, such as niche differences and demographic trade-offs, play a central role.

Seasonal variations in species composition, abundance, biomass and production rate of tintinnids (Ciliata: Protozoa) along the Hooghly (Ganges) River Estuary, India: a multivariate approach.

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.

Investigating Theoretical Frameworks: Comprehending the Relationship between σ, n, and µ in MnO2 Dispersed Films.

Solid polymer electrolytes (SPEs) made from a polymer-salt matrix show great potential for use in various applications, such as batteries, fuel cells, supercapacitors, solar cells, and electrochromic devices. Research on various theoretical and experimental aspects of these SPEs is highly pursued worldwide. However, due to the lack of direct experimental techniques for the measurement of the number of charge carriers (n) and their mobility (µ), reports on their correlation with conductivity (σ) and their exact theoretical justification are rare in literature studies. This paper is an attempt toward the search for the well-established theoretical formulation for n and µ that can justify the experimental results. In a previous attempt, it could only be demonstrated that the available theoretical bases show different values, but we could not come to any concrete conclusion. This research involves the use of three theoretical models, namely, the Rice and Roth model, the Trukhan model, and the Schutt and Gerdes model. The purpose of this study is to analyze the varying conductivity levels by calculating the concentration and mobility of charge carriers. To obtain the required parameters, impedance spectroscopy data were used. The Trukhan model was used to determine the precise value of the diffusion coefficient. By utilizing the dielectric tangent loss, the concentration of charge carriers and ion mobility were calculated. The Schutt and Gerdes (S&G) model was also used; this model is based on the dielectric constant and the relaxation frequency, which were derived from the EIS data. Finally, the Rice and Roth model was also employed, which is known for the ion transport in "super" ionic conductors. This was employed on the temperature-dependent impedance data for three different compositions of the films. A correlation is established between n and µ with σ using all three models. However, the Trukhan model is the most suitable for explaining the behavior of our system.

JAK-STAT and AKT pathway-coupled genes in erythroid progenitor cells through ontogeny.

BACKGROUND: It has been reported that the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway regulates erythropoietin (EPO)-induced survival, proliferation, and maturation of early erythroid progenitors. Erythroid cell proliferation and survival have also been related to activation of the JAK-STAT pathway. The goal of this study was to observe the function of EPO activation of JAK-STAT and PI3K/AKT pathways in the development of erythroid progenitors from hematopoietic CD34+ progenitor cells, as well as to distinguish early EPO target genes in human erythroid progenitors during ontogeny. METHODS: Hematopoietic CD34+ progenitor cells, isolated from fetal and adult hematopoietic tissues, were differentiated into erythroid progenitor cells. We have used microarray analysis to examine JAK-STAT and PI3K/AKT related genes, as well as broad gene expression modulation in these human erythroid progenitor cells. RESULTS: In microarray studies, a total of 1755 genes were expressed in fetal liver, 3844 in cord blood, 1770 in adult bone marrow, and 1325 genes in peripheral blood-derived erythroid progenitor cells. The erythroid progenitor cells shared 1011 common genes. Using the Ingenuity Pathways Analysis software, we evaluated the network pathways of genes linked to hematological system development, cellular growth and proliferation. The KITLG, EPO, GATA1, PIM1 and STAT3 genes represent the major connection points in the hematological system development linked genes. Some JAK-STAT signaling pathway-linked genes were steadily upregulated throughout ontogeny (PIM1, SOCS2, MYC, PTPN11), while others were downregulated (PTPN6, PIAS, SPRED2). In addition, some JAK-STAT pathway related genes are differentially expressed only in some stages of ontogeny (STATs, GRB2, CREBB). Beside the continuously upregulated (AKT1, PPP2CA, CHUK, NFKB1) and downregulated (FOXO1, PDPK1, PIK3CG) genes in the PI3K-AKT signaling pathway, we also observed intermittently regulated gene expression (NFKBIA, YWHAH). CONCLUSIONS: This broad overview of gene expression in erythropoiesis revealed transcription factors differentially expressed in some stages of ontogenesis. Finally, our results show that EPO-mediated proliferation and survival of erythroid progenitors occurs mainly through modulation of JAK-STAT pathway associated STATs, GRB2 and PIK3 genes, as well as AKT pathway-coupled NFKBIA and YWHAH genes.

Clinical and therapeutic relevance of PIM1 kinase in gastric cancer.

BACKGROUND: Gastric cancer is a leading cause of cancer-related mortality, and chemotherapeutic options are currently limited. PIM1 kinase, an oncogene that promotes tumorigenesis in several cancer types, might represent a novel therapeutic target in gastric cancer. METHODS: We studied the expression and genomic status of PIM1 in human primary gastric normal and tumor tissue samples by immunohistochemistry and array-based comparative genomic hybridization (aCGH). To ascertain whether PIM1 expression predicted susceptibility to PIM1 kinase-specific inhibition, the cytotoxic effect of a previously reported PIM1-specific small molecular inhibitor (K00135) was investigated in two gastric cancer cell lines with high (IM95) and undetectable (NUGC-4) PIM1 expression levels. RESULTS: PIM1 expression was exclusively nuclear in normal gastric epithelial cells, while aberrant expression/localization (decreased nuclear and/or increased cytoplasmic expression) was observed in 75.6% (68/90) of the human gastric cancer tissue samples, with a significant inverse correlation between nuclear and cytoplasmic expression levels. Clinicopathological analyses revealed that decreased nuclear PIM1 expression correlated with poorer survival and greater depth of tumor invasion, while increased cytoplasmic PIM1 expression correlated inversely with the presence of lymphovascular invasion. High-level PIM1 amplification was identified in 10.5% of gastric cancers by aCGH. K00135 impaired the survival of IM95, while it had no significant effect on NUGC-4 survival. CONCLUSION: Our findings demonstrate the clinical and therapeutic relevance of PIM1 in gastric cancers, and suggest that PIM1 represents a potential therapeutic target.

Geochemical fractionation of trace elements in sediments of Hugli River (Ganges) and Sundarban wetland (West Bengal, India).

A sequential extraction procedure was carried out to determinate the concentrations of 11 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in different geochemical phases of sediments collected along the Hugli (Ganges) River Estuary and in the Sundarban mangrove wetland, eastern coastal part of India. The chemical speciation of elements was determined using the three-step sequential extraction procedure described by the European Community Bureau of Reference. Total metal concentration was determined using a microwave-assisted acid digestion procedure. Metal concentrations were near the background level except for As for which a moderate pollution can be hypothesized. The mobility order of the metals was: Cd > Mn > Cu > Zn > As > Co > Pb > Ni > Fe > Cr > Al. The highest percentage of Cd (>60%) was found in the most labile phase. Residual fraction was prevailing for Fe, Cr and Al, while Pb was mainly associated with the reducible fraction. Data were compared with Sediment Quality Guidelines to estimate the relationship between element concentrations and adverse biological effects on benthic community, finding the possibility of some toxic effects due to the presence of As in the entire studied area and Cd, only in Calcutta.

Biogeochemistry of mercury and methylmercury in sediment cores from Sundarban mangrove wetland, India--a UNESCO World Heritage Site.

This study was performed to elucidate the distribution, concentration trend and possible sources of total mercury (Hg(T)) and methylmercury (MeHg) in sediment cores (<63 µm particle size; n = 75) of Sundarban mangrove wetland, northeastern part of the Bay of Bengal, India. Total mercury was determined by atomic absorption spectrometry (AAS) in a Leco AMA 254 instrument and MeHg by gas chromatography-atomic fluorescence spectrometry (GC-AFS). A wide range of variation in Hg(T) (0.032-0.196 µg g(-1) dry wt.) as well as MeHg (0.04-0.13 ng g(-1) dry wt.) concentrations revealed a slight local contamination. The prevalent low Hg(T) levels in sediments could be explained by sediment transport by the tidal Hugli (Ganges) River that would dilute the Hg(T) values via sediment mixing processes. A broader variation of MeHg proportions (%) were also observed in samples suggesting that other environmental variables such as organic carbon and microbial activity may play a major role in the methylation process. An overall elevated concentration of Hg(T) in surface layers (0-4 cm) of the core is due to remobilization of mercury from deeper sediments. Based on the index of geoaccumulation (I (geo)) and low effects-range (ER-L) values, it is considered that the sediment is less polluted by Hg(T) and there is less ecotoxicological risk. The paper provides the first information of MeHg in sediments from this wetland environment and the authors strongly recommend further examination of Hg(T) fluxes for the development of a detailed coastal MeHg model. This could provide more refine estimates of a total flux into the water column.

C-Reactive Protein Level can be a Better Indicator than Erythrocyte Sedimentation Rate in Assessing the Severity of Inflammation and Guiding Glucocorticoid Therapy in Subacute Thyroiditis.

Background: Despite the widespread use of several diagnostic tests in subacute thyroiditis (SAT), their usage remains largely subjective. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are useful indicators of inflammation in patients with SAT. The purpose of this study was to compare the scope for utilising CRP and ESR objectively in deciding the requirement of glucocorticoid therapy. Methods: A total of 28 patients with SAT were included in this study. Serum CRP and ESR were measured in all the patients. The characteristics of these tests were assessed firstly by using previously accepted positivity criterion for the particular diagnostic test. The area under the receiver operating characteristics (ROC) curve was obtained to provide an index of the overall discriminative ability of both tests. Results: Fifteen out of 28 patients were found to have features of significant thyroid inflammation eventually requiring glucocorticoid based on the current recommendations. The mean CRP value was significantly higher in patients requiring glucocorticoids. The ROC curves indicated that the optimal positivity criterion was 19.3 mg/L for the CRP level and 46 mm at the 1st hour for ESR. CRP with a sensitivity of 0.67, a specificity of 0.92, a positive likelihood ratio of 8.67, and an accuracy of 0.64 appeared better than ESR, which showed a sensitivity of 0.93, a specificity of 0.53, a positive likelihood ratio of 2.02, and an accuracy of 0.60. Conclusions: The serum CRP level provided a clear advantage over ESR in the assessment of the severity of inflammation before initiation of glucocorticoid therapy in SAT. However, a well-powered study is needed to examine the clinical relevance of such a role for CRP in thyroidology.

Real-time photovoltaic parameters assessment of carbon quantum dots showing strong blue emission.

The need for replacing conventional sources of energy with renewable ones has been on a swift rise since the last couple of decades. In this context, the progress in third-generation solar cells has taken a good leap in the last couple of years with increasing prospects of high efficiency, stability, and lifetime. Quite recently, a new form of carbon has been discovered accidentally in the form of carbon quantum dots (C QD), which is being pursued actively owing to its chemical stability and luminescent properties. In the current work, we report highly luminescent C QD prepared via a simple hydrothermal route. Transmission electron microscopy revealed an average particle size of 3.4 nm. The prepared C QD were used in a co-sensitized solar cell, where an improvement in the device characteristics was observed. The enhancement in the device characteristics is supported by impedance and electron life-time analysis. Further, the time-dependent analysis of the current and voltage revealed the functioning of the solar cell in real-time condition.

Nonobese population in a developing country has a high prevalence of nonalcoholic fatty liver and significant liver disease.

UNLABELLED: There is a paucity of community-based epidemiological data on nonalcoholic fatty liver (NAFL) among nonaffluent populations in developing countries. Available studies are radiological and/or biochemical and lack histological assessment, limiting their strength. We conducted a prospective epidemiological study comprising a 1:3 subsample of all adult (>18 years) inhabitants of a rural administrative unit of West Bengal, India. Subjects positive for hepatitis B virus and/or hepatitis C virus infection and consuming any amount of alcohol were excluded. Diagnosis of NAFL was by dual radiological screening protocol consisting of ultrasonographic and computed tomographic examination of the liver. Transient elastographic examination and liver biopsy were performed in a subset to identify significant liver disease. The risk factors of having NAFL were analyzed. A total of 1,911 individuals were analyzed, 7% of whom were overweight and 11% of whom had abdominal obesity. The prevalence of NAFL, NAFL with elevated alanine aminotransferase, and cryptogenic cirrhosis was 8.7%, 2.3%, and 0.2%, respectively. Seventy-five percent of NAFL subjects had a body mass index (BMI) <25 kg/m(2), and 54% were neither overweight nor had abdominal obesity. The subjects with the highest risk of having NAFL were those with a BMI >25 kg/m(2) (odds ratio 4.3, 95% confidence interval 1.6-11.5). Abdominal obesity, dysglycemia (fasting plasma glucose >100 mg/dL or elevated homeostatic model assessment of insulin resistance), and higher income were the other risk factors. Even having a normal BMI (18.5-24.9 kg/m(2)) was associated with a 2-fold increased risk of NAFL versus those with a BMI <18.5 kg/m(2). CONCLUSION: There is a significant prevalence of NAFL and potentially significant liver disease, including cryptogenic cirrhosis, in this predominantly nonobese, nonaffluent population in a developing country. NAFL will be a major determinant of future liver disease burden in countries of the developing world.

Baseline of butyltin contamination in sediments of Sundarban mangrove wetland and adjacent coastal regions, India.

The study reports the first assessment for the quantification and speciation of butyltins (BTs) in surface marine sediment samples (0-5 cm) from intertidal mudflats of Sundarban mangrove wetland along with the Hugli (Ganges) river basin, eastern coastal part of India. Concentrations of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were monitored at 16 stations and present at all study areas, in concentrations in sediments up to 84.2, 26.4 and 48.0 ng g(-1) of TBT, DBT and MBT, respectively. Significant correlations were obtained between MBT and DBT (r = 0.62, p = 0.01) and DBT and TBT (r = 0.54, p = 0.03). Calculated BT degradation index (BDI) values indicated recent contamination of BTs at 8 stations, and suggested either no degradation of TBT or very recent degradation at a 4 further stations. Additionally, BDI values also indicated no recent inputs of BTs in 4 stations (only MBT present in one of these stations). High concentrations of BTs, particularly TBT, have the potential to induce ecotoxicological impacts based on levels specified in Australian Sediment Quality Guidelines (SQGs). This study indicated that the majority of the analyzed stations were in the highest range of priority, due to high TBT concentrations.

Fluorescence Quenching by Förster Resonance Energy Transfer in Carbon-Cadmium Sulfide Core-Shell Quantum Dots.

Carbon quantum dots (QDs) are an active subject of research in many areas of science and engineering for various applications. The present work reports the first occurrence of a carbon-cadmium sulfide core-shell QD prepared by an extremely simplified wet chemical approach where the CdS shell plays the role of a fluorescence quencher to the carbon core. The quenching effect was confirmed by fluorescence spectroscopy (steady-state and lifetime). These QDs stand as a potential candidate for sensing and imaging applications.

Effect of cell microenvironment on the drug sensitivity of hepatocellular cancer cells.

The native hepatocellular cancer (HCC) microenvironment is characterized by more hypoxic, hypoglycemic, and acidic conditions than those used in standard cell culture. This study aimed to investigate whether HCC cells cultured in more native conditions have an altered phenotype and drug sensitivity compared to those cultured in standard conditions. Six HCC cell lines were cultured in "standard" (21% O2, 25 mM glucose) or more "native" (1% O2, 5 mM glucose, 10 mM lactate) conditions. Cells were assessed for growth rates, cell cycle distribution, relevant metabolite and protein levels, genome-wide gene expression, mitochondrial DNA sequence and sensitivity to relevant drugs. Many differences in cellular and molecular phenotypes and drug sensitivity were observed between the cells. HCC cells cultured in native conditions had slower doubling times, increased HK2 and GLUT, lower PHDA and ATP levels, and mutations in mitochondrial DNA. Thirty-one genes, including the hypoxia-associated NDRG1, were differentially expressed between the cells. HCC patients in The Cancer Genome Atlas (TCGA) with tumors with a high score based on these 31 genes had a poorer prognosis than those with a low score (p = 0.002). From 90 comparisons of drug sensitivity, increased resistance and sensitivity for cells cultured in native conditions was observed in 14 (16%) and 8 (9%) comparisons respectively. In conclusion, cells cultured in more native conditions can have a more glycolytic and aggressive phenotype and varied drug sensitivity to those cultured in standard conditions, and may provide new insights to understanding tumor biology and drug development.

An Ultra-Simple Method for Synthesis of Violet CdS Quantum Dots at Sub-Room Temperature.

The emergence of fluorescence quantum dots (QDs) has led to the development of variety of applications in science and technology. Owing to the diverse optical and electrical properties of CdS QDs we have synthesized the same using wet chemical method. The QDs have been prepared at sub-room temperature using a new solvent comprising a mixture of water and methanol. The QDs when seen under UV light radiate violet color. The band-gap of the QDs deduced from the absorption spectra was 3.08 eV while PL spectra of the QDs suggested possibility of multiple exciton generation with a close to narrow size distribution. XRD analysis confirmed cubic structure of the particles. The obtained results suggest that these QDs can play ideal role in quantum dot sensitized solar cells (QDSSC) or in light emitting diodes (LEDs).

Congener profiles of polychlorinated biphenyls in core sediments of Sunderban mangrove wetland (N.E. India) and their ecotoxicological significance.

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: CB138 > 153 > 149 > 101, 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.

An assessment of trace element contamination in intertidal sediment cores of Sunderban mangrove wetland, India for evaluating sediment quality guidelines.

This paper presents a comprehensive account regarding concentration, distribution and possible sources of trace elements (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in 20-30 cm sediment cores (<63 microm particle size) collected at the confluence of the Ganges River and Bay of Bengal (Sunderban wetland, India). This work aims to evaluate the fluvio-marine and geochemical processes influencing the metal distribution. The most interesting features are the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 10-15 cm observed in station Lot No.8 located along the main stream of the Ganges estuary as well as an overall elevated concentration of all the elements in the lower littoral zone. The interelemental relationship revealed the identical behaviour of elements during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of effluents originating from industrial and agricultural as well as from domestic sewage. Arsenic exceeded effects range - low (ER - L) concentrations, implying occasional or frequent adverse biological effects. For Cu, Ni and Cr a smaller proportion of samples had exceeded the ER - L values indicating that the dataset would be suitable for future use in evaluating predictive abilities of SQGs.

Biogenic synthesis and thermo-magnetic study of highly porous carbon nanotubes.

Nanomaterials synthesis using natural sources is the technology to up come with advanced materials through extracts of plant, microorganisms, poultry waste etc. In this study, the authors report the synthesis of porous carbon nanotubes using high-temperature decomposition technique facilitated by cobalt salt using chicken fats, a poultry waste as a precursor. Since chicken fats contain fatty acids which can decompose into short hydrocarbon chains and cobalt can act as the catalyst. The formation of carbon nanotubes was confirmed by Raman spectra, peaks at 1580 and 1350.46 cm-1 confirmed the graphite mode G-band and structural imperfections defect mode D-band, respectively. Transmission electron microscopy showed the formation of tube-like structures. Nitrogen adsorption-desorption studies showed the high-surface area of 418.1 m2g-1 with an estimated pore diameter of 8.1 nm. Thermogravimetry analysis-derivative thermogravimetric analysis-differential thermal analysis showed the instant weight loss at 517°C attributed to the rapid combustion of nanotubes. A vibrating-sample magnetometer showed the paramagnetic nature of the so-formed carbon nanotubes formed.

Venezuelan equine encephalitis virus infection causes modulation of inflammatory and immune response genes in mouse brain.

BACKGROUND: Neurovirulent Venezuelan equine encephalitis virus (VEEV) causes lethal encephalitis in equines and is transmitted to humans by mosquitoes. VEEV is highly infectious when transmitted by aerosol and has been developed as a bio-warfare agent, making it an important pathogen to study from a military and civilian standpoint. Molecular mechanisms of VEE pathogenesis are poorly understood. To study these, the gene expression profile of VEEV infected mouse brains was investigated. Changes in gene expression were correlated with histological changes in the brain. In addition, a molecular framework of changes in gene expression associated with progression of the disease was studied. RESULTS: Our results demonstrate that genes related to important immune pathways such as antigen presentation, inflammation, apoptosis and response to virus (Cxcl10, CxCl11, Ccl5, Ifr7, Ifi27 Oas1b, Fcerg1,Mif, Clusterin and MHC class II) were upregulated as a result of virus infection. The number of over-expressed genes (>1.5-fold level) increased as the disease progressed (from 197, 296, 400, to 1086 at 24, 48, 72 and 96 hours post infection, respectively). CONCLUSION: Identification of differentially expressed genes in brain will help in the understanding of VEEV-induced pathogenesis and selection of biomarkers for diagnosis and targeted therapy of VEEV-induced neurodegeneration.

Water quality assessment of the ecologically stressed Hooghly River Estuary, India: A multivariate approach.

Spatio-temporal and seasonal variation of the water quality characteristics of the Hooghly River Estuary, India were studied considering eight stations of diverse eco-hydrological characteristics. Wide variations in turbidity, total dissolved solids and fecal coliform exceeded the permissible BIS drinking water level limit. The estuary is observed to be relatively low-oxygenated, mesotropic and phosphate limiting. Spatial heterogeneity and impact of the southwest monsoon were remarkably pronounced in the distribution of the inorganic nutrients revealing the following values (expressed in µgatml-1): nitrate+nitrite (2.42-37.19), phosphate (0.41-1.52) and silicate (38.5-187.75). Water Quality Index (WQI) values confirmed the prevailing 'bad' condition, detrimental for sustenance of aquatic biota. Results of Principal Component Analysis identified the major factors liable for water quality deterioration while cluster analysis categorized the stations on the basis of similar water quality status. The authors recommend adopting preventive measures for water quality improvement linked to biodiversity conservation.

Concentration of polybrominated diphenyl ethers (PBDEs) in sediment cores of Sundarban mangrove wetland, northeastern part of Bay of Bengal (India).

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 47>99>100>154, 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.