Biomarker responses in the Coilia dussumieri exposed to petroleum hydrocarbons contamination in urbanized estuaries along the west coast of India.

The estuaries of Maharashtra are under continuous pressure due to uncontrolled dumping of persistent toxic organic pollutants into these regions and their impact on the marine environment. In this study, total petroleum hydrocarbons (TPHs) in water, sediments, fish, and biomarker responses in the Coilia dussumieri exposed to TPHs were determined in seven urbanized tropical estuaries along the west coast of India during the winter and summer. The results of the cluster analysis highlighted that the concentration of TPHs in the water, sediment, and fish in the study area was spatially varied, with the highest concentration in the northern area of Maharashtra (NM) estuaries than in the southern region of Maharashtra (SM) estuaries during both seasons. The enrichment of TPHs in water and sediment in the middle part of most estuaries highlights the addition of anthropogenic organic matter. A higher concentration of TPHs in the muscle tissue of Coilia dussumieri observed in NM during the winter season, indicates the energetic intake and storage of large quantities of TPHs in their muscle tissue. The biochemical results showed decreased levels of total protein (PRT) under exposure to TPHs, under oxidative stress and reversing correlations was observed between catalase (CAT) and lipid peroxidation (LPO) activities with the respective TPHs. Similarly, reduced activity of the CAT antioxidant and increased glutathione-S-transferase (GST) under exposure to TPHs were more likely to occur under hydrocarbon stress. However, current results indicate that Coilia dussumieri actively produces oxidative stress and antioxidant reaction that can be used as biomarkers of pollution in the study area.

Ecobiology and distribution of Streptomyces species from distinctive metal polluted sediment of tropical estuary, Northwest coast of India.

The present study aims to isolate diverse actinomycetes communities from the estuarine sediments of Patalganga located at Northwest coast of India. Total 40 actinomycetes were isolated from 24 sediment samples by dilution plating on six different isolation media. Among them, morphologically 18 distinct selected isolates of actinomycetes were verified by 16S rRNA gene sequencing and identified as Streptomyces spp. The relationship between diversity of total actinomycetes population (TAP) and its antagonistic behaviour with the physico-chemical characteristics of sediment samples were investigated. Multiple regression analysis revealed that the influencing physico-chemical factors comprises of sediment temperature, sediment pH, organic carbon and heavy metals. The results of statistical analysis showed that TAP is positively correlated (p < 0.01) with sediment organic carbon whereas, negatively correlated with Cr (p < 0.05) and Mn (p < 0.01). Based on Principle component Analysis (PCA) and cluster analysis results, the obtained six stations can be divided into three groups. Among them mobile fraction of metals, TAP could be the main factor reflecting the lower and middle estuary. The recovery of large number of actinomycete isolates suggests that Patalganga Estuary could be potential source of bioactive compounds with biosynthetic capabilities.

Effects of sedimentary heavy metals on meiobenthic community in tropical estuaries along eastern Arabian Sea.

The central west coast of India comprises the 720 km long coastline of Maharashtra state and houses widespread industrial zones along the eastern Arabian Sea. Sediments from seven industrial-dominated estuaries along the central west coast were studied for metal enrichment and benthic assemblages to determine sediment quality status and ecological effects in these areas. The suit of geochemical indices highlighted the contamination of sediment in the estuaries concerning heavy metals. Positive correlations of Hg with Co, Zn, Ni, Cr, and Pb indicated the source similarity and effect of anthropogenic activity. non-Metric Multidimensional Scaling (n-MDS) based on meiofaunal abundance showed a cleared separation of clusters through the gradient of heavy metal concentrations. The Canonical Correspondence Analysis (CCA) results with the Monte Carlo test signified those heavy metals influenced the meiobenthic community. Heavy metals (Cr, Ni, Zn, Cd, Pb, and Hg) were the main drivers shaping the meiofaunal community with a significant (p < 0.05) reduction in taxa richness, diversity, and evenness. Dominant meiofaunal assemblages evidence the tolerance of foraminiferans and nematodes. However, these taxa were affected by decreased abundance at impacted sites compared to other fauna. In conclusion, results demonstrated that impairment occurred in the meiofaunal community in most estuaries (except AB and KK).

Phytoplankton assemblage and chlorophyll a along the salinity gradient in a hypoxic eutrophic tropical estuary-Ulhas Estuary, West Coast of India.

Phytoplankton assemblage and chlorophyll a along the salinity gradient and oxygen zonation were studied in Ulhas Estuary. Oxic condition exist in euhaline region of the estuary that receives oxygenated coastal waters, while, poly-meso-oligohaline region is hypoxic due to the accumulation of voluminous amount of pollutants from industrial effluents, domestic/sewage and agricultural discharges. Additionally, anthropogenically generated nutrients enhanced phytoplankton biomass (chlorophyll a) and their senescence also led to hypoxia. The dominance of diatoms (>70%) was observed in the euhaline-oxic region, while a tremendous decrease in their contribution (18%) was observed in the oligohaline region. Meso to oligohaline region of the estuary is governed by cyanophytes and chlorophytes due to their affinity towards low salinity and high dissolved inorganic nutrients. Carlson's Trophic State Index (TSI) further substantiated the estuary as eutrophic. Additionally, the study could identify the adaptation of cyanophytes and chlorophytes in oxygen deficient water.

Multivariate assessment of outflow water quality in highly urbanized creek system: implication of natural and anthropogenic processes.

Nutrient source and transport study in tropical creeks adjacent to megacities are sparse on a regional and global scale. High-frequency chemical data collected during 2017-2018 in the Thane creek system, the largest micro-tidal urbanized creek in Asia, were analysed to assess the chemical water quality, with its linkage to different hydrological stages (southwest monsoon, post- and pre-monsoon) and ongoing anthropogenic activities. Cluster analysis indicates typical zonation between creek outflow and nearshore waters with distinctive physicochemical properties. The creek outflow upholds substantial amounts of nutrient and suspended sediment due to turbid water movement from the ephemeral mudflats and anthropogenic dredging. The year-round hyper-turbid condition in the bottom water triggers the addition of disproportionate nutrients (9% dissolved inorganic nitrogen (DIN) and 14% reactive phosphorous (PO43-) in the outflow region. The DIN and PO43- removal up to 10 and 35%, respectively, occurs in the nearshore region; sedimentation, which acts as a sinking interface for nitrogen and phosphorous, also causes shifting in their limiting conditions. The hyper-turbid condition causes removal of dissolved silicate (DSi) by 5% in the entire region. Ammonium (NH4+) is mainly sourced from the sewage in outflow waters and efficiently mineralized. Chemical indexing of water highlights that the bottom water column remained un-supportive to the balanced ecology. The findings of this study have implications for other tropical creek-estuary concerning management strategies against inadequate flushing. The stalled nutrient export affected balance ecology in tropical Thane creek, which need attention in order to accurately understand the impact on adjacent marine environment and to form effective mitigation policies.

Inter-annual variability of phytoplankton assemblage and Tetraspora gelatinosa bloom from anthropogenically affected harbour, Veraval, India.

Veraval, one of Asia's largest fishing harbours, situated on the south-west coast of Gujarat, India, has transformed into an industrial hub dominated by fish processing units, rayon manufacturing industry, and transportation facilities. The study investigated the high abundance of Tetraspora gelatinosa along with the augmented level of ammonia in the harbour. The high concentration of ammonia was associated with the accumulation of sewage, industrial, and fishery wastes in the harbour. Low-energy expenditure associated with assimilation of ammonia made it a principal nitrogen source for Tetraspora gelatinosa growth. Even though ammonia is the preferred nitrogen source by phytoplankton, elevated concentration causes toxicity to the cells. Augmented level of ammonia and high TSS hampered the efficiency of PS II, thereby impeding the chlorophyll a degradation and oxygen evolution. Built of the organic load from fish processing industries as well as domestic waste along with a reduction in photosynthetic oxygen evolution has made the harbour hypoxic (DO < 1.6 mg L-1)/anoxic (DO = 0.0 mg L-1). Shannon-Wiener diversity index as a pollution index suggested that the inner harbour area was highly polluted as the diversity ranged from 0.01 to 1.57. Whereas, the outer harbour (Near-shore and off-shore) with less anthropogenic effect recorded high diversity (av. 2.17) suggesting a healthy environment.

Factors controlling organic matter composition and trophic state in seven tropical estuaries along the west coast of India.

To understand the organic matter (OM) sources and trophic states, spatial and seasonal (post-monsoon and pre-monsoon) variation in sedimentary OM compositions was investigated in seven tropical estuaries of the state of Maharashtra along the central west coast of India. Based on the result of cluster analysis, estuaries were segregated into two distinct groups: Northern Maharashtra and Southern Maharashtra owing to dissimilarity in OM characteristics potentially constrained by geomorphology and catchment properties. Enrichment of Corg and major biochemical compounds (lipids, carbohydrates and proteins) in the middle zone of most estuaries highlighted towards the addition of allochthonous OM. Results of principal component analysis highlighted the similar source of OM in most of the estuaries during both seasons and their distribution largely constrained by grain size change. The benthic trophic state indicated the prevalence of eutrophic state in the middle zone of the investigated estuaries, which may be sporadic and dependent upon anthropogenic activities in the study area.

Behaviour of trace metals in the anoxic environment of Veraval harbour, India.

The purpose of the present study is to investigate the behaviour of trace metals in anoxic environment. Water column of the harbour was found to be anoxic (DO <0.2mgl-1) with high concentration of NH4+-N (av. 459±21µmoll-1) and H2S (av.73±2.5µmoll-1) irrespective of season and tide. High concentrations of Fe, Mn in bottom water indicated that Fe, Mn were diagenetically mobilized under the anoxic conditions prevailing in the harbour. In harbour sediments significant correlation of metals with TOC and TS indicated their diagenetic immobilization in anoxic environment. Fe was positively correlated with TS suggesting FeS formation in anoxic condition. TOC/TN ratio of sediments was higher (16±5.2) than the normal marine planktonic sediments suggesting an increased burden of terrestrial carbon in the harbour. A sediment core collected 10km away from the shore indicated build-up of trace metals in recent years, showing diagenetically upward movement of metals.

Role of heavy metals in structuring the microbial community associated with particulate matter in a tropical estuary.

Particulate matter (PM), which are chemically and biochemically complicated particles, accommodate a plethora of microorganisms. In the present study, we report the influence of heavy metal pollution on the abundance and community structure of archaea and bacteria associated with PM samples collected from polluted and non-polluted regions of Cochin Estuary (CE), Southwest coast of India. We observed an accumulation of heavy metals in PM collected from CE, and their concentrations were in the order Fe > Zn > Mn > Cr > Pb > Cu > Cd > Co > Ni. Zinc was a major pollutant in the water (4.36-130.50 µgL-1) and in the particulate matter (765.5-8451.28 µgg-1). Heavy metals, Cd, Co, and Pb were recorded in the particulate matter, although they were below detectable limits in the water column. Statistical analysis showed a positive influence of particulate organic carbon, nitrogen, PM-Pb, PM-Zn and PM-Fe on the abundance of PM-archaea and PM-bacteria. The abundance of archaea and bacteria were ten times less in PM compared with planktonic ones. The abundance of PM-archaea ranged between 4.27 and 9.50 × 107and 2.73 to 3.85 × 107 cellsL-1 respectively for the wet and dry season, while that of PM-bacteria was between 1.14 and 6.72 × 108 cellsL-1 for both seasons. Community structure of PM-bacteria varied between polluted and non-polluted stations, while their abundance does not show a drastic difference. This could be attributed to the selective enrichment of bacteria by heavy metals in PM. Such enrichment may only promote the growth of metal resistant archaea and bacteria, which may not participate in the processing of PM. In such cases, the PM may remain without remineralization in the system arresting the food web dynamics and biogeochemical cycles.

Pathogenic multiple antimicrobial resistant Escherichia coli serotypes in recreational waters of Mumbai, India: a potential public health risk.

Globally, coastal waters have emerged into a pool of antibiotic resistance genes and multiple antibiotic resistant microorganisms, and pathogenicity of these resistant microorganisms in terms of serotypes and virulence genes has made the environment vulnerable. The current study underscores the presence of multiple antibiotic resistant pathogenic serotypes and pathotypes of Escherichia coli, the predominant faecal indicator bacteria (FIB), in surface water and sediment samples of famous recreational beaches (Juhu, Versova, Mahim, Dadar, and Girgaon) of Mumbai. Out of 65 faecal coliforms (FC) randomly selected, 38 isolates were biochemically characterized, serotyped (for 'O' antigen), antibiogram-phenotyped (for 22 antimicrobial agents), and genotyped by polymerase chain reaction (for virulence factors). These isolates belonged to 16 different serotypes (UT, O141, O2, O119, O120, O9, O35, O126, O91, O128, O87, O86, R, O101, O118, and O15) out of which UT (18.4%), O141 (15.7%), and O2 (13.1%) were predominant, indicating its remarkable diversity. Furthermore, the generated antibiogram profile revealed that 95% of these isolates were multiple antibiotic resistant. More than 60% of aminoglycoside-sensitive E. coli isolates exhibited resistance to penicillin, extended penicillin, quinolone, and cephalosporin classes of antibiotic while resistance to other antibiotics was comparatively less. Antibiotic resistance (AR) indexing indicated that these isolates may have rooted from a high-risk source of contamination. Preliminary findings revealed the presence of enterotoxin-encoding genes (stx1 and stx2 specific for enterohaemorrhagic E. coli and Shiga toxin-producing E. coli, heat-stable toxin enterotoxin specific for enterotoxigenic E. coli) in pathogenic serotypes. Thus, government authorities and environmental planners should create public awareness and adopt effective measures for coastal management to prevent serious health risks associated with these contaminated coastal waters.

Seasonal distribution of phytoplankton and its association with physico-chemical parameters in coastal waters of Malvan, west coast of India.

Malvan coast is one of the Marine Protected Area (MPA) of Maharashtra because of its rich coral reef and biodiversity. The study investigated on phytoplankton assemblage and their diversity with respect to physico-chemical parameters covering protected and unprotected area of Malvan coast. Physico-chemical parameters such as salinity, nitrite, nitrate, and ammonia did not display seasonality due to inadequate fresh water influx and allochthonous nutrient input. Positive correlation of phosphate (r = 0.96, p < 0.0001) and silicate (r = 0.91, p < 0.0001) with Total Suspended Solids (TSS) confirmed their autochthonous origin as a result of resuspension of bottom sediments during monsoon. A total of 57 phytoplankton species were identified mostly dominated by Bascillariophyceae (40 species), followed by Dinophyceae (9 species), Chlorophyceae (5 species), Cyanophyceae (2 species), and Dictyochophyceae (1 species) from Malvan coast. Canonical correspondence analysis (CCA) revealed that water temperature and TSS were the most significant parameters influencing the distribution and seasonal shift in phytoplankton species such as Skeletonema costatum and Chaetoceros sp. during pre-monsoon and Psedo-nitzschia sp., Streptotheca thamensis, Eucampia zodiacus, and Lithodesmium undulatum during post-monsoon. Silicate and phosphate had minor influence on phytoplankton distribution. Shannon-Wiener diversity index as a pollution index suggested that the study area was incipiently polluted except at bay stations. Despite of various human interventions the water quality and phytoplankton assemblage of this area has not reached to an alarming situation. The current study provides a valuable baseline data on phytoplankton assemblage from Malvan coast.

A Preliminary Estimate of Total Petroleum Hydrocarbons in Water and Some Commercially Important Fish Species in the Amba Estuary, West Coast of India.

Amba Estuary, which receives effluent from several industries including a petrochemical complex, opens to the southern limits of the Mumbai Harbor. The study was conducted to find out the level of Total Petroleum Hydrocarbons (TPHs) in water and their bioconcentration in ten commercially important fishes from Amba Estuary during different months. In water high concentration of TPHs (39.7 µg/L) was obtained during December (middle of estuary) and minimum value (7.2 µg/L) was observed in September (lower estuarine). The maximum concentration of TPHs was found to be in Trichiurus savala (3.2 µg/g) during December and minimum in Boleophthalmus sp (0.4 µg/g) during May. Irrespective of the monthly variations, TPHs accumulation in all the species was considerably lower than hazardous levels. Although there was no statistical significance between TPHs and total length/weight, the T. savala recording maximum concentration during all months and it can be used as indicator of hydrocarbon pollution in this region.

Effect of heavy metals on the carbon and nitrogen ratio in Avicennia marina from polluted and unpolluted regions.

The accumulation of heavy metals and its impact on the C/N ratio of Avicennia marina of the Patalganga and Amba estuaries were studied. Vadinar was selected as a relatively uncontaminated location for comparison. Cd was accumulated in leaves of the Patalganga and Amba estuarine mangroves; however, at Vadinar it was accumulated and arrested only in roots and stems. Negative correlation of Cr, Cd, Pb and Zn with C in the mangroves suggested that their accumulation may lead to lowered C content in the mangroves. The average C/N ratios in mangroves of the inner Patalganga estuary, Patalganga mouth, and Amba estuary were found to be 80.1 ± 7.3, 105.8 ± 12.5 and 52.4 ± 3.4 respectively, whereas at Vadinar it was well within the expected range (26.4 ± 2.8). The results of the present study suggest: (i) metal accumulation, leading to less carbon content in plants; (ii) heavy metal enrichment in the root zone sediment, affecting the uptake of nitrogen by plants and resulting in altered C/N ratio.

Moving Cell Boundaries Drive Nuclear Shaping during Cell Spreading.

The nucleus has a smooth, regular appearance in normal cells, and its shape is greatly altered in human pathologies. Yet, how the cell establishes nuclear shape is not well understood. We imaged the dynamics of nuclear shaping in NIH3T3 fibroblasts. Nuclei translated toward the substratum and began flattening during the early stages of cell spreading. Initially, nuclear height and width correlated with the degree of cell spreading, but over time, reached steady-state values even as the cell continued to spread. Actomyosin activity, actomyosin bundles, microtubules, and intermediate filaments, as well as the LINC complex, were all dispensable for nuclear flattening as long as the cell could spread. Inhibition of actin polymerization as well as myosin light chain kinase with the drug ML7 limited both the initial spreading of cells and flattening of nuclei, and for well-spread cells, inhibition of myosin-II ATPase with the drug blebbistatin decreased cell spreading with associated nuclear rounding. Together, these results show that cell spreading is necessary and sufficient to drive nuclear flattening under a wide range of conditions, including in the presence or absence of myosin activity. To explain this observation, we propose a computational model for nuclear and cell mechanics that shows how frictional transmission of stress from the moving cell boundaries to the nuclear surface shapes the nucleus during early cell spreading. Our results point to a surprisingly simple mechanical system in cells for establishing nuclear shapes.

Bioaccumulation of heavy metals in commercially important marine fishes from Mumbai Harbor, India.

Seventeen commercially important marine fish species were caught in Mumbai Harbor using a trawl net and evaluated using Atomic Absorption Spectroscopy and ICP-OES. It was found that certain species of fish contained lower levels of all metals tested. J. elongatus and C. dussumieri had the highest levels of all 8 metals tested. The heavy metal concentrations were significantly varied within and between the studied fishes (p<0.05). However, a significant correlation among heavy metals was observed. This investigation indicated that various levels of heavy metals exist in the fish species sampled, but those concentrations are within the maximum residual levels recommended by the European Union and FAO/WHO. Therefore, fish caught in Mumbai Harbor can be considered safe for human consumption.

Diagenesis and bioavailability of mercury in the contaminated sediments of Ulhas Estuary, India.

Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0.46 and 6.40 microg g(-1) with significant decrease in surficial sediment as a result of closing of two Hg-cell based chlor-alkali plants. Results of sequential extraction showed that>65% Hg was strongly bound to organo-sulphur and inorganic sulphide species that are not bioavailable. Flux of only 18.8% of Hg was found compared to its value deposited on sediment-water interface. Hence, it is concluded that there is no significant diagenetic remobilization of Hg in Ulhas Estuary. This core also has been analyzed for (210)Pb geochronology. The estimated sedimentation rate is 0.31 cm y(-1) in the present sampling region.

Mercury in sediments of Ulhas estuary.

Hg levels in water, suspended particulate matter and sediment of the Ulhas estuary are under considerable environmental stress due to the indiscriminate release of effluents from a variety of industries including chlor-alkali plants. Concentration ranges of dissolved (0.04-0.61 micro gl(-1)) and particulate (1.13-6.43 micro gg(-1)) Hg reveal a definite enhancement of levels in the estuary. The Hg burden in sediment upstream of the weir that limits the tidal influence is low (0.08-0.19 micro gg(-1)) with low C(org) content (1.8-2.9%). The high Hg content of the sediment just below the weir varies seasonally (highest concentration recorded being 38.45 micro gg(-1)) due to incremental accretion of sediment as the fresh water flow over the weir progressively decreases. The 30 km segment of the estuary sustains markedly high levels of Hg in the sediment with an exponential decrease in the seaward direction from the weir. Higher concentrations than the expected background prevail in all the estuarine cores up to the bottom, though the overall concentration decreases from about 20 micro gg(-1) in core 7 (inner estuary) to 1 micro gg(-1) in core 31 (outer estuary). The Hg in sediment is associated with C(org), while its correlation with Al, Fe and Mn is poor. The Hg profiles in cores from the Arabian Sea (stations 34, 35 and 37) have a distinct horizon of enhanced concentration in the 5-60 cm segment. Based on 210Pb dating of core 37, the sediment at the bottom of this core is inferred to have been deposited in the year 1949, roughly two year prior to the establishment of the first chlor-alkali plant and represents the background (0.06-0.10 micro gg(-1)). The Hg profiles in the offshore cores indicate a marked increase in transfer of Hg to sediment subsequent to 1980, with a peak around 1990-1992. Based on the index of geoaccumulation it is considered that the estuarine segment between stations 4 and 23 is extremely polluted, while the sediment from the open coast is moderately polluted in the top 25-30 cm with respect to Hg. The enrichment factor of Hg in the sediment is 350-700 for core 4 and decreases to 0-7 for the open-shore cores.