Genotoxicity of two heavy metal compounds: lead nitrate and cobalt chloride in Polychaete Perinereis cultrifera.

The present study explores the in vivo and in vitro genotoxic effects of lead nitrate, [Pb(NO3)2] a recognized environmental pollutant and cobalt chloride (CoCl2), an emerging environmental pollutant in polychaete Perinereis cultrifera using comet assay. Despite widespread occurrence and extensive industrial applications, no previous published reports on genotoxicity of these compounds are available in polychaete as detected by comet assay. Polychaetes were exposed in vivo to Pb(NO3)2 (0, 100, 500, and 1000 µg/l) and CoCl2 (0, 100, 300, and 500 µg/l) for 5 days. At 100 µg/l Pb(NO3)2 concentration, tail DNA (TDNA) values in coelomocytes were increase by 1.16, 1.43, and 1.55-fold after day 1, day 3, and day 5, whereas, OTM showed 1.12, 2.33, and 2.10-fold increase in in vivo. Pb(NO3)2 showed a concentration and time-dependent genotoxicity whereas CoCl2 showed a concentration-dependent genotoxicity in in vivo. A concentration-dependent increase in DNA damage was observed in in vitro studies for Pb(NO3)2 and CoCl2. DNA damage at 500 µg/L showed almost threefold increase in TDNA and approximately fourfold increase in OTM as compared to control in in vitro. Our studies suggest that Pb(NO3)2 and CoCl2 have potential to cause genotoxic damage, with Pb(NO3)2 being more genotoxic in polychaete and should be used more carefully in industrial and other activities. Graphical abstract.

Genotoxicity of cadmium chloride in the marine gastropod Nerita chamaeleon using comet assay and alkaline unwinding assay.

This paper presents an evaluation of the genotoxic effects of cadmium chloride (CdCl2 ) on marine gastropod, Nerita chamaeleon following the technique of comet assay and the DNA alkaline unwinding assay (DAUA). In this study, the extent of DNA damage in gill cells of N. chamaeleon was measured after in vivo exposure to four different concentrations (10, 25, 50, and 75 µg/L) of CdCl2 . In vitro exposure of hydrogen peroxide (H2 O2 ; 1, 10, 25, and 50 µM) of the gill cells showed a significant increase in the percentage tail DNA, Olive tail moment, and tail length (TL). Significant changes in percentage tail DNA by CdCl2 exposure were observed in all exposed groups of snails with respect to those in control. Exposure to 75 µg/L of CdCl2 produced significant decrease in DNA integrity as measured by DAUA at all duration with respect to control. In vivo exposure to different concentrations of CdCl2 (10, 25, 50, and 75 µg/L) to N. chamaeleon showed considerable increase in DNA damage as observed by both alkaline comet assay and the DAUA. The extent of DNA damage in marine gastropods determined by the application of alkaline comet assay and DAUA clearly indicated the genotoxic responses of marine gastropod, N. chamaeleon to a wide range of cadmium concentration in the marine environment.

Polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in beaked sea snake Enhydrina schistose (Daudin, 1803) from the Mandovi estuary, Goa.

An ecotoxicological study were conducted to evaluate the concentrations of PAHs and n-alkanes, in gut, liver and kidney tissues of two individuals of Enhydrina schistose (Daudin, 1803), using gas chromatography/mass spectrometry. The concentrations of PAHs (0.10 µg/g) and n-alkanes (8.12 µg/g) were elevated in the gut, and liver (PAHs 0.05 µg/g tissue, n-alkanes 29.16 µg/g tissue). In kidney of both specimen-A and B the PAHs (0.01 and 0.1 µg/g) and n-alkanes (0.22 and 2.06 µg/g) concentration was detected. This was an initial survey (n = 2) and the main goal was to know accumulation and distribution of PAHs and n-alkanes in the sea snakes. This study indicates high accumulation of petroleum hydrocarbon in gut, liver and kidney of sea snake. Since, this species also act as pray for sea eagles and some predatory fishes such as tiger shark, there is high possibilities of PAHs being circulated in marine food chain.

Coral reef-associated brachyuran fauna (Crustacea: Decapoda: Brachyura) from Angria Bank off the west coast of India.

Underwater sampling via SCUBA and grab at the Angria Bank coral reefs off the central west coast of India in January 2014 revealed 11 species of Brachyura. Seven species, namely, Thusaenys irami (Laurie, 1906), Tanaocheles bidentata (Nobili, 1901), Portunus convexus De Haan, 1835, Xiphonectes macrophthalmus (Rathbun, 1906), Thalamita gatavakensis Nobili, 1906, Serenius ceylonicus (Laurie, 1906), and Soliella flava (Rathbun, 1894) are reported for the first time from Indian waters. Furthermore, the geographical distribution of T. irami and S. ceylonicus is extended westwards of hitherto known ranges.

Trait-based and taxonomic macrofauna community patterns in the upwelling ecosystem of the southeastern Arabian sea.

Coastal upwelling that occurs in the eastern Arabian Sea (EAS) drive the complex dynamics of the food chain. Macrofauna plays a key role in the functioning of coastal ecosystems, but few studies explored the taxonomic and functional patterns of macrofaunal communities under the influence of upwelling. These patterns have been investigated in this study by sampling macrofauna and environmental variables during March-December 2012 across six depths (13-100 m) over the continental shelf off Kochi, south EAS. Upwelling, set over outer shelf prior to March, occupies the entire shelf by May, peaked during June-July and withdrew rapidly by September. A total of 203 macrofaunal taxa were collected in this study. Multivariate analysis revealed that the macrofaunal composition showed a spatiotemporal variation. Taxonomic diversity increases from nearshore to mid shelf whereas abundance and biomass decreased. Macrobenthic functioning, assessed through Biological Trait Analyses, displayed similar trait modalities between depths and seasons but abundance driven differences in trait expression revealed important habitat filtering. Increase in organic matter and decrease in dissolved oxygen influenced by upwelling and the spatial variation in sediment texture were the strongest drivers of the macrofaunal taxonomic pattern. We suggest that taxonomic and biological trait information needs to be considered in ecological studies as it provides a better understanding of how biodiversity responds to and interacts with environmental changes.

Studies on heavy metal accumulation in aquatic macrophytes from Sevan (Armenia) and Carambolim (India) lake systems.

Aquatic macrophytes are unchangeable biological filters and they carry out purification of the water bodies by accumulating dissolved metals and toxins in their tissue. In view of their potential to entrap several toxic heavy metals, 45 macrophytes belonging to 8 families collected from two different physiographic locations (36 from Sevan Lake, Armenia; 9 from Carambolim Lake, Old Goa, India) were studied for estimation of 14 heavy metals. The study was aimed at understanding the importance of these macrophytes in accumulation of toxic metals and controlling the heavy metal pollution and suggesting the remedial measures, if any, for the preservation and restoration of lake ecosystem. Inductively Coupled Plasma-Atomic Emission Spectrometric (ICP-AES) analyses of these aquatic macrophytes have shown the importance of aquatic macrophytes in accumulation of heavy metals and maintaining the clarity of water bodies beside their role in trophic systems. Accumulation of most of the heavy metals was higher in root system. The representative macrophytes from two different physiographic locations show similar trends and order in accumulating different metals generally. Of the 14 metals investigated, 9 (Ca, Fe, Al, Cr, Cu, Ba, Ti, Co and Pb) showed higher rates of accumulation in the root whereas 3 (Mn, Zn and Mg) showed more accumulation in stem and 1 (Ca) showed higher accumulation in the leaves. In most of the samples Cu was accumulated more in the roots (50+/-47.15 microg/g) and less in flowers (9.52+/-3.97 microg/g). Occurrence of heavy metal was much higher in macrophytes of Sevan Lake than that of the Carambolim Lake. The accumulation of 14 elements was in order of Ca>Mg>Fe>Al>Mn>Ba>Zn>Ti>Cu>Cr>Co>Ni>Pb>Cd. The present study revealed that the aquatic macrophytes play a very significant role in removing the different metals from the ambient environments. They probably play a major role in reducing the effect of high concentration of heavy metals. Therefore, the macrophyte community of the Sevan Lake area needs to be protected and restored on a priority basis. Accumulation of highly toxic metals like--Cr, Cd, Pb and Ni was lower as compared to the essential metals like Ca, Fe and Mn in all the macrophytes from both the lake systems, consequently high metal concentrations observed in both the areas may not directly reflect on the pollution level.

Testing the efficiency of temperate benthic biotic indices in assessing the ecological status of a tropical ecosystem.

The objectives of the present study were to evaluate the ecological status of tropical coastal waters using the temperate benthic indices and examine the effect of seasonal variability on the performance of benthic indices. Macrobenthic samples were collected from northwest to southeast coast of India during 2003-2012 and we tested different univariate indices, ecological strategies, indicator species and multimetric indices. AMBI and multimetric indices performed satisfactorily in evaluating the ecological status. Seasonal variability on the biotic indices was observed during the southwest monsoon and fall intermonsoon period due to recruitment. Therefore, we recommended the non-monsoon period (January-May) as a suitable time of the year to use the indices for effective assessment of the Indian coastal waters. Results show that, the temperate benthic indices are efficient in assessing the tropical environmental status. However, complementary use of different indices is suggested for accurate assessment of the environmental status.

Global patterns and predictions of seafloor biomass using random forests.

A comprehensive seafloor biomass and abundance database has been constructed from 24 oceanographic institutions worldwide within the Census of Marine Life (CoML) field projects. The machine-learning algorithm, Random Forests, was employed to model and predict seafloor standing stocks from surface primary production, water-column integrated and export particulate organic matter (POM), seafloor relief, and bottom water properties. The predictive models explain 63% to 88% of stock variance among the major size groups. Individual and composite maps of predicted global seafloor biomass and abundance are generated for bacteria, meiofauna, macrofauna, and megafauna (invertebrates and fishes). Patterns of benthic standing stocks were positive functions of surface primary production and delivery of the particulate organic carbon (POC) flux to the seafloor. At a regional scale, the census maps illustrate that integrated biomass is highest at the poles, on continental margins associated with coastal upwelling and with broad zones associated with equatorial divergence. Lowest values are consistently encountered on the central abyssal plains of major ocean basins The shift of biomass dominance groups with depth is shown to be affected by the decrease in average body size rather than abundance, presumably due to decrease in quantity and quality of food supply. This biomass census and associated maps are vital components of mechanistic deep-sea food web models and global carbon cycling, and as such provide fundamental information that can be incorporated into evidence-based management.