Distribution of phytoplankton along an environmental gradient off Kakinada, East Coast of India

357-364In the present study phytoplankton distribution and species composition was examined on a salinity gradient from River (R), River Mouth (RM) and coastal water (RF) at surface and subsurface layers along the coast off Kakinada, East Coast of India. Average numerical abundance of phytoplankton at R, RM and RF are 336 nos.mL-1, 150 nos.mL-1 and 169 nos.mL-1 respectively. <span style="font-size: 9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU;mso-bidi-font-weight: bold" lang="EN-GB">Percentage contribution of each group of phytoplankton was in the order: Pinnate diatoms <span style="font-size:9.0pt;mso-fareast-font-family: Calibri;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-GB">> Cyanophyceans<span style="font-size:9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU; mso-bidi-font-weight:bold" lang="EN-GB"> > Centrales <span style="font-size:9.0pt;mso-fareast-font-family:Calibri; mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-GB">> Prasinophyceans<span style="font-size:9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU; mso-bidi-font-weight:bold" lang="EN-GB">. However, total phytoplankton species at surface and subsurface water at all the stations showed presence of 52 and 24 species respectively. At the group level, cyanophyceans were significant at RF locations. Pennate diatoms were more at the remaining locations. Species <i style="mso-bidi-font-style: normal">Oscillatoria limosa was found to be abundant at both the surface and subsurface water with 340 filaments.ml-1 and 488 filaments.mL-1 recpectively. Thalassiothrix longissima was found to be maximum at surface water but absent in subsurface water. Wide variation in evenness values (0.16-0.910) suggests uneven distribution of species along the environmental gradient. </span

Quantitative distribution of meiobenthos in the Gulf of Martaban, Myanmar Coast, north-east Andaman Sea

189-197Quantitative distribution of meiofauna in the depth range 20 to 1000 m of the Gulf of Martaban, Andaman Sea was studied from 46 stations during a synaptic survey carried out in April-May 2002 of ORV Sagar Kanya Cruise SK175. Fauna was dominated by three taxa: free living nematodes (80%) benthic copepods (5.9%) and foraminiferans (2.8%). Other groups together contributed more than copepods in total abundance. Total density ranged between 40 and 612/10 cm2 and dry weight biomass from 0.21 to 0.428 mg/10 cm2 in different sediment type and depth zone. Numerical abundance of meiofauna was high in fine silty clay and low in sandy bottom. Formation of three main clusters suggests the influence of dominant sediment texture of clayey sand sand silt clay, silty-clay clayey-silt, and sandy substratum. Fauna was contagiously distributed except at few stations where the distribution was regular. Meiofauna of the present study were similar to those of Andaman Sea and Bay of Bengal and the density changes appears to be related to hydrographic condition and sediment characteristics of the region

Distribution, abundance and diversity of phytoplankton in the inshore waters of Nizampatnam, South East coast of India

348-356Distribution, abundance and species assemblages of Phytoplankton were studied from inshore waters of Nizampatnam, South East coast of India in March 2007. <span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">Significant spatial variations in temperature, pH, salinity, dissolved oxygen (DO), nitrites (NO2) –N)<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">, nitrates (NO3) – N)<span style="mso-fareast-font-family:Calibri;mso-ansi-language: EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">, phosphate (PO4) –P),<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US"> silicate (SiO4) – (Si)<span style="mso-fareast-font-family:Calibri; mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US"> were monitored. A total of 90 species of phytoplankton (net hauls) represented by 5 groups were identified at nine stations, collected along three transects during low tide.<span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US"> Percentage contribution of each group of phytoplankton was in the order: Bacillariophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Dinophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Cyanophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Euglenophyceans<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">. Pleurosigma angulatum, Navicula sp. were dominant species in the study area. Bray - Curtis similarity and group average clustering, recommended identifying two assemblages of phytoplankton in the study area. High diversity of phytoplankton in the present area suggests stable environmental conditions. </span

A facile hydrothermal synthesis of CeO2 nanocubes decorated ZnO nanostructures: optical and enhanced photocatalytic properties

Synthesis of CeO2, ZnO, and CeO2 nanocubes decorated on the surface of ZnO ovals via a simple hydrothermal method was investigated. The crystalline nature and purity of CeO2, ZnO and CeO2 decorated ZnO were confirmed through X-ray diffraction (XRD) by the co-existence of cubic and hexagonal wurtzite phase of CeO2 and ZnO, respectively. The transmission electron microscopy (TEM) images revealed that CeO2 nanocubes were well decorated on the surface of ZnO in oval morphology. The optical properties of the prepared materials were investigated using diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectra and also, the oxidation species presented in the materials were identified through X-photoelectron spectroscopy (XPS) spectra survey. The photocatalytic activity of CeO2 decorated ZnO nanostructures against methylene blue (MB) as a model pollutant under visible light irradiation was enhanced when compared to those of the pure CeO2 and ZnO nanostructures. The reusability of catalyst studies revealed that the efficiency of the visibility light degradation of MB was increased upon the CeO2 deposited on the ZnO surfaces