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The marine microalga Nannochloropsis oculata was investigated for its biosorption capacity for the removal of Cd(II) ions from aqueous solution using batch mode experiments. pH (2-5), biomass dosage (0.0191 g/50 mL and 0.392 g/50 mL) and temperature (293-323 K) being the experimental parameters affecting the biosorption process were observed. To describe the experimental equilibrium data, Langmuir and Freundlich isotherms models were applied. The biosorption potential of N. oculata biomass for Cd(II) ions was found to be 232.55 mg/g. The calculated thermodynamic parameters (∆G°, ∆H° and ∆S°) showed that the biosorption of Cd(II) ions onto N. oculata was feasible, spontaneous and exothermic at 298-323 K. Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of Cd(II) by N. oculata well followed pseudo-second-order kinetics. The FTIR spectra indicated that the functional groups predominantly involved in the biosorption were -OH, COO-, -CH and phosphate groups. The XRD pattern of the biosorbent showed a change in crystallinity of N. oculata biomass after the biosorption. It was concluded that N. oculata can be used as an effective, low-cost and environmentally friendly biosorbent for the removal of Cd(II) from aqueous solution.

The present study deals with seasonal variations, correlation coefficient and biodiversity indices of phytoplankton during April 2011 to March 2012 in the Riwada reservoir, Visakhapatnam, Andhra Pradesh, India. Sampling was performed at five stations during pre-monsoon, monsoon and post monsoon. There were a total of 57 genera belonging to four major groups i.e., Chlorophyceae (27 genera), Bacillariophyceae (14 genera), Cyanophyceae (13 genera) and Euglenophyceae (three genera). Maximum and minimum total phytoplankton population and percentages were recorded at station three in pre monsoon and at station two during monsoon. The maximum and minimum species richness (Menhinick index R2) were found to be 1.29 at station one and 1.10 at station three respectively. Maximum and minimum species diversity (H1) were found at station four (3.98) and station two (3.71). Maximum species evenness was recorded at stations one, being four and five; minimum species evenness was recorded at station two. Correlation coefficient matrix indicated significant positive relationship with water temperature, pH, transparency, biological oxygen demand and chlorides, negative relationship with electric conductivity, total solids, total dissolved solids, total hardness, dissolved oxygen, nitrates, sulphates and phosphates of water. The diversity indices showed that the reservoir have a well balanced phytoplankton community.

The aim of the present investigation was to study the effect of nine pesticides and two biocides tested on fungal isolates from agricultural soil samples (Coffee,Turmeric and Vegetable) of Lammasinghi village, Chintapalli mandal in Visakhapatnam district. Nine different pesticides namely Fungicides, Insecticides and Herbicides and biocides were taken into study. During the investigation period Pencillium chrysogenum, Fusarium, Aspergillus niger, Alternaria, Aspergillus oryzae, Pencillium and Cladosporium fungal colonies were isolated. The maximum fungal counts were observed in agriculture field compared with hill area. The maximum fungal colony count (54 colonies) observed in Turmeric field and minimum count (20 colonies) observed in Vegetable field. In the hilly area the more colony count were seen in Vegetable field compared with Coffee and Turmeric. The short term inhibitory effect on the total fungal population was observed with the application of Fungicides, Insecticides and Herbicides. The study proved to be destructive on Aspergillus species by the use of Fungicides and Herbicides compared with Insecticides. The biological control did not inhibit their growth or merely in a lower degree.

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