http://nopr.niscair.res.in/handle/123456789/1644 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/1669 Title: Seasonal variation of some physicochemical parameters of the Chilika lagoon (east coast of India) after opening the new mouth, near Sipakuda <br/> <br/>Authors: Nayak, Lakshman; Behera, Durga Prasad <br/> <br/>Abstract: Some physicochemical parameters [temperature, transparency, pH, salinity, dissolved oxygen (DO) and nutrients, nitrate, phosphate and silicate] were studied during February 2001 to January 2002 at five locations in Chilika lagoon. This study was undertaken to assess the impact of the new mouth opened at Sipakuda in order to facilitate water exchange between the lagoon and the sea. High values of temperature 35.3ºC and salinity about 32 ppt were noticed near the mouth during the hot and dry premonsoon and postmonsoon periods respectively. The overall average salinity ranged from 0.32 – 32.0 ppt recorded at the northern sector (Kalupadaghat) and near the mouth. The maximum secchi disc value was 0.91 m only. Dissolved oxygen content and pH ranged from 3.9 to 13.9 ml/l and 6.4 to 9.8 respectively. The nutrient contents showed distinct seasonal and spatial variation. Higher phosphate value than the nitrate is a noteworthy feature during the present study period, which could be due to the addition of phosphate through the land drainage. Visible changes have been noticed in spatio-temporal variations of physico-chemical parameters as a result of the opening of new mouth. <br/> <br/>Page(s): 206-208 Sat, 29 May 2004 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1668 Title: Effect of alkali treatment on the yield and quality of agar from red alga Gracilaria verrucosa (Rhodophyta, Gracilariales) occurring at different salinity gradient of Chilika lake <br/> <br/>Authors: Rath, J.; Adhikary, S.P. <br/> <br/>Abstract: Gracilaria verrucosa was collected at salinity gradient of 4.2 to 28 ppt in the Chilika lake was used for agar extraction. Agar yield of 27-30% with gel strength 165 to 180 g/cm² was obtained from the alga occurring at two different locations of Southern sector of the lake showing salinity 6.5 to 8.0 ppt. NaOH pre-treatment strongly influenced the agar characteristics. Alkali pre-treatment of Gracilaria verrucosa yielded agar with increased gel strength but the yield was lowered. With 10% alkali pre-treatment the sulphate content of agar was reduced together with increase in 3,6,-anhydro galactose content and the gel strength. Using Gracilaria verrucosa from salinity ranges 6.5 to 8.0 ppt of Chilika lake and extraction with 10% alkali, good quality of agar with gel strength of 265 to 275 g/cm² and moderate yield of 25 to 26% was obtained suggesting its potential for commercial exploitation. <br/> <br/>Page(s): 202-205 Sat, 29 May 2004 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1667 Title: Effect of thermal effluent discharge on benthic fauna off Tuticorin bay, south east coast of India <br/> <br/>Authors: Kailasam, M; Sivakami, S <br/> <br/>Abstract: Benthic fauna of Tuticorin bay in relation to thermal effluent discharge was studied for a period of two years (March 1990 to April 1992). Station I situated closer to thermal effluent discharging site was characterized by high water temperature (surface mean 38.92ºC, Bottom mean 38.86ºC), low dissolved oxygen (surface mean 3.79±0.29 ml/l) and high percentage of sand (mean sand 87.96%, mean silt 7.57%, mean clay 4.87 %) with the record of only three benthic species mainly dominated by Cerithedia fluviatilis. Occasional record of Prionopsio sp. and Nassa pulla was also noticed at st. I. Higher water temperature recorded at st. I had resulted elimination of other benthic species with survival of fewer organisms. Station IV, situated far away from thermal effluent discharging site had better water quality parameters of temperature (surface mean 30.84ºC,), dissolved oxygen (surface mean 4.08 ml/l) and improved sediment particle size composition (mean sand 76.27 %, mean silt 16.11 %, mean clay 7.68%) with the record of 23 benthic species. Station I was recorded with the lowest benthic population density (480-1084 no/m²) and species diversity (0-0.44) while other stations showed the highest faunal density (2327-3452 no/m² at st.VI) and species diversity (2.12-2.54 at st. V). Temperature showed significant negative correlation with species diversity (1%), benthos density (5%) and benthos biomass (1%) at st. I, while in other stations, temperature was positively correlated with species diversity, benthos density and benthic biomass but statistically insignificant. Thermal effluent increased the temperature of receiving waters and thereby by affected the benthic population of Tuticorin bay. <br/> <br/>Page(s): 194-201 Sat, 29 May 2004 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1666 Title: Environmental influences on the species diversity, biomass and population density of soft bottom macrofauna in the estuarine system of Goa, west coast of India <br/> <br/>Authors: Harkantra, Sadanand N; Rodrigues, Nimi R <br/> <br/>Abstract: A total of 58 species were recorded belonging to polychaetes, molluscs, crustaceans and other minor groups in order of species abundance. eighteen species are new to the local fauna that were not reported earlier. The maximum mean species diversity index (Shannon-Wiener), total biomass (wet) and total population density recorded were 2.3 (Z1), 6.7 g/m² (M1) and 703 no./m² (M2) respectively. Significantly higher species diversity was observed at high salinity, fine sand and high sedimentary biochemical parameters of total organic carbon (TOC), total organic nitrogen (TON) and carbon of biopolymeric fraction (C-BPF) sites. Medium grain size sites supported significant high biomass whereas population density showed no significant difference among the sites. The best multiple linear regression model revealed that all the 13 parameters studied were significant influencing parameters on species diversity, biomass and population density with exception of temperature. Among these salinity and TON were the main significant parameters. The combination of significant influencing environmental parameters, % variation and Mallows' Cp values varied from sites to biotic parameters. This explained 32-72% of the total variance. The regression model derived from this data helps in detection of these biotic parameters and detection of pollution-induced effects. <br/> <br/>Page(s): 187-193 Sat, 29 May 2004 22:58:59 GMT