NISCAIR Online Periodicals Repository Collection: IJMS Vol.32(2) [June 2003]

Heavy minerals in beach sands of Gopalpur and Paradeep along Orissa coastline, east cost of India

Thu, 29 May 2003 22:58:59 GMT

Title: Heavy minerals in beach sands of Gopalpur and Paradeep along Orissa coastline, east cost of India

Authors: Behera, P.

Abstract: Selective sand samples were collected from Gopalpur and Paradeep beaches and studied for their heavy mineral assemblage. Beachsands of both the areas contain heavy minerals like sillimanite, ilmenite, garnet, pyroxene, rutile, sphene, biotite, hornblende, zircon and monazite. At Gopalpur, the percentage of concentration of sillimanite is the highest followed by limonite, garnet, pyroxene, rutile, sphene, biotite, hornblende, zircon and monazite. At Paradeep, almost similar trend was observed with some exceptions, i.e., concentration of pyroxene and biotite is more here. The mineral sphene was absent at Paradeep, whereas tourmaline was negligible at Gopalpur. Higher grade percentage of heavies at Gopalpur is linked with many favourable factors and is being mined by IREL whereas low grade percentage at Paradeep discourages mining.

Page(s): 172-174

Conservation of olive ridley sea turtle Lepidochelys olivacea (Reptilia/Chelonia) along the Nagapattinam coast, southeast coast of India

Thu, 29 May 2003 22:58:59 GMT

Title: Conservation of olive ridley sea turtle Lepidochelys olivacea (Reptilia/Chelonia) along the Nagapattinam coast, southeast coast of India

Authors: Bhupathy, S.

Abstract: Nesting and mortality of Lepidochelys olivacea (Eschscholtz, 1829) was studied in 50 km beach stretch along the Nagapattinam coast during December 2000 to May 2001. Lepidochelys olivacea was common constituting 97.1% of turtles recorded. This species emerged from sea for nesting during December and continued till April. The nesting of Lepidochelys olivacea was sporadic and the peak was observed in the second fortnight of February. The poor nesting (20 nests/ km) in the area could be due to high adult mortality (12% females) due to incidental catch in the gill nets, and nest predation (>90%) by human. The Nagapattinam coast will not sustain the nesting population of Lepidochelys olivacea longer, if immediate conservation measures are not undertaken.

Page(s): 168-171

Intense blooms of Trichodesmium erythraeum (Cyanophyta) in the open waters along east coast of India

Thu, 29 May 2003 22:58:59 GMT

Title: Intense blooms of Trichodesmium erythraeum (Cyanophyta) in the open waters along east coast of India

Authors: Jyothibabu, R.; Madhu, N. V.; Murukesh, Nuncio; Haridas, P. C.; Nair, K. K.C.; Venugopal, P.

Abstract: Two blooms of Trichodesmium erythraeum were observed during April 2001, in the open waters of Bay of Bengal and this is the first report from this region. The locations of the bloom were off Karaikkal (10°58N, 81°50E) and off south of Calcutta (19°44N, 89°04), both along east coast of India. Nutrients (nitrate, phosphate, silicate) concentration in the upper 30 m of the water column showed very low values. High-integrated primary production (Bloom 1- 2160 mgC m^-2 d^-1, Bloom 2-1740 mgC m^-2 d^-1) was obtained in these regions, which indicated the enhancement of primary production in the earlier stages of the bloom. Very low NO₃-N concentrations, brownish yellow bloom colour, undisturbed patches and high primary production strongly suggested that the blooms were in the growth phase. Low mesozooplankton biomass was found in both locations and was dominated by copepods followed by chaetognaths.

Page(s): 165-167

Biofouling deterrent activity of the natural product from ascidian, Distaplia nathensis [Chordata]

Thu, 29 May 2003 22:58:59 GMT

Title: Biofouling deterrent activity of the natural product from ascidian, Distaplia nathensis [Chordata]

Authors: Murugan, A.; Ramasamy, M. Santhana

Abstract: Growth of marine sedentary organisms causes notable damage to ship-hull, harbour structures and industrial cooling and filtration systems. TBT based antifouling paints are widely used worldwide and is to be phased out by the year 2008 because of its adverse effect on non-target organisms. Efforts are therefore being made to develop alternative eco-friendly antifoulant paints. The crude methanol: water extract of the ascidian, Distaplia nathensis showed antimicrobial activity against 12 out of 14 bacteria screened in the present study. At a concentration of 0.1 mg/ml, the crude extract completely inhibited the byssal production and attachment in the mussel Perna indica. The EC₅₀ and LC₅₀ were found to be 50±6.45 µg/ml and 150±19.2 µg/ml respectively. The gradient partition showed high polar nature of the active component. The indication of non-toxic nature of the extract in the toxicity assay and the broad spectral antimicrobial activity has revealed that it could be a potential source of the antifouling compound.

Page(s): 162-164