025854   Ehsan G (Geography Dep, Payame Noor University, PO Box 19395-3697, Tehran, Iran, Email: ehsangolmehr@pnu.ac.ir ) : Use of radar remote sensing for land use dynamic monitoring in South West Coast of Caspian Sea. Int J Geomatics Geosci 2011, 2(2), 472-80.

Southern coast of the Caspian Sea is characterized by high humidity with wide clouds and fog covers. Because of this feature in the region, it is difficult to acquire satisfactory optic image from satellite image for interpretation. This has influence on land use dynamic monitoring around the southern cost of the Caspian Sea. Radar remote sensing has many advantages on the application of land use survey in the study area because of less effect of weather in comparison with the Landsat TM data. In the study a developed image enhancement technique on the basis of Kalman filtering technique was proposed. Texture analysis of Radar SAR image was investigated. The method used in the current project for Land use/cover changes detection from 2005 to 2007 was to fuse images of different sources such as TM and SAR and then integrate the fused images of different times in such that the changes of these images can be highlighted. Radar SAR data and TM Images captured in 2005 and 2007 were used for this purpose. The techniques that are applicable to both the Radar data and to TM data as well as to the accuracy of results obtained for land use monitoring have been systematically compared. The results of the study verify the efficiency of the proposed Kalaman filtering technique for dynamic land use monitoring in particular study area.

5 illus, 30 ref

025853   Dimitrios K;Nikolaos K;Dimitra V (NO, Stylianidis Efstratios, Alexiou Constantinos, Georgoula Olga, Aristot, Greece, Email: kaimaris@auth.gr) : Digital processing of historical maps from Eastern Macedonia, Greece with the tuse of GIS-geography of settlements and toponyms in space and time. Int J Geomatics Geosci 2011, 2(2), 627-46.

Extensive research on the development of known toponymies in the wider region of Eastern Macedonia, Northern Greece is conducted. To this objective, digital processing of historical maps (from 1901 to 1945, at a scale from 1:200,000 to 1:20,000) in an environment of GIS has been utilized. The focus of the undertaken study is an area covered by 500 km², from the ancient Amfipolis to the town of Philippoi. The entire analysis (i.e. archaeological estimation) is based on orthophotomaps and satellite images. The data are retrieved from historical maps (from 1901 to 1945, at a scale from 1:200,000 to 1:20,000). The current study presents a detailed analysis of the historical maps and their digital processing, which allowed their cross-correlation and the export of precious information on the development of known toponymies and the localization of unknown up to today historical settlements and places. It is envisaged that the historical character of this region and the provided map analysis, is very useful for the spatial analysis of ancient Macedonia. This region is of a major archaeological importance, because of the continuous settlement from Paleolithic age and the acne, which presented at the Hellenistic and Roman years.

14 illus, 2 tables, 20 ref

025852   Bhattacharjee S;Narahari S T;Chandra Shekhar K (Geological Survey of India, EPMA Laboratory, Petrology Div, Southern Region, Banglaguda, Hyderabad-500 068, Email: santanu.bhattacharjee@gsi.gov.in) : Petro-tectonic implications of chrome spinel-bearing metaultramafics in Archaean Ramagiri Schist belt, Andhra Pradesh. Indian J Geosci 2011, 65(4), 297-310.

Ultramafic rocks occurring southwest of Ramagiri village in Anantapur District of Andhra Pradesh are described. On the basis of detailed field and petrological studies, two major variants are identified (a) talc-magnesite rock consisting of talc, serpentine, magnesite, and chromian chlorite (metadunite) and (b) chlorite schist consisting of chlorite and serpentine (metaharzburgite). Ramagiri ultramafics are deformed, metamorphosed and sheared. EPMA studies revealed that the opaque phases associated with the metadunite are typically chrome spinel while those associated with the metaharzburgite are magnetite and less commonly ilmenite. EPMA studies of the chrome spinels from metadunite revealed elemental zonation. The cores are relatively homogeneous chrome spinel with constant composition, while rims are Cr-poor magnetite. At places an intermediate ferritchromite zone is noticed with Cr and Fe-rich zone but with very low Al and Mg. A gradual decrease in MgO and A1₂O₃ from core to intermediate zone is seen and an abrupt decrease in Cr from intermediate zone to rim is noticed. The homogeneous cores of the chrome spinels in metadunite rock represent the primary chrome spinel. Serpentinisation of olivine resulted in the formation of magnetite rims over the chrome spinels either as replacement or overgrowth. Further metamorphism under lower greenschist facies conditions in the presence of CO₂ resulted in the formation of talc, chromian chlorite and magnesite. Low grade metamorphism of harzburgite in the presence of fluids resulted in the formation of chlorite from orthopyroxene, olivine and spinel. The Al was provided by the spinels which were more or less totally consumed by the reactions. However some relicts of ulvospinels are recorded during the BSE studies. Both types of ultramafics show inconsistent enrichment pattern of trace and REE elements. Chemical analysis of the metadunite produced significantly high PGE values. Out of 20 samples collected nine samples are found to be anomalous. Analytical results show <62> 200 ppb total PGE for four samples and 8.1 ppm total PGE for one sample, which is reported for the first time from this area. However, no PGE mineral could be identified so far. These samples also have high concentrations of Cr and Ni (Cr up to 1.5% and Ni up to 3500 ppm). Tectonic discrimination plots of chrome spinels indicate an are/ophiolitic setting.

10 illus, 9 tables, 18 ref

025851   Badhreenath S;Achyuthan H;Haricharan S; Mohandas K P (Archaeological Survey of India, Chennai Circle, Chennai-600 009, Email: hachyuthan@yahoo.com) : Saluvankuppam coastal temple-excavation and application of soil micromorphology. Curr Sci 2011, 100(7), 1071-5.

The 26 December 2004 tsunami exposed an inscription of the 10th century engraved on a rock boulder at Saluvankuppam, 6 km north of Mamallapuram. The inscription indicates the existence of a Subramanya temple. The temple and the mound around the granite inselberg were excavated by the Archaeological Survey of India, Chennai Circle. The excavation exposed the entire Subramanya temple complex constructed over a period of time (4th/5th CE to 12th/13th CE). The temple complex and the litho sections reveal phases of temple building activity. The cement and lime used for the temple complex contain fragments of shells. Soil micromorphology technique was applied to understand the type of textures and fabric in soil sediments, bricks, potsherds, well rims, bone fragments, etc., using a polarized microscope. Thin sections of the laterite bricks which formed the foundation indicate high content of hematite, magnetite, kaolinite patches and the porosity of the laterite brick varies from 5% to 10% only, whereas thin sections of potsherds indicate that the firing temperature was fairly low and that the pots were well fired. Geoarcheology study of this temple complex indicates that a number of naturally occurring raw materials have been used for con-structing this temple that were locally available.

7 illus, 3 ref

025850   Ambikapathy A;Gahalaut V K (NO, National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad-500 007, Email: ammani_ambikapathy@rediffmail.com) : Time clustering of earthquakes in the Sumatra-Andaman and Himalayan regions. Curr Sci 2011, 100(7), 1068-71.

Increased frequency of earthquakes in the Sumatra-Andaman region in the past 10 years reflects time clustering of earthquakes and does not necessarily imply low recurrence interval of earthquake in the region. Time clustering of earthquakes can occur either due to the stress change (either through static or dynamic stress transfer) caused by the occurrence of a great earthquake in the region, or it could just be a chance in which earthquake occurrence is almost simultaneous in two or more segments, despite differences in the earthquake cycle due to difference in the phase of strain accumulation, rheology, plate convergence rate, etc. in these segments. We note that the Himalaya and the adjoining regions too showed earthquake time clustering during 1897-1950.

5 illus, 2 tables, 24 ref

025849   Alea Yeasmin;Nazrul Islam M (Geography and Environment Dep, Jahangirnagar University, Dhaka, Bangladesh, Email: aleayeasmin@gmail.com) : Changing trends of channel pattern of the Ganges-Padma river. Int J Geomatics Geosci 2011, 2(2), 669-75.

Study analyzes the changing trends of channel pattern of the Ganges-Padma river. A time series of satellite images in the period of 1973-2006 are compiled for analysis. It is believed that the Ganges-Padma river is a meandering river. But lately the Ganges-Padma becomes braided river for high sediment transportation by Jamuna and deposition of Ganges-Padma river bed. For the purposes of study, the sinuosity ratio and braiding index were calculated in different time series. The analysis shows that the sinuosity ratio is increased over time. In 1973, it was 1.31 and in 1984, 1996, 2006 it was 1.33, 1.37, and 1.43 respectively. In 2006, though it was sinuous but it is very close to 1.5 which indicates meandering. In case of braiding index, it has been observed that in 1973, the braiding index was 1.3 and in 1984, 1996, 2006 it was 1.43, 1.62, and 1.92 respectively. The analysis also shows that in 1984, the braiding index was very close to 1.5. After 1996, it was exceeded 1.5 and continuously increasing. By analyzing the sinuosity ratio and braiding index, it has been observed that the changing rate of braiding index is more than sinuosity ratio.

4 illus, 3 tables, 17 ref

024832   Vijaya Lakshmi C S;Trivedi D;Srinivasan P; Murthy S G N;Nair R R (Ocean Engineering Dep, Indian Institute of Technology, Madras, Chennai-600 036, Email: rajeshnair.iitkgp@gmail.com) : Subsurface reflections of prograded paleoscarps in avis island, North Andaman, India. Indian J Geomar Sci 2011, 40(3), 331-7.

Prominent subsurface reflections from two GPR transect marked four lithological anomalies below Avis Island coral reefs. These scarps dip 5-10° towards sea and they consist of sands with more than 30-40% heavy mineral concentrations that produce distinct subsurface reflections that make possible to locate the buried erosional scarps. Heavy minerals are considered as the indicators of erosion as well as a proxy for sediment transport of extreme wave events. Heavy minerals including magnetite have higher magnetic susceptibility values: Lla:°644.6;°Llb:°556.8 , L2a: 5.84.2 and L2b: 612 x 10^-50SI units to the background magnetic susceptibility of 5-10 x 1O^-50SI units for quartz-rich sands suggest severe reworking process during an extreme wave event. The two profiles (L1 and L2) with four paleoscarps: L1a at a distance of 10 m from the shore, L2a approximately 15 m from the shore, L2b around 30 m from the shore and L1b nearly 35 m from the shore and the corresponding age of the dated coral above the paleoscarps increases towards land exhibiting progradation sequence. These subsurface reflections of paleoscarps were found at a depth of 1-1.5 m below the ground surface beneath the reported age of coral reefs suggesting that these coral reefs and the paleoscarps are found due to the same event.

4 illus, 32 ref

024831   Tripathi S;Unnikrishnan A S (NO, National Institute of Oceanography (CSIR), Dona Paula, Goa-403 004, Email: sila@nio.org) : Role of cyclones and other factors in the decline of the ports of Northern Orissa. Curr Sci 2011, 100(3), 305-12.

The maritime trade of Orissa with transoceanic countries is evident from the early historical period onwards. It has been observed that new ports were set up after the decline of old ports in the nearby vicinity; however, information on the decline of ancient ports is very sparse. The archival and historical records of the 16th and 19th centuries and the writings of contemporary scholars mention the ports of northern Orissa, viz. Balasore, Dhamra, Pipli, Chandbali, Laichanpur, Churamani and False Point, and their decline because of the shifting of the power centre, heavy taxation, bribes and sometimes due to natural forces such as siltation, formation of sandbars and cyclones. The devastating cyclones which occurred along the Orissa coast between 1823 and 1900 caused enormous loss of human lives and property and destroyed the ports and port structures. The role of cyclones in the decline of these ports is scarcely mentioned in contemporary literature. Occurrences of storm surges during cyclonic events combined with the relatively large tidal ranges present along the Orissa coast caused tremendous destruction in the coastal area. In this article, an attempt has been made to study the decline of the ports of northern Orissa between Paradip and Sugar and to understand the various causative factors such as cyclones, storm surges and siltation, besides anthropogenic factors.

4 illus, 2 tables, 31 ref

024830   Tiwari M;Rahul Mohan;Meloth T;Naik S S; Sudhakar M (National Centre for Antarctic and Ocean Research, Vasco-da-Gama, Goa-403 804, Email: manish@ncaor.org) : Effect of varying frontal systems on stable oxygen and carbon isotopic compositions of modern planktic foraminifera of Southern ocean. Curr Sci 2011, 100(6), 881-7.

Studies have been carried out in the Atlantic and "Pacific sectors of the Southern Ocean regarding the movement of its fronts (water-masses boundaries) with changing climate and other oceanic parameters. But the Indian sector of the Southern Ocean has received little attention. To fill in this lacuna, during the first Indian expedition to Southern Ocean in 2004, plankton net samples, sediment cores and other physical oceanographic parameters were collected. Here, we present the isotopic results obtained from planktic foraminifera from the plankton net samples and surface sediments. We find that, in this region too, plank-tic foraminifera secrete their shells in isotopic equilibrium with seawater and the planktic foraminifera from the core top sediments yield values akin to that obtained from plankton net samples. It implies that planktic foraminifera preserved in sediments record overlying seawater signatures in this sector. Thus, down-core foraminiferal isotopic data from the Indian sector of the Southern Ocean can be used as a proxy for reconstructing the temporal variations of different water masses.

3 illus, 2 tables, 28 ref

024829   Sujatha K;Iswarya Deepti V A;Shrikanya K V L (Marine Living Resources Dep, Andhra Univ, Visakhapatnam-530 003, Email: sujatha.mlr@gmail.com) : Allozyme electrophoretic studies in four species of groupers (Pisces:Serranidae) represented in the commercial fishery of Visakhapatnam-India. Indian J Geomar Sci 2011, 40(3), 365-71.

Several species of groupers belonging to the genus Epinephelus have overlapping colour patterns. In the present study four species of groupers, Epinephelus epistictus, E. latifasciatus, E. magniscuttis and E. radiatus, that are represented in the catches of Visakhapatnam were analysed for allozyme variation. The eleven enzyme systems screened twenty-five scorable loci. Sixteen loci in E. episticuts, nineteen in E. latifasciatus, fifteen in E. magniscuttis and twenty-two loci in E. radiatus were found to be polymorphic at p = 0.95 level. Average heterozygosity ranged form 0.0582±0.063 to 0.0704±0.0442. Diagnostic alleles that help in clearly distinguishing the species were identified. UPGMA dendrogram revealed that E. epistictus is closely related to E. magniscuttis compared to other two species.

5 illus, 3 tables, 20 ref

024828   Srivastava R;Ramesh R;Jani R A;Anilkumar N; Sudhakar M (NO, Physical Research Laboratory, Navrangpura, Ahmedabad-380 009, Email: rramesh@prl.res.in) : Stable oxygen, hydrogen isotope ratios and salinity variations of the surface Southern Indian ocean waters. Curr Sci 2010, 99(10), 1395-9.

Stable isotope (δ¹⁸O and δD) and salinity measurements were made on the surface waters collected from the Southern Indian Ocean during the austral summer (25 January to 1 April 2006) onboard R/V Akademik Boris Petrov to study the relative dominance of various hydrological processes, viz. evaporation, precipitation, melting and freezing over different latitudes. The region between 41 °S and 45°S is a transition zone: the region lying north of 41°S is dominated by evaporation/precipitation process whereas that south of 45°S (up to Antarctica) is dominated by melting/freezing processes. Further, the combined study of stable oxygen and hydrogen isotope (δ¹⁸O and δD) confirms that the Southern Indian Ocean evaporates in non-equilibrium conditions.

4 illus, 1 table, 27 ref

024827   Srivastava A K;Khare N;Ingle P S (Geology Dep, SGB Amravati Univ, Amravati-444 602, Email: Ashokamt2008@hotmail.com ) : Characterization of clay minerals in the sediments of schirmacher oasis, east antarctica: their origin and climatological implications. Curr Sci 2011, 100(3), 363-72.

A total of 16 glacial sediments consisting of loose admixture of sand, silt and clay have been collected from different parts of the Schirmacher Oasis and adjoining areas, viz. main rocky land, inland lakes, ice sheet and coastal area. The clay from the sediments has been separated and studied for mineral identification using different thermal analysis (DTA), thermogra-viraetric analysis (TGA) and X-ray diffraction (XRD) analysis. The thermograms of all the samples are almost similar, showing minor gain or loss of weight. DTA curves show a small notch around 585°C, i.e. kaolinite. XRD analysis of the samples treated with Ca and K, glycolated, and heated at various temperatures shows well-developed peaks of chlorite, illite, kaolinite, smectite and vermiculite. An attempt has been made to decipher the origin of clay minerals along with their climatological implications.

8 illus, 2 tables, 43 ref

024826   Siraswar R;Nayak G N (Marine Sciences Dep, Goa Univ, Goa-403 206, Email: gnnayak@unigoa.ac.in) : Mudflats in lower middle estuary as a favorable location for concentration of metals, west coast of India. Indian J Geomar Sci 2011, 40(3), 372-85.

Present study was aft attempt to understand hydrodynamic conditions and the main factors regulating the distribution of metals in mudflats in the recent past along Mandovi Estuary. Sediment cores of 20 cm length were collected from three mudflats viz. near the mouth, lower middle and upper middle regions representing monsoon season from Mandovi Estuary. Cores were sub sampled at every 2 cm interval and analyzed for sand, silt, clay, organic carbon and selected metals. Sand percentage is the highest in the mudflat situated near the mouth (Betim) and finer sediments are higher in the lower (Karyabhat) and upper (Ribander) middle regions of the estuary. Organic matter associated more with finer sediment fractions at Karyabhat and Ribander (2.19% to 2.37%) mudflat cores as compared to Betim (0.13%). The sediments of Betim fall in the class I to IV, whereas sediments of two cores collected from middle estuarine region fall largely in class III. Sediment samples were analyzed for selected metals. Fe is highest in Ribander mudflat as compared to other cores. Cr, Co, Cu and Pb distribution agrees largely with the pattern of Fe in all the cores. Distribution of Cu and Pb also agrees with that of Mn. Zn and Ni follow the pattern of Co agreeing Fe distribution pattern. Concentration of Fe and Mn along with Ni, Zn, Cr, Pb and Cu are higher in Karyabhat.

6 illus, 1 table, 57 ref

024825   Singh S;Parkash B;Awasthi A K;Kumar S (Earth Sciences Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: geoseema05@yahoo.co.in) : Late miocene record of palaeovegetation from siwalik palaeosols of the ramnagar sub-basin, India. Curr Sci 2011, 100(2), 213-22.

Stable carbon isotope analyses of pedogenic carbonates were conducted on two Siwalik sections, Jammu-Nandni and Purmandal-Uttarbehani, covering a lateral stretch of <126>25 km, in Ramnagar sub-basin, in order to reconstruct palaeovegetation history over the past <126> 12 Ma. The results revealed that the carbon isotopic record in studied sections fell in two broad divisions, an older part (> 7 Ma) characterized by δ¹³C-depleted isotopic values and a younger part (< 5 Ma) consisting of δ¹³ C-enriched values, indicating exclusive presence of C₃ and C₄ vegetation respectively. The present work provides an important link to the extensive palae-ovegetational studies done in the Pakistan and Nepal

5 illus, 2 tables, 53 ref

024824   Satya Prakash;Ramesh R;Sheshshayee M S;Rahul Mohan;Sudhakar M (NO, Indian National Centre for Ocean Information Sciences, Hyderabad-500 055) : Effect of high level iron enrichment on potential nitrogen uptake by marine plankton in the southern ocean. Curr Sci 2010, 99(10), 1400-4.

Iron fertilization of the Southern Ocean is believed to counter the increasing CO₂ concentration in the atmosphere and the consequent global warming. Though a number of large scale iron enrichment experiments have been done in the recent past in different parts of the world ocean, little effort has been made to understand the effect of iron enrichment on nitrogen uptake rates and f-ratios. Here we assess the effect of iron addition on N-uptake rates and f-ratio in the Indian sector of the Southern Ocean. This study shows, in contrast to the earlier belief, that iron addition enhances not only nitrate uptake (<126>3x) but it causes a significant increase in ammonium (<126>2x) and urea (<126>3x) uptakes as well. Also, since iron enrich-ment caused significant increase in the uptake of all N-substrates, its effect on f-ratio was insignificant.

1 illus, 3 tables, 27 ref

024823   Santra P;Mertia R S;Kushawa H L (NO, Central Arid Zone Research Institute, Regional Research Station, Jaisalmer-345 001, Email: priyabrata.iitkgp@gmail.com) : New wind-erosion sampler for monitoring dust-storm events in the Indian thar desert. Curr Sci 2010, 99(8), 1061-7.

Removal of soil particles by wind is an active land- degradation process in the Indian Thar Desert. To compute the soil loss due to wind erosion, eroded aeolian masses are mostly collected by samplers, which are available with different designs at desert areas of the world. In the Indian Thar Desert, dust catcher in the design of Bagnold sampler was generally used to collect eroded masses at different heights from the surface, but this had a few drawbacks. Keeping in mind the constraints of the existing sampler, a new wind-erosion sampler was designed, fabricated, tested and installed in the Indian Thar Desert at Jaisalmer. This erosion sampler has the ability to adjust its orifice towards the wind direction and thus is capable of collecting aeolian masses from any direction. With this sampler, eroded aeolian masses were collected and analysed during several dust-storm events and periodic wind-erosion events during June-September 2009. Computation of mass flux (ML^-2 T^-1) and soil loss from the collected aeolian mass data successfully captured the intensity of dust-storm/wind-erosion events and their variation within a season. Therefore, the new erosion sampler may be used as a tool to monitor and assess dust-storm events in the Indian Thar Desert.

4 illus, 2 tables, 18 ref

024822   Sairam B;Rastogi B K;Aggarwal S;Chauhan M; Bhonde U (NO, Institute of Seismological Research, Raisan, Gandhinagar-382 009, Email: sairambharat@rediffmail.com) : Seismic site characterization using Vs30 and site amplification in Gandhinagar region, Gujarat, India. Curr Sci 2011, 100(5), 754-61.

Gujarat is prone to earthquake hazard of different levels from moderate to high, assigned as zones II-V in the seismic zoning map of India. Many multistorey buildings collapsed in Ahmedabad city at a distance of 225 km from the location of the 2001 Bhuj earthquake. Gandhinagar falls in zone III where an intensity of VII or VIII from the regional large earthquakes or local earthquakes of magnitude 6 can be expected; which can damage single and multistorey buildings. Thus, there is a need for site characterization and seismic hazard mapping of the area. Shear-wave velocities were measured using the MASW technique at 63 sites in and around Gandhinagar. Based on Vs30 in most of Gandhinagar the soils have been classified as D-type (180-360 m/s) in accordance with the NEHRP provision, except the northern part of the city (sites 27, 51, 53 and 54), where Vs30 values larger than 360 m/s qualify the area as a NEHRP class C-type soil (360-760 m/s). However, nearly the whole of Gandhinagar soil has Vs <62> 250 m/s, that is considered to be strong. Further for the estimation of site amplification of the study area, we have used earthquake as well as microtremor records. Site amplification up to 4.4 was observed in the frequency range 0.4-2 Hz. The frequency range 3-10 Hz shows amplification up to 2.4 times at some sites. The frequency range 0.4-2.0 Hz falls in the natural frequency range of multistorey buildings with more than three floors. It is inferred from shear-wave velocity measurements and site amplification that multistorey buildings of more than three floors in this region require careful designing.

6 illus, 1 table, 23 ref

024821   Rohilla L N;Rohilla J (MPA Engg. Div, Netaji Subhas Institute of Technology, Sector-3 Dwarka, New Delhi-110 078, Email: nrohilla@gmail.com) : Direct beam radiation from global radiation for Jodhpur (India). Invertis J renewable Energy 2012, 2(2), 95-9.

The direct beam radiation has been correlated with global radiation because it was seen that beam radiation has a strong correlation with global radiation. By using regression technique, based on least square method, correlations between beam ratio and global ratio, in the form of K_B =f(K_T) on daily basis, have been determined. It has been seen that seasonal correlations yield better results for Jodhpur (Latitude 26.3°N; Longitude 73°E). The root mean square error for this station found to be around 5% for the three seasons summer, winter and spring/autumn.

6 illus, 8 ref

024820   Ray D;Rajan S;Rasik Ravindra (NO, National Centre for Antarctic and Ocean Research, Goa-403 804, Email: dwijesh@rediffmail.com) : Mineralogy of disseminated sulphides from the volcanics of Andaman Island. Curr Sci 2010, 99(8), 1021-4.

3 illus, 2 tables, 17 ref

024819   Ramana Murty T V;Malleswara Rao M M;Sadhuram T;Sridevi B;Maneesha K (NO, National Institute of Oceanography, Regional Center (CSIR), 176 Lawson's Bay Colony, Visakhapatnam-530 017, Email: tvrmurty@nio.org) : Objective mapping of observed sub-surface mesoscale cold core eddy in the bay of Bengal by stochastic inverse technique with tomographically simulated travel times. Indian J Geomar Sci 2011, 40(3), 307-24.

Present study consists the acoustic characteristics of a sub-surface cold core eddy observed (below the mixed layer between depths of 50 and 300m, with a diameter of about 200 km having temperature drop of 5°C at the center) in the Bay of Bengal during south-west monsoon season and explore possibility to reconstruct the acoustic profile of the eddy by Stochastic Inverse Technique. A simulation experiment on forward and inverse problems for observed sound velocity perturbation field has been attempted for a range of 650 km (in the vertical slice) keeping the single source-receiver configuration (at the channel axis depth) in the SOFAR channel, under peculiar characteristics viz, depth-limited environment and weak gradient waters of the Bay of Bengal. For the formulation of the Stochastic Inverse, both vertical and horizontal structure of the ocean has been modeled using empirical orthogonal modes. Present Ocean Acoustic Tomography's (OAT's) simulation experiment results reveal that one can objectively map/monitor even the small mesoscale sub-surface eddies by stochastic inverse technique keeping single source and receiver in the SOFAR channel separated probably by larger distances also under such depth-limited environment of the Bay of Bengal.

8 illus, 7 tables, 45 ref

024818   Rahul Mohan;Quarshi A A;Meloth T;Sudhakar M (National Centre for Antarctica and Ocean Research, Headland Sada, Goa-403 804, Email: rahulmohan@ncar.org) : Diatoms from the surface waters of the southern ocean during the austral summer of 2004. Curr Sci 2011, 100(9), 1323-7.

Thirty four surface water samples collected during the Pilot Expedition to Southern Ocean in the austral summer of 2004 along the latitudinal transect 25°S-56°S, were studied to understand the distributional pattern of different diatom species and their relationship with changing sea-surface temperature (SST), salinity and nutrient availability. Among the diatom species identified, Fragilariopsis kerguelensis (O'Meara Hust.) is dominant, contributing more than 90% of the total recorded from 41°S latitude polewards. All other species show a sparse distribution. There is a total absence of diatoms from 25°S to 40°S where SST ranges from 27.8°C to 18.3°C, salinity from 34.9 to 35.6 psu and the concentrations of nutrients (silicate and nitrate) are comparatively lower. However, the phosphate concentration does not show any control on the growth of diatoms in this region. The measurement details of dominant species F. kerguelensis from Subtropical Front to Polar Front Zone indicated an increased size relationship with decreasing SST and increasing nutrient concentration.

2 illus, 1 table, 25 ref

024817   Prasad A S S S R S;Venkateswarlu N;Reddy P R; Koteswara Rao P;Sarkar D;Vidya Sagar G (NO, National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad-500 606, Email: atreya2002@rediffmail.com) : Seismic wave pattern in West Bengal Basin compared to other coastal sedimentary basins of India. Curr Sci 2011, 100(1), 106-11.

Free surface multiples when used in conjunction with regular seismic phases can provide details of velocity gradients in sedimentary layers, an useful information for better constraining the velocity model. In the present study, an attempt has been made to understand the genesis of free surface multiples and their significance in deriving the velocity structure of the West Bengal sedimentary basin. To bring into focus, the area-specific structural and compositional peculiarities essential to generate free surface multiples, the derived velocity models of the West Bengal basin have been compared with models of other coastal sedimentary basins of India. It is clearly resolved from the analysis of velocity and its gradient, sedimentary thickness, period of sedimentation and the effect of water-saturated layers that the high velocity gradients and the presence of free surface multiples in the West Bengal basin are due to water saturation of the thick unconsolidated/semi-consolidated, compact and partially cemented sedimentary layers.

8 illus, 2 tables, 26 ref

024816   Pavan Kumar G;Manglik A (NO, National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad-500 606, Email: gayatripavan@ngri.res.in) : Effect of Himalayan topography on two-dimensional interpretation of magnetotelluric data. Curr Sci 2011, 100(3), 390-5.

Magnetotelluric method is a powerful tool for deep crustal studies of tectonically active mountainous regions such as the Himalaya, where logistic constraints severely limit the use of other artificial source electrical and electromagnetic methods. Topographic variations in mountainous regions distort apparent resistivity curves and thus lead to artefacts in interpreted models. In the present work, we have analysed a simplified two-dimensional (2D) model of the subsurface electrical resistivity structure along a profile in the Garhwal Himalaya for the effect of topography. The topography varies significantly along the profile between the foothills and the higher Himalaya. We first computed TE and TM-mode apparent resistivity and phase curves at various stations along the profile for a model with topography and then inverted these datasets for two cases. In the first case the surface of the earth was assumed to be flat, whereas in the second case the actual topography was included in the model. The results suggest that the interpreted model assuming flat earth is similar to the one obtained by including topography in the model. Inclusion of 10% Gaussian noise to the synthetic data does not change these results. Thus, we infer that the effect of 2D topography is not prominent in the 2D interpretation of the selected Garhwal Himalaya profile.

^ssc4 illus, 29 ref

024815   Parkash B;Rathor R S;Pati P;Jakhmola R P; Singh S (Earth Sciences Dep, Indian Institute of Technology, Roorkee-247 667, Email: parkash1941@gmail.com) : Convergence rates along the Himalayan frontal thrust inferred from terraces at Chandidevi Temple Hill, Hardwar, Northwestern Himalaya. Curr Sci 2011, 100(9), 1426-32.

Four Ganga river terraces have been recognized in the Chandidevi Temple Hill in the pilgrim town of Hardwar, in the eastern part of the Debradun Valley, Northwestern Himalaya, India. These terraces that are close to the Himalayan Frontal Thrust have been formed due to movements along this thrust. Dating of the sediments underlying the upper three terraces gives overall uplift, slip and convergence rates of 6.23 ± 1.29 mm/yr, 12.46 ± 2.58 mm/yr and 10.79 ± 2.23 mm/yr respectively. These rates are similar to those reported from the western part of the valley and are significantly less than those published from Eastern Nepal Himalaya. Differences in results are considered to be due to high rates of convergence and maintenance of the highest relief in the Himalaya, resulting in high sediment loads of rivers in the Nepal Himalaya and high rates of subsidence and narrow width of the adjoining Gangetic Plains. The reverse is true of the NW Himalaya and these differences are considered to be due to the segmented nature of the Himalaya and the adjoining Gangetic Plains. Also, rates of uplift caused by movements along a thrust in a particular cycle of activity decrease with time.

7 illus, 1 table, 42 ref

024814   Pandit C (Central Water Commission, National Water Academy, Government of India, Sinhagad Road, Khadakwasla R.S., Pune-411 024, Email: cmpandit@yahoo.com) : Monsoon. Curr Sci 2011, 100(4), 447.

1 ref

024813   Paliwal B S (Geology Dep, Jai Narain Vyas Univ, Jodhpur-342 005, Email: paliwalbhawani@yahoo.co.in) : Fossilized bamboo curtain from the quaternary gypsum deposit of thar desert at Jamsar Mine near Bikaner, Rajasthan, India. Curr Sci 2011, 100(4), 471-2.

^ssc3 illus, 1 table, 10 ref

024812   Niwas S (Earth Sciences, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: srsnpfes@iitr.ernet.in) : Nonlinear electrical conductivity response of shaly-sand reservoir - physical explanation. Curr Sci 2010, 99(8), 1017-21.

6 illus, 17 ref

024811   Narayana A C;Rahul Mohan;Mishra R (Marine Geology and Geophysics Dep, Cochin Science and Technology Univ, Kochi-682 016, Email: acnes@uohyd.ernet.in) : Morphology and surface textures of quartz grains from freshwater lakes of McLeoad island, larsemann hills, East Antarctica. Curr Sci 2010, 99(10), 1420-4.

The Larsemann Hills area in the eastern Antarctica constitutes a few of the small islands apart from the mainland. Many freshwater lakes are identified in the main land of the Larsemann Hills and in the McLeod Island. We have collected sediment samples from the exposed freshwater lakebeds during the special expedition of February-April 2006. In this article, we discuss the micro-textures of quartz grains studied under scanning electron microscope. We have recorded angular, sub-rounded and rounded grains, and varied surface textural features showing flow patterns, fractured/crushed features, etc. Authors have also analysed grains to understand the possible elemental composition of the grains with the help of energy dispersive spectrometer.

6 illus, 20 ref

024810   Naik R K;Chitari R R;Anil A C (NO, National Institute of Oceanography (CSIR), Dona Paula, Goa-403 004, Email: acanil@nio.org) : Karlodinium veneficum in India: effect of fixatives on morphology and allelopathy in relation to Skeletonema costatum. Curr Sci 2010, 99(8), 1112-6.

Dinoflagellates form an important component of marine and freshwater phytoplankton. They are a remarkably diverse and complex group with various modes of nutrition and ability to produce toxins, and are major contributors to harmful algal blooms. In the present work, we identify the presence of Karlo-dinium veneficum in India. Its detection in the coastal waters of India was possible because of live sample analysis. This species has both toxic and nontoxic strains and due to its bloom-forming capability, it is known to influence the coexisting phytoplankton community structure. In this communication we provide a description of this species, possible methods for its identification in preserved samples and effect of its extracellular and intracellular extract on the growth of Skeletonema costatum, an important and abundant diatom in the phytoplankton community in the Indian waters.

3 illus, 26 ref

024809   Naik P K;Naik K C;Choudhury A;Chakraborty D (NO, Rajiv Gandhi National Ground Water Training and Research Institute, Raipur-492 001, Email: pkr_pitha9@rediffmail.com) : Solving drinking water crisis in hard rock terrain of peninsular India. Curr Sci 2010, 99(10), 1309-10.

2 illus, 1 ref

024808   Mysaiah D;Maheswari K;SrihariRao M;Senthil Kumar P;Seshunarayana T (NO, National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad-500 606, Email: dasari_mysaiah@yahoo.co.in) : Ground-penetrating radar applied to imaging sheet joints in granite bedrock. Curr Sci 2011, 100(4), 473-5.

^ssc4 illus, 9 ref

024807   Murugan A;Dhanya S;Sarcar A B;Naganathan V; Rajagopal S;Balasubramanian T (NO, Gulf of Mannar Biosphere Reserve Trust (GOMBRT), 102/26 Jawan Bhavan, Kenikarai, Ramanathapuram-623 504, Email: arumugam.murugan@gmail.com) : Fishery biology, demography of three spotted seahorse, Hippocampus trimaculatus inhabiting Gulf of Mannar region, Southeast coast of India. Indian J Geomar Sci 2011, 40(3), 411-23.

Seahorse populations show social, spatial patterns in the wild and coupled with its biology that renders them more vulnerable to intense fishing. Seahorses are mainly exploited through gears like shrimp trawl net, country trawl net and shore seine operation and their catch is considered as fortuitous. During the demanding period target fishing like skin diving is also done. The ecosystem of the study area is well diverged with seagrass, seaweed and coral reef, which form the suitable habitat for these unique creatures. Present study provides the base line information regarding the species abundance, catch per unit effort, occurrence of brooding males, sex ratio for the four commonly found seahorses in the Gulf of Mannar. Length - weight relationship and growth studies were restricted to the dominant species H. trimaculatus. Information provided through the research will be helpful in the conservation of this unique creature since they are considered as endangered and placed in Schedule I of the Indian Wild Life Protection Act, 1972 from July, 2001.

9 illus, 6 tables, 52 ref

024806   Mishra R;Sudhakar M;Pednekar S M;Tyagi A (NO, National Centre for Antarctic and Ocean Research, Headland Sada, Goa-403 804, Email: ravimishra@ncaor.org) : Seabed morphology of the approach channel of Larsemann hills, Prydz Bay, East Antarctica. Curr Sci 2010, 99(10), 1405-12.

Seabed topography of the Approach Channel to the Larsemann Hills in the Prydz Bay is important to understand the Prydz Bay drainage basin and inter-linkage between its major topographic features. As India proposes to establish her third permanent station in Larsemann Hills, East Antarctica, the access to the site by safe navigation of vessels necessitated a bathymetric survey of the Approach Channel. The survey was divided into two blocks, a part of the Prydz Bay (latitudes 69°10'S to 69°22'S, longitudes 75°45'E to 76°15'E) and the Larsemann Hill Approach Channel (latitudes 69°22.00'S to 69°25.14'S, longitudes 76°04.00'E to 76°16.00'E). A total area of 55 km in length and 19 km in width was covered with 155 lines-km bathymetric data which was collected by deploying a boat-mounted shallow water multibeam echo-sounder system. Hull mounted multibeam system of R. V. Akademik Boris Petrov was used for the survey of the Prydz Bay and a total of about 410 lines-km of bathymetric data was collected. The survey area is a part of the Svenner Channel and maximum depth in the Prydz Bay was found to be 800 m. The maximum depth in the Approach Channel was found as 450 m. The area has variable morphological features and interlinks the Four Ladies Bank, Amery Ice Shelf and Amery Depression. Results indicate the glacial erosion in the channel. The Larsemann Hills Approach Channel was found to be in the depth range of 25-450 m, with a safe navigational passage up to the NE-SW boundary of the Larsemann Hills.

9 illus, 12 ref

024805   Michael L;Krishna K S (NO, National Institute of Oceanography (CSIR), Dona Paula, Goa-403 004, Email: krishna@nio.org) : Dating of the 85°E ridge (northeastern Indian ocean) using marine magnetic anomalies. Curr Sci 2011, 100(9), 1314-22.

The 85°E Ridge is a typical aseismic ridge in the northeastern Indian Ocean in view of the fact that it associates with exceptional gravity and magnetic signatures. The ridge possesses two different gravity anomalies: the north part (up to 5°N latitude) is associated with negative gravity anomaly, whereas the south part coincides with positive gravity anomaly. In contrast to this, the ridge consists of alternate streaks of positive and negative magnetic signatures distributed for asymmetrical extents. With the consideration of ridge seismic structure and geomagnetic polarity reversals, we modelled both positive and negative magnetic anomalies of the ridge. This shows that the 85°E Ridge was formed during the period of rapid changes in the Earth's magnetic field, earlier to that, the underlying oceanic crust was created in the Cretaceous super-long normal polarity phase. The results further reveal that the positive and negative magnetic signatures of the ridge have been created, in general, by a relief of the ridge and polarity contrast between the ridge material and adjacent oceanic crust, respectively. On correlation of the ridge's magnetization pattern to the geomagnetic polarity timescale, we believe that the 85°E Ridge volcanism started at anomaly 33r time (<126> 80 Ma) in the Mahanadi Basin by a short-lived hot-spot, thereafter the process continued towards south and finally ended at <126> 55 Ma in the vicinity of the Afanasy Nikitin Seamount.

7 illus, 25 ref

024804   Matin A;Malay Mukul (Geology Dep, Calcutta Univ, 35 Ballygunge Circular Road, Kolkata-700 019, Email: amatinindia@yahoo.com) : Phases of deformation from cross-cutting structural relationships in external Thrust Sheets: insights from small-scale structures in the Ramgarh Thrust Sheet, Darjiling Himalaya, West Bengal. Curr Sci 2010, 99(10), 1369-77.

Cross-cutting structural relationships are used in Pre-cambrian terrains as a routine tool to work out different phases of deformation even in the absence of chronological data. Such studies assume that the different phases are separated by large time-gaps. While such an assumption may be eventually supported by chronological data in Precambrian terrains, extending this approach to fold-and-thrust belt settings like the Himalayas is likely to result in wrong structural interpretations, as emplacement of each thrust sheet can result in several sets of structures that may be interpreted as 'phases' of structures based on cross-cutting relationships. Therefore, small-scale structures in thrust belts like the Himalaya need to be associated with well-constrained individual deformation events and not merely be attributed to 'phases' of deformation. authors illustrate this by looking at small-scale structures from the frontal Ramgarh thrust sheet in the Gorubathan area of the Darjiling Himalaya from which six 'phases of deformation' can be identified from cross-cutting relationships. Given that these structures are observed in an external thrust sheet near the mountain front formed during a single phase of Himalayan orogeny, it is extremely difficult to visualize six time-separated phases of deformation affecting the rocks in the Ramgarh thrust sheet. We describe the geometry of the small-scale structures in the Ramgarh thrust sheet from Gorubathan area and interpret them to be Himalayan in origin (pending confirmation from chronological data) and as related to the emplacement of the Ramgarh thrust sheet rather than multiple phases of deformation.

11 illus, 1 table, 55 ref

024803   Manikandan K;Natrajan S;Sivasamy R;Sankar M; Dadhwal K S (Directorate of Mushroom Research, Chambaghat, Solan-173 213) : Spatial and temporal variation in groundwater characteristics of the coastal regions of Tamil Nadu. Indian For 2011, 137(8), 1009-14.

This research work was aimed to study the spatial and temporal changes in groundwater quality of the coastal region of Cuddalore district, Tamil Nadu. The study was conducted during 2006 for which the coastal area was divided in to three zones based on 1.5 km spatial distance from sea. The groundwater was collected from 27 representative shallow wells for the whole year with three-month interval representing different seasons. The water samples collected were characterized for its chemical composition as well as electro-chemical properties. Based on the chemical composition, different quality parameters were arrived. The results revealed that 88 per cent of the wells recorded for slightly alkaline pH ranging from 7.6 to 7.9 with electrical conductivity varying from 1.1 to 4.0 dS m¹. The sodium and magnesium hazard was higher in most of the wells. Seawater intrusion is the key factor, which decides the quality of groundwater in this coastal zone. Natural rainfall is the next most important factor which balances the negative effects of seawater intrusion. In total, the groundwater quality of this coastal zone was poor during summer and optimum during monsoon and post monsoon seasons which necessitates that sufficient care may be taken when using this water for agricultural/agroforestry/forestry/other land use purposes.

1 table, 18 ref

024802   Mahapatra S;Chakrabarty A (Geology Dep, Durgapur Government College, Durgapur-713 214, Email: samiranmahapatra@rediffmail.com) : Dumortierite from Susunia hill, Bankura district, West Bengal, India. Curr Sci 2011, 100(3), 299-301.

2 illus, 2 tables, 9 ref

024801   Mahajan A K;Rai N (NO, Wadia Institute of Himalayan Geology, 33, GMS Road, Dehradun-248 001, Email: akmahajan@rediffmail.com) : Using MASW to map depth to bedrock underneath Dehradun fan deposits in NW Himalaya. Curr Sci 2011, 100(2), 233-8.

Dun Valley is an intermontane valley located within the Siwalik foreland basin in Garhwal Himalaya. With the evolution of Dun Valley, Dun gravels and post-Siwalik formations were deposited in this valley in the form of fan deposits. Earlier information on the thickness of Dun gravels in the Dehradun fan and bedrock depth level was based on stratigraphy studies and estimated to be 600 m. Later, based on tube-well boring and field observations, the thickness of the Dun gravels has been revised to 100-300 m. In the present communication, shear wave velocity (V_S) field has been calculated using multichannel analysis of surface Waves (MASW), surveyed using 4.5 Hz frequency geo-phones with Elastometer-aided weight drop hammer as a source. This enabled us to map the thickness of the Dun gravels and the depth to bedrock underneath the Dehradun fan deposits as 35 m in the northern flank of the syncline, 140 m in the centre of the broad syncline and 90 m in the southern flank of the syncline below the ground surface. The Middle Siwalik sand-stone and Upper Siwalik conglomerates bedrock have been assigned a shear wave velocity of <126>750-800 m/s and <126>950-1000 m/s respectively, after running a seis-mic profile directly on the respective bedrock exposed along the river sections. Based on ID and 2D V pro-files from north to south, a model of cross-section showing depth of bedrock_S/thickness of the Dun gravels has been presented. Different litho units of the Dehradun fan defined by earlier researchers have been validated with V_s. Each unit, i.e. units A-C, has been assigned V_s as 700-850, 500-700 and < 500 m/s respectively.

6 illus, 16 ref

024800   Kumar S;Pandey S K;Ahmad S (Centre of Advanced Study in Geology, Lucknow Univ, Lucknow-226 007, Email: surendra100@hotmail.com) : Occurrence of giant nodules in the Jodhpur sandstone, Sursagar area, Jodhpur, Rajasthan. Curr Sci 2011, 100(9), 1294-6.

3 illus, 1 table, 8 ref

024799   Krishnakanta Singh A;Bikramaditya Singh R K (NO, Wadia Institute of Himalayan Geology, Dehradun-248 001, Email: aksingh_wihg@rediffmail.com) : Zn- and Mn-rich chrome-spinels in serpentinite of tidding suture zone, Eastern Himalaya and their metamorphism and genetic significance. Curr Sci 2011, 100(5), 743-9.

Serpentinites of Tidding Suture Zone (TSZ), Eastern Himalaya contain enriched Zn (1.31-3.22 wt%) and Mn (3.01-3.94 wt%) in chrome-spinels (Cr-spinels). Microprobe analysis profiles across concentrically zoned grains of Cr-spinel confirm Zn- and Mn-rich core and magnetite towards the rim. Such enrichment of Zn and Mn of Cr-spinels at the core is related to greenschist facies metamorphism. The rim is formed as a result of metamorphic transformation and is enriched in Cr<35> (92.22-98.83), Fe<35> (97.54-98.40), and impoverished in Mg<35> (0.97-7.89) and Al<35> (0.03-0.19). The core has not re-equilibrated with the spinel composition derived as a result of metamorphic diffusion. The textural and chemical characteristics (Cr<35> = 86.98-94.40; Al<35> = 5.56-12.94; Mg<35> = 10.85-34.07) of the primary Cr-spinels suggest that the parent serpen-tinite of TSZ might have been derived at a high degree of partial melting from the depleted mantle source in the marginal ocean basin.

4 illus, 1 table, 32 ref

024798   Koshy K C;Dintu K P;Gopakumar B (NO, Tropical Botanic Garden and Research Institute, Palode, Thiruvananthapuram-695 562, Email: koshykc@hotmail.com) : Enigma of leaf size and plant size in bamboos. Curr Sci 2010, 99(8), 1025-7.

2 tables, 10 ref

024797   Juyal N;Thakkar P S;Sundriyal Y P (Physical Research Laboratory, Navrangpura, Ahmedabad-380 009, Email: navin@prl.res.in) : Geomorphic evidence of glaciations around mount kailash (inner kora): implication to past climate. Curr Sci 2011, 100(4), 535-41.

Geomorphological observations of palaeoglaciation around the southern flank of Mount Kailash (Serlung Chu valley) are presented. Three distinct events of glaciation with decreasing magnitude (Kailash stage (KS)-I to KS-III) are well represented by the trails of lateral moraine. Inferred chronology of the glaciations suggests that the KS-I event pre-dates the Last Glacial Maximum (LGM), KS-II is attributed to the LGM, whereas KS-III corresponds to the early/mid-Holocene. The push moraine and the exposed glaciated bedrock proximal to the Mount Kailash are assigned to the Little Ice Age (LIA). A decrease in glacier ice volume after KS-III glaciation is attributed to the decrease in monsoon and an increase in the summer temperature after LIA.3

9 illus, 1 table, 31 ref

024796   Joshi S C;Palni L M S (NO, G.B. Pant Institute of Himalayan Environment and Development, Himachal Unit, Mohal-Kullu-175 126, Email: joshisc@hotmail.com) : Is dew useful for Himalayan plants?. Curr Sci 2010, 99(10), 1434-9.

Dew formation is a common phenomenon during October to February for plants growing in the tropical and subtropical Himalaya. Occurrence of dew for such a lengthy period may have important implications on ecophysiological responses that contribute to the growth, survival and productivity of plants. A perusal of the literature, however, shows conflicting reports on the impact of dew formation in plants. Further, such studies are also lacking for Himalayan plants. The present study was, therefore, undertaken with twin objectives: (i) to understand the effects of dew on photosynthetic rate, photochemical efficiency of photosystem II (F_v/F_m ratio), transpirational water loss, stomatal conductances for CO₂ and water vapour, intercellular CO₂ concentration, water use efficiency (WUE) and relative water content (RWC) in the leaves of three multipurpose evergreen tree species, viz. Boehmeria rugulosa Wed., Grewia optiva Drum-mond and Olea glandulifera Wall, ex G. Don, and (ii) to identify species on the basis of their response to dew for plantation programmes during winter season. The dew-exposed plants of all the three species showed significant (P <60> 0.05) reduction in photosynthetic rate, F_v/F_m ratio, transpiration rate and stomatal conductances for CO₂ and water vapour and WUE. The reduction was more prominent in B. rugulosa and O. glandulifera than G. optiva, indicating that G. optiva is less sensitive to dew compared to the other two species. Dew also did not improve RWC rather it decreased in the dew-exposed plants of G. optiva. Based on the results it may be suggested that dew, though a form of water, may not be useful to the Himalayan plants at least for the three species studied. Thus without providing protective measures from dew these plant species may not be successful in plantation programmes during winter season in the Himalayan region.

3 illus, 3 tables, 41 ref

024795   Jha D K;Vinithkumar N V;Santhnakumar J;Abdul Nazar A K;Kirubagaran R (NO, National Institute of Ocean Technology, Port Blair-744 103, Email: dilipjha75@yahoo.com) : Assessment of post tsunami coral reef resource in Pongi Balu coast, South Andaman Islands. Curr Sci 2011, 100(4), 530-4.

In the present study, an assessment of the status of coral reefs along the Pongi Balu coast, south Andaman Islands, which is a part of the Mahatma Gandhi Marine National Park, has been made by scuba diving, low draft glass-bottom boat and visual interpretation in some places during low-tide condition. The coral reef boundaries have been accurately determined with the help of a low draft glass-bottom boat fitted with a real time kinematics global positioning system, and the existing coral reefs map of the area has been updated using the geographic information system technique. A total of 161.6 ha of previously existed live coral reefs were surveyed along the Pongi Balu coast and out of that 'live coral' was found over 81.4 ha and 'dead coral' was found over 60.6 ha whereas 19.6 ha area was found to have been lost from the existing coral reefs and categorized as 'no coral'. The study highlights a few natural and anthropogenic factors affecting the existing coral reefs and hindering the re-establishment of coral reefs in the study area.

3 illus, 2 tables, 16 ref

024794   Jenamani R K;Tyagi A (India Meteorological Dep, Meteorological Watch Office, New ATS Building (Room No. 211, 2nd Floor), IGI Airport, New Delhi-110 037) : Monitoring fog at IGI airport and analysis of its runway-wise spatio-temporal variations using meso-RVR network. Curr Sci 2011, 100(4), 491-501.

Fog affects aviation severely at the Indira Gandhi International (IGI) Airport. With nearly 700 flights operating daily, it requires efficient coordination among various stakeholders for mitigating the effect of fog. The Meteorological Watch Office (MWO) at the IGI Airport aims at providing best fog monitoring and forecasting solution through an integrated system by adopting innovative methods. In the present article, we briefly outline the fog monitoring, forecasting and dissemination system implemented by the India Meteorological Department (IMD) at the IGI Airport for providing weather service to all the three runways at the airport. In view of the following winter of 2008-2009 experienced very high duration of 147 h of CAT-III dense fog, attempts have been made to find their unique characteristics based on various visibility ranges by analysing hourly general visibility data of the season of 2008-2009 and similar data since 1981. Fog occurrence being a highly meso-scale event, another objective was to find runway-wise spatio-temporal variations of these fog characteristics, at various runway visual ranges (RVRs), using data from a very high resolution network of seven RVR instruments installed at these three runways.

8 illus, 6 tables, 5 ref

024793   Ingole B;Singh R (Biological Oceanography Div, National Institute of Oceanography, Dona Paula-403 004, Email: baban@nio.org) : Biodiversity and community structure of free-living marine nematodes from the Larsemann Ice Shelf, East Antarctica. Curr Sci 2010, 99(10), 1413-19.

Subtidal (500-700 m) meiofaunal assemblage of the Larsemann Ice Shelf, East Antarctica, is described with special emphasis on the free-living marine nema-todes. The sampling was conducted with a 25 x 25 X 40 cm VSNL Spade Box corer and sub-sampling was performed with an acrylic core (4.5 cm dia.). The meiofauna comprised of eight taxa dominated by nematodes. A total of 75 nematode genera and 4 species were identified. They were randomly distributed and showed a significant difference (P <60> 0.05) between the sampling stations. The total density varied from 239 to 639/20 cm² and maximum density was recorded at a water depth of 722 m. Nematodes constituted <62>82% of the total meiofauna. A total of 1053 nematodes were isolated from the three cores. Vertically, <126>90% nematodes were in the surface (0-2 cm) sediment, and their abundance decreased with sediment depth. Among the nematodes, selective feeder and non-selective deposit feeder were most abundant at the surface sediment, whereas omnivores and predators were higher at depth. Sabatieria and Paralinho-moeus were the most common genera. The higher nematode abundance at the surface was possibly due to their preferences to the freshly arriving food particles in the sediment-water interface. Availability of predatory omnivores in the deeper layers was perhaps due to their adaptation to the sedimentary conditions and could be their part of survival strategy in the harsh Antarctic environment.

5 illus, 2 tables, 32 ref

024792   Harinarayana T;Narayanan M;Murthy D N;Gupta A K;Narendra Babu (NO, National Geophysical Research Institute (CSIR), Hyderabad-500 007, Email: thari54@yahoo.com) : Stationary magnetotelluric monitoring system for earthquake research in Koyna region, Maharashtra. Curr Sci 2010, 99(8), 1027-30.

3 illus, 12 ref

024791   Gogoi L;Mazumdar K;Dutta P K (WWF-India, Western Arunachal Landscape Programme, Parvati Nagar, Tezpur-784 001, Email: lohitecology@gmail.com) : Occurrence of mallard (Anas platyrhynchos) in high-altitude lakes of Tawang district, Western Arunachal Pradesh, India. Curr Sci 2010, 99(8), 998.

1 illus, 18 ref

024790   George M;Cyriac N;Nair A;Hatha A A M (School of Environmental Sciences, Mahatma Gandhi Univ, Kottayam, Email: mohamedhatha@gmail.com) : Diversity of Bacillus and Actinomycetes in the water and sediment samples from Kumarakom region of Vembanadu Lake. Indian J Geomar Sci 2011, 40(3), 430-7.

Diversity of different groups of Bacillus and Actinomycetes in the water and sediment samples from Kumarakom estuary was analyzed to find out potential strains for further application. Bacillus genera were identified and grouped into five phenogroups such as Bacillus polymyxa, Bacillus subtilis, Bacillus sphaericus, Thermophiles and Alicyclobacillus. Phenogroups show differences in the shape of the spore (oval or spherical), position of the spore (central or terminal) and swelling of the sporangium. Ability of the isolates to elaborate various hydrolytic enzymes and their ability to reduce nitrate and ferment various carbohydrate sources were also studied. Different plating media such as glycerol arginine agar, starch-casein agar and soil extract agar were used to isolate the Actinomycetes. Glycerol arginine agar found to be superior to the other two plating media. Diversity of Actinomycetes was less when compared to that of Bacillus genera. Potential of the Actinomycetes to produce antibiotics were evaluated by well diffusion method against 6 serotypes of Salmonella, Vibrio parahaemolyticus and Escherichia coli.

2 illus, 4 tables, 26 ref

024789   Ganesan K;Bragadeeswaran S;Balasubramanian T (Centre of Advanced study in Marine Biology, Faculty of Marine Sciences, Annamalai Univ, Parangipettai-608 502, Email: drpragathi@gmail.com) : Comparative study on antibacterial activity of ascidians, Polyandrocarpa indica Michaelsen and Phallusia arabica Savigny from Tuticorin coast of India. Indian J Geomar Sci 2011, 40(3), 438-42.

Marine ascidians contain antibacterial agents of relevance to either antifouling technology or clinical pharmacology. In the present study two ascidians Polyandrocarpa indica and Phallusia arabica were examined for their antibacterial activity against ten bacterial pathogens. Antimicrobial activity of the crude extract of ascidians shows inhibitory activity against almost all the strains. However, methnolic extract of P. arabica shows prominent antibacterial activity against than that of P. indica. Maximum inhibition zone (17 mm) was observed against Salmonella typhi in the crude methanol extract of P. arabica and the minimum inhibition zone (1 mm) was noticed against P. mirabilis and P. aeruginosa in the ethyl acetate and diethyl ether extract of P. indica. In P. indica the crude extract range of inhibition of bacteria varied from 1-12 mm. Based on observed zone of inhibition, present study revealed that P. arabica extract are more effective than P. indica.

2 illus, 19 ref