Total visitors:2,635 since 12-12-03

Indian Journal of Marine Sciences

 

ISSN: 0379-5136  

   CODEN : IJMNBF

VOLUME 32

NUMBER 4

DECEMBER 2003

 

CONTENTS

Papers

 

Fractal behavior of electrical properties in oceanic and continental crust

Nimisha Vedanti & V.P.Dimri

273-278

 

 

Remote sensing of diffuse attenuation coefficient (K490) using IRS-P4 Ocean Colour Monitor (OCM) sensor

Prakash Chauhan, Arvind Sahay, A. S. Rajawat & Shailesh Nayak

279-284

 

 

Statistical forecasting of met-ocean parameters in the Cochin estuarine system, southwest coast of India

K. Srinivas, C. Revichandran & P. K. Dinesh Kumar

285-293

 

 

Indian Ocean dipole mode events in a simple mixed layer ocean model

C. Gnanaseelan, J. S. Chowdary, A. K. Mishra & P. S. Salvekar

294-304

 

 

Wave loads on open sea mooring dolphin with vertical cylinders due to regular waves

S. Neelamani, Cheduluri R Chandra Rao & S. Narasimha Rao

305-313

 

 

Vertical structure of the chemical properties of western Black Sea

Filiz Kucuksezgin & Idil Pazı

314-322

 

 

Lead in surface sediments of the Straits of Malacca

C. K. Yap, A. Ismail  & S. G. Tan

323-328

 

 

Fungal assemblage and diversity on periodically sampled intertidal woody litter

K. Prasannarai & K.R. Sridhar

329-333

 

 

Short Communications

 

Antibiotic susceptibility of luminous bacteria from shrimp farm environs of West Bengal

Tapti Sengupta, Debasis Sasmal & T. Jawahar Abraham

334-336

 

 

Chemical defense in ascidians Eudistoma viride and Didemnum psammathodes in Tuticorin, southeast coast of India: Bacterial epibiosis and fouling deterrent activity

M. Santhana Ramasamy & A. Murugan

337-339

 

 

Water repellent treatments for catamaran grade Bombax ceiba Linn. (Spermatophyta/
Dicotyledoneae) wood

Pankaj K. Aggarwal, S. S. Chauhan, N. R. R. Prasad & K. S. Rao

340-343

   

Redefining significant wave periods for modelling and prediction

N.Unnikrishnan Nair, G. Muraleedharan & P.G. Kurup

344-347

 

 

Book Review

 

Indian estuaries by S.Z. Qasim

A. Rajendran

348-350

 

 

Annual Author Index

351-352

 

 

Annual Key Word Index

353-355

 

 

Acknowledgement to Referees [2003]

356-358

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 273-278

 

Fractal behavior of electrical properties in oceanic
and continental crust

Nimisha Vedanti & V.P.Dimri*

 

The fractal behavior of electrical properties of oceanic and upper continental crust was examined for different lithological units encountered in boreholes of Ocean Drilling Program (ODP) and German Continental Deep Drilling Program (KTB), using wavelet transform and Welch averaged periodogram methods. Results obtained from both the sites reveal that the electrical properties in oceanic as well as upper part of continental crust are fractal in nature. The scaling exponent obtained by periodogram analysis has shown variation with lithology and for continental crust it decreases with an increase in depth, which reveals that the electrical crust is more homogeneous at deeper levels than at shallow levels.

 

Key words: Fractals, oceanic crust, spectral analysis,  wavelet transform

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 279-284

 

Remote sensing of diffuse attenuation coefficient (K490) using
IRS-P4 Ocean Colour Monitor (OCM) sensor

*Prakash Chauhan, Arvind Sahay, A. S. Rajawat & Shailesh Nayak

 

An algorithm relating the diffuse attenuation coefficient K(490) at 490 nm wavelengths to the ratio of normalized water-leaving radiance [Lwn(443)/Lwn(555)] has been developed through regression analysis of radiometric profiles obtained from three oceanographic cruises conducted in the north eastern Arabian Sea and off Orissa and Andhra coast in the Bay of Bengal. The regional K(490) algorithm has been applied on to the IRS-P4 Ocean Colour Monitor (OCM) satellite data and a limited validation of the algorithm has been performed for case I and case II waters off Gujarat coast in the Arabian Sea. The results of the satellite validation experiment conducted in the Arabian Sea for K(490) algorithm show that the algorithm captures very well the in situ K(490) values (RMS=0.011 m-1). The algorithm has also been validated for an independent in situ data set collected during SK-186 data collection campaign in the Arabian Sea; a good correlation was obtained for this data (r2 = 0.80, N=41).

 

Key words :  Arabian Sea, Bay of Bengal , diffuse attenuation coefficient, IRS-P4 OCM]

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 285-293

 

Statistical forecasting of met-ocean parameters in the Cochin estuarine system, southwest coast of India

*K. Srinivas, C. Revichandran & P. K. Dinesh Kumar

 

Three different statistical forecasting techniques - autoregressive, sinusoidal and exponentially weighted moving average (EWMA) were used to forecast monthly values of meteorological and oceanographic (met-ocean) parameters viz. sea surface temperature (SST), air temperature, atmospheric pressure, wind speed, rainfall, relative density and sea level, in the Cochin estuarine system. The EWMA technique (which yields forecast with a lead time of only one month) gave the lowest root mean square errors relative to the verifying observations. Atmospheric pressure could be forecast with less than 5 % of error while SST and air temperature with less than 10 % of error, by all the three techniques. 80% of the time, sea level could be forecast with less than 10 % error, by each of the three techniques. However, wind speed, relative density and rainfall could not be forecast by any of the three techniques with any acceptable degree of accuracy.

 

Key words : Cochin  estuarine system, met-ocean parameters, seasonal variation, statistical forecasting

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 294-304

 

Indian Ocean dipole mode events in a simple
mixed layer ocean model

C. Gnanaseelan, J. S. Chowdary, A. K. Mishra & P. S. Salvekar

 

A precise knowledge of sea surface temperature (SST) is very essential for climate and oceanographic studies. In this paper a simple two dimensional mixed layer ocean model and its numerical code have been developed and used to simulate the SST fields over the north Indian Ocean (20S-25N and 35E-115E) for a period of 10 years (1992-2001). The model simulated the SST variability reasonably well. The simple model could simulate the observed dipole of 1997 and 1994 very well, especially the eastern cooling. The model study showed that the interannual SST variability in the western equatorial Indian Ocean is not only due to the variability in the surface heat fluxes, but also due to the variability in wind and sea surface height (SSH). The OLR anomaly also shows positive (negative) anomaly over the negative (positive) anomalous SST region. The variability in the latent heat flux is found to be greatly influencing the SST variability in the eastern equatorial Indian Ocean.

 

Key words : Dipole mode index, mixed layer, upwelling

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 305-313

 

Wave loads on open sea mooring dolphin with
vertical cylinders due to regular waves

*S. Neelamani and

Cheduluri R Chandra Rao & S. Narasimha Rao

 

Mooring dolphin is one of the components of open sea marine terminal. A thorough knowledge on wave forces on this mooring dolphin is essential for its design. Experimental investigations were carried out on wave loads on an open sea mooring dolphin with vertical slender cylinders and deck in 0.60 m water depth. The deck slab was placed at nine different elevations above and below the still water level (emerged and submerged conditions) to study the effect of deck elevation on wave loads on mooring dolphin due to regular waves. A study on single cylinder is also carried out to compare the forces on mooring dolphin with the forces on single cylinder. Wave force on single cylinder can be calculated by using Morison equation. There is no theoretical method to calculate wave forces on slender cylinders with deck, especially when the deck is in submerged condition. It is found that the in-line and transverse forces are more when the bottom of deck slab is exactly at still water level and reduce significantly when it is submerged or emerged. Mooring dolphin receives maximum slamming force when the deck is in submerged condition.

 

Key words : Deck slab, in-line force, mooring dolphin, slamming pressure, transverse force, vertical slamming force

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 314-322

 

Vertical structure of the chemical properties of
western Black Sea

*Filiz Kucuksezgin & Idil Pazı

 

The data have been used to understand the variations of chemical features (distribution of nutrients, oxygen and sulfide) at specific density surfaces of the western Black Sea. The range and possible reasons of variations in the vertical profiles of nutrients, oxygen and hydrogen sulphide concentrations are discussed for the Black Sea. The concentrations of inorganic nutrients in the productive surface waters ranged between 0.02-0.30 μM for o.PO4-P and 0.10-0.50 μM for the TNOx-N. The maximum TNOx value of 6.5-7.0 μM was found between the sθ = 15.35-15.55 surfaces throughout the basin. The upper and the deeper phosphate maxima were observed at sθ = 15.50-15.60 and sθ = 16.20-16.25 surfaces, respectively. TNOx/PO4 ratios displayed distinct maxima at specific density surfaces of the upper nutricline. Si/TNOx and Si/PO4 were also calculated in the western Black Sea.

 

Key words: Black Sea, dissolved oxygen, hydrogen sulphide, inorganic nitrogen, o-phosphate

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 323-328

 

Lead in surface sediments of the Straits of Malacca

*C. K. Yap, A. Ismail  & S. G. Tan

 

The chemical fractionation of lead (Pb) was determined in surface sediments collected during two cruises in the Straits of Malacca. Total Pb (not included the terrigenous silicate) concentrations in the sediments range from 8.2 to 28.5 mg/g. Nonresistant fractions [easily or freely leachable and exchangeable (EFLE), acid-reducible and oxidisable-organic] contribute 74% (December 1998) and 71% (April 1999) of the total Pb concentration of the sediments. Among the nonresistant fractions, the oxidisable-organic fraction contributes 75-80%. This may indicate that although the total Pb concentrations in the sediments are relatively low in comparison with other regional data and established sediment quality guidelines, the chemical fractionation shows that most (about 70%) of the total Pb found in the sediment could be mostly related to anthropogenic sources although further validation is required.

 

Key words : Chemical fractionation, sediment, the Straits of Malacca

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 329-333

 

Fungal assemblage and diversity on periodically sampled intertidal woody litter

K. Prasannarai* & K.R. Sridhar**

 

Fungal assemblage, richness and diversity were assessed on 1,800 woody litter sampled periodically from three intertidal habitats of southwest coast of India for two successive years. Among 41 fungi encountered, 30 were ascomycetes, two were basidiomycetes and nine were deuteromycetes. Number of fungal occurrences (p=0.0276) and seawater temperature (p=4.1210-7) in different periods were significantly different. Percent wood colonized (85 vs. 65.8-71.9 %), mean number of fungi per wood (1.6 vs.1.2-1.3) and mean number of fungi per sampling (12.7 vs. 10.5-10.7) were highest during August (monsoon) which coincided with low seawater temperature (25.2 vs. 27.8-31.7C). A highest number of species (30) was recovered in August (in April, 25; in December, 24). Seventeen species showed the highest frequency of occurrence during August, while it was 14 in April and 10 in December. The relative abundance of Clavatospora bulbosa was highest (17 %) followed by Antennospora quadricornuta (13.6 %) and Periconia prolifica (13.2 %). Antennospora quadricornuta was most frequent (22.8 %) in August followed by Clavatospora bulbosa (20.6  %), Periconia prolifica (20.5 %), Zalerion varium (12.3 %), Torpedospora radiata (10.9 %) and Crinigera sp. (10.7 %). Species richness and diversity of fungi were highest during August. This study indicates that the assemblage, richness and diversity of marine fungi on intertidal woody litter dependent on the sampling period, which is highest during monsoon samples of the southwest coast of India.

 

Key words : Diversity, marine fungi, species richness, woody litter

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 334-336

 

 

Short Communication

 

Antibiotic susceptibility of luminous bacteria from
shrimp farm environs of West Bengal

Tapti Sengupta, Debasis Sasmal & T. Jawahar Abraham*#

 

Sensitivity of 175 isolates of luminous bacteria from various shrimp farming systems of West Bengal was tested against six antibiotics, viz., chloramphenicol (30g), ciprofloxacin (5g), co-trimoxazole (25g), gentamycin (10g), nitrofurantoin (300g) and oxytetracycline (30g). Besides, the minimum inhibitory concentration (MIC) of the antibiotics was determined against 60 isolates of Vibrio harveyi. The isolates were least susceptible to oxytetracycline followed by ciprofloxacin and nirofurantoin, and highly susceptible to chloramphenicol. Vibrio harveyi was the most resistant species. About 56% of the luminous isolates exhibited multiple antibiotic resistance. The MIC of oxytetracycline was observed to be in the range of 1.56->200 g/ml. Majority of the isolates were inhibited at a concentration of 0.10-0.78 g/ml of ciprofloxacin and 0.20-6.25 g/ml of chloramphenicol. The observations on the antibiotic resistance did not indicate that the luminous bacteria of certain shrimp culture systems of West Bengal is developing resistance to broad-spectrum antibiotics.

 

Key words: Antibiotic resistance, luminous bacteria, resistance profile, shrimp farming, Vibrio harveyi ]

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 337-339

 

 

Short Communication

 

Chemical defense in ascidians Eudistoma viride and Didemnum psammathodes in Tuticorin, southeast coast of India: Bacterial epibiosis and fouling deterrent activity

M. Santhana Ramasamy & A. Murugan*

 

The culturable epibacterial abundance in the ascidians Eudistoma viride and Didemnum psammathodes was studied and correlated with their antifouling activity. The epibacterial abundance varied significantly between E. viride and D. psammathodes. The antibacterial assay of the crude extracts of the ascidians showed inhibitory activity against all the 20 biofilm bacteria. However, E. viride showed prominent antibacterial activity than that of D. psammathodes with an average inhibition zone of 29.1 mm. The comparison between epibacterial abundance and the antifouling activity showed an interesting significant negative correlation [-0.910 (P<0.001)]. Though the ascidians showed activity against all biofilm bacteria, the presence of epibacteria still on its surface could be attributed to their selective inhibition against certain bacteria due to chemical defense mechanism or the ascidians may exhibit a surface property suitable for particular epibacteria which may be symbiotic and contribute to the reduced abundance of other bacterial epibionts.

 

Key words  : Antifouling, ascidian, biofilm, Didemnum psammathodes, epibacteria, Eudistoma viride

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 340-343

 

Short Communication

 

Water repellent treatments for catamaran grade Bombax ceiba Linn. (Spermatophyta/Dicotyledoneae) wood

*Pankaj K. Aggarwal, S. S. Chauhan, N. R. R. Prasad & K. S. Rao

 

Water repellency effectiveness (WRE) of four chemical formulations, namely polymeric methylene diisocyanate (PMDI), cashew nut shell oil (CSNL), varnish and chromium trioxide, was assessed on Cooper-Chrome-Arsenic (CCA) treated Bombax ceiba wood. Fifteen cycles of repeated wetting and drying were performed on water repellent coated and untreated wood. Water repellency was very high in the first cycle and then declined in all the coating system in subsequent cycles. After 10th cycle WRE became constant for all the systems. PMDI exhibited highest water repellency followed by chromium trioxide, CSNL and varnish. With the application of water repellent formulations, water uptake can be reduced considerably, which will maintain buoyancy of wood. The water repellents apart from reducing water holding capacity also reduces leaching of preservatives from the structures, which resulted in enhancing the durability of wood.

 

Key words : Bombax ceiba, catamaran, water absorption, water repellent

 

 

 

Indian Journal of Marine Sciences

Vol. 32(4), December 2003, pp. 344-347

 

Short Communication

 

Redefining significant wave periods for
modelling and prediction

N.Unnikrishnan Nair1, G. Muraleedharan2 & P.G. Kurup2*

 

Significant wave period is redefined and a modified Erlang distribution model is suggested for the redefined significant wave periods by the method of characteristic function. Various prediction formulae have also been derived from this model for the redefined significant wave period statistics and compared with actual values indicating that the estimated values have acceptable accuracy.

 

Key words : Significant wave approach, random wave, concept, modelling, redefined significant wave period, prediction