The characteristic tranquility of mudbanks. A clue to form them artiflcially-a hypothesis

The natural format ion of mudbanks (Chagaras) at certain locations along the Kera'a coast during The southwest monsoon is a well known phenomenon, an insight into the scientific reasons of the Varying tranquility of a spectrum of mud banks gives a clue as to how to form them artificially. The Clue, born of experience in the fields is described here. With appropriate engineering design of Devices the hypothesis may prove to be a useful proposition serving the cause of coastal fishermen Who make their living by operating canoes for fishing from the neritic wate

Determination of harmonic coefficients without the aid of conventional analytical schemes

Harmonic analysis converts periodic function into waves of primary frequency and higher harmonics. Analytical schemes, in the past, were developed to determine the harmonic coefficients. As all the waves at a time pass through each of the ordinates which are at their respective positions along the primary period, the arithmatic sum of the amplitudes put together at the time of passing through an ordinate is made equal to that ordinate, or atleast in the practical way, the sum of the amplitudes at each ordinate tends to be equal to that ordinate. This view makes it possible to find the harmonic coefficients from the selected ordinates. And thus, the coefficients could be directly determined without adopting any analytical scheme. The new method of detemining harmonic coefficients is applied to SST observations of the Bay of Port Blair. The SST observations were conducted from on board FORV Sugar Sampada during September 29th (18 Hrs) to 24 Hrs. on 30th September, 1988 at hourly intervals. The theoretically evaluated SST values from harmonic coefficients were found to be closer to the observed values

Ocean Currents

Looking at the sea one sees the ripples on the surface and the rolling waves, but a more keen observant sees that more portions on the shore arc submerged at times and exposed at other times owing to the rise and fall of sea surface, the tidal influence brought about by the gravitational pull of the sun and moon on the oceans. What one fails to notice is that the body of water is in constant flowing motion; this becomes obvious when one watches some debris floating on the surface. This movement of water is known as •current. Some of these currents are so enormous in extent that the Amazon could be found a rivulet. The speed of movement varies from a few meters per hour to several knots

Characteristics of neritic waters along the west coast of India with respect to upwelling, dissolved oxygen & zooplankton biomass

Assuming temperature of the water layer at 50' m depth along the shore as an inverse index of upwelling. zooplankton biomass of the pelagic waters off the west coast of India in relatitm to upwelling intensi ty is studied. Productive value of upwelling, is reflected in the abundance of biomass of the total zooplankton. At mu('h higher intensity of upwelling, the waters are very much depleted with respect to dissolved oxygen. Temporal and spatial lag of occurrence of zooplankton with upwelling is noticed in the analysis. Upwelling and plankton production take place earlier in the southern part of the coastline than in the northern

Studies of fisheries with the causative environmental factors - optimum utilisation of FORV Sagar Sampada’s capabilities

Retaining the multidisciplinary character of research, FORV Sagar Sampada cruises got evolved into species-wise and sector-wise investigations to obtain complete cyclic pictures of species and sectors over seasons round the year for the EEZ waters of India. The paper aims at further transformation of the system of her cruises into problem-oriented investigations. Specific problems in pelagic fisheries of the waters around India are reasoned out for effective utilization of the unique sea-lab, the FORV Sagar Sampada. A rethinking is needed in planning and implementation of cruise programmes towards achieving realistic synthesis of studies of fisheries with the causative environmental factors

Active cell hypothesis

In some waters (water masses, in general) and in the sea, phytoplankton cell count is more but primary production is less. It is the opposite in some other water masses where grazing by zooplankton and fish is attributed for the less count. More count and less production result in poor quality of water

Water characteristics, mixing and circulation in the Bay of Bengal during southwest monsoon

Influence of the freshwater influx, the wind forcing and the Indian Ocean monsoon drift current on the property distributions and the circulation in the Bay of Bengal during southwest monsoon has been quantified. At the head of the Bay, waters of low salinity, affected by the freshwater influx, occupy the upper 90 m water column. The isohaline 34.0 × 10−3 separating these waters from those of underlying saline waters shoals southward gradually and outcrops around 14N, 10N and 6N in the western, central and southeastern regions of the Bay respectively. The wind-stress-curl-induced upwelling effect is confined to depth limits of 50–100 m as is supported by a band of cold (24°–19°C) water in the central Bay. In the southern and central regions of the Bay, the monsoon drift current feeds the large scale cyclonic gyre apart from maintaining the northward flowing boundary current in the eastern Bay. A warm (27°–23°C), saline (35.0–35.2 × 10−3) watermass is advected northeastward along with the monsoon drift current into the Bay up to 14N at the depth limits of 50–100 m. Below this depth, in the western Bay a well-defined southward flow in the form of a boundary current is documented. Intense vertical mixing is inferred at the zones of salinity fronts in the depth limits of 40–100 m and also at deeper depths (\u3e 2200 m) and elsewhere lateral mixing is predominant

Kinetics of Oxidation of Methyl Orange & Methyl Red by V(V)*

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Observed changes in ocean acidity and carbon dioxide exchange in the coastal Bay of Bengal – a link to air pollution

Variations in surface water hydrographic properties and Dissolved Inorganic Carbon (DIC) were evaluated in the coastal Bay of Bengal using observations carried out during March–April 1991 and 2011, including 8 yr monthly time-series observations during 2005 and 2013. The coastal Bay of Bengal is characterised by relatively fresher, more basic and lower pCO2 in 1991 compared to 2011. The rates of decrease in pH, increase in DIC and pCO2 per decade were consistent with global trends in the Southwestern (SW) coastal Bay of Bengal, whereas rates in the Northwestern (NW) coastal Bay of Bengal were observed to be 3–5 times higher. The associated recent increase in sulphate and nitrogen aerosol loadings over NW Bay of Bengal from the Indo-Gangetic Plain and Southeast Asia during winter and spring may be mainly responsible for the increased acidity in recent years. Thus, this region, which was previously considered to be a significant sink for atmospheric CO2, now seems to have become a source of CO2 to the atmosphere

Nitrogen isotopes in mantle-derived diamonds: indications of a multi-component structure

Mantle nitrogen trapped in diamonds is commonly defined by an isotopic composition (δ15N) of ~-5% based on the central tendency of total combustion diamond data that vary from -25 to +18%. We present here the nitrogen isotopic data from stepped combustion of diamonds, which together with data from other mantlederived materials suggest a multi-component structure of diamond-nitrogen. Mantle nitrogen sampled in diamonds apparently has δ15N ~-15%, similar to that observed in mantle xenoliths and mid-oceanic ridge basalts (MORBs), while nitrogen in a minor population of diamonds from China is consistent with contributions from an ocean island basalt like mantle source