Biogeochemistry of trace metals in the Indian EEZ of the Arabian Sea and Bay of Bengal

The present study has been initiated to unravel the distribution of trace metals and its geochemical behavior in the Indian EEZ of the Arabian Sea and Bay of Bengal. Trace metal accumulation in aquatic consumers is of interest to ecologists and environmentalists so as to understand the fate and effect of contaminants in the food web dynamics and the biogeochemical cycling of trace metals. It is well established that oceanic distribution of macronutrients such as nitrate, phosphate and silicate provide critical to biological growth and related geochemical processes. In this study it can be inferred, that there is a need for a better understanding of background informations on trace metal concentrations with respect to space and time and their fluctuations in the Arabian Sea and Bay of Bengal zooplankton. Without a sound knowledge on spatio-temporal fluctuations, it will be impossible to differentiate anthropogenic metal inputs from natural background concentrations with a routine biomonitoring programme. Fe, Cu, Zn, Cd & Pb showed a slight enrichment in zooplankton from the Arabian Sea during spring intermonsoon compared to intermonsoon fall. The relative enrichment of Fe, Cu & Zn in zooplankton from the Arabian Sea during intermonsoon spring than intermonsoon fall was due to favourable bioaccumulation factors of these elements during this season. Nevertheless this study can be looked upon as a starting point for further investigations on these biogeochemically important processes, which are vital in addressing the dynamics of productivity of waters.

Marine Yeasts from the Slope Sediments of Arabian Sea and Bay of Bengal

The present study provides an account of the occurrence and diversity of marine yeasts in the slope sediments of Arabian Sea and Bay of Bengal. It also gives a clear idea about the role of yeasts in the benthic realm of marine ecosystem. The lipolytic potential of the organisms indicate the presence of rich lipid moieties in the study area. The isolates, Candida sp. SD 302 and Pichia guilliermondii SD 337 were proved to have potential oil degrading property and can be employed as bioremediators of oil spill after further characterization. The black yeasts isolated during the study area were found to have high commercial value by virtue of the by-products obtained from them. The melanin and the melanin degrading enzyme extracted from these organisms are potential bioactive materials for application in cosmetology.

Inertial oscillation forced by the September 1997 cyclone in the Bay of Bengal

Time-series measurements from a moored data buoy located in the Bay of Bengal captured signals of inertial oscillation forced by the September 1997 cyclone. The progressive vector diagram showed mean northeastward current with well-defined clockwise circulation. Spectral analysis exhibited inertial peak at 0.67 cpd with blue shift and high rotary coefficient of –0.99, which signifies strong circular inertial oscillation. The wind and SST also exhibited spectral peak at inertial band (0.69 cpd) with higher blue shift. The inertial amplitude of 148.8 cm/s corresponding to a wind stress of 0.99 N/m2 and spectral peak near the local inertial frequency (0.653 cpd) indicate that the transfer of momentum was high.

Studies on influance of environmental parameters affecting the biology of oyster crassostrca madrasensis(Preston)

The Indian edible oyster Crassostrea madrasensis (Preston) is known to be a highly suitable candidate species for culture. Though Q, madrasensis has been subjected to intensive research, there has been no significant attempt to culture this oyster commercially. One major reason for the lack of interest in oyster culture could be the disparity in growth, survival and production reported by earlier workersf from different regions along the Indian coast. Greater predictability of production can create confidence and encourage entrepreneurs interested in oyster culture. The present study, which is a detailed investigation on the influence of various environmental variables on growth and reproduction of Q, madrasensis, is not confined to the impact of only hydrological parameters but is also extended to study the effect of different degrees of aerial exposure on growth and survival. The main objective of the study is to develop a background for subsequent development of a site suitability index for culture of Q, madrasensis along the Indian coast. Two sets of experiments were conducted during the present study. Details of the experiments are presented in the thesis under two major chapters comprising four sections each. Each chapter has a separate introduction, materials and methods, results and discussion. .

Studies on the Back Water Oyster, grassostrea madra— sensis (Preston) of Cochin Harbour

A detailed study of the hydrography of the Cochin Backwaters, the habitat off crassostrea madrasensis has been carried out. Data pertaining to air temperature, water temperature, salinity, dissolved oxygen, turbidity and rainfall have been collected and presented. The temperature fluctuation was in the range of 5°C only and that of salinity between 1.1%o and 32.9%o. Fairly steady salinity has been recorded during the pre-monsoon period (February to May) and drastic declension during the monsoon period (June-September).Dissolved oxygen varied between 2.5 ml/l and 6.5 ml/l. Turbidity was highest in June (27.9 p.p.m.) and minimum (10.2 p.p.m.) in February. A detailed study on marine biofouling in the Cochin Backwaters has been made with special reference to primary film, settlement and growth of the fouling organisms such as hydroids, bryozoans, tube-dwelling polychaetes, barnacles and modiolus

Studies on energy exchange between sea and atmosphere from the indian ocean with special reference to arabian sea and bay of bengal

There are only a few attempts in the Indian ocean to evolve reliable climatic models of energy exchange fluxes and to study their inter annul variations. Large space scale and time history of the flux fields could be estimated by the bulk aerodynamic exchange and radiation equation, making use of the climatic normal’s of the related parameters derived from the remarkably good amount of surface marine observations compiled and made available on magnetic tape TDF II by the national climatic centre of NOAA for the period of years 1854 –early 1973. In this thesis the author has made an attempt to calculate the thermal energy exchange fluxes in a meaningful way, using the bulk aerodynamic coefficients which depend on the changes in the wind speed. The spatial and temporal distribution of the exchanges of energy between the ocean and atmosphere , are presented and their impact on the climatic variations of the Indian ocean are discussed from the point of view of predominating air sea interaction processes.

Studies on some fish larvae of the arabian sea and bay of bengal

Though several scientific expeditions surveyed tha Indian ocean. their findings on larval fishes were fragmentory and incomplete. During the International Indian ocean expedition (1960-1965) zooplankton samples were collected from vast area at the lndian ocean adopting standard procedures by participating vessels. These planktons provided an opportunity for a general study of the zooplanltton as well as their anotomy. abundance and distribution.. Realising the imortance of the analysis and classification of fish larvae at the family level being one of the most important information required then for the Indian Ocean region the fish larval portion sorted out from the above zooplankton samples was allocated to the author by the UNESCO consultative committee for the Indian Ocean Biological centre. In spite of the emhasis laid on The study of the family scombridae. owing to the paucity of the scombridae material in tne collection. much could not be done about it.However the record and description of the very early stages of morakel larvae made in 1967 as part of this study was the first of its kind. The present study on the distribution aspects o fish larva of such large area in the Indian ocean is also unique and first of its kind

Mesozooplankton of the Arabian Sea and the Bay of Bengal with special reference to planktonic ostracods

The Arabian Sea and the Bay of Bengal are both highly dynamic ecosystems, due to the seasonally reversing monsoon winds, but the processes affecting the mesozooplankton community remain poorly understood. These are important basins exhibiting enhanced biological production as a result of upwelling, winter cooling and other episodic events such as eddies and gyres. Zooplankters are primarily the prey for almost all fish larvae. Seasonal changes in the biogeochemical processes can strongly affect zooplankton density and distribution, which in turn, strongly affect the larval growth, and consequently, the pelagic fish recruitment. It is clear that plankton biomass and biogeochemical fluxes are not in steady state. Acoustic data on mesozooplankton abundance suggests that they also exist in the mesopelagic zone. Earlier studies were confined only to the upper 200 m and hence the structure of mesozooplankton community in the deeper layers was not well known. Copepods are the dominant mesoplankton group, and therefore the majority of the studies were focused on them. The planktonic ostracods are the second major crustacean group and at times, their swarms can outnumber all other planktonic groups. The understanding of the community structure of the ostracods is essential to establish their role in the marine food web. Mesozooplankton is responsible for the vertical flux of organic matter produced by phytoplankton and is assumed to be equivalent to new production (Eppley & Peterson, 1979). Since the fate of newly produced organic matter depends upon their consumers, the zooplankton biomass must be estimated in size fractions or taxonomic components to understand the vertical flux of organic carbon. It is thus important to update our knowledge on different groups of zooplankton on the basis of seasonal and temporal distribution. The distribution in space and time is essential for modeling the carbon cycling that structure the marine ecosystems

Studies on The Eco Biology of The Indian Pearl Oyster, Pinctada Fucata (Gould)

The present work aims to study induced maturation of the pearl oyster for induced spawning experiments. The work on larval development was done with a view to developing techniques for the artificial rearing of commercially important pearl oyster P fucata, and also to elucidate the principles and problems of tropical bivalve larvae in general for detailed investigations in the future. The present study is designed to probe into the details of the basic aspects of the biology related to the hatchery technology of Pinctada fucata and the understanding of the factors which influence induction of maturation, spawning, larval rearing and spat settlement. This would go a long way in the upgradation of hatchery technology of the Indian Pearl oyster Pinctada fucata fora commercial level seed production..