Vinu, Prakash; Dr.Narayana, A C(Cochin University of Science And Technology, November , 2012)
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Abstract:
All over the world, several Quaternary proxy data have been used to
reconstruct past sea levels, mainly radiocarbon or OSL dating of exposures of
marine facies or shore line indicators (e.g. Carr et al., 2010) as well as paleoenvironmental
indicators in lagoon or estuary sediments (e.g. Baxter and
Meadows, 1999). Estuaries and deltas develop at river mouths during
transgressive and regressive phases, respectively (Boyd et al., 1992). In
particular, the postglacial Holocene sea-level rise has contributed importantly to
the estuary-to-delta transition (Hori et al. 2004). By analyzing radiocarbon ages
of the basal or near-basal sediments of the world’s deltas, Stanley and Warne
(1994) showed that delta initiation occurred on a worldwide scale after about
8500–6500 years BP and concluded that the initiation was controlled
principally by the declining rate of the Holocene sea-level rise.
Worldwide there were different regional sea-level changes since the last
glacial maximum (LGM) (Irion et al., 2012). Along the northern Canadian
coast, for example, sea level has been falling throughout the Holocene due to
the glacial rebound of the crust after the last glaciation (Peltier, 1988). This is
comparable to the development in Scandinavia (Steffen and Kaufmann, 2005)
where sea level drops today. From about Virginia/USA to Mexico there is a
constant sea-level rise similar to the Holocene sea-level development of the
southern North Sea (e.g. Vink et al., 2007). From the border of Ceará/Rio
Grande do Norte down to Patagonia, indicators of Holocene sea level point to a
level that was up to 5 m higher than today's mean sea level (Angulo et al., 1999;
Martin et al., 2003; Caldas et al., 2006a, b)
Description:
School of Marine Sciences, Cochin University of Science And Technology
Varghese, Tiju I; Prakash, T N(Cochin University Of Science And Technology, December 18, 2014)
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Abstract:
The evolution of coast through geological time scale is dependent on the
transgression-regression event subsequent to the rise or fall of sea level. This
event is accounted by investigation of the vertical sediment deposition patterns
and their interrelationship for paleo-enviornmental reconstruction. Different
methods like sedimentological (grain size and micro-morphological) and
geochemical (elemental relationship) analyses as well as radiocarbon dating are
generally used to decipher the sea level changes and paleoclimatic conditions of
the Quaternary sediment sequence. For the Indian coast with a coastline length of
about 7500 km, studies on geological and geomorphological signatures of sea
level changes during the Quaternary were reported in general by researchers
during the last two decades. However, for the southwest coast of India
particularily Kerala which is famous for its coastal landforms comprising of
estuaries, lagoons, backwaters, coastal plains, cliffs and barrier beaches, studies
pertaining to the marine transgression-regression events in the southern region
are limited. The Neendakara-Kayamkulam coastal stretch in central Kerala where
the coast is manifested with shore parallel Kayamkulam Lagoon on one side and
shore perpendicular Ashtamudi Estuary on the other side indicating existence of
an uplifted prograded coastal margin followed by barrier beaches, backwater
channels, ridge and runnel topography is an ideal site for studying such events.
Hence the present study has been taken up in this context to address the gap area.
The location for collection of core samples representing coastal plain, estuarylagoon
and offshore regions have been identified based on published literature
and available sedimentary records. The objectives of the research work are:
To study the lithological variations and depositional environments of
sediment cores along the coastal plain, estuary-lagoon and offshore
regions between Kollam and Kayamkulam in the central Kerala coast
To study the transportation and diagenetic history of sediments in the area
To investigate the geochemical characterization of sediments and to
elucidate the source-sink relationship To understand the marine transgression-regression events and to propose
a conceptual model for the region
The thesis comprises of 8 chapters. The first chapter embodies the
preamble for the selection and significance of this research work. The study area
is introduced with details on its physiographical, geological, geomorphological,
rainfall and climate information.
A review of literature, compiling the research on different aspects such as
physico-chemical, geomorphological, tectonics, transgression-regression events
are presented in the second chapter and they are broadly classified into three viz:-
International, National and Kerala.
The field data collection and laboratory analyses adopted in the research
work are discussed in the third chapter. For collection of sediment core samples
from the coastal plains, rotary drilling method was employed whereas for the
estuary-lagoon and offshore locations the gravity/piston corer method was
adopted. The collected subsurficial samples were analysed for texture, surface
micro-texture, elemental analysis, XRD and radiocarbon dating techniques for
age determination.
The fourth chapter deals with the textural analysis of the core samples
collected from various predefined locations of the study area. The result reveals
that the Ashtamudi Estuary is composed of silty clay to clayey type of sediments
whereas offshore cores are carpeted with silty clay to relict sand. Investigation of
the source of sediments deposited in the coastal plain located on either side of the
estuary indicates the dominance of terrigenous to marine origin in the southern
region whereas it is predominantly of marine origin towards the north. Further
the hydrodynamic conditions as well as the depositional enviornment of the
sediment cores are elucidated based on statistical parameters that decipher the
deposition pattern at various locations viz., coastal plain (open to closed basin),
Ashtamudi Estuary (partially open to restricted estuary to closed basin) and
offshore (open channel). The intensity of clay minerals is also discussed. From
the results of radiocarbon dating the sediment depositional environments were
deciphered.The results of the microtextural study of sediment samples (quartz grains)
using Scanning Electron Microscope (SEM) are presented in the fifth chapter.
These results throw light on the processes of transport and diagenetic history of
the detrital sediments. Based on the lithological variations, selected quartz grains
of different environments were also analysed. The study indicates that the
southern coastal plain sediments were transported and deposited mechanically
under fluvial environment followed by diagenesis under prolonged marine
incursion. But in the case of the northern coastal plain, the sediments were
transported and deposited under littoral environment indicating the dominance of
marine incursion through mechanical as well as chemical processes. The quartz
grains of the Ashtamudi Estuary indicate fluvial origin. The surface texture
features of the offshore sediments suggest that the quartz grains are of littoral
origin and represent the relict beach deposits.
The geochemical characterisation of sediment cores based on geochemical
classification, sediment maturity, palaeo-weathering and provenance in different
environments are discussed in the sixth chapter.
In the seventh chapter the integration of multiproxies data along with
radiocarbon dates are presented and finally evolution and depositional history
based on transgression–regression events is deciphered.
The eighth chapter summarizes the major findings and conclusions of the
study with recommendation for future work.
Badarudeen,A; Dr.Sajan,K(Cochin University Of Science And Technology, March 5, 1997)
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Abstract:
As a result of the issues of care and conservation and sustainable utilisation,
the proper management of mangrove forests have become more pressing than
ever. Much recent ecological and toxicological debate has been centered around
the question of validity of making predictions about the future of mangrove ecosystemas a result of the newly evolved environmental policy. Though muchinformation exist on the biodiversity, floristic composition and characteristics, geographical distribution and uses of mangroves, systematic documentation of the various sedimentological and geochemical phenomena in relation to the mangrove flora are scarce. Hazardous, persistent, man-made chemicals and waste produces are entering the mangrove ecosystem at from the adjacent watersheds which strengthened alarming rates the indispensible need for further researches on the environmental behaviours, fate and the effect of such products. Studies on the effect of heavy metals, pesticides and the other toxic signals through bioassay and toxicity tests on mangrove species as well as in sediments definitely will furnish ample clues to establish the actual operative mechanisms of these environments. A thorough review of literature made in this angle reveals that some attempts have already been initiated the world over the record the physico-chemical characteristics of major abiotic components such as sediments and water of many mangrove ecosystem, however, adequate information is lacking in the Indian Environmental Science scenario. The present investigation is an attempt to record the sedimentological, mineralogical and geochemical characteristics of sediments as well as the heavy metal enrichment in the various species ofmangrove flora of three important mangrove ecosystems of Kerala, located at Veli (SouthKerala), Kochi (Central Kerala) and Kannur (North Kerala). The results of the above investigation have been analysed statistically, discussed based on the available literature and presented in this thesis under seven chapters
Description:
School of Marine Sciences,
Cochin University of Science and Technology
Revi Kala, S; Dr. Ramamurthy, V D(Cochin University Of Science And Technology, March 14, 1985)
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Abstract:
The present study was undertaken to observe the phytoplankton (distones,dinoflageliates,and blue green algae) blooms occurring along the south west coast of India at various seasons from February 1982 to august 1984.The centers selected for collection and observation were off Quilon, off Alleppey ,off Calicut. A total number of 25 phytoplankton blooms were studied. Characterisation of phytoplankton blooms include observing the cell counts from the day of its appearance to its day of disappearance. The appearance ,duration and locality of the blooms were also noted
Description:
School Of Marine Sciences
Cochin University Of Science And Technology
Noble,A; Dr.Silas, E G(Cochin University of Science and Technology, February , 1986)
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Abstract:
Mackerel fishery at many places in the country including Cochin
as well as at all—India level, besides its seasonal changes to
have long-term flucations apparently evincing a ten-year cycle.
Published literature on the fishery and biology of mackerel at
many places are available. But attempts on population studies
and assessment of stock are scanty. The researchers attention
at this juncture turned to investigations on population dynamics
of the mackerel .On account of the long-term Fluctuations
in the fishery, it was felt desirable to have data For a
number of years together to facilitate adequate coverage of a
unit of time in the 10-year cycle. Investigations on length weight
relationships for 16 seasons were hence carried out.
This thesis is written eection'by section embodying‘ the
results and_findings of the work carried out under different
subject areas. It contains sections on identity of the species,
information on its spatial and temporal distribution along the
Indian coast, study on length-weight relationships, growth and
age determination, population studies and stock assessment, and
discussions.This dissertation is the outcome of the works of the
candidate on the Indian mackerel. The work, however is based
on exploited resource of the inshore waters. In the course
of this analysis, lacunae existing in the investigations on
the Indian mackerel are therefore identified and presented
For future work
Saji, Susan Mathew; Dr. Chennubhotla, V S K(Cochin University of Science and Technology, January , 1991)
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Abstract:
In the present thesis , observations on the ecology of seaweed flora of Kerala, their distribution and zonation pattern, monthly/seasonal density of seaweeds at each station, frequency of occurrence, standing crop, monthly/seasonal/place-wise data on physico—chemical characters of ambient waters at the stations and their influence on seaweed density have been made. This data will help us in the farming of economically important seaweeds, by providing information on the ideal conditions of seaweed biomass production. Biochemical observations on protein, carbohydrate and lipid contents of different species of nutritive value. Seaweeds with high content of proteins, carbohydrates and lipids can be recommended for food and feed formulations after subjecting them to toxicological studies. The study on monthly/seasonal/placewise variation in biochemical composition of seaweeds will provide necessary information on the appropriate time and place of harvesting the algal species for exploiting its constituents .
Shoji, Joseph; Dr.Diwan, A D(Cochin University of Science and Technology, May , 1996)
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Abstract:
The growing demand for quality prawn seed from the farmers‘ and entrepreneurs, coupled with uncertainity of their availability from nature at the appropriate time in required quantities has prompted‘ research on problems connected with prawn seed production. Endocrine control of reproduction in the penaeid shrimp _P_. monodon has been investigated in detail by adopting a comprehensive approach to the problem. The major aspects of the study included in depth investigations of the cytological details of the reproductive and neuroendocrine organs in correlation with the process of gonadal maturation. Based on the conclusions drawn from such ultrastructural studies various endocrine manipulations were carried out to see their effects on gonadal maturation. Besides that studies on the reproductive quality of male P_. monodon and the cryopreservation of spermatophores form a part of the present investigation.
The shrimp 3; Inonodon used in the present study were collected from the offshore waters of Cochin, Madras and Mandapam and from the culture ponds of Vypeen Island near Cochin (Kerala) . The entire investigation on the cytological aspects were carried out using standard histological and electron-microscopic methods. Endocrine manipulations and cryopreservation studies is also carried out using the standard methods.
Janat Augustine, K; Dr.Chandramohanakumar, N(Cochin University of Science & Technology, September , 2002)
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Abstract:
Humic substances are complex polymeric structures.No other polymers with such a wide range of properties are so widely distributed in nature.But still their moleculer structures are unknown. A structural knowledge is essential in determining their reactivity with metals.In the present work structural elucidation of humic acids from three different mangrove ecosystems of Cochin area is done with the available data from functional group analysis and various spectroscopic methods.13C NMR spectra of the solid samples with CPMAS,IR and SEM are very promising in revealing the complex structures of these polymeric substances.Sorptional studies on the sediment and humic acid of mangrove ecosystem reveals that the major portion of the organic matter is not extractable with Sodium hydroxide and humic acid only a small portion of the total organic matter. Humic acid is a good complexing agent and scavenger. Due to the nonextractable nature of the organic matter present with the sediment left after alkali extraction it is a better scavenger.
Description:
Department of Chemical Oceanography,Cochin University of Science and Technology