Indian Journal of Marine Sciences

(www. niscair.res.in )

[ISSN: 0379-5136      CODEN : IJMNBF ]

Total visitors: 68         since  18-12-07

 

VOLUME 36

NUMBER 4

DECEMBER 2007

 

 

CONTENTS

 

Special Issue  on

Marine  Micropaleontological Studies from the Northern Indian Ocean

 

 

A journey through morphological micropaleontology to molecular micropaleontology

      M.S. Srinivasan

251-271

 

 

Foraminiferal studies in nearshore regions of western coast of India and Laccadives Islands: A review

      S.N. Bhalla, N. Khare, D.H. Shanmukha & P.J. Henriques

272-287

 

 

An overview of foraminiferal studies in nearshore regions off eastern coast of India, and Andaman and Nicobar Islands

      N. Khare, S.K. Chaturvedi & A. Mazumder

288-300

 

 

Appraisal of laboratory culture experiments on benthic foraminifera to assess/develop paleoceanographic proxies

      V .N. Linshy, S.S. Rana, S. Kurtarkar, R. Saraswat, & R. Nigam

301-321

 

 

Influence of monsoon upwelling on the planktonic foraminifera off Oman during Late Quaternary

      Pothuri Divakar Naidu

322-331

 
 

Paleoceanographic evolution of the northeastern Indian Ocean during the Miocene : Evidence from deep-sea benthic foraminifera (DSDP Hole 216A)

      Ajoy K. Bhaumik, Anil K. Gupta, M. Sundar Raj, K. Mohan, Soma De & Sudipta Sarkar

332-341

 

 

Surface circulation in the eastern Indian Ocean during last 5 million years: Planktic foraminiferal evidences

      Devesh K Sinha & Ashutosh Kumar Singh

342-350

 

Symbiont-bearing benthic foraminifera of Lakshadweep

      Pratul Kumar Saraswati

 

351-354

Relict benthic foraminifera in surface sediments off central east coast of India as indicator of sea level changes

      Sanjay Singh Rana, Rajiv Nigam & Rajani Panchang

355-360

Neogene oceanographic and climatic changes in the northern Indian Ocean: Evidence from Radiolaria

      V. Sharma & L.Bhagyapati Devi

361-368

 

 

Distribution of Ostracoda in marine and marginal marine habitats off Tamil Nadu and adjoining areas, southern east coast of India and Andaman Islands: Environmental implications

      S.M. Hussain, P. Ganesan, G. Ravi, S.P. Mohan & S.G.D. Sridhar

369-377

 

 

Episodic preservation of pteropods in the eastern Arabian Sea: Monsoonal change, oxygen minimum zone intensity and aragonite compensation depth

      A.D. Singh

378-383

 

 

A review of the studies on pteropods from the northern Indian Ocean region with a report on the pteropods of Irrawaddy continental shelf off Myanmar (Burma)

      Rajani Panchang, Rajiv Nigam, Frank Riedel, Arie W. Janssen, & U Ko Yi Hla

384-398

 

 

Organic matter distribution pattern in Arabian Sea: Palynofacies analysis from the surface sediments off Karwar coast (west coast of India)

      Vandana Prasad, Rahul Garg, Vartika Singh & Biswajit Thakur

399-406

 

 

 

 

Acknowledgement to Referees

 

407-408

Annual Contents

 

409-413

Annual Index

 

415-419

 

 

 

 

 

 

  

Abstracts of the Papers

 

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp. 251-271

 

A journey through morphological micropaleontology to
molecular micropaleontology

M. S. Srinivasan

Geology Department, Banaras Hindu University, Varanasi- 221005, India

[E-mail: mssrinivasan@rediffmail.com ]

Micropaleontology has undergone a remarkable change over the past 150 years. With the recognition of biostratigraphic utility of microfossils in petroleum exploration, micropaleontology received a new impetus from the early descriptive stage to noticeable and exciting trends in the early part of the 20th century. The changes have been primarily in the areas of systematics of smaller benthic foraminifera, biostratigraphy and precision in paleoecology mainly to cater the needs of oil companies. This marks the first major milestone - the development of Industrial micropaleontology. A dazzling shift in micropaleontology occurred in the seventies and eighties with the advent of intensive scientific ocean drilling programmes and availability of new instrumentation and analytical techniques to study microfossils. In addition, efforts to evolve multiple microfossil biostratigraphies and their integration with other fields such as magnetostratigraphy, stable isotopic stratigraphy, carbonate stratigraphy, computer application and more recently with molecular biology opened up multifaceted approach to micropaleontological research. This was indeed another important milestone in the history of development of micropaleontology. This led to a qualitative change in research emphasis in the areas of correlation, paleobiogeography, plankton evolution, paleoclimatology and paved way for new research areas like paleoceanography and molecular micropaleontology. Of late, microfossils have emerged as a very powerful and reliable tool to trace past variations in monsoon and to characterize tsunamigenic sediments. Thus, the subject of micropaleontology is becoming more and more important branch of Earth System Science for finding solutions to contemporary issues and that its future is indeed very bright.

       [Key words: Paleontology, morphology, molecular studies, foraminifera, DSDP]

**********************

 

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.272-287

 

Foraminiferal studies in nearshore regions of western coast of
India and Laccadives Islands: A review

S.N. Bhalla1*, N. Khare2, D.H. Shanmukha3 & P.J. Henriques4

 

1A-525, Sarita Vihar, New Delhi - 110 076

2National Centre for Antarctic and Ocean Research, (Ministry of Earth Sciences),  

   Headland Sada, Vasco-da-Gama, Goa - 403 804, India

3National Institute of Oceanography, CSIR, Dona Paula, Goa - 403 004, India

4St Xavier College, University of Mumbai, Mumbai - 400 032, India

                             *[E-mail: satbhalla@gmail.com ]

The literature published on foraminiferal investigations carried out till date on nearshore, shallow water regions up to a depth of 50 m, along western coast of India, including Laccadive Archipelago has been reviewed. The aim is to prepare a bibliography of the foraminiferal studies from the tropical Arabian Sea bordering west coast of India and to highlight the major contribution made towards various studies of foraminifera.

The review shows that most of the studies discussed taxonomical and/or ecological aspects as evident by 53 publications, followed by 21 papers on paleoenvironment/climate/monsoons, etc., and only 3 papers on modern environmental implications. Besides other applied aspects of foraminifera, studies on a few new fields such as laboratory culture, molecular systematic analysis, isotopic studies, trace elements analysis, etc., have also been initiated on the foraminifera collected along western coast of India.

[Keywords: Foraminifera, west coast of India, Laccadives Islands, bibliography of the foraminiferal studies, Arabian Sea, taxonomy, culture, review of foraminifera]

**********************

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.288-300

 

An overview of foraminiferal studies in nearshore regions off eastern coast of India, and Andaman and Nicobar Islands

N. Khare1*, S.K. Chaturvedi2 & A. Mazumder1

1 National Centre for Antarctic and Ocean Research, (Ministry of Earth Sciences),

Headland Sada, Vasco-da-Gama,Goa-403 804,  India

2 Shanmugha Arts, Science, Technology and Research Academy (SASTRA), SASTRA

University, Thanajavur-613 402, TN, India

*[E-mail: nkhare@ncaor.org ]

Foraminiferal studies carried out on beaches, mudflats, estuaries and in nearshore shallow water regions along eastern coast line of India up to 50 m water depth, including Andaman and Nicobar Islands, have been reviewed. The review suggests that as far as beaches, mudflats and estuaries of east coasts are concerned, a total of 34 papers have been published, whereas, 82 research papers have dealt with foraminifera of shallow water regions. The review also shows that majority of the studies undertaken along eastern Indian coast have concentrated on taxonomic and/or ecological aspects and very few attempts have been made for applied aspects of foraminiferal contents. A bibliographical account and themewise review of various past publications have also been provided in this paper.

       [Key words: Forminifera, east coast of India, Andaman Is, Nicobar Is, Overview, 

                           taxonomy, bibliographic review, Bay of Bengal ]

 

**************************

 

 

 

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.301-321

 

Appraisal of laboratory culture experiments on benthic foraminifera to assess/develop paleoceanographic proxies

V.N. Linshy1, S.S. Rana,1 S. Kurtarkar,1 R. Saraswat,2 & R. Nigam *1

1 Micropaleontology Laboratory, National Institute of Oceanography, CSIR,

        Dona Paula, Goa-403 004, India

2 Center for Advance Studies in Geology, Department of Geology,

        University of Delhi, Delhi- 110 007, India

[E-mail: nigam@nio.org ]*

The laboratory culture studies, carried out on benthic foraminifera, with the aim to refine paleoceanographic/paleoclimatic or environmental application of benthic foraminifera, have been reviewed. The review includes studies, which refined the understanding of factors that bring out changes in benthic foraminiferal abundance, morphology and chemical composition (of the test). Additionally, studies dealing with taxonomic aspects of benthic foraminifera have also been discussed, since such studies have significantly improved application of benthic foraminifera for stratigraphic correlation.

Most of the laboratory culture studies on benthic foraminifera in the early days were carried out to monitor the complete life-cycle of selected species. Such studies revealed presence of morphologically different stages in the life-cycle of single species. Thus the forms that were earlier recognized as different species were later on clubbed as developmental or ontogenetic stages of single species. Interesting relationship between mode of reproduction and coiling direction were also observed. Later on, with the growing application of foraminiferal characteristics for past climatic and oceanographic reconstruction, benthic foraminifera were maintained under controlled physico-chemical conditions in the laboratory. Such studies helped to refine the differences in the foraminiferal characteristics from physico-chemically different environments, as observed in the field. As it was proposed that the amount and type of food material is the major factor that controls the benthic foraminiferal population, numerous studies were carried out to assess the response of benthic foraminifera to different type and amount of food and oxygen concentration. Surprisingly limited laboratory culture studies have been carried out to understand the factors that govern the chemical composition of the benthic foraminiferal tests. It probably reflects the difficulties in simulating the conditions under which physico-chemical parameters can be kept constant throughout the experiment. Towards the end of 20th century application of molecular systematic analysis techniques on foraminifera started and such studies refined the evolutionary history and taxonomic position of foraminifera as well as helped recognize cryptic species. However, despite a large number of culture studies being carried out on benthic foraminifera with their paleoceanographic/paleoclimatic application in focus, still much more efforts are needed to understand the parameters affecting the benthic foraminiferal abundance, morphology and chemical composition.

[Key words: Foraminifera, paleoceanography, paleoclimate, laboratory culture]

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.322-331

 

Influence of monsoon upwelling on the planktonic foraminifera            off Oman during Late Quaternary

Pothuri Divakar Naidu

National Institute of Oceanography, CSIR, Dona Paula, Goa-403 004, India

[E-mail: divakar@nio.org ]

Planktonic foraminifer abundances, fluxes, test sizes, and coiling properties are influenced in various ways by the south-west monsoon winds and associated upwelling in the western Arabian Sea. The influence of monsoon driven upwelling on the planktonic foraminifer species abundances, coiling directions of Globigerinoides bulloides and Neogloboquadrina pachyderma and size variations of selected planktonic foraminifer species and carbon isotopic composition of Globigerina bulloides is summarized here.

[Key words: Indian Ocean, Arabian Sea, Oman margin, monsoon, upwelling, planktonic foraminifera]

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.332-341

 

Paleoceanographic evolution of the northeastern Indian Ocean during the Miocene: Evidence from deep-sea benthic foraminifera (DSDP Hole 216A)

Ajoy K. Bhaumik, Anil K. Gupta*, M. Sundar Raj, K. Mohan, Soma De & Sudipta Sarkar

Department of Geology and Geophysics, Indian Institute of Technology,

Kharagpur-721 302, India

*[E-mail: anilg@gg.iitkgp.ernet.in ]

Statistical analyses (factor and cluster) were performed on 30 highest ranked deep-sea benthic foraminifer species from >149 µm size fraction from Deep Sea Drilling Project Hole 216A to understand Miocene (~20.5 to ~7 Ma) paleoceanographic evolution of the northeastern Indian Ocean. Factor and cluster analyses enabled us to identify five biofacies defining five clusters. Known ecological preferences of benthic foraminifera were used for environmental interpretations. The faunal data documents a shift in deep-sea ventilation and productivity at 15-14 Ma, coinciding with the abrupt cooling in the middle Miocene. This coincides with the beginning of permanent ice sheets in Antarctica during the middle Miocene.

        [Key words: Benthic foraminifera, Indian Ocean, paleoceanography, Miocene]

 

************************

 

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.342-350

 

Surface circulation in the eastern Indian Ocean during last            5 million years: Planktic foraminiferal evidences

Devesh K. Sinha*

Center of Advanced Study in Geology, Delhi University, Delhi- 110007, India

and
Ashutosh Kumar Singh

Planetary and Geosciences Division, Physical Research Laboratory,

Ahmedabad-380 009, India

*[E-mail: devasinha@yahoo.com ]

The paper describes the major circulation changes in the eastern Indian Ocean during last 5 million years based on variation in planktic foraminiferal assemblages in various ODP and DSDP cores examined by various workers. The Late Miocene/Pliocene transition is characterized by weakening of the Leeuwin Current and migration of the polar front towards north. The early Pliocene is marked by closing of the Indonesian Seaway for surface waters and strengthening of the Leeuwin Current, a general warming of the surface waters and thickening of the mixed layer in the eastern Indian Ocean. The Late Pliocene and Pleistocene witnessed severe climatic fluctuations and episodic weakening and strengthening of the Leeuwin Current in response to either ENSO induced changes in the Western Pacific Warm Pool or lowering of sea level and reduction in Indonesian throughflow due to ice sheet expansion.

       [Key words: Planktic foraminifera, ocean circulation, Pliocene; Pleistocene, Indian  

                           Ocean, foraminiferal evidence, circulation, West Australian current, 

                           Indonesian seaway, Leeuwin current]

 

**************************

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.351-354

 

Symbiont-bearing benthic foraminifera of Lakshadweep

Pratul Kumar Saraswati*

Department of Earth Sciences, Indian Institute of Technology – Bombay, Powai,

Mumbai-400 076, India

(E-mail: pratul@iitb.ac.in)

Eleven genera of symbiont-bearing benthic foraminifera, also known as “larger benthic foraminifera”, are recorded from the lagoon waters of Lakshadweep. The assemblage is comparable to that of any other high diversity reef assemblages of the Indian and Pacific oceans and the diversity may even be higher if a detailed study of fore-reef areas is carried out. The potential of these foraminifera as proxy of sea-surface temperature and a tool to monitor the health of coral reefs need to be explored. Recent studies on stable isotopes and trace elements in some selected species of these foraminifera indicate their usefulness as proxy of sea surface temperature. The longer life spans and larger size of the symbiont-bearing species are advantageous to assess their potential as geochemical proxies of palaeoenvironment. The lagoons of Lakshadweep provide natural laboratory for the same and a major initiative is required in this direction.

      [Key words: Foraminifera, symbiosis, Indian Ocean, stable isotopes, trace elements,                

                        Lakshadweep, benthic foraminifera]

 

***************

 

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.355-360

 

Relict benthic foraminifera in surface sediments off central east coast of India as indicator of sea level changes

Sanjay Singh Rana*, Rajiv Nigam & Rajani Panchang

Micropaleontology Laboratory, National Institute of Oceanography, CSIR, Dona Paula, Goa - 403 004, India

*[E-mail: sanjay@nio.org ]

An attempt has been made to reconstruct sea-level variations along the central east coast of India during the late Pleistocene and early Holocene. A total of 39 surface sediment samples collected from water depth range of 27 – 2,777 m were studied for foraminiferal content. The samples within the depth range of 36-110 m showed presence of relict foraminiferal tests along with recent foraminifers. The relict foraminiferal assemblage of Amphistegina, Operculina, Calcarina and Alveolinella in the selected surface samples is characteristic of coral reef environment and has been inferred as evidence for past low sea levels. Based on extrapolation of previously published radiocarbon dates from the region, we propose a pliable sea level curve for the period between ~9,000 to ~14,000 years BP.

         [Keywords: Sea level, Holocene, relict foraminifera, coral sclerites, coral reef]

 

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.361-368

 

Neogene oceanographic and climatic changes in the northern Indian Ocean: Evidence from Radiolaria

*V. Sharma & L. Bhagyapati Devi

Department of Geology, University of Delhi, Delhi-110007, India

*[E-mail: vsharma752004@yahoo.co.in ]

Neogene is one of the important periods in the earth’s history in view of significant changes that took place during the period in climatic and oceanographic conditions. Radiolarians from well preserved cores, uplifted marine sequences, and surface sediments from the northern Indian Ocean provided opportunity to reconstruct the Neogene oceanographic and climatic events. Studies based on radiolarians from land-based sections revealed episodes of cooling and warming in the late Early Miocene to Middle Miocene. Investigations of radiolarian upwelling fauna in the cores from the western Arabian sea demonstrated strengthening and weakening of upwelling during late Middle Miocene to Recent. Examination of radiolarians from surface sediments suggested presence of Antarctic Bottom water in the Mozambique and Madagascar basins of the western Indian Ocean. Certain radiolarian species are found useful in understanding paleomonsoonal changes and have been used to interpret such changes.

[Key words: Radiolaria, Indian Ocean, Neogene, paleoceanography, paleoclimate, climatic changes, oceanographic changes, biochronology, circulation, upwelling, paleotemperature, monsoonal changes]

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.369-377

 

Distribution of Ostracoda in marine and marginal marine habitats off Tamil Nadu and adjoining areas, southern east coast of India and Andaman Islands: Environmental implications

*S.M. Hussain, P. Ganesan, G. Ravi, S.P. Mohan  &  #S.G.D. Sridhar

*Department of Geology and #Department of Applied Geology, School of Earth and Atmospheric Scineces, University of Madras, Guindy Campus,

Chennai-600 025, India

*[E-mail: smhussain7@hotmail.com ]

Ostracods successfully inhabit almost all types of aquatic environment, from deep oceans to brackish water lagoons, estuaries and even freshwater streams, lakes, etc. The major controlling factors governing ostracod population and distribution in estuarine environments and continental shelf zones are water temperature, salinity and substrate. In this paper, the distribution and ecology of marine ostracoda in relation to the environmental parameters such as temperature, salinity, dissolved oxygen of the bottom waters, organic matter, and CaCO3, along with the sand-silt-clay ratio of sediments from the inner shelf sediment region off Karikkattukuppam (near Chennai), off Rameswaram, off Tuticorn and Andaman Islands is discussed. Additionally, similar studies on the brackish water ostracods from the Adyar estuary, Pitchavaram mangroves and Tamiraparani estuary have also been presented. The work pertaining to the statistical parameters of ostracoda such as carapace/valve ratio, ornamentation and grain size to infer the environment of the study area, from the Indian region is also discussed.

       [Key words: Ostracoda, Tamilnadu coast, Andaman Islands, ecology, environmental 

                           implications]

******************

Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.378-383

 

Episodic preservation of pteropods in the eastern Arabian Sea: Monsoonal change, oxygen minimum zone intensity and               aragonite compensation depth

A. D. Singh

Department of Geology, Banaras Hindu University, Varanasi-221 005, UP, India

[E-mail: arundeosingh@yahoo.com  ]

The preservational record of pteropod shells (aragonite) for the last 30 kyr has been studied in a core (SK17) recovered from the eastern Arabian Sea margin at off Goa coast (depth 840m, lat. 15°15’N, long. 72°44’E). The chronostratigraphy of the core established on the basis of high resolution stable isotope record of a planktic foraminifera (Globigerinoides ruber) and several AMS radiocarbon ages demonstrates millennial scale variation in d 18O defining Younger Dryas and Heinrich like Events. Records of absolute abundance of pteropods (1g/dry wt >125 mm), abundance ratio of pteropod and planktic foraminifera, aragonite (wt %), organic carbon (OC) (wt %) and CaCO3 (wt %) show major changes during these isotopic events. Aragonite maxima and higher number of well-preserved pteropod shells, are noticed during cold stadial periods. The study indicates a negative correlation between aragonite and OC % (productivity index). On the other hand, total CaCO3 content (calcite and aragonite) is positively correlated with the aragonite. The variation patterns of pteropod shells and aragonite content in the sediment core are suggested to be controlled by the preservational conditions associated with the fluctuation in Aragonite Compensation Depth (ACD) and Oxygen Minimum Zone (OMZ) intensity. It is suggested that the high biological productivity during intensified summer monsoons in late Holocene and inter-stadial periods might have resulted in severe oxygen depletion (strong OMZ) leading to shallowing of the ACD. A weak summer monsoon and low productivity condition prevailing during cold stadial periods would have resulted in a weak OMZ and deepening of the ACD.

      [Key words: Pteropods, OMZ, aragonite compensation depth, Arabian Sea, monsoonal 

                        change, preservational records, foraminifera, chronostratigraphy, 

                         planktic foraminifera, sediment core, gravity core]

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.384-398

 

A review of the studies on pteropods from the northern Indian Ocean region with a report on the pteropods of Irrawaddy continental shelf off Myanmar (Burma)

Rajani Panchang1*, Rajiv Nigam1, Frank Riedel2, Arie W. Janssen3† & U Ko Yi Hla4

   1Micropalaeontology Lab, Geological Oceanography Division,  National Institute of 

             Oceanography, CSIR, Dona Paula, Goa-403 004, India

    2Interdisciplinary Centre for Ecosystem Dynamics in Central Asia, Geology Department,  

             Branch Paleontology, Malteserstrasse 74-100, Haus D, D-12249, Berlin, Germany

    3National Museum of Natural History (Palaeontology Department), P.O. Box 9517,

             NL 2300 RA Leiden, The Netherlands

     4Deaprtment of Geology, University of Mawlamyine, Mawlamyine 12012, Myanmar

       *[E-mail: prajani@nio.org ]

 

Ever since the Challenger Expedition the Indian Ocean pteropods have been recognized as important constituents of biogenic flux. Initially they were of interest only to biologists or the fishery departments and their distribution was studied only in plankton tow samples. Over the past three decades micropalaeontologists have paid attention to investigate pteropods from water and sediment samples to understand their distribution and ecological significance. Since then substantial work has been reported in the Gulf of Aqaba, Red Sea, northern Arabian Sea, along west coast of India and around the Andaman Nicobar Archipelago. Work has neither been attempted in the Bay of Bengal nor in the northern Andaman Sea. These aragonitic microfossils have proved to be reliable indicators of bathymetry, productivity, upwelling, current circulation, intensity of Aragonite Compensation Depths, Oxygen Minimum Zone and monsoons, thus very useful in palaeoclimatic reconstructions. Works on its counterparts such as foraminifers and ostracods have been reviewed earlier and this is the first time a review of the pteropod studies in the northern Indian Ocean is being attempted, in view of the vast data generated in this region. The pteropod assemblages from two cores collected on the Irrawaddy continental shelf, in the northern Andaman Sea is also reported for the first time. The downcore distribution of pteropods suggests that no significant sea level change has occurred over the past ~1280 Cal yrs.

       [Key words: Pteropods, Indian Ocean, aragonite compensation depth, oxygen minimum 

                          zone, Irrawaddy continental shelf, Myanmar, Burma]

 

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Indian Journal of Marine Sciences

Vol. 36(4), December 2007, pp.399-406

 

Organic matter distribution pattern in Arabian Sea: Palynofacies analysis from the surface sediments off Karwar coast                           (west coast of India)

Vandana Prasad*, Rahul Garg, Vartika Singh & Biswajit Thakur

Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow-226 007, India

[*E-mail- vanprasad@yahoo.co.uk ]

Central Arabian Sea region, situated off the Karwar coast, is characterized by intense mid depth (~120-1200 m) oxygen minima zone and shows preservation and accumulation of relatively high organic matter content. Palynofacies analysis was carried out with a view to understand the organic matter production, preservation and degradation in the surface sediments of Arabian Sea from 15 m-2750 m depth off Karwar [14.47-14.40° N -70.77-74.25° E transect]. Palynofacies analysis, which involves qualitative and quantitative estimation of terrestrial and marine organic matter is a useful tool to decipher and assess paleoenvironmental changes in various water depth zones from shelf-slope region off the Karwar coast. There is a marked change in the palynofacies characteristics of the organic matter recovered from various depth zones. High SW monsoonal activity over Karwar coast results in increased runoff and nutrient loading in the coastal waters. This enhances primary productivity in the inner shelf region. Organic walled dinoflagellate cysts as important constituent of primary productivity, predominate under such conditions, being converted into Amorphous organic matter (AOM) as a result of degradation under low oxygen environment. Hence, in the present study high AOM is used as proxy for the low oxygen content at sediment-water interface. It also provides evidence of high primary productivity in the photic zone. Study further reveals that terrestrially derived charcoal and woody plant tissue resistant to degradation, are transported to continental slope regions at greater depths. Occurrence of a large proportion of well preserved labile organic matter (exoskeleton fragments of planktonic crustaceans) and AOM in the mid-outer slope surface sediments indicate enhanced primary productivity and high rate of burial efficiency making these areas, characteristic of low oxygen. The study shows that the Karwar coast margin is highly productive as a result of runoff related nutrient loading and is the primary cause for oxygen minima conditions.

[Key words: Palynofacies, primary productivity, oxygen minima zone, Karwar coast, Arabian Sea, west coast of India,          organic matter, sediments, amorphous organic matter]

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Acknowledgement  to  Referees [ 2007 ]

 

 

  The Publisher and Editor of the Indian Journal of Marine Sciences (IJMS) are most grateful to the experts given below, in assisting the peer-review process of the journal. The referees have spared some of their valued time on critically reviewing the research papers submitted to IJMS during the year 2007. Their kind cooperation in critical reviewing, at times re-reviewing, is highly appreciated, which has immensely helped in maintaining the quality of the papers published in IJMS. We are thankful to them for their continuing efforts.

 


Anil A C, Goa, India

Bhadury Punyasloke, Princetorn, USA

Bonilla Sylvia, Montevideo, Uruguay

Boufadel M C, Philadelphia, USA

Bruni Vivia, Messina, Italy

Bull Alan T, Canterbury, UK

Chauhan Prakash, Ahmedabad, India

Cutting Simon M, Egham, UK

Davis Jana,Annapolis, USA

DileepKumar M, Goa,India

Duan Delin, Qingdao, PR China

El-Sabbagh Nasser, Glasgow, UK

Fernandes Lissette, Goa,India

Giordano Mario, Ancona, Italy

Holmes Mary, Newton Park, UK

Hu Qiao, Woods Hole, USA

Kagami Yayoi, Chiba, Japan

Kannan Seralathan K,Jeonju, South Korea

Kaplan Issac, Seattle, USA

Kim Gwang Hoon, Kongju, Korea

Leonardos Nilos, Colchester, UK

Levin R E, Amerhest, USA

Li Z, Shanghai, PR China

Livi Silvia, Rome, Italy

Lyard Florent, Toulouse, France

Montes-Hugo Martin A, La Jolla, USA

Moore A B, Dunedin, New Zealand

Mourre Baptiste, Barcelona, Spain

Mueller W E G,Mainz, Germany

Nair Shanta, Goa, India

Naithani Jaya, Louvain-la-Neuve,Belgium

Newman David J, Frederick, USA

Parameswaran P S, Goa, India

Pavasant Prasert, Bangkok, Thailand

Plaganyi-Lloyd Eva, Rondebosch, South Africa

PrasannaKumar S., Goa, India

Pugnetti Alessandra, Venezia, Italy

Ramaiah N, Goa,India

Ramprasad T, Goa, India

Reddy C R K, Bhavnagar,India

Rye Henrik, Trondhiem, Norway

Sarkar S K, Calcutta, India

Sarma Nittala S, Visakhapatnam, India

Selvin Joseph, Tiruchinapalli, India

SethuRaman, Raleigh, USA

Shao K T,Taipei, Taiwan

Shindo Katzutoshi, Tokyo, Japan

Siddhanta A K, Bhavnagar, India

Singh O P, New Delhi, India

Song Jinming, Qingdao, PR China

Spatharis Sofie, Athens, Greece

Subba Rao T, Kalpakkam, India

Unnikrishnan A S, Goa, India

Venkata Mohan S,Hyderabad, India

Vinayachandran P N,Bangalore, India

Yamagishi Takahiro, Kobe, Japan

Yamazaki Jun-ya, Chiba, Japan