Ecology of Chaetognaths in the Indian EEZ
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Ecology of Chaetognaths in the Indian EEZ Thesis submitted to the COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY In partial fulfillment of the degree of DOCTOR OF PHILOSOPHY IN MARINE SCIENCE UNDER THE FACULTY OF MARINE SCIENCES by Kusum Komal Karati, M. Sc. NATIONAL INSTITUTE OF OCEANOGRAPHY Regional Centre, Cochin - 18 - June 2012 Declaration I here by declare that the thesis entitled “ECOLOGY OF CHAETOGNATHS IN THE INDIAN EEZ” submitted by me is an authentic record of research carried out by me, under the supervision of Dr. T.V. Raveendran, Senior Principal Scientist, National Institute of Oceanography, Regional Centre, Cochin -18, in partial fulfillment of the requirement for the Ph. D degree of the Cochin University of Science and Technology in Marine Science and that no part of this thesis has been presented before for any other degree, diploma, or associateship in any university. Kochi 20-6-2012 (Kusum Komal Karati) Certificate I hereby certify that the thesis entitled “ECOLOGY OF CHAETOGNATHS IN THE INDIAN EEZ” submitted by Kusum Komal Karati, Research Scholar (Reg.No. 3787), National Institute of Oceanography, Regional Centre, Cochin-18, is an authentic record of research carried out by him, under my supervision in partial fulfillment of the requirement for the Ph. D degree of Cochin University of Science and Technology in Marine Science and that no part of this thesis has previously formed the basis for the award of any degree, diploma, or associateship in any university. Dr. T.V. Raveendran Kochi -18 Supervising Guide, 20-06-2012 Senior Principal Scientist National Institute of Oceanography Regional Centre, Cochin- 18 Acknowledgement I am deeply indebted to my guide, Dr. T.V. Raveendran, Senior Principal Scientist, National Institute of Oceanography, Regional Centre, Cochin, for the guidance, encouragement and support, which enabled me to complete the thesis. I express my sincere gratitude to Dr. S.R. Shetye, Director, National Institute of Oceanography, India and Dr. P.S. Parameswaran, Scientist-in-Charge, National Institute of Oceanography, Regional Centre, Cochin, for their support and also for providing the facilities needed for the study. My heartfelt thanks to Dr. C.T. Achuthankutty, former Scientist- in -Charge, National Institute of Oceanography, Regional Centre, Cochin and Dr. P.K. Dinesh Kumar, Senior Principal Scientist, NIO, RC, Cochin, for the valuable advice, moral support and blessings extended towards me. I am also grateful to Dr. V.N. Sanjeevan, Director, Centre for Marine Living Resources and Ecology (formerly Department of Ocean Development), Kochi, for giving me an opportunity to work under the National Research Program “Marine Research - Living Resource Assessment (MR-LR)” in the Indian EEZ and also for FORV Sagar Sampada utilizing the facilities of the research vessel , during various oceanographic research cruises. I am greatly indebted to Council of Scientific and Industrial Senior Research Fellowship Research, New Delhi, for the award of during the tenure of this work. I express my sincere gratitude to Dr. K.K.C. Nair and Dr. N. Bahulayan, former Scientist- in –Charge for the support and encouragement. I express my thanks to Dr. K.V. Jayalakshmi, Senior Principal Scientist, National Institute of Oceanography, Regional Centre, Cochin for her valuable help in the statistical analysis. The timely help rendered by Dr. C. Revichandran, Dr. N.V. Madhu, Dr. R. Jyothibabu, Mr. K.R. Muraleedharan, and Ms. C.K Haridevi, Scientists, National Institute of Oceanography, Regional Centre, Cochin is also greatly acknowledged. I also extend my sincere thanks to Dr. K.K. Balachandran, Senior Technical Officer, National Institute of Oceanography, Regional Centre, Cochin, for giving me positive energy in my work and thoughts. My gratitude to Dr. M. Nair, Senior Technical Officer, and Mr. K.E. Thampi, Librarian, National Institute of Oceanography, Regional Centre, Cochin for their encouragement. I express my sincere gratitude to Dr. Vijayalakshmi. R. Nair, former Deputy Director, National Institute of Oceanography, Regional Centre, Mumbai, for the guidance and scientific help in the field of taxonomy. Sincere thanks to MRLR 2nd phase NIO colleagues specially Dr. P.K. Karuppasammy, Dr. P. Jasmine, Dr. K. J. Jayalakshmi, Dr. A. Biju, Dr. Habeebrehman, Ms. C.R. Ashadevi, and Ms. G. Sumitha for the support and encouragement during the study. The work would not have been completed without the sincere support of my wife, Vineetha Gopinath, who helped me in each and every step of this work. I express my thanks to all the administrative staff and research fellows of National Institute of Oceanography, Regional Centre, Cochin, especially my biological oceanography lab mates, P.D. Reny, N. Ullas, Ms. V.P. Pravitha, T.V. Rehitha, P. Meenu, R. Ashwini and R. Rakhi for their direct or indirect help extended towards me during the period of study. Last but not the least I thank each and every person who has helped me in completing this thesis in time. Most importantly, I thank Almighty God for His blessings throughout my life that has enabled me to fulfill this accomplishment. Dedicated to my parents List of acronyms and abbreviations AS Arabian Sea ASHSW Arabian Sea High Salinity Water Mass BoB Bay of Bengal BoBPS Bay of Bengal Process Studies BT Base of the Thermocline cm Centimetre CTD Conductivity Temperature Depth DH Depth of Haul DO Dissolved Oxygen DV Displacement Volume E East e.g. exempli gratia (Latin word, meaning ‘for example’) etc. et cetera (Latin word, meaning ‘and other similar things’) EEZ Exclusive Economic Zone EICC East India Coastal Current et al. et alii (Latin word, meaning ‘and others’) Fig. Figure FIM Fall Inter Monsoon FORV Fisheries and Oceanographic Research Vessel GFO Geosat Follow-On GISST Global Sea Ice Sea Surface Temperature i.e. id est (Latin word, meaning ‘that is’) ICOADS International Comprehensive Ocean Atmospheric Data Set IIOE International Indian Ocean Expedition JGOFS Joint Global Ocean Flux Studies LL Lakshadweep Low M metre MLD Mixed Layer Depth ml millilitre mm millimetre MPN Multiple Plankton Net N North ODW Oxygen Depleted Water OMZ Oxygen Minimum Zone PCA Principal Component Analysis RV Research Vessel S South SM Summer Monsoon Sp. species SW South West SSS Sea surface salinity SST Sea Surface Temperature TC Thermocline VWF Volume of Water Filtered Viz videlicet (Latin word, meaning ‘namely’ or ‘that is to say’) W West WICC West India Coastal Current WM Winter Monsoon µm micro meter Contents Chapter 1: Introduction 1-27 1.1. Ecological groups of zooplankton 3 1.2. Chaetognath, a carnivorous zooplankton 5 1.3. General biology of chaetognath 7 1.3.1. Distribution 1.3.2. Morphology 1.3.3. Food and feeding 1.3.4. Breeding 1.4. Historical resume 15 1.5. Classification 17 1.6. Review of literature on Indian Ocean chaetognaths 19 1.7. Scope and purpose of study 24 Chapter 2: Study area 28-36 2.1. Arabian Sea 30 2.2. Bay of Bengal 33 2.3. Summary 35 Chapter 3: Materials and methods 37-49 3.1. Sampling 37 3.2. Physico-chemical variables 38 3.3. Biological variables 39 3.3.1. General zooplankton 3.3.2. Chaetognath 3.4. Long term monitoring of chaetognaths 43 3.5. Statistical analysis 44 3.5.1. Diversity indices 3.5.2. Cluster analysis 3.5.3. Principal component analysis 3.5.4. Mann-Whitney test 3.5.5. Wilcoxon matched pair test Chapter 4: Results – Physico-chemical features 50-76 4.1. Physical features 50 4.1.1. Arabian Sea 4.1.2. Bay of Bengal 4.2. Chemical feature 57 4.2.1. Arabian Sea 4.2.2. Bay of Bengal 4.3. Statistical analysis 61 4.4. Summary 61 Chapter 5: Results – Biological environment 77-103 5.1. Summer monsoon 77 5.1.1. Zooplankton biomass and abundance 5.1.2. Major groups of zooplankton 5.1.3. Contribution of chaetognath 5.1.4. Trophic relationship 5.2. Fall inter monsoon 80 5.2.1. Zooplankton biomass and abundance 5.2.2. Major groups of zooplankton 5.2.3. Contribution of chaetognath 5.2.4. Trophic relationship 5.3. Winter monsoon 83 5.3.1. Zooplankton biomass 5.3.2. Major groups of zooplankton 5.3.3. Contribution of chaetognath 5.3.4. Trophic relationship 5.4. Statistical analysis 86 5.5. Summary 86 Chapter 6: Results - Chaetognath distribution and ecology 104-162 6.1. Arabian Sea 104 6.1.1. Summer monsoon 6.1.2. Fall inter monsoon 6.1.3. Winter monsoon 6.1.4. Diel vertical migration 6.1.5. Temporal variation 6.2. Bay of Bengal 114 6.2.1. Summer monsoon 6.2.2 . Fall inter monsoon 6.2.3. Winter monsoon 6.2.4. Diel vertical migration 6.2.5. Temporal variation 6.3 Statistical analysis 123 6.4. Summary 126 Chapter 7: Long term monitoring 163-169 7.1. Physico-chemical variables 163 7.2. Long term changes in abundance 164 7.3. Summary 165 Chapter 8: Discussion 170 Chapter 9: Summary and Conclusion 195 References 206 List of Figures Page Fig. 1 A typical chaetognath (adapted from Hyman, 1959 and Nair, 27 2003). Fig. 2 Sampling locations in the Indian Exclusive Economic Zone. 36 Fig. 3 Vertical distribution of temperature (°C), along different 63 latitudinal transect in the upper 1000 m of the Arabian Sea during summer monsoon. Fig. 4 Vertical distribution of salinity, along different latitudinal 64 transect in the upper 1000 m of the Arabian Sea during summer monsoon. Fig. 5 Vertical profiles of the physicochemical variables, in the upper 64 1000 m of the Arabian Sea during summer monsoon. Fig. 6 Vertical distribution of temperature (°C), along different 65 latitudinal transect in the upper 1000 m of the Arabian Sea during fall inter monsoon. Fig.