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CHEMICAL EVAL OF SELECTED ORGANICS AND TRACE METALS IN THE MANGROVE MACROFLORA OF COCHIN A thesis submitted to Cochin University of Science and Technology In partial fulfillment of the requirements for the degree of Philosophiae Doctor in Environmental Chemistry Under the faculty of Marine Sciences By GEETHA ANDREWS DEPARTMENT OF CHEMICAL OCEANOGRAPHY SCHOOL OF MARINE SCIENCES COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY KOCHI- 682016 July 2010 Dedicated to my beloved parents Prof (Mrs) and Mr. E.S. Andrews Certificate This is to certifiz that this thesis entitled Chemical Evaluation of Selected Organics and Trace Metals in the Mangrove Macroflora Of Cochin is a bonafide record of the research work carried out by Smt. Geetha Andrews under my supervision and guidance in the Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology, in partial fulfillment of the requirements for the degree of Philosophiae Doctor of the Cochin University of Science and Technology and no part thereof has been presented before for any other degree, diploma, associateship, fellowship or any other similar title or recognition. %<>’fv///ale//Ce <br:ra:65f1E'cEsr July,Kochi-16 2010 Supervising Guide Declaration I hereby declare that this thesis entitled Chemical Evaluation of Selected Organics and Trace Metals in the Mangrove Macroflora Of Cochin is an authentic record of the research work carried out by me under the supervision of Dr. Jacob Chacko, Professor, Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology, in partial fulfillment of the requirements for the Ph.D degree of the Cochin University of Science and Technology and no part of it has previously formed the basis for the award of any degree, diploma, associateship, fellowship or any other similar title or recognition in any University. July,Kochi-16 2010esearch Scholar) 5tha Andrews waJ Acknowledgments T o begin with, I humbly bow my head before the Almighty for giving me the grace to complete the research work against all odds. I remember with gratitude the encouragement, support, timely guidance and constructive suggestions rendered by my esteemed guide Dr. Jacob Chacko, Professor, Department of Chemical Oceanography, Cochin University of Science and Technology. My thanks are also to Dr. N. Chandramohanakumar, Registrar and Head of the department of Chemical Oceanography, CUSAT, for providing me with the necessary facilities to carry out my research work. My heartfelt gratitude to Rev. Sr. Tessa CSST, former Principal of St. Teresa ’s College Ernakulam, who encouraged me to take up research and permitted me to avail the FIP fellowship of UGC, to pursue my research. I am deeply indebted to Rev. Sr. Christabelle, CSST, Principal, St. Teresa ’s College Ernakulam, for her constant support and encouragement, which played a valuable role in making my thesis work a reality. My thanks are also due to Dr.Muraleedharan Nair and Dr. C.H. Sujatha, faculty members of the Department of Chemical Oceanography, CUSAT as well as to Dr. K.J. Joseph, retired Professor, Dept. of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, CUSAT and all the research scholars of the department of Chemical Oceanography for their help during my research work. I am also grateful to Dr. Jeevanadan, Reader, Department of Statistics, U.C. College, Alwaye and Mr. MC. Jose, Lecturer, Department of Statistics, S.B. College Changanassery, for helping me with the statistical analysis. Words fail me when I try to express my feelings of gratitude to my beloved parents, my husband Simon, my children Anjali and Antony and all other members of my family, who stood by me during the difficult period of my research work. It was their love and innumerable sacrifices that fuelled my journey through the research world. I wind up by acknowledging the encouragement given by my dear fiiends and colleagues at St. Teresa's College Ernakulam, which propelled me forward and played a catalytic role in the successful completion of my research work. Geetha Andrews Contents Chapter I: The Legacy of Mangroves Page No 1.1. 1 Introduction 1.1.2 Flora and fauna of mangrove ecosystems 1.1.3 Ecological role of mangroves 01 CA)-5 1.1.4 Traditional and commercial uses of mangroves 1.2.1 Distribution of Mangroves-a world profile 1.2.2 Mangroves of India 10 1.2. 3 Mangroves of Kerala 12 1.3 .1 Major threats to mangrove ecosystems 13 1.3.2 Conservation of mangroves 15 1.4.1 Metal pollution in inter- tidal sediments 16 1.4.2 Uptake of metals by mangrove flora and fauna 19 1.5 Significance of the study 22 References 25 Chapter II: Study Sites, Materials and Methods 2.1 The Cochin Estuary 34 2. 2 Sampling Sites 35 2.3 Materials and Methods 40 2.3.1 Sampling Procedures 40 2.3.2 Analytical Techniques 40 2.3.2.1 Hydrography 40 2.3.2.2 Sediment Analysis 43 2.3.2.3 Mangrove Plant Part analysis 45 References 48 Chapter III-Hydrography of Mangroves 3.1 Introduction 50 3.2 pH 52 3.3 Salinity 55 3.4 Dissolved Oxygen 57 3.5 Nutrients 60 3.5.1 Dissolved Ammonium 62 3.5.2 Dissolved Nitrite 64 3.5.3 Dissolved Inorganic Phosphate 67 3.6 Hydrogen Sulphide 70 3.7 Alkalinity 74 3.8 Conclusion 77 References 80 Data and Graphs 91 Chapter IV-Sediment Chemistry 4.1 Mangrove sediments — an over view 121 4.2. Total Organic Carbon 124 4.3 Tannins and Lignin 128 4.4 Exchangeable ammonium 134 4.5. Proteins 139 4.6 Trace metals 142 4.6.1 Iron 146 4.6.2 Manganese 151 4.6.3 Zinc 154 4.6.4 Nickel 157 4.6.5 Lead 160 4.6.6 Copper 164 4.6.7 Cadmium 167 Conclusion 171 References 173 Data and Graphs 187 Chapter V- Mangrove Plant Chemistry 5.1 Introduction 219 5.2 Moisture 221 5.3 Organic Carbon 224 5.4 Proteins 228 5.5 Metals in mangrove plants 233 5.5.1 Iron 238 5. 5. 2 Manganese 243 5. 5. 3 Zinc 246 5.5.4 Nickel 252 5.5.5 Lead 256 5.5.6 Copper 261 5.5.7 Cadmium 267 5.6 Tannin and Lignin in leaves 272 5.7 Chloride content of leaves 276 Conclusion 280 References 281 Data and Graphs 297 Chapter I The Legacy Of Mangrove Ecosystems 1.1.1 Introduction Mangrove ecosystems are near shore marine habitats formed by a very special association of flora and fauna that live in the inter tidal areas of low lying tropical and subtropical regions. They are one of the most threatened ecosystems of the world, with climate change playing a prominent role in their survival (Eric et al, 2008). The earliest known references on mangroves are found in an inscription from the time of the Egyption King Assa between 3580­ 3536 B.C. The mangrove ecosystem serves as a transient zone between land and ocean (Wattayakorn, 2000). They are highly productive and auto tropic in nature, as all nutrients such as C, N, H20 and 02 are cycled in this ecosystem. Nitrogen turnover is found to be very large indicating an active coupling between production and decomposition processes in the ecosystem (Alongi,2004). They also act as a filter for the exchange of suspended particles, nutrients and pollutants between the land and ocean and modify solutes and particulates by physical, chemical and biological processes (Pinsak and Erik, 2002). Tidal exchange and deposition of fine particles are the most determining factors for the existence and distribution of the mangroves (Alongi, 2002). Closely related and complex physical, chemical and biological processes are involved in the formation and maintenance of the mangrove ecosystem. Soil characteristics such as siltiness, electrical conductivity, pH, cation exchange capacity as well as nutrients have a major influence on mangrove growth. Mangroves show salt tolerance, but it varies among different species. Extremely high salinity is always detrimental to mangroves. Similarly, sedimentation rates also play an important role because, as the sediment grain size varies, changes in sediment food quality, faunal movement etc tend to vary with sedimentation, affecting the ecosystem. The mangrove ecosystem is a fragile one and a slight disturbance in any one of the above mentioned parameters is sufficient to effect a disturbance. Mangrove forests (Alongi, 2002) comprise of trees, shrubs, palms, epiphytes, ground ferns and grasses. The ecosystem is also rich in algae, fungi, bacteria, as well as phytoplankton, of which diatoms such as coscinodiscus, bidduIphia,etc are the dominant ones. The zoo plankton population varies from protozoa to eggs. They are also breeding grounds for various types of birds, reptiles, mammals and fishes. It is well known that mangrove sediments are under permanent reducing conditions due to water logging, has high concentrations of organic matter and significant presence of sulphate reducing bacteria. Mangrove waters may contain pollutants like pesticides, fertilizers, untreated domestic sewage and industrial waste as well as chemicals like tannic acid and flavanoids. Thus they act as sinks for anthropogenic contaminants (Machado et al, 2002). Mangrove ecosystems have served as the life-blood to societies that depend on them for their livelihood, by providing resources that sustain them and also by promoting various economic activities. Apart from resources such as fishing, they support agriculture, herding of domestic livestock and hunting of wild herbivores migrating in response to flooding pattern. Human activities hundreds of kilometers inland such as digging of canals, diversion of water flows, construction of roads, dredging and filling, etc greatly modify mangrove wet land conditions by changing ground water flow and modifying salinity levels. Over the recent past, the mangrove ecosystems are threatened owing to the pressures of unplanned urbanization and land use pattern for alternative agricultural practices.

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