• Abstract and Figures
• Public Full-text

Old Dominion University ODU Digital Commons OES Theses and Dissertations Ocean & Earth Sciences Winter 1998 Non-Volatile Dissolved Organic Iodine in Marine Water Xianhao Cheng Old Dominion University Follow this and additional works at: https://digitalcommons.odu.edu/oeas_etds Part of the Ecology and Evolutionary Biology Commons, Fresh Water Studies Commons, and the Oceanography Commons Recommended Citation Cheng, Xianhao. "Non-Volatile Dissolved Organic Iodine in Marine Water" (1998). Doctor of Philosophy (PhD), Dissertation, Ocean & Earth Sciences, Old Dominion University, DOI: 10.25777/q3m1-b335 https://digitalcommons.odu.edu/oeas_etds/124 This Dissertation is brought to you for free and open access by the Ocean & Earth Sciences at ODU Digital Commons. It has been accepted for inclusion in OES Theses and Dissertations by an authorized administrator of ODU Digital Commons. For more information, please contact [email protected]. NON-VOLATILE DISSOLVED ORGANIC IODINE IN MARINE WATER by Xianhao Cheng B.S. January 1982, Zhejiang University, P.R. China A Dissertation Submitted to the Faculty of Old Dominion University in Partial Fulfillment of the Requirement for the Degree of DOCTOR OF PHILOSOPHY OCEANOGRAPHY OLD DOMINION UNIVERSITY December 1998 Approved by: G M g j e T . F~. Wong ^Director) William M. Diurfstan (Member) Donat (Member) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT NON-VOLATILE DISSOLVED ORGANIC IODINE IN MARINE WATER Xianhao Cheng Old Dominion University, 199 8 Director: Dr. George T. F. Wong An analytical scheme for the determination of marine DOI has been established. The concentration of DOI is estimated as total iodine (TI) minus total inorganic iodine (TII). The concentration of total iodine is determined as 10'. after DOI has been oxidized to inorganic iodine quantitatively by intensive UV-irradiation and all the inorganic iodine in the samples had been converted to 10'. by the addition of NaCIO. Production of DOI in seawater can be via both non­ phytoplankton and phytoplankton related processes. In the former, iodide is converted to DOI. In the latter, most likely, iodate is converted to DOI. Naturally occurring phytoplankton in shelf break water contribute more to the production of DOI than that in the open ocean. DOI can be rapidly decomposed when exposed to sunlight. The half life of the photolysis was only on the order of hours. The product of the photolysis is iodide, while iodate concentration remains constant. In a sample, at least 70% of DOI can be decomposed by UV-A to visible light. In the stratified water column of the Chesapeake bay, high concentrations of DOI could only be found in the surface mixing layer. While normalized total inorganic iodine appeared Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. depleted in surface water, normalized total iodine had little change in the water column. A box model calculation for the Chesapeake Bay water column demonstrates that iodate in the incoming open ocean water is the major source of DOI in the estuary. In the slightly stratified James River estuary, DOI was the dominant species of iodine, where iodate was absent below the salinity of 15. From the riverine input (0.0) to the Chesapeake Bay mouth (18.6), total iodine displayed a linear relationship with salinity. Thus, iodine behaved conservatively in the investigated environment. Instead of the removal or addition of iodine from solid phase, it was the species conversion among the dissolved forms which led to more or less non-conservative behavior of the individual species. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGMENTS I would like to express my sincerest thanks to Dr.Wong, for giving me the opportunity to come to ODU, and for his guidance, support and necessary push to complete this study; Drs. William M. Dunstan and John R. Donat, my committee members, for their encouragement, significant comments and suggestions for improvement of this work. Sincere thanks also to Claudette Lajoi for her work in phytoplankton incubation, Li Zhang for the determination of sulfide concentration and Lisa Drake for the correction of my English. Sincere thanks also to R. C. Kidd and R. Bray who assisted in field sampling. The convenience and assistance provided by the administrative staff, Dana Oblak and Holly Park is also greatly appreciated. I am deeply grateful to all my friends at the Oceanographic Department. I am especially indebted to Yong Zhang, Shi-Jun Fan, Ching-chang Hung, Shi-long Zheng, Rob Ellison, and to all my other friends both in the Oceanography Department and around this area for their friendship and help. Financial support for this research and tuition provided by the grant from NSF to Dr. George Wong and by the Department of Oceanography are gratefully acknowledged. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. V TABLE OP CONTENTS Page LIST OF TABLES........................................... viii LIST OF FIGURES............................................. x Chapter I. INTRODUCTION....................................... 1 INTRODUCTION....................................... 1 QUESTIONS AND APPROACHES.......................... 4 A BRIEF REVIEW OF THE MOST RELEVANT PREVIOUS WORKS.............................................. 7 II. DETERMINATION AND ANALYTICAL IMPLICATION OF MARINE DISSOLVED ORGANIC IODINE............... 23 INTRODUCTION...................................... 23 EXPERIMENTAL...................................... 24 RESULTS AND DISCUSSION............................26 Optimization of the UV System................. 26 Determination of Total Iodine for the Estimation of DOI ..............................30 Analytical Implications....................... 34 CONCLUSIONS....................................... 47 III. THE EFFECT OF SAMPLE PREANALYSIS HANDLING ON THE DETERMINATION OF IODINE SPECIES........... 48 INTRODUCTION...................................... 48 MATERIAL AND METHODS..............................49 RESULTS AND DISCUSSION............................50 The Effect of Filtration....................... 50 The Effect of Storage Time and Containers 53 The Effect of Temperature...................... 56 CONCLUSIONS....................................... 58 IV. THE PRODUCTION OF DISSOLVED ORGANIC IODINE IN MARINE WATER................................... 59 INTRODUCTION...................................... 59 EXPERIMENTAL...................................... 60 RESULTS AND DISCUSSION............................69 DOI Production from Non-phytoplankton Related Process................................ 69 DOI Production from Inoculated Incubation 81 DOI Production from Two Naturally Occurring Phytoplankton Communities..................... 88 CONCLUSIONS...................................... 102 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vi (Continued) Chapter Page V. SUNLIGHT INDUCED IODINE PRODUCTION: THE DECOMPOSITION OF DOI IN MARINE WATER........103 INTRODUCTION..................................... 103 MATERIALS AND METHODS............................104 RESULTS AND DISCUSSION...........................107 The Decomposition of L-thyroxine............. 107 Decomposition of DOI in Marine Water......... 110 Photochemical Characteristics and Geochemical Significance of DOI Photolysis............... 121 Exploring the Kinetics of DOI Photolysis 125 CONCLUSIONS...................................... 129 VI. DISSOLVED ORGANIC IODINE IN THE CHESAPEAKE BAY...............................................130 INTRODUCTION..................................... 130 SAMPLING AND ANALYSIS............................131 RESULTS.......................................... 132 Hydrography and Nutrients.................... 132 Distribution of Iodine Species.............. 140 DISCUSSION....................................... 143 The Participation of DOI in Iodine Cycle 144 The Geochemical Dynamics of Iodine Species...149 CONCLUSIONS...................................... 158 VII. SPECIATION OF IODINE IN THE JAMES RIVER ESTUARY.......................................... 160 INTRODUCTION..................................... 160 SAMPLING AND ANALYSIS............................162 RESULTS AND DISCUSSION...........................164 General Feature of the Environment.......... 164 Distribution of Iodine Species.............. 167 Conservative and Non-conservative Behavior of Iodine..................................... 172 CONCLUSIONS...................................... 176 VIII. SUMMARY AND SUGGESTION FOR FUTURE RESEARCH..... 177 SAMPLE HANDLING AND DETERMINATION OF IODINE SPECIES................................ 177 THE PRODUCTION OF DISSOLVED IODINE IN MARINE WATER.................................. 178 DECOMPOSITION OF DOI IN MARINE WATER............ 179 THE GEOCHEMICAL BEHAVIOR OF DISSOLVED ORGANIC IODINE IN THE CHESAPEAKE BAY AND THE JAMES RIVER.............................................180 SUGGESTION FOR FUTURE RESEARCH.................. 181 REFERENCES.................................................183 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vii APPENDICES................................................. 192 A. DETERMINATION ANDSAMPLE HANDLING.................192 B. EXPERIMENTS ON THE PRODUCTION OF DOI FROM PHYTOPLANKTON AND

Load more

  223

Copy Link