DEVELOPMENT OF A MARINE MERCURY CYCLING MODEL FOR PASSAMAQUODDY BAY, NEW BRUNSWICK by Elsie M.H.A. Sunderland B.Sc. McGill University, 1997 THESIS SUBMITTED IN PARTIAL FUFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the School of Resource and Environmental Management O Elsie M.H.A. Sunderland 2003 SIMON FRASER UNIVERSITY March 2003 All rights reserved. This work may not be reproduced * in whole or in part, by photocopy or other means without the permission of the author. Approval Name: Elsie M.H.A. Sunderland Degree: Doctor of Philosophy Title of thesis: Development of a Marine Mercury Cycling Model for Passamaquoddy Bay, New Brunswick Examining Committee: Chair: Dr. Ken Lertzman - or, School of Resource and weah~ewoung Associate Professor, Department of ~iolo# Supervisor Dr. Brian Branfireun Assistant Professor, Department of Geography University of Toronto Supervisor Ur. Peter ~flls Research ~clentis&onment Canada Supervisor Dr. Margo Moore Associate Professor, Department of Biology -SFU Examiner DY. David ~rabbinhbft Research Hydrologist/Geochemist U.S. Geological Survey External Examiner Date Approved: PARTIAL COPYRIGHT LICENCE I hereby grant to Simon Fraser University the right to lend my thesis, project or extended essay (the title of which is shown below) to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users. I further agree that permission for multiple copying of this work for scholarly purposes may be granted by me or the Dean of Graduate Studies. It is understood that copying or publication of this work for financial gain shall not be allowed without my written permission. Title of Thesis/Project/Extended Essay Development of a Marine Mercury Cycling Model for Passamaquoddy Bay, New Brunswick Author: ABSTRACT Despite large reductions in mercury emissions from anthropogenic sources, high mercury levels in wildlife, fish and avifauna in the Bay of Fundy region of Maritime Canada remain a problem. The objectives of this research were to: (i) develop a comprehensive "ecosystem-based" understanding of the environmental fate of anthropogenic mercury in a temperate coastal marine environment; and (ii) formulate an empirical model that links anthropogenic mercury inputs to concentrations in sediments, water and benthic organisms that will aid in developing strategies for reducing the impacts of mercury in coastal ecosystems. Analysis of sediment cores from the Bay of Fundy region revealed that approximately 65% of present mercury inputs from the atmosphere are composed of natural and recycled anthropogenic mercury. Thus, in the short term, the maximum decline in atmospheric mercury loading achievable through emissions reduction programs is approximately 35%. A field study of mercury speciation showed a proportional relationship between total mercury and methylmercury concentrations in Passamaquoddy Bay (Bay of Fundy) sediments, but these concentrations are also affected by sediment geochemistry. These relationships indicate that declines in mercury loading should eventually translate into proportional declines in concentrations in organisms if the geochemical characteristics of sediments remain unchanged. Sediment core and composition analysis revealed a deep active sediment layer that provides a large pool of available and actively cycling total mercury and methylmercury. Mass budget calculations show that: (i) the sediment compartment contains the majority (>90%) of the mercury in Passamaquoddy Bay; and (ii) there is a large daily turnover of mercury through methylation and demethylation. The principal findings of this study show that: (i) environmental changes that shift the present equilibrium between methylation and demethylation could result in rapid accumulation of methylmercury in the sediment compartment that could subsequently be taken up by marine organisms; and (ii) while concentrations in the water column of Passamaquoddy Bay reach steady state rapidly in response to changes in mercury inputs, the overall dynamics of mercury in this system are governed by the slow rate of change in mercury concentrations in the sediments. These results help to explain why mercury concentrations in marine organisms in the Bay of Fundy region remain elevated despite large emissions reductions. Acknowledgements The work presented in this thesis would not have been possible without the support and collaboration of many colleagues, friends and family. I would like to thank my senior supervisor, Frank Gobas, for his positive attitude and insights into environmental modeling. Each of my supervisory committee members, Leah Bendell-Young, Brian Branfireun and Peter Wells, provided invaluable guidance for this project and I thank all of them for their ongoing support. In its early stages this work also benefited from the input of Randall Peterman, who for me has always provided the example of how to push for rigorous, groundbreaking science. I would also like to acknowledge the critical role of the departmental staff, Rhonda, Bev, Mary Ann, Anissa and Laurence, in facilitating my completion and helping to maintain my sanity. I received financial support for this work from NSERC, the Gulf of Maine Council on the Marine Environment, Mountain Equipment Co-op, the Department of Fisheries and Oceans, and the Joseph & Rosalie Segal Foundation. I would also like to especially thank two other de facto members of my supervisory committee: Ray Cranston from the Geological Survey of Canada and Andrew Heyes from Chesapeake Biological Laboratory (CBL) at the University of Maryland, who both assisted me in all aspects of this project. Thanks are also due to: Debby Heyes at CBL for training me in the often-incomprehensible world of mercury analysis; to Gail Chmura at McGill University who inspired me to begin this research many years ago; and to Brian and Mamie Branfireun for providing me with a surrogate family in Toronto and for continually reminding me that the incremental benefit of running one more distillation might not be worth lasting insanity. The staff at Hunstman Marine Science Center in St. Andrews, NB, particularly Fred, Stephen and Mick, provided much needed logistical support for the majority of field work conducted as part of this study, and I thank the facility for in-kind contributions to the work. I also thank Hugh Akagi and Dave Wildish at the Biological Station in St. Andrews for continual use of their probes, lab and reagents while I was in the field and for not minding when I happened to break a piece of glassware. Thanks also to the crews ofthe coastguard vessels J.L. Hart and J. V. Navicula and to Bob "Murph" Murphy for being our favorite field technician and calling me "boss" in front of the crew. I am grateful to John Dalziel, Gareth Harding, Tim Milligan, Doug Loring, Mike Parsons and Peter Vass at Bedford Institute of Oceanography for countless hours of discussion, access to data, field equipment, and in-kind contributions that made this work possible. Yes, John I do owe you another bottle of rum. Angelika Bayer and Janice Weightman also deserve special mention as the two masters students that have contributed to the development of this project. "Red Rooster" will always be my favorite breakfast spot in New Brunswick and I promise never to insist on sampling during a hurricane again. Thanks are also due to the people in the REM toxicology lab and good friends at REM who have been an integral part of this experience. Finally, my greatest debt of gratitude is owed to my parents, Julie, Laura and Mark who accepted and supported my choices and decisions over these past few years without question. I thank Julie for always providing me with the example of what was possible and for lying to me when necessary. Lastly to Mark, I know this process has been especially challenging and demanding for both of us and I am so grateful for your unyielding love and support. Table of Contents .. Approval Page ................................................................................. ...11 Abstract ........................................................................................ 111 Acknowledgements........................................................................... v Table of Contents ............................................................................. vii List of Tables .................................................................................. ...X List of Figures ................................................................................. Xlll List of Abbreviations ......................................................................... xvii 1.0 Introduction.......................................................................... 1 1.1 General Background ........................................................ 2 1.2 Mercury in Coastal Ecosystems .......................................... 5 1.3 The Problem of Regulation ................................................ 7 1.4 Major Scientific Questions Addressed in Thesis ........................ 9 1.5 Thesis Outline ............................................................... 10 1.6 Thesis Methods ............................................................. 12 1.6.1 Field Research ...................................................... 12 1.6.2 Contributions of Co-investigators ................................ 13 1.7 Literature