Mya truncata as a Bioindicator of Chronic Municipal Wastewater Exposure and Anthropogenic Activity in Frobisher Bay, NU. by Christina Mae Schaefer A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE Department of Biological Sciences University of Manitoba Winnipeg, Manitoba December 2020 Copyright © 2020 by Christina Mae Schaefer i Abstract Municipal wastewater effluent is one of the largest sources of pollution to Canadian waters. Until recently, the disposal of wastewater was not of great concern to Arctic communities, but growing populations and urbanization bring more diverse contaminants that could cause deterioration of an already fragile environment. Bivalves have proven extremely useful in their ability to evaluate the importance and spatial distribution of contaminants. Thus, this thesis investigated the effects of Iqaluit’s (NU, Canada) primary treated municipal effluent in Frobisher Bay on the Arctic truncate soft-shell clam, Mya truncata. Clams were sampled from six locations along a gradient in proximity to Iqaluit’s wastewater effluent source. Four sites were chosen for their proximity and potential direct exposure to wastewater effluent and two were chosen for their distance and environmental barriers from the effluent source. Patterns of growth, stable isotopes and trace elements in the shell were linked to environmental variation on an annual scale and a parallel analysis measured the tissue-specific mRNA transcriptional response of the soft-shell clam. The results displayed slower growth and smaller shell lengths in organisms of the same age near the wastewater effluent source. Common side-effects of wastewater effluent like brackish water, increased organic input, and higher average calculated temperatures were evidenced by significantly lower ratios of carbon (1.38‰) and oxygen (1.31‰) isotopes in clam shells nearest the wastewater treatment plant (WWTP). Clams nearest the wastewater effluent source also had metals (lead and copper) characteristic of wastewater effluent accumulate in their shells over time. Given the environmental variation recorded in the shells near the WWTP, further evidence of chronic exposure impacts was supported by the cellular stress and xenobiotic response. The clams nearest the outfall exhibited lower expression of mRNA involved in the physiological response functions including antioxidants, metabolic regulators, molecular chaperones, and phase I and II detoxification response, but had heightened expression of mRNA of genes coding for enzymes that bind and remove xenobiotics. The culmination of these results demonstrates the presence of contamination and provides an early warning system into the possible adverse physiological changes that could result from chronic municipal wastewater exposure in Frobisher Bay. ii Acknowledgements First, I would like to recognize my supervisor Dr. Ken Jeffries. I am extremely grateful for all the guidance and pep talks you’ve given me, for taking the time to mentor me and for helping me get through that first field season, for that, I am ever grateful. I would also like to express my gratitude to my second supervisor Dr. David Deslauriers. Thank you for all of your guidance and coding help, it absolutely would have been a mess without you. Thanks to my committee members Dr. Mark Hanson and Dr. Dirk Weihrauch you both have provided great insight and resources that made this project what it is today. A big thank you to Dr. Jason Treberg for providing equipment and facilities to age my organisms. To Jordan, my Iqaluit partner. Thank you for keeping me company, checking in, burning popcorn, learning with me and for all our northern adventures. To Dr. Chris Lewis, you sparked my passion for the Arctic. Thank-you for taking the time to bring me out on the ocean, for showing me the life changing honey Dijon mustard, and for all the laughs. I am extremely grateful to all the members of the Hunters and Trappers Association, as well as my boat captains Davidee Qaumariaq, Mathew Alainga, and Alex Flaherty. I appreciate you touring me around the bay, sharing stories and food and for showing me your culture. I would like to specifically thank Danny Gedig, who aged every single clam. I sold it as ‘easy’ when it was far from it. Dr. Alyssa Weinrauch, my first science mentor. Thanks for encouraging me when I thought R was going to defeat me, for reading over nearly everything I have written, for supporting me and coming to this new city with me. Thank-you for being the best roommate and friend I could have ever asked for. Truly, you changed my life. To my boyfriend, Bryce Dodd, you have been my biggest support. Thank- you for getting excited about the graphs I showed you with absurd yelling, for bragging about my research, and for being there for every breakdown. You cheered me on when I was discouraged, wiped my tears away when there were research catastrophes, made sure I took breaks, but most of all made me laugh away the mistakes. Lastly, to my mom, Terese and sister, Kate. Thank you for always supporting me. It has meant so much that you have answered every call and acted interested as I carefully described the innards of a clam. You both brought me back to earth and made me laugh when I most needed it. This research would not have been possible without the financial support provided through an NSERC Discovery Grant, the University Indigenous Research Program Grant and Fisheries and Oceans Canada Coastal Environmental Baseline Program. iii Dedication This thesis is dedicated to the memory of my Oma, Ruth Schaefer, who passed away during my field season in Iqaluit. She would have loved to pretend to understand what was going on in this thesis and always encouraged me to chase my dreams. iv Table of Contents Abstract ........................................................................................................................................................ ii Acknowledgements .................................................................................................................................... iii Dedication ................................................................................................................................................... iv List of Tables ............................................................................................................................................. vii List of Figures ........................................................................................................................................... viii List of Abbreviations ................................................................................................................................. ix List of Equations ........................................................................................................................................ xi Chapter 1: General Introduction ............................................................................................................... 1 The Canadian Arctic ............................................................................................................................... 1 Arctic Ocean Contamination Concerns ................................................................................................ 1 Local Anthropogenic Impacts ................................................................................................................ 2 Canadian Wastewater Management ................................................................................................. 3 Biomonitors ............................................................................................................................................. 6 Biomarkers .............................................................................................................................................. 6 Sclerochronology ................................................................................................................................. 7 Cellular Stress Response .................................................................................................................... 9 Study Species: Mya truncata ................................................................................................................ 10 Aims of this Thesis ................................................................................................................................ 11 Figures and Tables ................................................................................................................................ 13 Chapter 2: Shell sclerochronology, trace elements and stable isotopes of the bivalve Mya truncata from Inner Frobisher Bay: Implications of chronic exposure to primary treated wastewater ......... 15 Abstract .................................................................................................................................................. 15 Introduction ........................................................................................................................................... 15 Materials and Methods ......................................................................................................................... 17 Sampling ............................................................................................................................................ 17 Growth Pattern Analysis