The University of Maine DigitalCommons@UMaine Electronic Theses and Dissertations Fogler Library Fall 11-17-2016 Linking Rising pCO2 and Temperature to the Larval Development, Physiology and Gene Expression of the American Lobster (Homarus americanus) Jesica Waller University of Maine - Main, [email protected] Follow this and additional works at: http://digitalcommons.library.umaine.edu/etd Part of the Marine Biology Commons Recommended Citation Waller, Jesica, "Linking Rising pCO2 and Temperature to the Larval Development, Physiology and Gene Expression of the American Lobster (Homarus americanus)" (2016). Electronic Theses and Dissertations. 2527. http://digitalcommons.library.umaine.edu/etd/2527 This Open-Access Thesis is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of DigitalCommons@UMaine. LINKING RISING pCO2 AND TEMPERATURE TO THE LARVAL DEVELOPMENT, PHYSIOLOGY AND GENE EXPRESSION OF THE AMERICAN LOBSTER (HOMARUS AMERICANUS) By Jesica Davis Waller B.S. University of New Hampshire, 2013 A THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Marine Biology) The Graduate School The University of Maine December 2016 Advisory Committee: Richard Wahle, Research Professor, Co-advisor David Fields, Bigelow Laboratory for Ocean Sciences, Co-advisor Spencer Greenwood, University of Prince Edward Island Lawrence Mayer, Professor of Oceanography THESIS ACCEPTANCE STATEMENT On behalf of the Graduate Committee for Jesica Waller I affirm that this manuscript is the final and accepted thesis. Signatures of all committee members are on file with the Graduate School at the University of Maine, 42 Stodder Hall, Orono, Maine. Dr. Richard Wahle, Research Professor December 5th, 2016 ii LIBRARY RIGHTS STATEMENT In presenting this thesis in partial fulfillment of the requirements for an advanced degree at The University of Maine, I agree that the Library shall make it freely available for inspection. I further agree that permission for "fair use" copying of this thesis for scholarly purposes may be granted by the Librarian. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature: Date: LINKING RISING pCO2 AND TEMPERATURE TO THE LARVAL DEVELOPMENT, PHYSIOLOGY AND GENE EXPRESSION OF THE AMERICAN LOBSTER (HOMARUS AMERICANUS) By: Jesica Davis Waller Thesis Co-Advisors: Dr. Richard Wahle and Dr. David Fields An Abstract of the Thesis Presented in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Marine Biology) December 2016 Anthropogenic warming and ocean acidification are occurring as CO2 continues to accumulate in the atmosphere (OA). Few studies have evaluated the joint effects of elevated temperature and partial pressure of CO2 (pCO2) on marine organisms. In this study we investigated the interactive effects of Intergovernmental Panel on Climate Change (IPCC) predicted temperature and pCO2 for the end of the 21st century on key aspects of larval development of the American lobster, Homarus americanus, an otherwise well-studied, iconic, and commercially prominent species in the northeastern United States and Atlantic Canada. Our experiments showed that larvae (stages I-III) and postlarvae (stage IV) reared at the temperature projected for the Northwest Atlantic by the year 2100 (19 °C) experienced significantly lower survival, developed twice as fast, and had significantly higher oxygen consumption rates, than those in 16 °treatments. Larvae from the high pCO2 (750 ppm) treatment at 16 °C had significantly longer carapace lengths, and greater dry masses in stages I-III and C: N ratios in the postlarval stage than postlarvae from all other treatments. Postlarvae raised in the high pCO2 treatment at 19 °C had significantly higher feeding rates and swimming speeds compared to postlarvae from the other three treatments. Together these results suggest that projected end- century warming will have greater adverse effects than increased pCO2 on larval survival, however the interactive effects of increased temperature and pCO2 have an additive impact on larval metabolism and behavior. To complement and expand upon our suite of results, we examined gene expression in postlarvae raised in each of the two pCO2 treatments at 16 °C. We selected 13 annotated genes of interest (GOIs) that were differentially expressed between postlarvae from the two pCO2 treatments. We found 11 GOIs related to cuticle formation that were significantly downregulated in postlarvae from the high pCO2 treatment, and two GOIs related to metabolism and stress response that were significantly upregulated. These preliminary results in tandem with our developmental, physiological and behavioral measurements provide insight into how H. americanus postlarvae compensate for the stresses of an end-century pCO2 and maintain successful development under these conditions. As is the case for most experiments of this nature, our results may have been biased by the fact that we were only able to conduct measurements on the small number of larvae that survived the rearing experiment. The results must therefore be interpreted with caution. Understanding how the most vulnerable life stages of the lobster life cycle respond to climate change is essential in connecting the northward geographic shifts projected by habitat quality models, and the underlying genetic mechanisms that drive their ecology. ACKNOWLEDGEMENTS Thank you to the faculty and staff at the University of Maine Darling Marine Center and Bigelow Laboratory for Ocean Sciences for their assistance and encouragement. I would especially like to thank Dr. Meredith White and the Balch laboratory at Bigelow laboratory for their assistance with the larval rearing system and carbonate chemistry analysis. Thanks to Andrew Goode, Kathleen Reardon and Les White for the collection and maintenance of adult lobsters. Thank you to Dr. Spencer Greenwood and Dr. Fraser Clark at the University of Prince Edward Island for their guidance and understanding. I would also like to thank Dr. Larry Mayer for helping me to think about this work in new ways. Thank you to my wonderful family of non- researchers who have always tried to read my papers and offered me support without question. I would also like to thank Andy Dickens for his endless encouragement and sense of humor. This work would not have been possible without my co-advisors Dr. Rick Wahle and Dr. David Fields. Thank you for fostering my confidence as a researcher and making my science dreams come true. This research was supported by two graduate fellowships from the University of Maine Canadian-American Center (2014-2016), Program Development funds from Maine Sea Grant (Project # 5405693), USDA National Institute of Food and Agriculture (Hatch project 1010290), the National Science Foundation (#OCE-1220068) and funding from NOAA (NOAA- OAR-CPO-2011-2002561) awarded to DMF. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................... iii LIST OF TABLES ............................................................................................................. vi LIST OF FIGURES ....................................................................................................................vii LIST OF EQUATIONS ............................................................................................................... ix CHAPTER 1. INTRODUCTION .................................................................................................................... 1 2. LARVAL SURVIVAL, DEVELOPMENT AND PHYSIOLOGY ................................... 6 2.1 Introduction ..............................................................................................................6 2.2 Methods....................................................................................................................7 2.3 Results ....................................................................................................................14 2.4 Discussion ..............................................................................................................26 3. DIFFERENTIAL GENE EXPRESSION ............................................................................ 31 3.1 Introduction ............................................................................................................31 3.2 Methods..................................................................................................................32 3.3 Results ....................................................................................................................34 3.4 Discussion ..............................................................................................................38 4. CONCLUSION ....................................................................................................................... 42 REFERENCES ............................................................................................................................ 44 APPENDICES ............................................................................................................................. 52 APPENDIX A. ANNOTATED TRANSCRIPT DATA ........................................... 52 APPENDIX B. ANNOTATED TRANSCRIPTS .....................................................