A Paleolimnological Assessrnent of the Diatom Communities of Lake Opeongo, Ontario, Canada Jeannine-Marie St-Jacques A thesis submitted in canformity with the requirements For the degree of Master of Science, Graduate Department of Botany, University of Toronto O Copyright by Jeannine-Marie StJacques 2000 National Library Bibliothèque nationale 191 du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. nie Wellington Ottawa ON KIA ON4 Ottawa ON K1A ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distibute or sel1 reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. A Paleolimnological Assessment of the Diatom Communities of Lake Opeongo, Ontario, Canada JeannineMarie St-Jacques Master of Science, 2000 Graduate Department of Botany University of Toronto Abstract Lake Opeongo is an oligotrophic lake in Algonquin Provincial Park, Ontario, Canada (45'42' N, 78O 22' W). Limnological conditions over the past 300 years were tracked using diatoms preserved in the sediments and applying diatom-based transfer functions to infer total phosphorus (TP). Before European settlement, Lake Opeongo was highiy oligotrophic, with the diatom community consisting of Cyclotella stelligera complex with subdorninants Tabellana fJocculosa lllp and Aulacoseira distans. No changes occurred until ca. 1956 when the diatom community shifted to the cuvent mesotrophic assemblage consisting of Asterionella fornosa with lesser amou nts of Cyclotella bodanica var lemanica, C. stelligera cornplex, Fragilaria crotonensis and T. flocculosa /Ilp. This s hift could have occurred due to increased direct human impacts on the watershed; increased post-war fertilizer use; global warrning, including changes in the thermal conditions of the lake; and trophic level changes caused by human manipulation of the fish community of the lake, To Allan and Anita with thanks iii Acknowledgments This research was made possible with financial support from an NSERC grant awarded to M.S.V. Douglas and support to J.M.H. St-Jacques from SATL (Scientific Assessrnent Technology Laboratory, University of Toronto). My supeniisor, Marianne Douglas, deserves my sincere thanks and appreciation, as do my cornmittee rnembers: Bob Jefferies, Helene Cyr, Jock McAndrews and Ann Zimmeman. l thank the Harkness Fisheries Laboratory and Chad Gubala for the use of their facilities during field work and Dr. &an Shuter (Ontario Ministry of Natural Resources) for his help in retneving unpubtished data from the Ontario Ministry of the Environment. Scott Milne and Mark Ridgway shared their knowledge of Lake Opeongo and its fish populations with me. Special thank you's are extended to John Birks, Brian Cumming, Roland Hall, and Euan Reavie for their statistical discussions, to Marie-Andree Fallu, Elizabeth Haworth, Jennifer Havelock, Eugene Stoermer and Norman Andresen for their taxonomie help and to Peter Leavitt for his discussions about trophic cascades. Pollen anafysis was done by Jock McAndrews. Finally, l should like to tttank first Nations House, University of Toronto, for all the encouragement and support over the years. Table of Contents ABSTRACT .....................m.......~............m......mm........m.......m....w...............................m.......m. II ACKNOWLEDGMENTS ...................m.m.............mm..m........mm.....m.....w......................w........IV LlST OF TABLES ................... ................~..........................................................~.........V1l LlST OF PLATES ...................m.........m.~....m..m......m~.m...........................w.................m.......V1l1 LlST OF FIGURES .............................................e...........m............m.....m....s..mm................ IX LIST OF APPENDICES ................... .m............m.......................m...................~...................X CHAPTER 1: INTRODUCTION .........................~~.....I~.................m......e.e..........~.....m....... 1 CHAPTER 2: SITE DESCRIPTION .e.t............. ............................m..m......................m.m..m.. 6 Natural conditions:.t ............m......m..m....m.....m..~m.........m.......................m..w....w..................... 6 Background studies: .................... ................m............................. ........ ................... .... 10 Human impacts on the watershed: .....................m...m................m..~....m.mm.m.mm....mm..e...... 10 CHAPTER 3: MATERIALS AND METHODS ................... ~.......I....m.m.m.....mmm.....m..m...m....12 Microfossil preparation and analysis: mm...mm.mmmmmm.m..mtm~mm*~mmmm~.m~m-.*~.wmt 12 Sediment chronology: ........................m..m......................................m............................13 Statistical analysis: .................................................................................................... 14 CHAPTER 4: PALEOLIMNOLOGICAL RECONSTRUCTION RESULTS .................. 19 CHAPTER 5: TAXONOMY ..........................m.....................m.........................................43 CHAPTER 6: DISCUSSION ........................................................................................ 60 APPENDICES .............................................................................................................. 86 List of Tables Table 1 Selected physical and chernical characteristics of Lake Opeongo........................................ 9 Table 2. Summary of calibrstion set statistics: ?and RMSE calculated directly from the calibration set and ?,, and RMSE, derived from bootstrapping..................................................................... 35 Table 3. Lake Opeongo diatom species list. lncludes ail taxa found in al1 core samples. their maximum relative abundance, and number of occurrences. Species with maximum abundance or number of occurrences of zero were found during initial taxonornic surveys of the slides but did not appear in the actual counts ................................................................................................................................. 52 Table 4 Total phosphorus preferences of the common diatoms from the literature. All values in pg TPIL. (na) denotes not available, (?) denotes taxonomie uncertainty.............................................. 61 Table 5. Ranges of selected physical and chemical characteristics of the lakes included in the calibratian sets. (na) denotes not available............................................ ................................. 63 vii List of Plates Plate 1..................................... .......................................................................... 46 Plate 2........................................................................................................................................................ 4û Plate 3...................................................................................................................................................... 50 List of Figures Figure 1. Location of Lake Opeongo, Ontario showing coring sites 1and 2. Cores 1 and 2 ftom site 1, cores 3 and 4 From site 2................................. .. ........................................................................... 7 Figure 2. (a) Plot of 210Pbactivity (Bq/g) against core depth (cm) for Lake Opeongo core 3. (b) Plot of sedimentation rates (g/m2&r) from analysis versus calendar year dates, assuming constant rate of supply. ................................................................................................................... 20 Figure 3. The relative abundance of common diatoms of Lake Opeongo cor8 3 plotted against core depth. Shown are the taxa with a relative abundance of at least 5% in at least one stratigraphic level. lncluded is the percent planktonic species. Also included are calendar year dates derived hm*'OPb analysis together with their standard deviation................................................................. 24 Figure 4. Rare diatoms (percentage) of Lake Opeongo core 3 plotted against core depth. Shown are the taxa of at least 1% relative abundance in at least one stratigraphic level but always less than 5% relative abundance. The x-axis scales show a maximum relative abundance of 10%. Also included are calendar year dates derived frorn *lOPbanalysis together with their standard deviation. .................................................. ................................................................................................26 Figure 5. Breakdown of Aulacoseira distans, Fragilaria capucina and Tabellana flocculosa varieties in Lake Opeongo core 3 plotted against depth in core........... ....................... ............... 28 Figure 6. Plot of major diatoms in Lake Opeongo core 1 plotted against core depth. The major