TERRESTRIAL INPUT TO ESTUARINE BIVALVES AS MEASURED BY MULTIPLE STABLE ISOTOPES TRACERS. CAROLINE LeBLANC

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1 TERRESTRIAL INPUT TO ESTUARINE BIVALVES AS MEASURED BY MULTIPLE STABLE ISOTOPES TRACERS BY CAROLINE LeBLANC B.Sc., M.Sc. A thesis Submitted to the School of Graduate Studies In Partial Fulfilment of the Requirements for the Degree Doctor of Philosophy McMaster University September 1989

2 STABLE ISOTOPES STUDY OF ESTUARINE BIVALVES

3 DOCTOR OF PHILOSOPHY (Geology) McMASTER UNIVERSITY Hamilton, Ontario TITLE: Terrestrial input to estuarine bivalves as measured by multiple stable isotopes tracers. AUTHOR: Caroline LeBlanc, B.Sc. Biologie (Universite du Qu~bec l Rimouski) M.Sc. Oc~ano9raphie (Universit' du Qu'bec l Rlmouskl) SUPERVISORS: Dr. Henry P. Schwarcz Dr. Michael J. Risk NUMBER OF PAGES: xv, 201 ii

4 ABSTRACT Stable isotope ratios of carbon, nitrogen, hydrogen and oxygen were used here, of terrestrial input to estuarine to trace bivalves the extent (Mytilus edulis) during the summer of 1984 records indicate a stronger river and Salinity influence in 1985 compared to Fatty acids rat!os (C24/C16, C24/Cl4l are intercallbrated with stable isotopes of carbon (6 13 Cl and nitrogen (6 15 N) to characterize the sediments of a Negro Harbour, a small estuary which receives mixed terrestrial input. The relative contrjbution of terrestrial and organic matter calculated through fatty acid and stable isotope ratios were generally in agreement for sample sites in the upper pa~t of the estuary. However, changes in the relative contribution of peat compared to higher terrestrial plants are more readily noticed using fatty acid ratios than with isotope ratios C and 6 l5 N were both compared in the organic matrix (lifetime average diet) and in the flesh (shorttime variationl as well as in the stomach content (which were assumed to reflect the diet), the sediments, POC ~nd marine plants. Based on 6 13 C of the flesh more so than for 6 15 N values, it seems that Mytilus edulis take up iii

5 some of the terrestrial material coming from Clyde river. The uptake was higher in 1985 which agrees with the river influence being stronger during that period of time. The isotopic fractionation between the organic matrix of M. edulis and the stomach content (assumed to be the immediate diet) average about 4%0 for carbon and 2.0%0 for nitrogen. There seems to be less fractionation between the flesh and the organic matrix using nitrogen isotope compared to carbon isotope ratio C and 6 15 N of organic matrices do not change over a period of one year and are therefore useful in evaluating long-term changes in diet of bivalves and regional differences. The organic matrix resemble in certain characteristics, the collagen of bone, which is widely used in paleodiet studies. Thus, the organic mat~ix could be used in well preserved fossils to learn about the past diet of molluscs. Stable isotopes of carbon and oxygen of the calcitic shell of M. edulis were also investigated since carbonates are often used to indicates freshwater input in paleoenvironments. In general, shells were close to equilibrium with the surrounding water. But, the results obtained here showed that the use of carbonates to detect past estuarine environment could lead to misinterpretation due to possible biological effects that inhibits calcification (as noted near the head of the estuary). iv

6 A Ati, pour 1 'amour, le perpetuel encouragement et les chases. v

7 ACKNOWLEDGMENTS I wish to expres my gratitude to both Drs Henry P. Schwarcz and Michael J. Risk, my research supervisors, for their guidance through all phases of this work and also for their patiencp. during my apprenticeship of the english language. Appreciation is also expressed to Dr. Rick A. Bourbonniere (CCIW, Burl ington) for the use 0 f his labocatory facilities and also for his advice during the analyses and interpretation of the fatty acld results. Special thanks for my field helpers, Ati Kagazchi, Cris Rose, Jim Magwood and Liz Dowil. Most special thanlts to Martin Knyf, indispensable figure in the isotope laboratory. I would also like to thank the Quebec Government (FCAR) for its funding. Thanks are also Fisheries and Oceans of expressed to the Department at the Bedford Institute of Oceanography the ir boat. (Dartmouth, Nova Scotia) for the use uf I extend my gratutide to the excellent support staff of the Department of Geology, McMaster University. Finally, I would like to thank my family, Ati and Jos~ for their love and support throughout this work. vi

8 TABLE OF CONTENTS INTRODUCTION 1 CHAPTER 2. STUDY AREA 6 CHAPTER 3. EXPERIMENTAL METHODS Field techniques, Sample preparation Sediment and POM Mollusc Soft tissues and stomach contents Extraction of organic matrix from mollusc shell Preparation of shell for carbonate analysis Analytical methods Fatty acid analysis Stable isotopes analysis Stable carbon and nitrogen isotope ratios of organic material Stable hydrogen ratio Oxygen isotope ratios of water Carbonates 27 vii

9 Stable isotope ratio expression and precision of analysls Total organic carbon Salinity and temperature 0 29 CHAPTER 4. NEGRO HARBOUR SEDIMENTS ANALySIS Theoretical review Carbon isotope ratios Nitrogen isotope ratlos Fatty acids Sources of organic matter in Negro Harbour carbon isotope ratios Fatty acid ratios Nitrogen isotope ratios Organic inputs o N results from Negro Harbour sediments Mixing equation Carbon isotopes Fatty acic1 ratios Nitt"ogen isotopes Comparison of mixing equation data (6 13 C, 6 15 N, fatty acids) «1. Conci us ions 0 81 CHAPTER 5. Hytilus edulis AND FEEDING BEHAVIOR 83 CHAPTER 6. STABLE ISOTOPES IN THE SOFT TISSUES Of viii

10 Hytl1us edulis, t t, t Stable carbon isotopes, Review of 6 13 C in consumers Results from Negro Harbour Stable nitrogen isotopes Review of 6 15 N in consumers Results from Negro Harbour Stable hydrogen isotopes Theoretical review Results from Negro Harbour D in biogenic silica 113 CHAPTER 7. ORGANIC MATRIX Theoretical review Shell and organic matrix of Mytilus edulis and Arctica islandica EDTA-HCl comparison Results from Negro Harbour Carbon isotope ratios Nitrogen isotope ratios Comparison between 6 13 C and 6 15 N results... ". t t " "." Discussion. t t." t, "" t,,, " 141 CHAPTER 8. STABLE ISOTOPES IN THE CARBONATES OF MOLLUSC SHELL Theoretical review Oxygen isotopes 150 ix

11 Carbon isotopes C and in bivalve shells Results from Negro Harbour 154 CHAPTER 9. GENERAL CONCLUSIONS 170 REFERENCES I t " " 17'7 APPENDIX 1. GLOSSARy 201 x

12 LIST OF FIGURES page FIGURE 2.1 Study area and its peat deposits 9 FIGURE 2.2 Salinity profiles at low and high tide for 1984 and 1985, FIGURE 3.1 Location of sediment sample sites 14 FIGURE 3.2 Location of water sample collection sites 16 FIGURE 3.3 Flow-diagram representing the extraction of fatty acid methyl esters 23 FIGURE C of the sediments of Negro Harbour fot" 1984 and FIGURE 4.2 Fatty acid concentration and % TOC in the sediments of Negro Harbour for 1984 and Curves plotted with averaged values 59 FIGURE 4.3 Fatty acid t"atio in the sediments of Negro Harbour for a) C24/C16 and b) C24/C14 62 FIGURE 4.4 o15n in the sediments of Negro Harbour fot" 1984 and FIGURE 4.5 Plot of o13c against o15n sediments values of Negro Hat"bour, 70 FIGURE 4.6 Percentage of terrestrial organic matter down estuary as measured by a) stable cat"bon isotope ratios; b) C24/C16; c) C24/C14 77 FIGURE C values of different tissues of Hytilus edulis down estuary (1984) 92 xi

13 FIGURE C values of different tissues of Hytilus edul is down estuary (1985) 94 FIGURE N values of different tissues of Hyt.ilus edul is down estuary (1984) 106 FIGURE N values of different tissues of Hytilus edulis down estuary (1985) 108 FIGURE 7.1 Radial section of the mantle edge of a shell to show the relationships between the shell and mantle (not to scale) 122 FIGURE 7.2 Layers of organic matrix (after Weiner et al., 1982) 126 FIGURE 7.3 Cross-section of a Hytilus edulis shell displaying the outer calcitic layer and the inner aragonitic layer 130 FIGURE 7.4 Plot of o13c values in the flesh and organic matrix at all sites against its corresponding 6 15 N values 1110 FIGURE C and values in the shell calcite of Hytilus edulis down estuary for 1984 and 1985 (su mme r ) FIGURE 8.2 Temperature and salinity gradient at low tide for summer of a) 1984 and b) FIGURE 8.3 Expected variation in values of the water relative to the salinity l6~ FIGURE 8.4 Calculated and observed in Hytilus edulis shell calcite, down estuary 157 xii

14 LIST OF TABLES page TABLE 3.1 Dissolution test on shells (6 13 C, 6 15 N) 19 TABLE 4.1 General range of 6 13 C values of carbon sources in coastal ecosystems 31 TABLE C (%0) of terrestrial and marine sources of organic matter 41 TABLE l3 C (%0) of POM in the Clyde river for 1984 and ".. ".""... ".""... t " 42 TABLE l3 C values of plankton of temperate areas TABLE C values of organic matter in the sediments of Negro Harbour for 1984 and TABLE 4.6 Fatty acid concentration (ug/g ) and ratio in various plants from Negro Harbour and Barrington bog area 49 TABLE 4.7a Fatty acid ratio (corrected, uncorrected, % errors) for TABLE 4.7b Fatty acid ratio (corrected, uncorrected, % errors) for TABLE 4.8 Spring (1984) C24/C16 uncorrected values TABLE 4.9 Fatty acid concentration (ug/g ) and % TOC for 1984 and Average in brackets 54 TABLE 4.10 Fatty acid ratios in the sediments of Negro Harbour. Average in brackets TABLE N values of plankton 63 xiit

15 TABLE N values of seagrasses 65 TABLE S N values in Negro Harbour sediments 68 TABLE 4.14 Percentage of terrestrial organic matter deduced from 6 13 c, 6 15 N and fatty acid ratios for 1984 and TABLE 6.1 Carbon isotope ratios from the flesh, organic matrix and stomach contents of Mytilus edulis from the summer of Average value in brackets 95 TABLE 6.2 Carbon isotope ratios from the flesh, organic matrix and stomach contents of Mytilus edulis from the summer of Average value in brackets 96 TABLE C values from the flesh of bivalves (filterfeeders) 98 TABLE N values in different tissues of Mytilus edulis from TABLE N values in different tissues of Mytilus edulis from TABLE N values (%0) from the flesh of bivalves (filter-feeders) 110 TABLE values of the water from Clyde river collected at two sites, CR1 (freshwater) and CR5 (mixture of fresh and sea waters) in the summer of 1984 and 1985 and the winter of TABLE values from a plankton sample, peat sample, xiv

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THE DECO~WOSITION OF AMMONIA ON TUNGSTEN SURFACES

THE DECO~WOSITION OF AMMONIA ON TUNGSTEN SURFACES THE DECOMPOSITION OF AMMONIA ON TUNGSTEN SURFACES by YU.KWANG PENG, DIPL. CHEM. A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment