CONTENTS 



Page 



General summary 1 



Introduc tion 1 



Physical limnology 2 



Chemistry 2 



Phytoplankton h 



Zooplankton 6 



Bottom organisms 8 



Effects of pollution on the fishery 9 



General introduction 10 



Need for investigation 10 



Previous investigations in Lake Erie 11 



History of the present investigation 12 



Plan of investigation l6 



Scope of the report 19 



Acknowledgments 20 



Physical limnology of VJestern Lake Erie 22 



Hydrography 22 



Fluctuations of lake level 32 



Fluctuations owing to changes in volume 32 



Seasonal fluctuations 32 



Annual fluctuations 35 



Fluctuations in glacial and post-glacial time 35 



Transient fluctuations 35 



Waves 37 



Seiches 38 



Tides 38 



Currents 39 



Meteorological data Ul 



Water temperature UU 



Introduction UU 



Thermal stratification UU 



Seasonal changes in temperature 52 



Transparency 55 



A chemical study of Western Lake Erie 57 



Introduction 57 



Previous investigations in the Great Lakes 57 



Scope and me thods 60 



Data and discussion 6l 



Island Section 6l 



Oxygen, carbon dioxide, and hydrogen-ion concentra- 

 tion 61 



Season of 1928 6l 



Season of 1929 63 



Season of 1930 70 



General discussion 78 



