THE FAUNA OF ROCK BOTTOM PONDS.* 



Frederic H. Krecker. 



TABLE OF CONTENTS. 



Introduction 427 



One Year Pond: 



General Conditions 430 



Stations 431 



Plankton 437 



Discussion 438 



Five Year Pond: 



General Conditions 441 



Stations 442 



Plankton 447 



Discussion 447 



Ten Year Pond: 



General Conditions 450 



Stations 451 



Plankton 454 



Discussion 454 



Fifteen Year Pond: 



Conditions 457 



Discussion 459 



Plankton 460 



Thirty Year Pond: 



Conditions 460 



Discussion 463 



Plankton 464 



General Discussion of the Series: 



Physical Features 464 



The Fauna 466 



INTRODUCTION. 



This investigation was undertaken for the purpose of 

 studying the fauna and also the physical changes in a series of 

 rock bottom ponds successively greater in age. Although ponds 

 of various types have been studied, either individually or with a 

 view to determining the succession of life in a series of different 

 ages, so far as I am aware no one has studied a group which 

 originated on a substratum of bare rock. 



The ponds in question are in a number of limestone quarries 

 near Sandusky, Ohio. Within a radius of fifteen miles there is a 

 series of five ponds which at the time of the investigation were 

 one, five, ten, fifteen and thirty years old respectively. They 

 were forined as the result of striking water in the course of 



* Contribution from the Department of Zoology and Entomology, Ohio State 



University No. 58. 



427 



