Lake Maxinkuckee, Physical and Biological Survey 119 



THE AQUATIC FLORA 

 Introduction 



The entire animal life of any lake is dependent for its sustenance 

 ultimately upon the plant life of the same lake. The complete de- 

 struction of the plant life would inevitably result sooner or later in 

 the total disappearance of all animal life. This general statement 

 includes, of course, the microscopic as well as the macroscopic flora 

 and fauna, the diatoms, desmids and all minute forms of plant life, 

 and all entomostraca and other minute forms of animal life, as well 

 as all those larger, more conspicuous forms of animal and plant life 

 which are evident even to the most casual observer. 



Without the plants the lake would be uninhabitable and zoolog- 

 ically, an uninhabited desert. The plants of the lake are as im- 

 portant to its animals as are the grasses of the plains to the cattle 

 that range over them. The importance of the microscopic flora is 

 discussed elsewhere in this report in connection with the subject 

 of plankton ; we may therefore omit from detailed consideration 

 at this time the subject of infant fishes and their food, and pass 

 directly to a discussion of the more conspicuous plant life of the 

 lake and the more evident phenomena connected with its relation 

 to the lake's fauna. 



Uses of the Aquatic Flora 



As oxygenators: — The plants of a lake perform an important 

 function in furnishing a supply of oxygen to the water. The im- 

 portance of this function in any lake depends upon its area as com- 

 pared with its depth ; in other words, upon the ratio between the 

 surface area where oxygen can be absorbed, and the volume of 

 water to be oxygenated. In a lake with large area and little depth, 

 and winds sufficient in strength and frequency to keep the surface 

 well disturbed, the need of oxygenation by plants is less imperative. 

 Lake Maxinkuckee, with its considerable areas of deep water and 

 infrequency of summer storms, needs the assistance of aquatic- 

 plants to keep up the supply of oxygen. Their presence, provided 

 there are enough fishes and other animals to use up the oxygen, 

 makes the lake a large balanced aquarium. 



Some idea of the activity of the plants in supplying oxygen to 

 the water may be obtained by visiting and observing largo, dense 

 patches of certain water-weeds in clear shallow water on any bright 

 day. On a bright day in autumn it was observed that the con- 

 stant breaking of minute bubbles above dense patches of Philotria 



