Davis: 



it very closely here with the ground water. Of course, the 

 ground water and this value here in the marsh should represent 

 about the average climatic temperature. 



I would like to introduce the idea of an air block. In some peat 

 deposits you get a layer of air between two water tables. It 

 may not be apparent all the time but it is particularly true in 

 the Juncus romerianus tops over Spartina bottoms. Sometimes 

 the amount of water in many samples I have taken is almost 

 down to the dry point in the layer between the two types of peat 

 so that your thermal gradients would not be the same. I just 

 wanted to mention the air block. It occurs in some peats. I 

 am quite sure that that is true. I think there are differences 

 of course in the character of material. There might very well 

 be this sort of distortion. I have one curve which I made out 

 in the Puget Sound area which is apparently quite atypical. 

 One thing which I might mention in closing is that from this 

 equation, knowing the value of rn which we have determined, 

 and knowing the period, you can find out how much a diurnal 

 or weekly or two-weekly variation will penetrate. It works out 

 that a two -week variation would be compressed to about 1/5 

 this. In other words the fluctuations associated with the two- 

 week tidal period would become unmeasurable at about one 

 meter. Those associated with day and night would not go down 

 more than about six inches so that you have a method of deter- 

 mining what these valuations are and furthermore you have a 

 method of determining what the mean surface regime is without 

 measuring it every day because if you get down here, your curves 

 will give you a nice smooth sinusoidal curve, and if you know 

 your attenuation, you simply calculate back, and very quickly 

 have a very good picture of the annual trend without worrying 

 about the short term variations. 



Bradley: I have some figures that may be comparable or may not. The 



flat in which we measured the thermal conductivities does not 

 drain out and water is still standing in the ripple troughs 

 throughout the half tidal cycle. There is no peat over it. In 

 other words this was a bare shandy mud. We got thermal con- 

 ductivities of 4.4 

 to your m. 



4. 6 X 10" . I suppose this is comparable 



Redfield: Yes, it is the same. It would be then about twice as great. 



Bradley: The depth to which the diurnal temperature range went in mid- 



summer was almost exactly 60 centimeters. 



Odum: What is the depth there approximately on your graph of 



chloride ? 



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