Bradley: Otherwise you would have no decrease in chloride at all. 



Redfield: I suppose so, if this were over a rock bottom. I want very much 



to get a series of these out across this marsh and get out a mile 

 or two in between large creeks, which would give a very good 

 opportunity for surface water to come up, and see how the whole 

 thing varies. 



Bradley: Wouldn't you get some upward movement of water, perhaps geo- 



logically slow, from compaction of the sediments so that there 

 is always a slight advection? 



Redfield: It would be geologically slow. 



Bradley: It must be or you would not have compaction. 



Redfield: Actually there is not much evidence of compaction in the column 



until you get within a foot or two of the bottom and then you get 

 an increase in the mineral content and a decrease in the water 

 content. 



Rubin: Bringing geologic time into the picture, I was interested in 



whether or not there would be a lot of movement of humic acids 

 in a bog and so I investigated one. This was in a kettle in 

 glacial till in Iowa. I had pictured a churning motion of the 

 water in a bog taking humic acid from the surface and mixing 

 it and having it stain the peat at the depths. This then would 

 give you carbon of different age being introduced as a contam- 

 inant to the lower section. So I took samples from the bottom 

 and from different strategic places along the peat bog and sep- 

 arated the humic acid from the cellulose with sodium hydroxide 

 separation. After that 1 ran radiocarbon on the two. In the peat 

 at the bottom the cellulose ran 11,400 years and the humic acid 

 at that level ran 11,400. The next level was 8,000 years and 

 the humic acid 8,000. The next level I had was 6,000 and 6,000 

 and there was no appreciable difference in the two fractions as 

 far as our error of measurement which at that range was between 

 100 and 200 years. 1 do not think that you picture a completely 

 stagnant bog through 11,000 years. It may be that the humic 

 acid has no way of getting into the structure of the peat, because 

 it is already saturated, and this stuff is immediately washed off 

 with the first washing, but at least I must revise my idea of a 

 churning bog with complete overturning. 



Redfield: I think that comes out to something like 5 feet a year. You see 



it is a very slow movement. It is all essentially in one direction 

 so that soluble materials produced down here would tend to be 

 very generally carried up and swept away. For example, this 

 material does not impress me as having hydrogen sulphide in it. 



86 



