Moul: I don't know. I refer you to Dr. Redfield or Dr. Jenner. 



Redfield: Well, I object to the term "Barnstable mud". There is very 



little mud there. It ranges from sand to fine silty sand. It 

 isn't the kind of stiiff that sticks to your boots and you don't 

 sink into it. It is pretty firm stuff. 



Bradley: I believe I can throw some light on the quantity of organic mat- 



ter. I sampled a tidal flat not very dissimilar to the Barnstable 

 flat, with sandy mud, but in the upper reaches of it quite muddy 

 (1 am speaking very qualitatively now). 1 expected a great deal 

 of organic matter in that mud. Actually there was about 2 per- 

 cent of organic matter and in the sandy part ol the flat, which 

 was reeking with hydrogen sulphide and black a centimeter or 

 so below the surface. I expected quite a bit there. Actually 

 there is about 0.2 percent organic matter. 



Chronic: The rest clay particles? 



Bradley: No. Very few clay particles. 



Jenner: There is a piece of zoological information that belongs right here, 



I think, in talking about Barnstable flats, and that is that there is 

 an animal (Nassa obsoleta) out there on those flats that undoubted- 

 ly has an enormous role in what is going on. We are just begin- 

 ning to suspect what an interesting problem this is. These are 

 called mud snails and in the sense that they are there on the 

 Barnstable flats, this is a mud flat, although it is a mud -sand 

 area. Literature describes these animals as being carnivorous. 

 Any ecologist could recognize the foolishness of this statement 

 because of the enormous numbers in which they are present. 

 They are actually very specialized bottom feeders. They are 

 getting their food from the organic content of the mud and out of 

 the plants and animals and bacteria that are there; also detritus 

 1 am sure. They are so specialized in their feeding that they in- 

 gest enormous quantities of mud, so specialized in fact that they 

 can load up and discharge their gut twice in every tidal cycle, 

 and so, whatever the organic content of that sand is, these things 

 are undoubtedly modifying it tremendously through their feeding 

 activities. This has never been measured and it is only recently 

 that we have realized that they are playing this role in the ecology 

 of the mud flats. 



Stevenson: I have been champing at the bit here. We have some salt marshes 



in southern California too. A lot of these questions that have 

 come up, we have studied, particularly about this organic busi- 

 ness. We made a tremendous number of quantitative evaluations 

 of organic material in the salt marshes and it varies of course 

 due to a great number of conditions: the abundance of plant life. 



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