a look at in the future. It is something I have not paid attention 

 to. I cannot give you any help on that one at all. 



Oppenheimer: Dr. Moul, I wondered if you had thought anything about the con- 

 sistency of your sediments with respect to uniformity -- with 

 respect to changes of water above it. For example, 1 find that 

 many of these organisms that are in the water are also present 

 in the sediments at appreciable depths both in aerobic and an- 

 aerobic sediments, so therefore you have a rather uniform 

 stratum below the mud-water interface which is not going to 

 change as rapidly as the water above. 



Moul: I can answer that by saying that last summer 1 got interested in 



the mud of Barnstable Harbor, and we took six-inch cores. We 

 took these cores and sliced them, and what you say is correct. 

 The greatest number of diatoms were on the surface and living 

 diatoms were down as far as six centimeters. What 1 learned 

 last summer in this preliminary study of the mud of Barnstable 

 Harbor is that these living diatoms are down there, and also 

 Merismopedia, a blue -green alga, occurred on the surface and 

 down about 2 centimeters. 



Oppenheimer: Then you have a reservoir, a biological reservoir, in the mud 

 with a rather constant environment. 



Moul: That's right. 



Chapman: I agree with Dr. Moul that Euglena can occur on maritime muds 



but in the cases I am familiar with, it is invariably associated 

 with an outfall of sewage. For example, it has been described 

 on the mud flats of the river Avon in Great Britain outside 

 Bristol, and it also occurs on the mud flats in the other river 

 Avon outside Christ Church in New Zealand, but in both cases 

 it is associated with sewage outfall. It is an organism that quite 

 frequently develops under such circumstances. I would be very 

 interested to know of any further cases of that sort because I 

 think the Euglena is then acting almost as a final purifier, puri- 

 fication element, that is, in the sewage. 1 would like to know 

 whether that is the case there. The other question, before you 

 answer, concerns the advent of what one regards as normally 

 open sea algal species such as Polysiphonia and Aghardiella in 

 the pannes or pools of the salt marsh. Now in Great Britain 

 you can find - also in New England salt marshes - species of 

 Polysiphonia, Ectocarpus and others growing actually attached 

 to the roots of the phanerogams where there is an undercut and 

 an overhang on the pools. I think those are growing there quite 

 naturally and will subsist so long as the pools remain full of 

 water for the greater portion of the year. In the higher pools I 

 agree with you they are casual, thrown in and probably not 



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