business. I have seen it in Jamaica and other places. I think 

 between the temperate Spartina and the tropical Thalassia, you 

 would have to incorporate the manatee grass. The manatee 

 grass (Cymodocea) is very abundant. If you have been along the 

 Florida beaches, you can see that at certain times of the year 

 that is much more important than Thalassia. You go out in 

 about 6 feet of water and get to about 20 feet of water and you 

 have still got a mixture of the two. So if you want to describe 

 these marshes you might include those and then you have two 

 or three other species. 



Burkholder: Yes, that is right. 



Davis: So you end up with a submarine, or if you wish to call it benthic 



marsh, or submarine type vegetation which begins with Thalassia 

 and changes gradually to Spartina as you go north, but I think your 

 word "marsh" is entirely correct. When you get to marsh man- 

 groves 1 go with Dr. Chapman on that; you must buy the propo- 

 sition that mangrove peat itself can form without Thalassia. It 

 can do it right on top of other mangrove peat, Thalassia will 

 seek soft mud. Cymodocea will seek hard sand. There is 

 quite a bit of difference in the bottom elements, but you can re- 

 place them all with mangrove. 



Oppenheimer: I would like to make a few comments on Dr. Burkholder's work 

 with Thalassia because I have been working in Thalassia beds 

 too in our shallow bays down in Texas. It is rather unique in 

 that we have a rather strong onshore wind most of the year and 

 our Thalassia beds grow in a sort of mucky material which is a 

 fine silt with diatoms, algae and bacteria, but during the times 

 that the wind blows these sediments all go up into suspension. 

 We have been able to find differences in Thalassia beds which 

 we think may be due either to chemical precipitation by some- 

 thing put out by the Thalassia beds or due to the filter action of 

 certain organisms, mainly shelled organisms which are in the 

 beds. So, therefore, in one bed the water will remain cloudy 

 for a good long period of time, the material settling out from 

 the water onto the Thalassia leaves. The material builds up 

 on the leaves. Then it sloughs off and falls down onto the 

 bottom, but in the other beds the water becomes clear within a 

 very short time after the storm and we think that this is due to 

 one of these two processes (we don't know whicn one). We think 

 that it is filter feeding organisms that are picking all the bac- 

 teria, the diatoms, the algae, and the silt with other organic 

 material adsorbed on it as a nutrient source. 



Burkholder: Are ciliates in your Thalassia beds ? 



Oppenheimer: Yes, very abundant. There are ciliates and just about every- 



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