decomposition of mangrove leaves, and the export of mangrove leaf 

 material; 3) qualifications to the hypothesis, including magnitude 

 and total production of the mangrove ecosystem; and 4) location of 

 consumer communities. (J,B.) 



Keywords: mangrove, primary productivity, detritus, Florida 



III-B-6 



Blum, J.L. 1968. Salt marsh Spartinas and associated algae. Ecological 

 Monographs 38:199-221. 



An investigation of the algae of the high salt marsh, particularly 

 their microdistribution and ecology, and the relationships between 

 algae and the graminoid vegetation was conducted in Barnstable marsh 

 on Cape Cod between 1959 and 1965. 



The ontogeny of the habitats of principal algal communities of the 

 high salt marsh is outlined; in particular, the steps by which the 

 Spartina patens community becomes prostrate and converted to a 

 horizontal, well -aerated mat-like structure are described. Spartina 

 patens exhibits a series of adaptations which permit the construction 

 and maintenance of this mat: temporary vane action of the leaf blade, 

 subsequent sclerification of much of the blade and subtending internode, 

 gravity, wind, tidal submergence, "prop" leaves, leaning of the plant 

 and a culm base which bends easily but which exhibits considerable 

 tensile strength, are all involved in this process. Many of the 

 features of this mat are also found in dense stands of Distichlis 

 spicata . Light conditions of certain algal habitats become marginal 

 as the salt marsh graminoids grow during summer months. Light values 

 at the soil surface under mature stands of S. patens and D. spicata 

 are probably limiting or marginal at all times. On the Barnstable 

 marsh, soil under mature S. patens is slower to warm in spring than 

 under S. alterni flora ; particularly is this true when S. alterni flora 

 of creekbanks is considered. 



Relative humidity values at the level of surface grass on the dead 

 S. patens mat are commonly low and probably prevent algal growth 

 here. Humidity values at deeper levels with the mat of dead grass 

 are more favorable, but light becomes limiting here and algal growth 

 is usually conspicuous only where the mat is relatively thin. The 

 primary and most successful algal colonist on the moist portion of the 

 dead S. patens is a species of Calothrix . Widespread algal colonization 

 of the S. patens mat would clearly contribute materially to the rapid 

 destruction of the mat. Due to the levels of humidity and light that 

 are achieved through the presence of the S. patens mat in mature stands, 

 the growth of algae is effectively suppressed. In contrast to the 

 sparse or non-existent algal colonization of mature S. patens and 

 mature Distichlis spicata , a continuous and nearly ubiquitous algal 

 layer is present under high marsh (stunted) S. alterni flora . Partly 



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