increasing pressure from industrial and suburban developments and they 

 have been widely used as garbage dumps. In view of future plans, it is 

 imperative that the marshes be thoroughly studied ecologically and their 

 value assessed on productivity as part of the coastal ecosystem. 

 Their economic value is far-reaching and intermeshed with the commercial 

 fisheries, as well as recreational aspects of south Mississippi. Some 

 people find the marshes of aesthetic value and a place to refresh them- 

 selves. An initial study was conducted in 1968 and 1969 to determine 

 the composition, area, zonation, organic production, and some of the 

 regulating factors influencing the marsh vegetation. A summary of the 

 observations and conclusions is presented in this paper. 



Mississippi marshes were sampled during 1968 and 1969 by line transect 

 and list count quadrats, and the composition of vascular plants through- 

 out the salinity gradient was determined in three estuarine systems. 

 Profile diagrams were prepared to illustrate lateral zonation of the 

 plant communities. Marsh acreage, measured by planimeter from survey 

 maps, was determined. Organic production of the vascular marsh plants 

 in Mississippi was estimated. Present and projected manmade changes 

 in the marshes are discussed. Some observations on composition and 

 zonation of plant colonization on spoilbanks and landfills are presented. 



The paper is especially relevant to marsh productivity. It discusses 

 plant species and their distribution in relation to salinity; dominant 

 plant species; the grass-rush-sedge complex; regions of the marsh; and 

 composition of saline, brackish, intermediate, and freshwater marshes. 

 Other headings deal with zonation of the marsh, acreage and production, 

 dredge and fill operations and plant colonization. An overall dis- 

 cussion sums up production estimates and concludes that "the role of 

 marshes in an estuary are many and varied. Biological, chemical and 

 physical systems interact in complex fashions, and these are generally 

 poorly understood. One of the key roles of marsh vegetation is the 

 converting of inorganic compounds, water and sunlight, into plant 

 tissues which can be utilized by consumer organisms in the marsh 

 and open waters of the estuary. The marshes also serve as protective 

 habitats for astronomical numbers of animal organisms." (G.S.) 



Keywords: salt marshes, productivity, Mississippi 



II-B-IO 



De la Cruz, A. A. 1974. Primary productivity of coastal marshes in 

 Mississippi. Gulf Research Reports 4:351-356. 



Coastal marshes are commonly characterized as sites of extremely high 

 primary production. The author contends that the available data 

 are insufficient to support or refute such a generalization. It is 

 more likely that marshes differ considerably in their productivity. 

 The diverse nature of marshlands along the Gulf Coast of Mississippi 



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