II-B-14 



Mclntire, G.L., and W.M. Dunstan. 1975. The seasonal cycle of growth and 

 production in three salt marshes adjacent to the Savannah River. Skida- 

 way Institute of Oceanography, Savannah, Georgia, Technical Report 

 No. 75-2. 19 pp. 



Three geographically similar Spartina alterniflora marshes near 

 Savannah, Georgia, were studied monthly during 1974. Production levels, 

 percent ash, and other growth parameters were measured. While general 

 growth trends were similar at all three sites, the levels of production 

 varied significantly, with the marsh on the Savannah River showing the 

 greatest production. Measurements of standing dead Spartina revealed 

 a ready supply of detrital energy which is available to the adjacent 

 estuarine regions throughout the year. The Savannah River marsh 

 demonstrated that studies of river systems with high levels of industrial 

 municipal effluents must consider increased plant production as well 

 as inhibitory or toxic effects. The study is a first step toward 

 a "condition index" for coastal salt marshes that would enable in- 

 dustrial and governmental agencies to determine the effects of environ- 

 mental perturbations on these important natural resources. (A. A.) 



Keywords: primary productivity, Spartina , salt marshes, Georgia 



II-B-15 



Gallagher, J.L., R.J. Reimold, and D.E. Thompson. 1972. Remote sensing 



and salt marsh productivity. Photogrammetric Engineering 38:591. (Abstr.) 



The feasibility of using photography or thermal imagery from fixed- 

 wing aircraft for assessing salt marsh productivity is being investi- 

 gated. Kodak Aerochrome Infrared 2443 and Aerocolor Negative 2445 

 films and a Bendix Thermal Mapper are being used. Remote sensing 

 flights (from 1,250 to 20,000 feet) are made in conjunction with acquisition 

 of ground-truth data consisting of chlorophyll per unit area, the 

 density of living and dead plants by number, and biomass for each species 

 and each one-half meter height class. 



A number of windows in the 2 to 13 micrometer wavelength range are 

 being tested with the thermal mapper to ascertain which gives the best 

 discrimination of spatial productivity patterns. Color enhancement 

 of the imagery has proven useful in defining the extent of these areas 

 and predicting tidal hydrography in the intertidal zone. 



Color patterns in the color-infrared photographs, due in part to 

 differences in plant species, density, growth form, and pigmentation, 

 are being quantified by: (1) planimetry of handdrawn visual inter- 

 pretation of projected transparencies; (2) planimetry of visual inter- 

 pretation using a Kernplotter; and (3) microdensitometry of each zone 

 defined by a Joyce Loeble Microdensitometer coupled with a four-color 

 isodensitracer. 



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