Figure 50. Net epiphytic production on 

 stems of Spartina al terni f1 ora collected 

 at the water' c edge and inland 1.5 m with 

 the averages, extremes, and fitted curve 

 for the water's edge production 

 superimposed (Stowe 1972). 



in protein than the dominant grasses. 

 Furthermore the diatoms are already 

 "bite-sized" and may be much more readily 

 available to the consuming members of the 

 community. Therefore they may be more 

 important metabol ical ly than has been 

 commonly real ized. 



Benthic Microflora in Marsh Ponds 



There have been no studies on the 

 gulf coast of the benthic flora found in 

 marsh ponds. Most individuals who have 

 taken the trouble to examine these ponds 

 when they are exposed at low tide can 

 testify that there is almost always a 

 golden sheen to the mud surface. Under 

 the microscope this sheen is resolved into 

 a dense layer of diatoms of many species. 



Recently Moncreiff (1983) studied the 

 algal mats found on the edges of the 





V 



CO « 

 S~ 3 



o^ 



I-'" 



<e 



o 



" 1 



o 



z 



— 0-10 cm 



- 10-20 cm 

 •- 20-30 cm 



Figure 51. Number of shore-line epiphytic 

 diatoms/ cm culm surface area of Spartina 

 al terniflora . Results are pooled averages 



and 



for four stations 

 (Stowe 1982). 



height classes 



freshwater marshes in the Atchafalaya 

 Delta, and Shaffer (LSU Department of 

 Marine Sciences; pers. comm.) measured 

 metabolic rates of algae on mud flats 

 adjoining salt marshes in 

 Both measured high rates of 

 respiration. Moncreiff 

 production rates of about 



Barataria Bay. 

 production and 

 reported 

 400 g C/m 



net 



/yr 



as 



with individual measurements as high 

 300 mg C/mVhr. 



Submerged Grasses in Marsh Ponds 



There have been no measurements of 

 productivity of submerged plants in marsh 

 ponds. Chabreck (1971a) identified the 

 species found there (Table 19), and it is 

 known that growth is enhanced by 

 stabilizing the water level at shallow 

 depths (Chabreck 1975), as is done with 

 weirs. Periodic water drawdowns also 



stimulate growth by consolidating the 

 substrate to reduce turbidity. This is a 

 fertile field for further research. 



DECOMPOSITION 



One of the important insights that 

 has developed in ecology in the past 25 

 years has been that the major flow of 

 organic energy in most ecosystems is 

 through a detrital food chain. Open 

 oceanic ecosystems are one exception; 



55 



