Recently, certain revisions have been 

 proposed of early concepts of detritus 

 outwellinq from coastal marshes (Haines 

 197Q). There is evidence of no net export- 

 of particulate organic matter (POM) from 

 salt marshes under certain conditions 

 (Woodwell et al. 1Q77). Odum et al. 

 (1^179) have hypothesized that net fluxes 

 of POM from coastal marshes depend on the 

 qeomoroholoqy of the wetland basin, the 

 maqnitude of the tidal ranqe, and upland 

 freshwater inout. In the Apalachicola 

 estuary, the tidal ranqe is relatively 

 small. Marsh distribution is limited 

 larqely to the delta area (East Bay) and 

 laqoonal portions of the barrier islands. 

 The considerable river runoff and the 

 associated export of orqanic matter due to 

 floodinq would amplify the importance of 

 the East Ray marshes accordinq to the Odum 

 model (Odum et al . l^^yg). 



The salt marshes of the bay svstem 

 contribute only a small fraction of the 

 particulate orqanic loadinq to the bay 

 system (Livinqston et al . 1974), althouqh 

 such areas are important nurseries for 

 estuarine fishes and invertebrates 



(Livinqston 1^80c). However, the marshes 

 may olay a role in the export of orqanic 

 material to the bay system. Ribelin and 

 Collier (1P79) showed that local marshes 

 export detrital agqreqates or films that 

 averaqe ?5-50 m in thickness and are 

 produced by benthic alqae rather than by 

 microbial decomposition of the marsh 

 plants. Tidal action lifts these films of 

 alqae out of the marshes, especially 

 durinq late summer ebb flows. Thus, while 

 the vascular tissue of the marsh qrasses 

 is decomposed beneath a layer of benthic 

 alqae, it is essentially retained within 

 the marsh proper. Amorphous aqqreqates of 

 "nanodetritus" composed of microalqae may 

 play a more important role in the nutrient 

 budget of the bay svstem than previously 

 thouqht, esoecially during late summer and 

 early fall periods. 



The seasonal abundance and spatial 

 distribution of nutrients and detritus in 

 the Apalachicola Bay system result from a 

 combination of forces, some of which are 

 quite localized and specific in nature. 

 For example, the timing and magnitude of 

 localized hydrologic events such as 



Table 10. Nutrient yields for various drainage areas in 

 Chattahoochee-Flint River system. Data are presented on an areal 

 Mattraw and Elder 1982). 



the Apalachicola- 

 basis (adapted from 



39 



