RIVER-DERIVED INPUT OF DETRITUS INTO 

 THE APALACHICOLA ESTUARY 



Robert J. Livingston 



Department of Biological Science 

 Florida State University 

 Tallahassee, Florida 



ABSTRACT 



The exact significance of 

 river-derived particulate organic 

 matter to estuarine biota remains in 

 doubt. This is due, in part, to al 

 lack of information regarding 

 temporal (seasonal, annual) features 

 of detrital loading. Quantitative as 

 well as qualitative aspects of such 

 detritus movement are probably an 

 important feature of estuarine 

 productivity. Long-term (5-year) 

 studies of detritus movement into the 

 Apalachicola estuary indicate that 

 the timing of river flow peaks, 

 together with changes in the wetlands 

 vegetation along the flood plain and 

 macrophyte cycles within the estuary, 

 are important determinants of short- 

 and long-term trends of the input of 

 particulate organic matter. Research 

 by the Florida State University 

 Aquatic Study Group is currently 

 addressing the specific response of 

 estuarine biota to multiple climato- 

 logical factors in an attempt to 

 evaluate the biological significance 

 of river flow into the Apalachicola 

 estuary. 



INTRODUCTION 



River-derived freshwater input 

 has various effects on receiving 



coastal systems. Some studies have 

 described the production and movement 

 of particulate organic matter in 

 streams and rivers (Kaushik and 

 Hynes, 1971; Hynes et al., 1974; de 

 la Cruz and Post, 1977). De la Cruz 

 (1979) has reviewed various aspects 

 of the production and transport of 

 detritus in estuaries . Post and de 

 la Cruz (1977) estimated the trans- 

 port of allochthonous particulate 

 organic matter into a gulf coast bay 

 and found that variation of net in- 

 put depended on qualitative features 

 of the leaf litter and the hydrolog- 

 ical features of the system. Var- 

 ious factors such as local meteoro- 

 logical conditions, flow variation, 

 litter fall and decomposition rates, 

 river size and configuration, topo- 

 graphy of the drainage system and 

 physiography of the receiving estu- 

 ary are all involved with the net 

 input of organic matter to river- 

 dominated estuaries. While various 

 studies indicate that there is con- 

 siderable seasonal and annual varia- 

 tion in sediment discharge into bay 

 systems, there is relatively little 

 information concerning the qualita- 

 tive composition of particulate 

 organic matter as it moves into 

 coastal areas and the temporal varia- 

 bility of such movement. Such 

 aspects of detrital flux could be 

 of importance to the biological 

 organization of the receiving estuary 

 although there are few analyses that 



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