In creeks draining Sapelo marshes, organic detritus ranges from 

 2 mg/1 at mid-flood tide to 20 mg/1 at mid-ebb tide, and makes up about 

 90-99 percent of the total seston. The small suspended particles are 

 70-80 percent ash; but the organic portion is rich in protein, containing 

 up to 24 percent on an ash-free basis as compared with 10 percent in 

 living grass and only 6 percent in dead grass as it enters the water. 

 Oxygen consumption (BOD) per gram is more than five times as great 

 in "nanno detritus" (that which passes through a No. 25 net-200 meshes 

 per inch; 0.064mm per aperture) as compared with coarse detritus 

 (that retained by a No. 6 net-74 meshes per inch; 0.239mm per aperture), 

 indicating increasing microbial activity with age. The nanno fraction 

 comprises 95 percent of the total particulate organic matter. Thus, 

 the bacteria-rich detritus is nutritionally a better food source for 

 animals than is the Spartina tissue that forms the original base for 

 most of the particulate matter. (Author's summary) 



Keywords: productivity, detritus, Spartina alterni flora , estuaries, 

 Georgia 



III-B-4 



Heald, E.J. 1971. The production of organic detritus in a South Florida 

 estuary. University of Miami Sea Grant Technical Bulletin No. 6. 110 pp. 



The mechanisms and pathways by which uead plant material is incorporated 

 into the aquatic system, thereby constituting an important energy source, 

 are delineated and quantified. Estimations of the annual production of 

 dead material by red mangrove, sawgrass, and blackrush were made. 

 The mechanisms by which such material enters the detrital pool, the 

 rate at which this proceeds, determination of the fluctuations in the 

 quantity, nature and origin of the detrital load were ascertained along 

 with the potential nutrient value of dead material, if consumed at any 

 specific stage of decomposition. (A. A.) 



Keywords: detritus, estuaries, Florida 



III-B-5 



Odum, W.E., and E.J. Heald. 1974. Mangrove forests and aquatic productivity. 



Pages 129-136 in^A.D. Hasler, ed.. Coupling of land and water systems. 



Springer-Verlag, Berlin. 



The importance of terrestrial primary production as a source of energy 

 in aquatic ecosystems is outlined. Detritus particles originating from 

 trees, shrubs, sedges, and grasslands in the watershed are the primary 

 energy source. Mangrove swamps are used as an example. The article 

 discusses: 1) mangrove swamps and coastal waters, including an inter- 

 action hypothesis and evidence from a Florida mangrove swamp; 2) 

 production and losses of organic matter, including foliage production, 



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