can'dean shrimp, penaeid shrimp, crabs, filter-feeding bivalves, and 

 a few species of fishes. The omnivorous detritus consumers appear to 

 obtain nutrition primarily from the microorganisms adsorbed upon detritus 

 particles. The destruction of mangrove forests will remove a source 

 of food input into an estuary and directly limit the production of 

 detritus consumers and those predators that feed upon them. (A. A.) 



Keywords: mangrove, energy flow, food chain, estuaries, Florida 



III-E-15 



Kuenzler, E.J. 1961. Phosphorous budget of a mussel population. Limnology 

 and Oceanography 6:400-415. 



The common horse mussel ( Modiolus demissus ), which is abundant in 

 the marshes, is extremely important in the phosphorous cycle. In 

 filtering water to obtain its food, the mussel deposits huge quantities 

 of organic particles by producing pseudofeces that sink to the bottom. 

 Organic matter is thus retained in the marsh and made readily available 

 to the algae and fiddler crabs. This study was one of the earliest 

 to suggest the great complexity of the food chain in estuarine areas. 

 (J.B.) 



Keywords: food chain, horse mussel, phosphorous 



III-E-16 



Heinle, D.R., D.A. Flemer, J.F. Ustach, R.A. Murtagh, and R.P. Harris. 1973. 

 The role of organic debris and associated microorganisms in pelagic 

 estuarine food chains. Maryland Water Resources Research Center, 

 College Park, Technical Report No. 22. 123 pp. 



Production on marshes adjacent to the upper Patuxent estuary was 

 1,000 to 1,500 grams dry weight per m^ per year. Approximately 6 to 

 9 percent of the annual production was exported to the estuary as partic- 

 ulate carbon. Production was comparable to other marsh systems, but 

 export (as percentage of production) was less, probably due to poor 

 tidal exchange. In spite of the relatively low percentage of their 

 fixed carbon contributed to the estuary, the marshes provide about one- 

 third of the total carbon budget in the upper Patuxent. A large portion 

 of the marsh carbon enters the estuarine system in early spring when 

 levels of algal primary production are low. Substantial production 

 of the calanoid copepod Eurytemora affinis occurs with detrital 

 carbon as the apparent food base. Feeding experiments indicate that 

 E. affinis can reproduce when fed a diet of detritus enriched with 

 bacteria and protozoa, or when fed only protozoa. Diets of detritus 

 and microorganisms alone were seldom equal to algal controls, however, 

 suggesting that detritus provides only part of the carbon requirement. 



131 



