B. Detritus Production 



III-B-1 



Reimold, R.J., J.L. Gallagher, R.A. Linthurst, and W.J. Pfeiffer. 1975. 

 Detritus production in coastal Georgia salt marshes. Pages 217-228 in^ 

 L.E. Cronin, ed., Estuarine research. Vol. 1. Academic Press, New York. 



The change in quantity of dead material and the detritus production 

 flux (instantaneous rate of disappearance) were measured at four-week 

 intervals in three plant stands in Georgia salt marshes. Detritus 

 production (areal rate of disappearance) was calculated from these data. 

 The average standing crop of dead material was highest in Juncus 

 roemerianus and lowest in short-form Spartina alterniflora. The 

 detritus production fluxes were an average of 7 mg g"lday-l for tall- 

 form S. alterniflora , 18 mg g"'day"^ for short-form S. alterniflora 

 and 7 mg g"lday"^ for J. roemerianus . The average monthly detritus 

 production of tall-form S. alterniflora (197.9 g m"^) was significantly 

 greater than short-form S. alterniflora detritus production (113.6 q m"^) 

 The average monthly J. roemerianus detritus production (188.4 g m"^) 

 was significantly greater than that in short-form but not that in 

 tall -form S. alterniflora . Mean annual detritus production from the 

 aerial portion of the plants (weighted for the percentage of the water- 

 shed occupied by each stand) was 1845.8 g m"^yr." (A. A.) 



Keywords: detritus, productivity, Georgia -- 



III-B-2 



De la Cruz, A. A. 1965. A study of particulate organic detritus in a 



Georgia salt marsh-estuarine ecosystem. Ph.D. Thesis. University of 



Georgia, Athens. 141 pp. (Diss. Abstr. 27:363-B) 



In Georgia estuaries dominated by Spartina alterniflora marshes, 

 organic detritus is the chief link between primary and secondary 

 productivity, since only a small portion of net production of the 

 marsh grass is grazed while in the living state. Six aspects of detritus 

 were studied at the University of Georgia Marine Institute at Sapelo 

 Island, namely: 1) origin and formation (i.e., decomposition) of organic 

 detritus; 2) size distribution and standing crop of detritus particles 

 and composition of total seston; 3) tidal transport of detritus in and 

 out of a ten-hectare area of marsh drained by a single small tidal 

 creek; 4) metabolism of detritus particles; 5) caloric and nutritive 

 values of the different age and size particles; 6) heterotrophic 

 utilization of organic detritus by the marsh and estuarine consumers. 



In creeks draining the Sapelo salt marshes, the dry weight of organic 



detritus particles ranged from 5 mg (at mid-flood tide) to 20 mg 



Cat mid-ebb tide) per liter. Approximately 90-99 percent total seston 



was detritus, of which over 90 percent originated from the Spartina 



98 



