standing crop Cwhich occurred In pannes) were associated with infrequent 

 floodings and wide ranges of salinities. Both sites are dominated 

 by Spartina alterniflora . with the tall form occurring along creeks 

 and the stunted form occurring in pannes. (A. A.) 



Keywords: salt marsh, marsh plants, Spartina , productivity. New 

 Jersey 



II-B-32 



Nadeau, R.J. 1972. Primary production and export of plant materials 



in the salt marsh ecosystem. Ph.D. Thesis. University of New Jersey. 



175 pp. (Diss. Abstr. 33:1504-8) 



Metabolism of mudflat algal, marsh surface algal, and drainage 

 ditch phytoplankton communities for a New Jersey salt marsh ecosystem 

 was investigated for two years (November 1968-August 1970). Standing 

 crop measurements of the salt marsh grass community were determined 

 midway and at the end of each growing season. 



2 



Mudflat algal productivity rates averaged 7.5 mg C/m /hr during 



1969 (July-November) and 10 mg C/m^/hr for 1970 (Apri 1 -August) . 



Marsh surface algal production^rate averaged 3.0 mg C/m^/hr during 1969 



(July-November) and 5.0 mg C/m /hr for 1970 (April -August) . Hourly 



respiration rates for both communities were less than gross productivity 



rates for most of the season. Total respiration for a 24-hour day 



was greater than gross productivity, resulting in negative net productivity 



for both communities during the summer and autumn. 



Gross production rates for the drainage ditch phytoplankton community 

 averaged 268 mg C/m^/day from November 1968 through October 1969 and 

 360 mg C/mVday from November 1969 through August 1970. In the winter, 

 respiration and production were less than in the summer. 



Spartina alterniflora , growing along thepditch borders, had the 

 largest end-of-year standing crop (520 g/m ) for both seasons. The high 

 marsh salt meadow grass, S. patens , was nearly as productive, averaging 

 409 g/m^ for both seasons. Short form S^. alterniflora was not so 

 productive (385 g/\rr) . 



2 



Litter accumulation from previous growth averaged 260 g (dry wt)/m 



in the high marsh area, whereas in the border zone the litter was 

 removed by tidal action and accumulation was negligible. The amount 

 present in the high marsh decreased as the growing season progressed, 

 signifying (1) incorporation of litter into the soil-building process 

 and (2) herbivore consumption. 



Seven tidal cycles were monitored during the study. A seine was 

 used to collect floating debris, mainly S. alterniflora stalks and 

 leaves, which were removed from the ecosystem during each ebb tide. 



58 



