Spartina is due to the lack of available N, There was no response 

 to applications of iron to support previous speculation that iron 

 might be a limiting factor in growth. 



Nitrogen and P fertilizers were also shown to enhance growth of 

 seedlings and transplants artificially established on sandy dredge 

 spoil. This may be of practical benefit since establishing a vegeta- 

 tive cover rapidly may be critical in stabilizing an area. (A. A.) 



Keywords: productivity, Spartina alterni flora , mineral nutrition, 

 North Carolina 



II-E-5 



Pomeroy, L.R., R.E. Johannes, E.P. Odum, and B. Roffman. 1969. The phosphorus 

 and zinc cycles and productivity of a salt marsh. Pages 412-419 j_n 

 D.J. Nelson, ed.. Proceedings of the Second National Symposium on 

 Radioecology, U.S. Atomic Energy Commission, Washington, D.C. 



By synthesizing the results of two field experiments using phosphorus (P) 

 and zinc (Zn) with earlier work on Georgia salt marshes, the cycles of the 

 elements P and Zn are quantitatively described. Marsh grass and sediments 

 dominate both cycles. The uppermost meter of sediments contains enough 

 P to support Spartina production for 500 years and enough Zn for 5000 

 years. Spartina production removes P and Zn from the subsurface 

 sediments and introduces them into the water (via bacterial utilization 

 of dead Spartina and subsequent utilization of the bacteria by detritus 

 feeders) at a rate that replaces total water P in a month and total 

 water Zn in a year. A significant part of the P is exported from the 

 marsh in organisms and detritus. The P and Zn in the estuarine water 

 are in equilibrium with plankton, bacteria, and surface sediments. 

 The equilibrium strongly influences the sediments. The transfer of P 

 and Zn from the dry sediments to the water by Spartina explains the 

 high concentration of these elements in the water of marshy estuaries. 

 (L.H.) 



Keywords: salt marsh, productivity, mineral nutrition, Spartina , 

 Louisiana 



II-E-6 



Thayer, G.W. 1974. Identity and regulation of nutrients limiting 



phytoplankton in the shallow estuaries near Beaufort, North Carolina. 



Ocelogia 14:75-92. 



Enrichment experiments to test the hypothesis that nitrogen was the 

 prime limiting nutrient and experiments to determine whether microbial 

 competition for nitrogen and phosphorus might limit the availability of 

 these nutrients to the phytoplankton are described. Inorganic nutrients 



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