during June and July. Maximum nitrate concentrations occurred during 

 late May. The pulse in production during summer was ascribed to the 

 accumulation of available nitrogen prior to, and increases in dissolved 

 inorganic phosphorus during, the pulse. A general dearth of nutrients 

 was probably the prime factor limiting production. 



Nutrient enrichment experiments indicated that nitrate was more 

 limiting than phosphate. The addition of organic compounds low in 

 nitrogen and phosphorus depressed photosynthesis. This suggested that 

 bacterial immobilization of nitrogen and phosphorus during decomposition 

 of organic matter that may be added to the system may account for the 

 paucity of nutrients. 



Much of the phosphorus in the system was in an organic form as 

 particulate phosphorus and dissolved organic phosphorous. Phosphorous 

 turnover was more rapid in the estuarine areas than in the adjoining 

 ocean. Phosphorous turnover appeared rapid enough to supply sufficient 

 dissolved inorganic phosphorus for phytoplankton growth. (A. A.) 



Keywords: phytoplankton, primary production, estuaries. North Carolina 



II-C-13 



Odum, H.T., and CM. Hoskins. 1958. Comparative studies on the metabolism 



of marine waters. Publications of the Institute of Marine Science, 



University of Texas 5:16-46. 



Metabolic methods were used for rapid study of whole water areas. 

 Measurements of metabolic rates in contrasting waters indicated 

 qualitative contrasts and a wide range of values in quantitative 

 data. Such data can provide an understanding of shallow marine bay 

 systems anywhere and a basis for resolving conflicts. 



The diurnal curve method for measuring metabolism was widely applied 

 in the study in coastal waters with a number of tests of the methods. 

 Rates of gross community photosynthesis (primary production) and total 

 community respiration were determined with diurnal curve methods, dark 

 bottle methods, mud bottle methods, and bell jar methods in marine waters 

 of Texas, North Carolina, and British West Indies. Metabolic rates 

 ranged from 1 to 24 gm/m^/day oxygen. Depth of the environments ranged 

 from a few centimeters of water over blue-green algal mats to 15 m of 

 water on the Gulf of Mexico shelf. Replications of the diurnal curve 

 method at three similar stations were within 20 percent of the mean. 

 Two contrasting stations were within 35 percent of the mean. Difficulties 

 in estimating trajectory, depth, and daytime respiration were principal 

 sources of error. Diurnal curves in open shelf waters were measurable 

 where large numbers of duplicate Winkler analyses were made. Shapes and 

 variations in diurnal curves were presented including inverted curves. 



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