SOME MICROBIOLOGICAL ASPECTS OF MARINE 

 PRODUCTIVITY IN SHALLOW WATERS 



by 



Paul R. Burkholder 

 Brooklyn Botanic Garden 



Salt marshes of the eastern coast of North America and the Caribbean 

 vary greatly in kind of substrate and floristic composition. Dominant plants 

 with submerged roots and rhizomes and aerial shoots frequently occur in the 

 tidal areas of these marshes. Spartina is abundant in the temperate regions, 

 and species of mangrove are characteristic of tropical areas. Submerged 

 plants such as eel grass, manatee grass and turtle grass are abundant primary 

 producers in their respective areas. Oftentimes associated with shallow water 

 communities of mangrove and turtle grass, such as occur in Puerto Rico, are 

 the coral reefs, which are unique associations of symbiotic coelenterates and 

 photosynthetic dinoflagellates (Mc Laughlin and Zahl, Proc. Soc . Exp, Biol. 

 Med., 95, 115, 1957). The mud surface in different latitudes appears gener- 

 ally to support growth of diatoms, blue-green algae and other primary produc- 

 ers. In all of these areas periodic blooms of planktonic diatoms and dino- 

 flagellates are at various times important to the total productivity. Studies on 

 the crops and residues of typical communities indicate that microbial decom- 

 position plays an important role in the turnover of the primary organic matter 

 for consumption by herbivores and carnivores. Bacteria constitute an active 

 group of small plant converters which aid in formation of detritus, much of 

 which then is available for the micro- and macro -fauna of marshes and nearby 

 marine areas . 



The amount of standing crop of plankton or of flowering plants may pro- 

 vide a rough indication of the productivity. Thus, suspended dry materials in 

 blooms, measured by millipore filter technique, in Long Island Sound, at 

 Sapelo, Ga. , and in the Bahia Fosforescente , Puerto Rico, have given the fol- 

 lowing values in milligrams per liter: 16.8, 22 to 159, and 14.4. Great 

 variations occur, and this approach only indicates what is present at any given 

 time, not the overall production. Other methods, e.g., measurements of 

 carbon fixation with C-14, oxygen production in dark and light bottles, etc. , 

 provide better indices to primary productivity. Our raw data on productivity 

 of marshes, using these methods, are not ready for presentation. 



The decomposition of plankton by marine bacteria, now under considera- 

 tion in Long Island Sound, appears to occur rapidly in laboratory experiments. 

 Extracts of both zooplankton and phytoplankton support growth of bacteria in 

 sea water media. Growth is proportional to concentration of extracts over the 

 range of soluble matter derived from 1 milligram to 16 milligrams of plankton 

 per milliliter of sea water. It appears that scarcity of organic material in 

 solution limits the population of marine bacteria in Long Island Sound and else- 

 where. 



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