although some truly oceanic plankton species may be brought in by tidal 

 action or wind. 



The nutrient level of the water has a great deal to do with the number 

 of diatoms an estuary will support. Compared with the open sea, estuaries 

 are usually fairly high in nutrients. Diatom population varies with 

 the amount of nutrients provided. 



The algae are one of the most important groups at the base of the 

 food chain or web, and so the more diversified the community of algae 

 is, the more useful it will be to a greater variety of organisms that 

 prey upon it. The distribution of the biomass of algae into a few 

 species jeopardizes its usefulness as food. 



Not only the biomass, but also the diversity pattern and the kinds of 

 species, must be considered to understand a community or to relate it 

 to the flow of energy in the food chain. It is conceivable that a 

 much smaller biomass of species that provides desirable sources of 

 food might be more valuable to the food chain than a larger biomass 

 fixed in undesirable food species. The total biomass may be correlated 

 with nutrient level of the water, but its importance in the food chain 

 is greatly influenced by the kinds of species that compose it. (H.D.) 



Keywords: diatoms, estuaries, nutrient levels, biomass 



III-D-12 



Hackney, C.T. 1977. Energy flux in a tidal creek draining an irregularly 



flooded Juncus marsh. Ph.D. Thesis. Mississippi State University. 



83 pp. 



The flux of suspended organic detritus, floating debris and animal 

 biomass from a Mississippi tidal creek was studied during ten diurnal 

 tidal periods (24 hour) and three semi-diurnal tidal periods (12 hour) 

 between May 1975 and April 1976. There was a net export of floating 

 debris (3.1 kg) and animals (0.49 kg), but a net import of suspended 

 particulate detritus (38.5 kg) during the 13 tidal periods studied. 



The concentration of suspended particulate organic detritus was 

 predictable during ebb tide and was dependent primarily on tidal height, 

 season, physical characteristics of the water (e.g., temperature, 

 salinity and dissolved oxygen) and the concentration of the fauna within 

 the creek. The concentration of particulate organic detritus was not 

 predictable during flood tide. 



Thirty species of fishes and six species of invertebrates were collected 

 during the study. The blue crab ( Callinectes sapidus ) and the gulf 

 menhaden ( Brevoortia patronus ) were the only commercial species that 

 were numerous components of the living biomass export. Centrarchid 



?r 



species, notably the largemouth bass ( Micropterus salmoides ) and the 



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