II-C-4 



Gallagher, J.L. 1971, Algal productivity and some aspects of the ecological 



physiology of the edaphic communities of Canary Creek tidal marsh. 



Ph.D. Thesis. University of Delaware. 125 pp. (Diss. Abstr. 32:6353-6). 



Gross algal primary productivity and edaphic community respiration 

 estimates were made for five areas of Canary Creek tidal marsh near 

 Lewes, Delaware. Oxygen changes in water overlying cores of the marsh 

 incubated in the laboratory were used as the indication of metabolic 

 activity. Environmental factors of light, temperature, salinity, pH, 

 nutrient content of surface water and the nitrogen and phosphorus 

 content of the grass were measured. 



Bare bank and panne algal productivity did not vary significantly 

 from one part of the year to another. Algal productivity in the tall 

 Spartina alterni flora and Distichlis spicata areas was greatest in 

 the period from mid-January to mid-May. In the dwarf form Spartina 

 alterni flora area algal productivity did not drop in the warmest part 

 of the year as it did in the two other grassy areas. Algal productivity 

 in the several areas tested was not inhibited by illuminances of 103 

 kilolux from quartz-bromide lamps. Saturation occurred at approximately 

 one-half of full light in most cases. An apparently die!, endogenous 

 productivity rhythm was observed in the tall and dwarf Spartina areas. 



It was estimated that the algae produce 160 g of ash free dry matter 

 per m2/year. About 0.1 percent of the ^^liotosynthetically active energy 

 available above the angiosperms was stored by the algae. Edaphic 

 community respiration requires nearly three times the algal oxygen 

 output. Respiration was approximately twice as high during the mid-May 

 through mid-September period as in either of the other 2 four-month 

 periods of the year. No endogenous respiratory rhythm with appreciable 

 amplitude was detected. Exogenous respiratory rhythms were present 

 as the result of temperature changes during the day. Qip, values 

 ranged from 1 .1 to 2.2. '^ 



Although the gross algal production is only about one-third the net 

 angiosperm production, the algal production may be more important than 

 its annual production indicates, since much of it occurs at a time 

 when the grasses are dormant. (A. A.) 



Keywords: algae, primary productivity, tidal marsh, Spartina , Distichlis , 

 Delaware 



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