EFFECTS OF SUSPENDED SOLIDS ON SELECTED 

 ESTUARINE PLANKTON 



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J. A. Sherk, Jr., J.M, 0' Connor , 

 and D.A. Neumann 



I, EFFECTS ON SUSPENDED SOLIDS ON CARBON ASSIMILATION 

 OF SELECTED SPECIES OF ESTUARINE PHYTOPLANKTON 



1. Introduction . 



Phytoplankton growth is usually measured in terms of photosyn- 

 thesis (carbon uptake and oxygen evolution) . This growth responds in 

 a complex way to various single or combined factors. Some of the more 

 important factors are nutrition, temperature, salinity, and ligh.t 

 (Jitts, et al., 1964). 



The release of silt, clay, and fine sand-sized particles (organic 

 and inorganic) into the water column is a dominant feature of bay and 

 estuarine areas (Sherk, 1971). These releases may be caused by beach 

 erosion, river contribution, storm agitation, dredging, and disposal 

 of dredged material. An important effect of the resulting suspended 

 load is reduced light penetration (by absorption, Raleigh small and 

 large particle scatter), which limits the depth of water in which 

 light intensity is sufficient for the rate of phytoplanktonic photo- 

 synthesis to exceed the respiration rate. 



The experimental work investigating the effects of increasing 

 concentrations of extremely fine silicon dioxide particles on the 

 carbon assimilation of various monospecific cultures of phytoplankton 

 grown at estuarine salinities is presented in this section. 



2. Materials and Methods. 



a. Culture. Cultures of phytoplankton were obtained from the 

 Woods Hole Oceanographic Institution (WHOI) as follows: 



Name WHOI clone symbol 



Monoahrysis lutheri Mono 



Nannoahloris sp. GSB Nanno 



St-ichoaoGcus sp. GSB Sticho 



Chlorella sp. 0-10 



These cultures were grown in Guil lard's f/2 medium (Guillard and 

 Ryther, 1962) made with autoclaved (15 pounds per square inch; 30 

 minutes) Patuxent River water which was previously filtered through 

 sintered Whatman GFC glass-fiber filters. 



