:Sfcr>:^Asr>^^«**Cfc ^-^ -Mil-- 



Figure 9.— Northern Bota Ciega Bay uear Johns Pass in 1!H>3 showing bayflll areas (iiliotograpli courtesy of Airflite. 



St. Petersburg, Fla. ). 



chiced in summer over tlie soft sediments of access 

 canals. Tidal movements in the bay probably make 

 some oxygen availal>le throusrhout the water 

 cohmm at most times, but occasional reductions 

 limit some marine animals (Emery and Stevenson, 

 li)57;Reish, 1959). 



Pvlsewhere in Tampa Bay, marked oxygen reduc- 

 tion near the bottom has been recorded only in 

 Hillsborough Bay (Saloman et al., 1964), where 

 pollution from sewage is heavy, summer water tem- 

 perature is high, and water circulation is poor. 

 Additional bayfill development in Boca Ciega 

 Bay would increase sewage volume, impede water 

 circulation, and further reduce dissolved oxygen. 



PHOSPHORUS AND NITROGEN 



Phosphorus concentration was high in surface 

 and bottom water at dredged and undredged lo- 

 cations. At dredged locations, bottom concentration 

 was generally higher than surface concentration. 

 At undredged locations, however, concentration 

 did not vary consistently with water depth (table 

 (> ) . Phosphorus was probably reduced in calm, sur- 

 face water between finger-fills by deposition of 

 sorbed phosphates bound to particles of silt and 

 clay (Pomeroy, Smith, and Grant, 1965). 



Nitrogen was not measured in this study, but 

 other data show that it is plentiful in Boca Ciega 

 Bay (table-!). 



KFFECTS OF IiyUKAlLIC UKEDGIXG AXD COASTAL DEVELOPMENT IN BOCA CIEGA BAY, FLA. 



223 



