174 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



I0-: 

 5 

 



HILLSBOROUGH RIVER 

 STATION 29 STATION 30 



ALAFIA RIVER 

 STATION 31 STATION 32 



LITTLE MANATEE RIVER 

 STATION 33 STATION 34 



1 I 



MANATEE RIVER 



.STATION 35 



STATION 36 



1 



T 



10 20 10 



NO3 NOg N ^g. at. /I. 



20 



Figure 8. — Distribution of nitrate-nitrite nitrogen for rivers flowing into Tampa Bay, October 1958-December 1959. 



and others (1961) have shown an extremely 

 low mean concentration of nitrate-nitrite nitrogen 

 (0.3 /ig.at./l.) for Tampa Bay during the period 

 of the present study. 



Higher nitrate-nitrite concentrations near the 

 Bay than at the upstream stations of the Hills- 

 borough River suggested that enricliment of this 

 river might be from waters somewhere between 

 stations 29 and 30. To check this possibility our 

 observations were extended in October, November, 

 and December 1959 to Sulphur Springs, an 

 underground tributary, located between stations 

 29 and 30. Nitrate-nitrite nitrogen concentra- 

 tions in these springs varied from 11.1 to 17.0 

 /xg.at./l., with a mean value of 13.5 /ig.at./l. which 

 is comparable to the maximimi value observed at 



station 29. These results suggest that enrich- 

 ment in nitrate-nitrites at station 29 is partially 

 attributable to these springs. 



The copper concentrations in Tampa Bay and 

 adjacent neritic waters for the period from Octo- 

 ber 1958 through December 1959 varied from 0.00 

 to 0.10 jLig.at./l. with an average of 0.03 /j-g-nL/l. 

 (Dragovich and others, 1961). Thus the mean- 

 copper concentration of Tampa Bay is about half 

 of that observed in tlie rivers. 



Copper is generally considered to be an essen- 

 tial constituent of protoplasm, especially in the 

 syntliesis of haemocyanin, haemoglobin, cyto- 

 chrome ff, and certain metalloflavoproteins (Mah- 

 ler, 1956). Copper is taken up by phytoplankton 

 (Atkins, 1953). The concentrations of copper in 



