COPPER 



Concentrations of total dissolved copper at all 

 stations varied from 0.00 to 0.23 ng.&t. per liter. 

 The levels were highest at fresh-water station 6 

 (Myakka River) and lowest at station 9 (Caloosa- 

 hatchee River). In 82.5 percent of the observa- 

 tions, copper values were below 0.09 Mgn-t. per liter; 

 76 percent of the values that exceeded 0.09 

 /ug.at. per liter were in the Myakka River. 

 Although the highest values of copper came in 

 January (0.08 iig.&t. per hter), February (0.07 

 /ig.at. per liter), anff September (0.08 Mgat. per 

 liter), at periods of high river discharge, the 

 contribution of copper to the sea by the rivers 

 was determined to a large extent by volume of 

 river water, not by actual concentration. The 

 largest total quantitj- of copper was contributed 

 by the Peace River, and the lowest by the 

 Caloosahatchee River (table 4) . 



Concentrations of copper were greater than 

 those in Tampa Bay and adjacent waters of the 

 Gulf of Mexico. The mean values for the Myakka 

 River at station 6 exceeded those from Tampa 

 Bay tributaries; values in the Peace and Caloosa- 

 hatchee Rivers and at station 5 of the Myakka 

 River were similar to the mean values for the 

 Hillsborough, Alafia, and Manatee Rivers. Mean 

 concentrations of copper were higher than those 

 from San Juan Channel, Wash. (Chow and 

 Thompson, 1952), but the mean concentrations 

 at stations 5, 7, 8, and 9 are comparable with 

 those reported by Chow and Thompson (1952) 

 for the lower Mississippi River (table 6). 



In general, changes in copper follow those of 

 iron. This agreement results from the chemical 

 scavenging of the colloidal Fe(0H)3 for copper, 

 which is absorbed to the surface of the particles. 



Copper plays an important part in biological 

 processes of higher aquatic organisms (Vinogra- 

 dov, 1953; Galtsoff, 1964; Dragovich and May, 

 1962); it is adsorbed by phytoplankton (Atkins, 

 1953) and is selectively toxic to barnacles, algae, 

 and moUusks. The dose of copper lethal to Gymno- 

 dinium breve under laboratory conditions is about 

 0.5 A«gat. per liter (W. Wilson, personal communi- 

 cation). None of the values observed in this study 

 approached that level. 



Table 6. — Concentrations of total dissolved copper m 

 Florida west roast rivers, Tampa Bay, and the adjacent 

 Gulf of Mexico waters and in the Mississippi River and 

 the San Juan Channel, Wash. 



RELATION OF THE INPUT OF FLORIDA 

 WEST COAST TRIBUTARIES TO THE 

 ABUNDANCE OF GYMNODINIUM BREVE 



Water samples for analysis of G. breve were col- 

 lected each month from 22 stations in Tampa Bay, 

 Charlotte Harbor, and the adjacent offshore 

 waters (Dragovich and Kelly, 1966). G. breve was 

 absent in samples from Tampa Bay and present 



474 



r.S. FISH AND WILDLIFE SERVICE 



