This paper presents the data on phosphorus and its possible bearing on 

 the incidence of the destructive red tide. 



MET HDDS 



The locationsof stations are shown in figure 1. Station 1 is at 

 Fort Myers at mid-channel on the Caloosahatchee River. Station 2 is at 

 Punta Gorda in the mouth of the Peace River. At these two stations collec- 

 tions were made from the highway bridges crossing the rivers. Station 3 is 

 in Charlotte Harbor into which the Peace River flows. Stations k to 8 • - in 

 the open Gulf in a line extending 120 miles westward from Boca Grande Pass, 

 the entrance to Charlotte Harbor. 



The original program of survey included only Stations 1 to 8. After 

 16 months, in August 19i>0, the program was revised. Stations 1, 2, 7 , and 

 8 were discontinued as a regular part of the survey and Stations 9 to 13 

 were established. Stations 9 and 11 are on the 10-fathom line; Stations 

 10 and 12 are on the 20-fathom line. Station 13 is at the mouth of Big 

 Pass, Sarasota Bay. In the revised program, there are three stations on the 

 10-fathom line and three stations on the 20-fathom line. The data included 

 in this report are principally from the original 16-month study but some 

 values from the newly established stations are also included. 



Observations were made at intervals f rom t he surface to the bottom at 

 all stations except the river and Charlotte Harbor stations, where one sam- 

 pling usually at a depth of about one meter was considered adequate because 

 of the shallow depth and thorough mixing of the water column. 



Inorganic phosphate determinations were made according to the conven- 

 tional Deniges method as described by Robinson and Thompson (19U8). Compari- 

 sons were made visually against appropriate series of standards and against 

 blanks made up at the same time. Total phosphorus was determined by the 

 method described by Harvey (19U8) , except that comparisons were made by 

 visual colorimetry as in the case of the inorganic determinations. Organic 

 phosphorus is reported as the difference between the inorganic and the total. 



No high degree of accuracy is claimed for the analyses of the river 

 water, especially at Station 2 (Peace River) . Concentrations there were 

 frequently so high that dilutions with salt solutions were necessary. Fur- 

 thermore, yellowish or greenish tints often developed in the samples so that 

 addition of dyestuffs to the standards was necessary in order to effect a 

 match in color. 



In an effort to clarify the water, some river samples were centrifuged. 

 It was found that not only the total, but also the inorganic phosphorus was 

 less in these samples, indicating that some of the inorganic phosphorus occurs 

 in particulate form. This condition i s not peculiar to these waters, as 



