SOME CHEMICAL CHARACTERISTICS OF SEA-WATER AT TORTUGAS 

 AND AROUND BISCAYNE BAY, FLORIDA. 



By R. B. Dole. 



INTRODUCTION. 



The chemical tests at Tortugas were performed by the writer in June 

 1913, in the Marine Biological Laboratory, Tortugas, Florida, for the 

 primary purpose of ascertaining what soluble effect, if any, carbon dioxide 

 in sea-water might have on coral and other deposits of calcium carbonate. 

 The tests of waters from Biscayne Bay were made to ascertain the differ- 

 ences in concentration of sea-water in the bay and the diluting effect of 

 Miami River. The samples for the latter work were collected by the 

 writer June 23, 1913, and they were examined during the summer by E. C. 

 Bain, junior chemist, U. S. Geological Survey. 



DETERMINATION OF CARBON DIOXIDE. 



To 100 c.c. of the sample, in a Nessler tube measuring 17.5 cm. to the 

 graduating mark, 10 drops of i per cent phenolphthalein was added and 

 the solution was titrated to an acid reaction by means of N/20 sulphuric 

 acid. This is the usual procedure for estimation of normal carbonates 

 in water. The result of the titration has been calculated to "carbon dioxide 

 (CO2) present as carbonate (CO3) " by means of the formula A = 22Q/d, 

 in which A represents milligrams per liter of carbon dioxide, Q the number of 

 cubic centimeters of N/20 sulphuric acid required, and d the density of the 

 water. 



A sufficient excess of N/20 sulphuric acid was added to 200 c.c. of the 

 sample in a Jena flask and the solution was gently boiled long enough to 

 drive off carbon dioxide, after which the total quantity of acid consumed 

 was determined by titrating the excess with barium hydrate in presence 

 of phenolphthalein. This procedure was followed by Fox^ and others in 

 ■determining the alkalinity of sea-water. The "carbon dioxide (CO2) 

 present as bicarbonate (HCO3)" was computed by means of the formula 

 B = ii{Q' — 4.Q)ld, in which B represents milligrams per liter of carbon diox- 

 ide, and Q' the total quantity of acid required. The result of the second 

 titration has also been expressed as "total alkalinity in equivalent OH" 

 in order to afford comparison with the results of certain other analysts. 

 This calculation has been made by the formula C = /^.2'j^Q'ld, in which 

 C represents the equivalent alkalinity in milligrams per liter of the hydroxyl 

 radicle (OH). 



' Fox, C. J. J., On the coefficients of absorption of the atmospheric gases in distilled water and sea- 

 water. Conseil permanent international de la mer, pub. de circonstance 44. February 1909. 



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