McCarthy and kamykowski: urea and other nitrogenous nutrients 



,6 0.8 1.0 1.2 1.4 



0.2 0.4 0,6 0.8 



0.2 0.4 . 0.6 0.8 1.0 



21 Morch 1970 



STATION n 



24 Morch 1970 



— I 1 — 



STATION rn 



Figure 3. — Ammonium and urea concentrations for paired stations on five successive sampling days. The 



depth of the thermocline is indicated by the dashed line. 



The tail coefficient was used to examine ammo- 

 nium and urea concentrations for correlation in 

 each of the three periods. From the z approx- 

 imation the following pattern emerged: for 



Period A there was no correlation (P = 0.030), 

 for Period B the correlation was positive (P — 

 0.009), and for Period C there was no correla- 

 tion (P = 0.124). Values for the probabilities 



1267 



