8.0 

 7.0' 

 6.0 

 5.0 

 4.5' 

 z 40- 



UJ 



t— 



8 3 - 5 ' 



I 10- 



o 



cc 



t 2.5-1 



2.0- 



1.5 



1.0- 



.5 



HALIMEDA INCRASSATA 



>- 

 cr 

 o 



>- 

 a: 



Q 



i 



CO 



% DRY MASS 



1600 2000 0000 0400 0800 1200 1600 2000 0000 0400 0800 OLD 



TIME OF DAY 



Figure 5. Nitrogen (top graph) and organic (bottom graph) 



content of newly forming segments of Halimeda incrassata as 

 a function of time of day (=age). Graphs plot X+1SE. N for 

 each mean in the lower graph is given in parentheses. N for 

 nitrogen content as a function of dry mass is 2 except where 

 noted. "Old" segments were collected 4-6 segments below the 

 apex. Their true age is unknown but given the rate of 

 segment production noted in other studies at this site (V. 

 Paul and M. Hay, personal observation), minimum segment age 

 was probably 4 days. The nitrogen content as a % of segment 

 ash-free-dry mass/dry mass ratios (lower graph). The arrow 

 on the x-axis in the upper figure indicates the approximate 

 time during which the new segments become pigmented. 



380 



