day (Petipa, 1964; Petipa and Makarova, 1969) suggests that 

 synchronized division of phytoplankton could have effects on 

 herbivory similar to those proposed for the seaweeds investigated 

 in this study. This seems especially promising since filter 

 feeders select food items based upon both particle size (Frost, 

 1977) and particle flavor ( Rassoulzadegan et al., 1984; Huntley 

 et al . , 1986) and since both of these parameters may change with 

 cell age. It is therefore possible that the processes and 

 interactions documented in this study of Halimeda and its grazers 

 may be similar to those occurring among other, very different, 

 types of species. It appears that coordinating diel patterns of 

 growth with rapidly mobilizable defenses against predators could 

 be an important component of the ecology of many organisms. 



ACKNOWLEDGMENTS 



The majority of this work was funded by NOAA's National 

 Undersea Research Program. Additional facilities and support 

 were provided by the University of North Carolina's Institute of 

 Marine Sciences, the College of the Virgin Islands, Coral World, 

 the Marine Systems Laboratory of the Smithsonian Institution, and 

 N.S.F grant #CHE83-15546 to W. Fenical. The divers and staff 

 associated with Hydrolab worked extremely hard to facilitate this 

 project; its completion would have been impossible without their 

 support. Emmett Duffy, Jane Lubchenco, Paul Renaud, and Alan 

 Shanks reviewed the manuscript. This is NURP publication #J-458. 



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