Table 1. --Comparison of sediment production rates of infauna (control rocks) 



and urchins (experimental rocks) 



Control (rock, no urchin) 



Date and 

 Duration 



Total Organic-free 



Sediment Recovered 



(dry wt, mg) 



Rock Surface 

 Area (cm^) 



Sediment Production 

 Rate by Infauna 

 (mg cm - ? dayl) 



25-27 August 1982 

 43.5 hr 



13-15 April 1983 

 45.5 hr 



25-27 August 1982 

 43.5 hr 



13-15 April 1983 

 45.5 hr 



21-23 June 1983 

 49.5 hr 



abrading more tightly cemented eolianite grains, yielding mud (fig. IB). 

 Infaunal bioeroders produced a much broader spectrum of particle sizes (fig. 2, 

 bottom), perhaps due to the many species of bioeroders active within these 

 rocks. 



Evacuation of Bore Holes 



Inspection of eolianite at the bottom of urchin bore holes by low-power 

 microsr pe and SEM revealed no scratches on the substrate (fig. IB). Individual 



156 



