Effects of Algal Excreted Substances on the Respiration Activities of Epiphytic Bacteria on the Brown Alga, <i>Eisenia bicyclis</i> Kjellman

Abstract

The respiration activity of epiphytic bacteria on Eisenia bicyclis Kjellman was determined by using 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT). In June and August, the percentage of active bacteria on the surface of new blades were 59.6% and 51.6% respectively and that on old blades was almost 100%. The bacterial respiration activity became low when the blades were incubated in the light. The phenol excretion rate from algal blades was high in new blades and in the light. These results suggested that epiphytic bacterial activity on E. bicyclis is suppressed by excreted algal phenols.