QUANTIFYING INTERSPECIFIC COAGULATION EFFICIENCY OF PHYTOPLANKTON

Non-sticky latex beads and sticky diatoms were used as models to descr ibe mutual coagulation between sticky and non-sticky particles. in mix ed suspensions of beads and Thalassiosira nordenskjoeldii, both types of particles coagulated into mixed aggregates at specific rates, from which the interspecific coagulation efficiency could be calculated. St ickiness between beads and T. nordenskjoeldii was 50% of that of T. no rdenskjoeldii in monospecific suspensions, and this ratio remained con stant throughout 12 experiments covering 1 order of magnitude variatio n in the stickiness level of T. nordenskjoeldii. Mutual coagulation be tween Skeletonema costatum and the non-sticky cel:ls of Ditylum bright wellii also proceeded with hall the efficiency of S. costatum alone. T he latex beads were suitable to be used as 'standard particles' to qua ntify the ability of phytoplankton to prime aggregation of suspended p articles.