Feeding in Euchlanis dilatata lucksiana Hauer on filamentous cyanobacteria and a prochlorophyte

Abstract

Ingestion and assimilation rates of Euchlanis dilatata lucksiana Hauer, isolated from Lake Loosdrecht (The Netherlands) and cultured on lake water (seston<33 μm), were measured in the laboratory using the 14C-tracer technique. The five taxa used as tracer foods, together with 6–7 mg C 1−1 of lake seston in each case, included four species of filamentous cyanobacteria (Oscillatoria redekei, O. limnetica, Aphanizomenon flos-aquae, Anabaena PCC 7120) and a prochlorophyte (Prochlorothrix hollandica). Except Anabaena, they are all commonly encountered in eutrophic Loosdrecht lakes, including Lake Loosdrecht, and their dimensions ranged between 150 and 250 μm in length and 2 and 3.5 μm in width. The small and large Euchlanis used as experimental animals had mean lengths of 217–223 μm and 276–305 μm, respectively.