Fig. 1.

Scheme of the experimental design for assessing the functional response of natural heterotrophic flagellates. Several bottles with increasing amounts of prey (native bacteria plus added FLBs, 10⁶ total prey) were prepared. Bacterial and HF concentration (cells ml⁻¹) are indicated for the diluted (left) and undiluted (right) sets. A short‐term ingestion experiment was performed in each experimental bottle.