The effects of thin layers on the vertical distribution of the rotifer, Brachionus plicatilis

摘要: Microscale patches of resources occur in both the horizontal and vertical dimensions, latter case are referred to as thin layers. These layers may affect ecological processes like behavior, predation, growth reproduction phytoplankton zooplankton. The objective this study was determine possible effects physical biological on distribution diel migration rotifer Brachionus plicatilis. We used four, 2 m tall, experimental tanks fitted with video cameras which panned extent each tank enabled us sample centimeter scale. consisted a layer (25 cm thick) Nannochloropsis oculata, whereas control homogeneously distributed algae. Rotifers aggregated N. dispersed (becoming evenly distributed) after depleting algae within (ca. 6 h). In contrast, aggregation shorter duration 2.5 h) rotifers were homogenously for remainder experiment despite persistent salinity stratification. No signs noted either or tanks. A second set experiments run examine response choice food, i.e., diatom, Skeletonema costatum versus eustigmatophyte, oculata. For experiments, two created, one food option. Our results suggest that B. plicatilis aggregates feeds preferentially oculata over S. costatum. types responded, terms distribution, first half-hour introduction remained until source depleted. be important grazers because their ability quickly locate take advantage ephemeral patches.