Functional response of the appendicularian Oikopleura dioica

• DOI: 10.4319/lo.2000.45.3.0608
• Publication Date: 2010-06-02T08:24:26Z
• Authors: José Luis Acuña; Markus Kiefer
• Keywords: Isochrysis galbana; Tetraselmis suecica; Clearance rate; Mixotroph; Tetraselmis; Saturation (graph theory)

Different concentrations of 14 C radiolabeled cultures the prymnesiophyte Isochrysis galbana (5.5 µm in size), prasinophyte Tetraselmis suecica (9.5 µm), and chlorophyte Chlorella sp. (3.5 µm) were offered as food to groups 2–5 Oikopleura dioica determine response clearance (CR) ingestion (IR) rates concentration (FC). At high FCs I. , IR CR O. decreased with age house. Aging had little effect on functional (FR) because most decrease occurred during initial 10% house lifespan. The FR resembled a type II model for presented saturation inhibition at FC (>100 µg L −1 )of . Fits curves animals weighing ca. 3 ind Michaelis Menten yielded I max (maximum IR) 198 ± 28, 498 171, 489 150 ng h Km (half FC) 38 21, 225 177, 290 205 prey T. sp., respectively. values are two three cases exceed maximum ingestible particles found natural habitat, which suggests that is adapted phytoplankton concentrations. In contrast classical models, remained nearly constant all Particles cleared from suspension by ingested transformed into fast‐sinking fecal pellets low FC, while they mainly accumulated slow filter houses implies considerable shifts biogeochemical role these changing particle