Despite living in a micro-scale world governed by viscosity, heterotrophic nanoflagellates are able to clear great volumes of water for prey by creating feeding flows with their flagellum. A new study from the Centre describes how flagellates with different feeding strategies overcome the impeding effect of viscosity, and provides a mechanistic underpinning of observed functional responses.
Heterotrophic nanoflagellates are the main consumers of bacteria and picophytoplankton in the ocean. These single-celled organisms possess a hairy flagellum that generates a feeding current to draw prey towards them. In their micro-scale world, viscosity impedes predator-prey contact, and the mechanisms that allow flagellates to daily clear a volume of water for prey corresponding to 106 times their own volume are unclear. It is also unclear what limits observed maximum ingestion rates. We describe the feeding flows, flagellum kinematics, and prey searching, capture, and handling in four species with different foraging strategies. With simple models we estimate the (large) forces required to generate the feeding flows, and we show that the hairs on the flagellum is key to foraging in nanoflagellates. Our estimates of maximum ingestion and clearance rates from behavioral observations are similar to those obtained from incubation experiments and our findings thus provide a mechanistic underpinning of functional responses in flagellates.
Read the paper here: http://doi.org/10.1002/lno.12077
Suzuki-Tellier S , Andersen A, Kiørboe T (2022) Mechanisms and fluid dynamics of foraging in heterotrophic nanoflagellates