Flow and transport effect caused by the stalk contraction cycle of Vorticella convallaria

Jiazhong Zhou, Sangjin Ryu, David Admiraal

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Vorticella convallaria is a protozoan attached to a substrate by a stalk which can contract in less than 10 ms, translating the zooid toward the substrate with a maximum Reynolds number of 1. Following contraction, the stalk slowly relaxes, moving the zooid away from the substrate, which results in creeping flow. Although Vorticella has long been believed to contract to evade danger, it has been suggested that its stalk may contract to enhance food transport near the substrate. To elucidate how Vorticella utilizes its contraction-relaxation cycle, we investigated water flow caused by the cycle, using a computational fluid dynamics model validated with an experimental scale model and particle tracking velocimetry. The simulated flow was visualized and analyzed by tracing virtual particles around the Vorticella. It is observed that one cycle can displace particles up to 190 μm with the maximum net vertical displacement of 3-4 μm and that the net transport effect becomes more evident over repeated cycles. This transport effect appears to be due to asymmetry of the contraction and relaxation phases of the flow field, and it can be more effective on motile food particles than non-motile ones. Therefore, our Vorticella model enabled investigating the fluid dynamics principle and ecological role of the transport effects of Vorticella's stalk contraction. Published by AIP Publishing.

Original languageEnglish (US)
Article number034119
Issue number3
StatePublished - May 1 2017

ASJC Scopus subject areas

  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics
  • Fluid Flow and Transfer Processes
  • Colloid and Surface Chemistry


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