Flow generation by the corona ciliata in Chaetognatha - quantification and implications for current functional...

Area of Science:

• Marine biology
• Zoology
• Invertebrate zoology

Background:

• The corona ciliata in Chaetognatha (arrow worms) is a ciliated groove with suggested roles in sensory perception, excretion, respiration, and reproduction.
• Previous research has not experimentally verified the functional role of the corona ciliata in generating water flow.

Purpose of the Study:

• To provide the first experimental evidence and visualization of water flow generated by the corona ciliata in arrow worms.
• To quantify the flow dynamics and assess the functional implications of this flow for arrow worm biology.

Main Methods:

• Utilized experimental approaches to visualize and quantify water flow produced by the corona ciliata in Spadella cephaloptera.
• Measured maximal flow speeds and volumetric flow rates to characterize the hydrodynamics of the corona ciliata.

Main Results:

• Demonstrated that the cilia of the corona ciliata generate significant water flow, accelerating water towards the structure in a funnel-shaped pattern.
• Quantified maximal flow speeds of approximately 140μms⁻¹ and a volumetric flow rate of Q=0.0026μls⁻¹.
• Observed water expulsion laterally and caudally, with some recirculation.

Conclusions:

• The corona ciliata actively generates directional water flow, supporting its role as a multifunctional organ in arrow worms.
• The observed funnel-shaped flow pattern suggests a potential mechanism for directional chemosensation.
• These findings highlight the hydrodynamic significance of the corona ciliata in arrow worm physiology and behavior.