PhD defence on the fluid mechanics of barnacle feeding

Suspension feeding is the most common type of foraging in the ocean and spans from microscopic unicellular marine organisms to whales. The ocean is typically a dilute suspension of organic particles, including phytoplankton, zooplankton and detritus, forcing suspension feeders to evolve effective feeding mechanisms to obtain enough food.

In coastal areas of all major oceans, barnacles, which are small crustaceans, are among the most common benthic invertebrates. They rely on specialized appendages which are swept through the water to capture food particles. The diversity of particles barnacles capture, as well as the highly variable environment they inhabit suggest that they have a unique and specialized feeding mechanism adapted to these conditions. 

PhD Student Kristian Maar from DTU Aqua has investigated the feeding mechanisms of three barnacle species to provide new insights into these mechanisms, which can also contribute to the understanding of barnacles’ ecological role in coastal ecosystems. The studies were conducted using high-speed videography, particle image velocimetry and fluid mechanical modelling.

The studies show that barnacles can capture evasive prey (zooplankton) in quiescent water by generating a highly asymmetrical feeding current, enabling the transport of the prey through regions of low deformation. This asymmetrical feeding flow develops as barnacles mature, which implies that newly settled juveniles are unlikely to rely on zooplankton. The results also show that the switching between feeding modes is gradual rather than sudden in response to ambient flow. Finally, Kristian Maar and his colleagues found that barnacles are more active and capture more particles in ambient flow, though ambient flow does not increase their chances of capturing evasive prey. 

About the defence

Kristian Maar will defend his PhD thesis, The fluid mechanics of barnacle feeding, on Friday, 5 April 2024, at 13:00. The defence can be followed online or at DTU Lyngby Campus (please find details below).

Examiners 

• Senior Researcher Camille Saurel, DTU Aqua (chair)
• Professor Emeritus Hans Ulrik Riisgård, University of Southern Denmark
• Professor Henrik Glenner, University of Bergen, Norway

Chairperson at defence

• Senior Researcher Sigrun Jonasdottir, DTU Aqua

Supervisors

• Principal supervisor: Professor Thomas Kiørboe, DTU Aqua
• Co-supervisor: Associate Professor Anders Peter Andersen, DTU Aqua
• Co-supervisor: Professor Uri Shavit, Israel Institute of Technology

Learn more

A copy of the thesis is available for reading at DTU Aqua. Please contact PhD Coordinator Susan Zumbach Johannesen, szjo@aqua.dtu.dk