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Functional ecology of tiny suspension feeders


Juvenile barnacle, Balanus glandula,
feeding from atop a rock
Suspension-feeding invertebrates play remarkably strong roles in a breadth of marine food webs.  As a consequence, much effort has been devoted to understanding the manner in which these organisms capture small food particles from the water.  Researchers have learned a great deal about general principles by focusing on mathematical and physical models of animal feeding appendages (also called “collectors”).  The tradition has been to represent such collectors as rigid cylinders extending perpendicularly into flow.  However, the feeding appendages of real animals are not perfectly rigid, and therefore deflect or bend in flow, sometime strongly.  These deformations alter the positioning of collectors relative to oncoming food particles and modify their capacity to acquire food.


Tow tank filled with high-viscosity corn syrup, used for testing dynamically scaled models

Our group became intrigued by this issue because smaller suspension-feeding individuals with smaller capture apparatus are intrinsically more susceptible to deformation-induced inefficiencies in food acquisition.  This trend may create positive selection pressure for delayed settlement and planktonic larval phases characterized by rapid growth.  This effect could in turn contribute to the persistence of known major themes in marine life histories.  Our lab group is rapidly developing this line of inquiry and we envision it becoming a substantial research thrust in coming months.  Thus far, we have conducted laboratory experiments using dynamically scaled physical models that demonstrate that structural flexibility of particle collectors indeed changes how fluid flow passes through and around suspension feeding appendages.


Top view looking down into the tank of corn syrup, showing an array of four model "collectors"

Selected publications:

Ferner, M.C., and B. Gaylord.  2008.  Flexibility foils filter function: Structural limitations on suspension feeding.  Journal of Experimental Biology 211: 3563-3572.

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