Mammoth grazers on the ocean’s minuteness: a review of selective feeding using mucous meshes

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Mucous-mesh grazers (pelagic tunicates and thecosome pteropods) are common in oceanic waters and efficiently capture, consume and repackage particles many orders of magnitude smaller than themselves. They feed using an adhesive mucous mesh to capture prey particles from ambient seawater. Historically, their grazing process has been characterized as non-selective, depending only on the size of the prey particle and the pore dimensions of the mesh. The purpose of this review is to reverse this assumption by reviewing recent evidence that shows mucous-mesh feeding can be selective. Researchers focus on large planktonic microphages as a model of selective mucus feeding because of their important roles in the ocean food web: as bacterivores, prey for higher trophic levels, and exporters of carbon via mucous aggregates, faecal pellets and jelly-falls. Researchers identify important functional variations in the filter mechanics and hydrodynamics of different taxa. Researchers review evidence that shows this feeding strategy depends not only on the particle size and dimensions of the mesh pores, but also on particle shape and surface properties, filter mechanics, hydrodynamics and grazer behavior. As many of these organisms remain critically understudied, investigators conclude by suggesting priorities for future research.

An article related to this research can be found in The Conversation, May 2, 2018

Authors: Conley, Keats R.;  Lombard, Fabien; Sutherland, Kelly R.