Research ArticleBIOPHYSICS

Manta rays feed using ricochet separation, a novel nonclogging filtration mechanism

See allHide authors and affiliations

Science Advances  26 Sep 2018:
Vol. 4, no. 9, eaat9533
DOI: 10.1126/sciadv.aat9533
  • Fig. 1 The manta ray filtering apparatus effectively separates plankton from seawater.

    (A) Manta ray during feeding behavior (photo credit: S. Kajiura, Florida Atlantic University). (B) Gill raker (left) and tracing of filter lobes (right) (20) [photo credit: E.W.M.P.-T., California State University Fullerton (CSUF)]. (C and D) Fluid pathlines visualized using dye injection for filter lobes in wing (C) and spoiler (D) orientations. (E and F) Trajectories of solid particles (hydrated Artemia sp. cysts) passing over filter apparatus and vertical velocity of particles (median ± SEM, n = 12) for wing (E) and spoiler (F) orientations.

  • Fig. 2 Computational modeling indicates that solid particles ricochet off manta ray filter lobes.

    (A) Flow field around the M. birostris filtering apparatus in wing (top) and spoiler (bottom) configuration, predicted using CFD model (streamlines in white; background indicates the velocity magnitude). (B) Calculated trajectories of fluid (blue) and solid particles (center of mass, red; diameter, 350 μm; neutrally buoyant) as they pass over the filtering apparatus. The outline of a representative particle (dark red) shows the size of the particles relative to the filtering apparatus. Although they start from the same position, fluid passes through the filter pore, while solid particles are excluded. (C) Predicted filtration efficiency of the apparatus as a function of solid particle diameter and density (in kg/m3), with the pore size indicated. Sizes of plankton indicated on the background. Small zooplankton (51 to 100 μm; dark gray), microcrustaceans (101 to 500 μm; medium gray), and large zooplankton (>501 μm; light gray).

  • Fig. 3 Morphology of filtering apparatus determines filtration properties.

    (A) M. tarapacana filter (top) and a μCT reconstruction of a single row of filter lobes (bottom) (photo credit: E.W.M.P.-T., CSUF). (B) Calculated trajectories of fluid (blue) and solid particles (center of mass, red; diameter, 350 μm; neutrally buoyant) as they pass over the filtering apparatus. The outline of a representative particle (dark red) shows the size of the particles relative to the filtering apparatus. (C) Predicted filtration efficiency of the apparatus as a function of solid particle diameter and density (in kg/m3), with the pore size indicated. Sizes of plankton indicated on background. Small zooplankton (51 to 100 μm; dark gray), microcrustaceans (101 to 500 μm; medium gray), and large zooplankton (>501 μm; light gray).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/9/eaat9533/DC1

    Supplementary Materials and Methods

    Fig. S1. Details of experiments used to measure particle filtration.

    Fig. S2. Geometry of the M. birostris filtering apparatus.

    Fig. S3. Computational modeling predicts particle filtration.

    Fig. S4. Geometry of the M. tarapacana filtering apparatus.

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • Fig. S1. Details of experiments used to measure particle filtration.
    • Fig. S2. Geometry of the M. birostris filtering apparatus.
    • Fig. S3. Computational modeling predicts particle filtration.
    • Fig. S4. Geometry of the M. tarapacana filtering apparatus.

    Download PDF

    Files in this Data Supplement:

Navigate This Article