- Physical Review Journals
All JournalsPhysics Magazine

PRX Life

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Featured in Physics
  • Open Access

Unravelling Three-Dimensional Active Transport by Ciliary Arrays on Coral Surfaces

Siluvai Antony Selvan1,2,*, Cesar O. Pacherres3,*, Michael Kühl3, Angus Butler1, Max S. Dhillon4, Linda L. Blackall5, Peter W. Duck2, Draga Pihler-Puzović6,†, and Douglas R. Brumley1,‡

  • *These authors contributed equally to this work.
  • †Contact author: draga.pihler-puzovic@manchester.ac.uk
  • ‡Contact author: d.brumley@unimelb.edu.au
PDF

PRX Life 4, 023020 – Published 26 May, 2026

DOI: https://doi.org/10.1103/fhfw-f1nv

Abstract

Cilia-driven flows in corals are crucial for exchanging nutrients, removing waste, and maintaining the ambient conditions necessary for corals' survival. While various studies have identified that ciliary activity can influence mass transport, the effect of local ciliary orientation and heterogeneity remains relatively unexplored. In this study, we combine noninvasive experimental measurements of ciliary distribution and alignment, with quantification of flow fields and spatial oxygen distributions among several species of reef-building corals, and develop a mathematical model based on singularity solutions of the Stokes equations to investigate mass transport near the coral's surface. Our findings reveal that counter-rotating vortices robustly emerge in three dimensions as a result of the ciliary arrangement on the coral surface. The rate at which ciliated tissue can exchange nutrients with the surrounding fluid depends strongly on the diffusivity of the dissolved organic matter and is enhanced through the inherent heterogeneity in ciliary orientation—for nutrients with low molecular diffusivity, ciliary heterogeneity increases mass transport by more than 50%. However, the presence of an externally imposed shear flow serves to diminish the overall rate of mass transport across all cases studied. This study highlights the critical role of ciliary orientation in modulating transport processes and exemplifies the role of ciliary transport, particularly in low-flow regimes.

View figure in article

Physics Subject Headings (PhySH)

Viewpoint

How Corals Stir Seawater

Published 26 May, 2026

A new model explains how the microscopic hairs carpeting corals coordinate their beating to shape fluid flow.

See more in Physics

Article Text

Supplemental Material

References (58)

  1. T. Goreau and W. Hilbertz, Marine ecosystem restoration: Costs and benefits for coral reefs, World Resour. Rev. 17, 375 (2005).
  2. F. Ferrario, M. Beck, C. Storlazzi, F. Micheli, C. Shepard, and L. Airoldi, The effectiveness of coral reefs for coastal hazard risk reduction and adaptation, Nat. Commun. 5, 3794 (2014).
  3. T. Goreau, N. Goreau, and T. Goreau, Corals and coral reefs, Sci. Am. 241 124 (1979).
  4. N. Shashar, Y. Cohen, and Y. Loya, Extreme diel fluctuations of oxygen in diffusive boundary layers surrounding stony corals, Biol. Bull. 185, 455 (1993).
  5. C. Miller, The Stokes-Einstein law for diffusion in solution, Proc. R. Soc. London A 106, 724 (1924).
  6. A. Marshall, Calcification in hermatypic and ahermatypic corals, Science 271, 637 (1996).
  7. M. Merks, A. Hoekstra, J. Kaandorp, and P. Sloot, Polyp oriented modelling of coral growth, J. Theor. Biol. 228, 559 (2004).
  8. O. Shapiro, V. Fernandez, M. Garren, J. Guasto, F. Debaillon-Vesque, E. Kramarsky-Winter, A. Vardi, and R. Stocker, Vortical ciliary flows actively enhance mass transport in reef corals, Proc. Natl. Acad. Sci. USA 111, 13391 (2014).
  9. C. Pacherres, S. Ahmerkamp, G. Schmidt-Grieb, M. Holtappels, and C. Richter, Ciliary vortex flows and oxygen dynamics in the coral boundary layer, Sci. Rep. 10, 7541 (2020).
  10. C. Pacherres, S. Ahmerkamp, K. Koren, C. Richter, and M. Holtappels, Ciliary flows in corals ventilate target areas of high photosynthetic oxygen production, Curr. Biol. 32, 4150 (2022).
  11. S. Ahmerkamp, F. Jalaluddin, Y. Cui, D. R. Brumley, C. Pacherres, J. Berg, R. Stocker, M. Kuypers, K. Koren, and L. Behrendt, Simultaneous visualization of flow fields and oxygen concentrations to unravel transport and metabolic processes in biological systems, Cell Rep. Methods 2, 100216 (2022).
  12. C. Pacherres, A. Huber, S. Murthy, and M. Kühl, A scanning particle image velocimetry system for spatial mapping of steady flow and O2 concentration fields around aquatic organisms, Methods Ecol. Evol. 16, 1674 (2025).
  13. D. Mitchell, The evolution of eukaryotic cilia and flagella as motile and sensory organelles, in Eukaryotic Membranes and Cytoskeleton: Origins and Evolution (Springer, New York, 2007), pp. 130–140
  14. R. Golestanian, J. Yeomans, and N. Uchida, Hydrodynamic synchronization at low Reynolds number, Soft Matter 7, 3074 (2011).
  15. J. Blake, Infinite models for ciliary propulsion, J. Fluid Mech. 49, 209 (1971).
  16. J. Blake, Mechanics of muco-ciliary transport, IMA J. Appl. Math. 32, 69 (1984).
  17. W. Gilpin, V. Prakash, and M. Prakash, Vortex arrays and ciliary tangles underlie the feeding-swimming trade-off in starfish larvae, Nat. Phys. 13, 380 (2017).
  18. G. Saggiorato, L. Alvarez, J. Jikeli, U. Kaupp, G. Gompper, and J. Elgeti, Human sperm steer with second harmonics of the flagellar beat, Nat. Commun. 8, 1415 (2017).
  19. S. Rode, J. Elgeti, and G. Gompper, Sperm motility in modulated microchannels, New J. Phys. 21, 013016 (2019).
  20. R. E. Goldstein, M. Polin, and I. Tuval, Noise and synchronization in pairs of beating eukaryotic flagella, Phys. Rev. Lett. 103, 168103 (2009).
  21. D. R. Brumley, M. Polin, T. J. Pedley, and R. E. Goldstein, Hydrodynamic synchronization and metachronal waves on the surface of the colonial alga Volvox carteri, Phys. Rev. Lett. 109, 268102 (2012).
  22. D. R. Brumley, M. Polin, T. J. Pedley, and R. E. Goldstein, Metachronal waves in the flagellar beating of Volvox and their hydrodynamic origin, J. R. Soc. Interface 12, 20141358 (2015).
  23. P. Satir and S. Christensen, Overview of structure and function of mammalian cilia, Annu. Rev. Physiol. 69, 377 (2007).
  24. G. R. Ramirez-San Juan, A. J. T. M. Mathijssen, M. He, L. Jan, W. Marshall, and M. Prakash, Multiscale spatial heterogeneity enhances particle clearance in airway ciliary arrays, Nat. Phys. 16, 958 (2020).
  25. T. J. Pedley, Spherical squirmers: Models for swimming micro-organisms, IMA J. Appl. Math. 81, 488 (2016).
  26. T. Omori and T. Ishikawa, Ciliary fluid dynamics of swimming, feeding, pumping, and sensing, Phys. Rev. Fluids 10, 080501 (2025).
  27. D. Babu and S. Roy, Left–right asymmetry: Cilia stir up new surprises in the node, Open Biol. 3, 130052 (2013).
  28. E. Causa, D. Das, L. Feriani, J. Kotar, and P. Cicuta, Cilia dynamics create a dynamic barrier to penetration of the periciliary layer in human airway epithelia, Proc. Natl. Acad. Sci. USA 122, e2419032122 (2025).
  29. M. Garren, K. Son, J. Raina, R. Rusconi, F. Menolascina, O. Shapiro, J. Tout, D. Bourne, J. Seymour, and R. Stocker, A bacterial pathogen uses dimethylsulfoniopropionate as a cue to target heat-stressed corals, ISME J. 8, 999 (2014).
  30. D. Gysbers, M. A. Levenstein, and G. Juarez, Effect of substrate topography on benthic boundary layer flow: Implications for marine larval transport and settlement, Phys. Rev. Fluids 10, 064501 (2025).
  31. J. Blake, A model for the micro-structure in ciliated organisms, J. Fluid Mech. 55, 1 (1972).
  32. E. Gauger and H. Stark, Numerical study of a microscopic artificial swimmer, Phys. Rev. E 74, 021907 (2006).
  33. A. Vilfan and F. Jülicher, Hydrodynamic flow patterns and synchronization of beating cilia, Phys. Rev. Lett. 96, 058102 (2006).
  34. J. Blake, A spherical envelope approach to ciliary propulsion, J. Fluid Mech. 46, 199 (1971).
  35. D. R. Brumley and T. J. Pedley, Stability of arrays of bottom-heavy spherical squirmers, Phys. Rev. Fluids 4, 053102 (2019).
  36. S. A. Selvan, P. W. Duck, D. Pihler-Puzović, and D. R. Brumley, Point torque representations of ciliary flows, Phys. Rev. Fluids 8, 123103 (2023).
  37. S. A. Selvan, P. W. Duck, D. Pihler-Puzović, and D. R. Brumley, Mass transport by ciliary point torques in flow, J. Fluid Mech. 1007, A14 (2025).
  38. E. Llabrés, E. Re, N. Pluma, T. Sintes, and C. Duarte, A generalized numerical model for clonal growth in scleractinian coral colonies, Proc. R. Soc. B 291, 20241327 (2024).
  39. J. H. McBride, Significance of Corallite Patterns in Fossil Anthozoan Colonies: ABSTRACT, AAPG Bull. 66, 602 (1982).
  40. C. Page, W. Leggat, S. Heron, A. Fordyce, and T. Ainsworth, High flow conditions mediate damaging impacts of sublethal thermal stress on corals' endosymbiotic algae, Conserv. Physiol. 9, coab046 (2021).
  41. J. Schindelin, I. Arganda-Carreras, E. Frise, V. Kaynig, M. Longair, T. Pietzsch, S. Preibisch, C. Rueden, S. Saalfeld, B. Schmid, J.-Y. Tinevez, D. J. White, V. Hartenstein, K. Eliceiri, P. Tomancak, and A. Cardona, Fiji: an open-source platform for biological-image analysis, Nat Methods 9, 676 (2012).
  42. E. Stamhuis and W. Thielicke, Pivlab—Towards user-friendly, affordable and accurate digital particle image velocimetry in Matlab, J. Open Res. Softw. 2, e30 (2014).
  43. MathWorks, Inc. (2025). MATLAB (Version R2025a) [Computer software], The MathWorks, Inc. https://www.mathworks.com
  44. See Supplemental Material at http://link.aps.org/supplemental//10.1103/fhfw-f1nv for additional figures and movies.
  45. S. Ahmerkamp, C. Pacherres, M. Mosshammer, M. Godefroid, M. Wind Hansen, M. Kuypers, L. Behrendt, K. Koren, and M. Kühl, Novel approach for lifetime-proportional luminescence imaging using frame straddling, ACS Sens. 9, 5531 (2024).
  46. Python Software Foundation (2024), Python (Version 3.13), [Computer software], https://www.python.org/
  47. J. S. Guasto, R. Rusconi, and R. Stocker, Fluid mechanics of planktonic microorganisms, Annu. Rev. Fluid Mech. 44, 373 (2012).
  48. T. J. Pedley, D. R. Brumley, and R. E. Goldstein, Squirmers with swirl: A model for Volvox swimming, J. Fluid Mech. 798, 165 (2016).
  49. T. J. Pedley, N. A. Hill, and J. O. Kessler, The growth of bioconvection patterns in a uniform suspension of gyrotactic micro-organisms., J. Fluid Mech. 195, 223 (1988).
  50. M. Bees and N. Hill, Wavelengths of bioconvection patterns, J. Expt. Biol. 200, 1515 (1997).
  51. E. Bodenschatz, W. Pesch, and G. Ahlers, Recent developments in Rayleigh-Bénard convection, Annu. Rev. Fluid Mech. 32, 709 (2000).
  52. P. J. Ralph, U. Schreiber, R. Gademann, M. Kühl, and A. W. D. Larkum, Coral photobiology studied with a new imaging pulse amplitude modulated fluorometer, J. Phycology 41, 335 (2005).
  53. M. Kühl, D. A. Nielsen, and S. M. Borisov, In vivo lifetime imaging of the internal O2 dynamics in corals with near-infrared-emitting sensor nanoparticles, ACS Sensors 9, 4671 (2024).
  54. D. R. Brumley, F. Carrara, M. Hein, G. Hagstrom, S. Levin, and R. Stocker, Cutting through the noise: Bacterial chemotaxis in marine microenvironments, Front. Mar. Sci. 7, 527 (2020).
  55. M. Garren, K. Son, J. Tout, J. Seymour, and R. Stocker, Temperature-induced behavioral switches in a bacterial coral pathogen, ISME J. 10, 1363 (2016).
  56. https://doi.org/10.4225/49/58ead90dceaaa.
  57. https://doi.org/10.37807/GBMF9206.
  58. S. A. Selvan et al. (2026), https://github.com/Antony221195/Coral-Rotlet.

Outline

Information

PRX Life 4, 023020– Published 26 May, 2026
  • Received 15 August 2025
  • Accepted 30 March 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation