Bridging advection and diffusion in the encounter dynamics of sedimenting marine snow.
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| Title: | Bridging advection and diffusion in the encounter dynamics of sedimenting marine snow. |
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| Authors: | Turczynowicz, Jan1,2, Waszkiewicz, Radost2,3, Słomka, Jonasz4 jslomka@ethz.ch, Lisicki, Maciej1 mklis@fuw.edu.pl |
| Source: | Journal of Fluid Mechanics. 3/25/2026, Vol. 1031, following p1-19. 27p. |
| Subjects: | Peclet number, Collisions (Physics), Diffusion kinetics, Mass transfer coefficients, Mass transfer, Sedimentation & deposition, Advection |
| Abstract: | Sinking marine snow particles, composed primarily of organic matter, control the global export of photosynthetically fixed carbon from the ocean surface to depth. The fate of sedimenting particles is partly regulated by their encounters with suspended objects, which leads to mass accretion and potentially alters their buoyancy, and with bacteria that can colonise the particles and degrade them. Their collision rates are typically calculated using two types of models focusing either on direct (ballistic) interception with a finite interaction range, or advective-diffusive capture with zero interaction range. Yet, since many relevant marine encounter scenarios span across both regimes, quantifying such encounters remains challenging because the two models yield asymptotically different predictions at high Péclet numbers. We reconcile the two approaches by quantifying encounters in the general case using theoretical analysis and simulations. By solving the advectiondiffusion equation in Stokes flow around a sphere to model mass transfer to a sinking particle by finite-sized objects, we determine a new formula for the Sherwood number as a function of the Péclet number and the ratio of particle sizes. Contrary to the common assumption, we find that diffusion still plays a significant role in generating encounters even at high Péclet numbers. We predict that at Péclet numbers as high as 106 the direct interception model underestimates the encounter rate by up to two orders of magnitude. This overlooked contribution of diffusion to encounters suggests that processes affecting the fate of marine snow may proceed at a rate much higher than previously thought. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 192858591 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Bridging advection and diffusion in the encounter dynamics of sedimenting marine snow. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Turczynowicz%2C+Jan%22">Turczynowicz, Jan</searchLink><relatesTo>1,2</relatesTo><br /><searchLink fieldCode="AR" term="%22Waszkiewicz%2C+Radost%22">Waszkiewicz, Radost</searchLink><relatesTo>2,3</relatesTo><br /><searchLink fieldCode="AR" term="%22Słomka%2C+Jonasz%22">Słomka, Jonasz</searchLink><relatesTo>4</relatesTo><i> jslomka@ethz.ch</i><br /><searchLink fieldCode="AR" term="%22Lisicki%2C+Maciej%22">Lisicki, Maciej</searchLink><relatesTo>1</relatesTo><i> mklis@fuw.edu.pl</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 3/25/2026, Vol. 1031, following p1-19. 27p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Peclet+number%22">Peclet number</searchLink><br /><searchLink fieldCode="DE" term="%22Collisions+%28Physics%29%22">Collisions (Physics)</searchLink><br /><searchLink fieldCode="DE" term="%22Diffusion+kinetics%22">Diffusion kinetics</searchLink><br /><searchLink fieldCode="DE" term="%22Mass+transfer+coefficients%22">Mass transfer coefficients</searchLink><br /><searchLink fieldCode="DE" term="%22Mass+transfer%22">Mass transfer</searchLink><br /><searchLink fieldCode="DE" term="%22Sedimentation+%26+deposition%22">Sedimentation & deposition</searchLink><br /><searchLink fieldCode="DE" term="%22Advection%22">Advection</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Sinking marine snow particles, composed primarily of organic matter, control the global export of photosynthetically fixed carbon from the ocean surface to depth. The fate of sedimenting particles is partly regulated by their encounters with suspended objects, which leads to mass accretion and potentially alters their buoyancy, and with bacteria that can colonise the particles and degrade them. Their collision rates are typically calculated using two types of models focusing either on direct (ballistic) interception with a finite interaction range, or advective-diffusive capture with zero interaction range. Yet, since many relevant marine encounter scenarios span across both regimes, quantifying such encounters remains challenging because the two models yield asymptotically different predictions at high Péclet numbers. We reconcile the two approaches by quantifying encounters in the general case using theoretical analysis and simulations. By solving the advectiondiffusion equation in Stokes flow around a sphere to model mass transfer to a sinking particle by finite-sized objects, we determine a new formula for the Sherwood number as a function of the Péclet number and the ratio of particle sizes. Contrary to the common assumption, we find that diffusion still plays a significant role in generating encounters even at high Péclet numbers. We predict that at Péclet numbers as high as 106 the direct interception model underestimates the encounter rate by up to two orders of magnitude. This overlooked contribution of diffusion to encounters suggests that processes affecting the fate of marine snow may proceed at a rate much higher than previously thought. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1017/jfm.2026.11282 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 27 StartPage: 1 Subjects: – SubjectFull: Peclet number Type: general – SubjectFull: Collisions (Physics) Type: general – SubjectFull: Diffusion kinetics Type: general – SubjectFull: Mass transfer coefficients Type: general – SubjectFull: Mass transfer Type: general – SubjectFull: Sedimentation & deposition Type: general – SubjectFull: Advection Type: general Titles: – TitleFull: Bridging advection and diffusion in the encounter dynamics of sedimenting marine snow. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Turczynowicz, Jan – PersonEntity: Name: NameFull: Waszkiewicz, Radost – PersonEntity: Name: NameFull: Słomka, Jonasz – PersonEntity: Name: NameFull: Lisicki, Maciej IsPartOfRelationships: – BibEntity: Dates: – D: 25 M: 03 Text: 3/25/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 1031 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
| ResultId | 1 |
