# Spatial inhomogeneities in the sedimentation of biogenic particles in ocean flows: analysis in the Benguela region

## TL;DR

This study investigates how oceanic flow dynamics cause inhomogeneous sedimentation patterns of biogenic particles, highlighting the roles of flow-induced stretching and particle properties through numerical experiments in the Benguela region.

## Contribution

It introduces a Lagrangian framework to analyze sedimentation in ocean flows, emphasizing the impact of flow stretching and particle characteristics on distribution inhomogeneities.

## Key findings

- Faster or larger particles distribute more uniformly.
- Flow-induced stretching significantly affects particle distribution.
- Numerical experiments confirm the importance of flow and particle properties.

## Abstract

Sedimentation of particles in the ocean leads to inhomogeneous horizontal distributions at depth, even if the release process is homogeneous. We study this phenomenon considering a horizontal sheet of sinking particles immersed in an oceanic flow, and determine how the particles are distributed when they sediment on the seabed (or are collected at a given depth). The study is performed from a Lagrangian viewpoint attending to the properties of the oceanic flow and the physical characteristics (size and density) of typical biogenic sinking particles. Two main processes determine the distribution, the stretching of the sheet caused by the flow and its projection on the surface where particles accumulate. These mechanisms are checked, besides an analysis of their relative importance to produce inhomogeneities, with numerical experiments in the Benguela region. Faster (heavier or larger) sinking particles distribute more homogeneously than slower ones.