Preprints
https://doi.org/10.5194/egusphere-2024-2520
https://doi.org/10.5194/egusphere-2024-2520
04 Nov 2024
 | 04 Nov 2024
Status: this preprint is open for discussion.

SISSOMA (v1): modelling marine aggregate dynamics from production to export

Andre Visser, Anton Vergod Almgren, and Athanasios Kandylas

Abstract. A mechanistic approach linking the population dynamics of plankton communities to the export of detrital material to the oceans interior, remains a largely unresolved component of global bio-geochemical models. We propose that the self-similarity of aggregation provides a tractable modelling framework for simulating the dynamics and sinking speed of natural marine particle aggregates. It provides a means to track both size and excess density of aggregates as they are formed and transformed by aggregation, degradation and fragmentation processes. A self-similarity parameter a in the range 1.8 to 2.1 is well supported by direct observations drawn from an extensive database of aggregate size and sinking speed. We provide a simple model, SISSOMA, that uses a 2 dimensional state-space representation of aggregate dynamics for which we conduct sensitivity analyses for the self-similarity parameter, stickiness, turbulent dissipation rate and the production rate of primary particles. The model provides size and density resolved estimates of the export flux of detrital material generated by a diverse community of primary producers. While open to improvement in several aspects, the model compares well with observations of aggregate size spectra covering the global ocean.

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Andre Visser, Anton Vergod Almgren, and Athanasios Kandylas

Status: open (until 30 Dec 2024)

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Andre Visser, Anton Vergod Almgren, and Athanasios Kandylas
Andre Visser, Anton Vergod Almgren, and Athanasios Kandylas
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Latest update: 04 Nov 2024
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Short summary
Global models largely rely on empirical estimates of the rate at which this material is produced and sinks. Here we propose a mechanistic model that tries to capture the most important processes regulating the size and density of particulate organic material from when it is produced by living organisms, through its aggregation and fragmentation into particles of different size and density, degradation by microbes and eventual sinking into the ocean’s interior.