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Physical modeling of gelatinous zooplankton sinking in the deep global ocean
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  • Matjaz Licer,
  • Martin Vodopivec,
  • Gerhard J Herndl,
  • Tinkara Tinta
Matjaz Licer
National Institute of Biology

Corresponding Author:[email protected]

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Martin Vodopivec
National Institute of Biology
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Gerhard J Herndl
University of Vienna
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Tinkara Tinta
National Institute of Biology
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Abstract

Decaying gelatinous zooplankton (GZ) originating from surface waters has been proposed as a possible major contributor to the biological carbon pump. However, studies arrived at largely diverging conclusions concerning the role of decaying GZ as organic matter supply for the deep-sea heterotrophic biota. We complement previous approaches to GZ sinking by proposing the first dynamically consistent physical model coupling GZ sinking speed and its mass. We evaluate GZ contribution to deep-ocean carbon sequestration and to the soft-tissue carbon pump by solving the model equations on the global ocean grid employing monthly climatological temperature fields and published exponential and linear temperature dependencies of mass decay rates. We present the global ocean distribution of the fraction of GZ-mass sinking out of the euphotic zone (200 m depth), twilight zone (1000 m depth) and the fraction of mass reaching the global ocean floor. Solutions in the upper water column are strongly dependent on the mass decay rate. Since most of the decay happens in the initial phase of the sinking process, the sinking-decay coupling exerts a substantial impact on sinking rates but has limited effect on the fraction of mass reaching the bathypelagic and abyssal ocean. Our model approach indicates that there are substantial latitudinal differences in the potential supply of GZ detrital matter to the deep sea. While at low latitudes only negligible amounts of GZ biomass are deposited at the ocean floor, high latitudes allow for substantial GZ detrital mass transport to depths below 1000 m.
15 Sep 2023Submitted to ESS Open Archive
17 Oct 2023Published in ESS Open Archive