We report on an influence of jellyfish fragmentation on vertical and lateral distribution of its mass during settling period. Jellyfish organism is modeled as a sphere with density which is 0.1% higher than the density of seawater. Organism fragmentation is modeled as a recursive decay of each existing fragmented particle into N new particles, but following exponential mass distribution over all fragmented masses. Strict mass conservation is enforced during each fragmentation event. Decay probability scales as a nonlinear function of mass so that more massive particles decay with larger probability. Vertical settling velocity of each fragment is computed as the terminal velocity of the respective buoyant particle in the linear Stokes drag regime. It scales nonlinearly with mass, making more massive particles sink faster, leading to a vertical dispersion of mass and particle distribution. Settling velocity of the mass distribution maximum seems consistent with reported estimates. Horizontal currents are simulated as a linear combination of semi-diurnal and diurnal tidal signals, perturbed by a stochastic component of similar amplitude. We simulate an ensemble of scenarios over a broad range of decay probabilities, fragmented mass distributions and circulation regimes. This allows us to estimate that fragmented organism in an ocean of 4000 m depth may take hundreds of hours to sink in its entirety. Horizontal distribution of fragmented matter may reach radiuses of several kilometers. Both numbers represent a substantial departure from a non-fragmented terminal velocity settlement of a single organism.
Primary Presenter: Matjaz Licer, Slovenian Environment Agency, National Institute of Biology (matjaz.licer@gmail.com)
Authors:
Matjaz Licer, Slovenian Environment Agency (matjaz.licer@gov.si)
Martin Vodopivec, National Institute of Biology (martin.vodopivec@nib.si)
Tinkara Tinta, National Institute of Biology (tinkara.tinta@nib.si)
Modeling of jellyfish fragmentation and its impact on vertical and lateral mass distribution during settling process
Category
Scientific Sessions > SS056 Jellyfish in the Changing Ocean
Description
Time: 06:30 PM
Date: 7/6/2023
Room: Mezzanine