Migrant Pump Depth-Time Model: Diel Vertical Migration Flux

What Diel Vertical Migration Is

Diel vertical migration is a behavior exhibited by many marine organisms, including zooplankton, where they move vertically through the water column on a daily basis. This movement is primarily driven by light availability and can have significant impacts on nutrient cycling in aquatic ecosystems.

The term 'migrant pump' refers to the mechanism by which these vertical movements contribute to the transport of nutrients from deeper waters to surface layers, enhancing productivity and carbon export.

How Diel Vertical Migration Works

Zooplankton migrate vertically in response to daily changes in light intensity. During the night, when light levels are low, they move up into the upper layers of the water column where food is more abundant and predation risk lower.

During the day, as light intensifies, they descend back down to deeper waters to avoid predators and conserve energy.

The Fokker-Planck Equation in Action

The Fokker-Planck equation is a partial differential equation that describes how the probability density of a particle's position changes over time, taking into account both advection (movement due to currents) and diffusion (random motion). In the context of diel vertical migration, it models the movement of zooplankton in response to light-driven forces.

By solving this equation numerically using a finite-volume method, we can simulate the depth-time profile of a zooplankton population and compute key metrics such as carbon export flux.

Why It Matters

Understanding diel vertical migration is crucial for predicting how changes in light conditions due to climate change might affect marine ecosystems. Changes in the timing or intensity of migrations can alter nutrient cycling, affecting primary productivity and higher trophic levels.

The migrant pump mechanism also plays a significant role in global carbon cycles by transporting organic matter from surface waters to deeper layers, where it can be stored for long periods.

Frequently asked questions

Try it live

Everything above runs in your browser — open Migrant Pump Depth-Time Model: Diel Vertical Migration Flux and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.