carrion_dynamics: Carrion dynamics

In gustavdelius/mizerUR: Unstructured Resources for Mizer

Description

Calculates the biomass of carrion (dead animals) at the next timestep from the current biomass.

Usage

carrion_dynamics(
  params,
  n,
  n_pp,
  n_other,
  rates,
  t,
  dt,
  carrion_external = params@other_params$UR$carrion_external,
  ...
)

Arguments

params	A MizerParams object
n	A matrix of current species abundances (species x size)
n_pp	A vector of current plankton abundance by size
n_other	List of abundances of other dynamic components
rates	A list of rates as returned by getRates()
t	Current time
dt	Time step size
carrion_external	External inflow rate of carrion biomass
...	Unused

Details

The equation for the time evolution of the carrion biomass B is assumed to be of the form

dB/dt = inflow - consumption * B + external

where

• inflow comes from

  • Discards from fishing.

  • Animals killed by fishing gear.

  • Animals that have died by causes other than predation.

• consumption is by scavenger species, where the encounter rate is specified by rho[, "carrion", ].

• external is an influx from external sources. It can be negative in which case it represents a loss to external sources.

This equation is solved analytically to

B(t+dt) = B(t) exp(-consumption * dt) +(inflow + external)/(consumption) * (1 - exp(-consumption * dt)).

This avoids the stability problems that would arise if we used the Euler method to solve the equation numerically.

Value

A single number giving the biomass of carrion at next time step

See Also

Other resource dynamics functions: detritus_dynamics()

gustavdelius/mizerUR documentation built on June 24, 2020, 6:28 p.m.