K.1 Carbon

Carbon has the simplest uptake calculation, as per Equation (K.1).

\[\begin{equation} F_{C-uptake}^{phy} = R_{prod\langle computed\rangle}^{phy} \times \left[PHY\right] \tag{K.1} \end{equation}\]

\(F_{C-uptake}^{phy}\) is the uptake of carbon, \(R_{prod\langle computed\rangle}^{phy}\) is the computed primary productivity rate and \(\left[PHY\right]\) is a computational cell’s phytoplankton concentration. This flux is summed over all simulated phytoplankton groups to compute the community carbon uptake, \(F_{C-uptake\langle computed\rangle}^{comm}\).

Carbon does not need to be explicitly simulated as a computed variable for this uptake to occur, but because carbon is used as the units of accounting for phytoplankton biomass, its uptake is computed by the WQ Module in order to report phytoplankton concentrations. These concentrations are either mmol C per m\(^3\) or \(\mu\)g chlorophyll a per litre (using a specified or default conversion), depending on the specified simulation units system. Carbon stores from which phytoplankton uptake can draw are assumed to be unlimited and unaccounted for when carbon is not explicitly included in a simulation as a computed variable.