MOdel Shopping Tool ( MOST )
"Fe, dissolved iron budget module" from PISCES v1 Equations
Equation Description :
Not shown in the equation are additional terms in the code which ensure iron conservation during grazing, and are needed due to the differences in Fe/C ratios between prey and grazer. Dissolved Fe is assumed in the free inorganic form and 'complexed' iron. Both forms are assumed equally accessible to phytoplankton despite recent evidence to the contrary (Chen et al., 2003)
Atmospheric iron is simulated by the model of Tegen & Fund (1995). Iron content and surface solubility are set as constants at 3.5% and 2% (Moore et al., 2004). Dust iron sinks at 5 md-1 and dissolves at 0.0002%d-1 (Bonnet & Guieu, 2004).
Parameter values and definitions:
delta = 0.05 (exudation by phytoplankton, no units);
lambda* POC = in situ POC remineralization rate;
sigma = 0.3 (fecal pellets production);
mu = production by phytoplankton groups (P) and (D);
D = concentration of diatoms in micro mol C l-1;
e = 0.35 (zooplankton growth efficiency);
Fe/C zoo = 3 micro mol Fe mol C-1 (Fe/C ratio of zooplankton);
g = 4, 0.7 d -1 (max grazing rate for micro-(Z) and mesozooplankton (M));
K M = 0.1 micro mol C l-1 (half-saturation constant for excretion for M);
K Z = 0.1 micro mol C l-1 (half-saturation constant for excretion for Z);
M = concentration of mesozooplankton in micro mol C l-1;
P = concentration of nanophytoplankton in micro mol C l-1;
r = 0.03, 0.008 d-1 (excretion rate for micro- and mesozooplankton);
Z = concentration of microzooplankton in micro mol C l-1;
References:
Bonnet, S., and C. Guieu, 2004. Geophys. Res. Lett., 31, L03303, doi:10.1029/2003GL018423.
Chen, M. 2003. Marine Chemistry, 81, 177-189;
Moore, J. K. 2004. Global Biogeochem. Cycles, 18, GB4028, doi:10.1029/2004GB002220;
Tegen, I., and I. Fung 1995. J. Geophys. Res., 100, 18,707-18,726;
