Table 2. Rank of the importance of the model parameters for the target output, i.e. the maximum internal toxin concentration.

The rank is based on the absolute values of the standardized regression coefficients (|β|). The list includes a subset of the model parameters in Table 1, i.e. those that have statistically significant regression coefficients (t-statistic, p< 0.05).

	Parameter	Rank	| β |
Q Tmax	Maximum tox:C ratio	1	0.765
S P	P-stress threshold	2	0.324
r detr	Fraction of labile DOM derived from lysis and exudation	3	0.313
α	Initial slope of PI-curve	4	0.206
Q Pmin	Minimum P/C ratio	5	0.187
r A.res	Respired fraction of PP	6	0.111
$s_P^{res}$	P-stress threshold for respiration decrease	7	0.097
r B.res	Basal respiration rate	8	0.088
Q 10	Q10 parameter	9	0.073
p A.exu	Fraction of excreted carbon	10	0.069
r lys	Minimum lysis rate	11	0.063
φ	Carbon fraction invested in toxin production under nutrient stress	12	0.055
$Q_{N min}^{chl}$	Minimum N/C ratio for chlorophyll synthesis	13	0.049
$s_N^{upt}$	N-threshold for max. uptake	14	0.033
S N	N-stress threshold	15	0.032
σ P	Extinction coefficient of algal biomass	16	0.0284
Q Tmin	Carbon fraction invested in basal toxin production	17	0.0283
$s_N^{chl}$	N-stress threshold for chlorophyll synthesis	18	0.023