The Oder Estuary - IOW

Table 3.1 Sensitivity index values (IS) for each state variable in the model and all analyzed
parameters. Each value of IS corresponds to the change of the state variable in percent
for 1% change in the parameter value.
parameter
Phyto
pl
Ndet
Nsed
IS value for each state variable [%]
DIN
PO4
Pdet
Psed
111
Mean IS
for each
paramet
er
temp_coeff_
phyt
1.63 0.20 0.31 0.65 1.69 0.19 0.30 0.71
µmax 1.63 0.35 0.58 7.33 3.54 0.33 0.55 2.04
Iopt 0.02 0.01 0.02 0.23 0.28 0.01 0.14 0.10
ext_phytopl 0.60 0.17 0.28 2.63 1.47 0.17 0.27 0.80
ext_Ndet 0.64 0.15 0.24 0.63 0.81 0.14 0.23 0.41
kN 0.001 0.001 0.0003 0.05 0.001 0.001 0.0003 0.01
kP 0.000 0.0001 0.0001 0.001 0.01 0.0001 0.0000 0.0002
1
1
coeff_sedim 0.47 0.41 0.39 0.56 0.21 0.40 0.40 0.41
coeff_mort 0.74 0.06 0.21 1.75 0.79 0.06 0.20 0.54
temp_coeff_
min
0.31 0.29 0.24 0.50 0.19 0.28 0.24 0.29
temp_coeff_
min_ sed
0.005 0.004 0.17 0.13 0.33 0.003 0.17 0.11
coeff_min N 0.15 0.19 0.07 0.37 0.28 0.05 0.08 0.17
coeff_ min P 0.01 0.003 0.003 0.04 0.55 0.26 0.17 0.15
coeff_
min_sed N
0.01 0.01 0.47 0.28 0.05 0.01 0.01 0.12
coeff_
min_sed P
0.005 0.003 0.003 0.03 0.56 0.003 0.48 0.15
coeff_burial
N
0.01 0.01 0.25 0.26 0.03 0.01 0.01 0.08
coeff_burial
P
0.004 0.002 0.002 0.02 0.38 0.002 0.22 0.09
coeff_denitr 0.03 0.02 0.03 1.16 0.11 0.02 0.03 0.20
Mean IS for
each state
variable
0.35 0.10 0.18 0.92 0.63 0.11 0.19
The sensitivity analysis results indicate that the Szczecin Lagoon system, as seen in the model, is
driven mainly by the phytoplankton growth. Parameters that govern primary production are the
most sensitive ones, among them: maximum growth of algae (µmax), temperature coefficient of
algal growth (temp_coeff_phyt), phytoplankton mortality (coeff_mort) and sinking rates
(coeff_sedim). It can be seen, that 1% of the change in some of these parameters might cause over
1.6% change of the phytoplankton state variable value during simulated five year period.
Phytoplankton state variable is also sensitive to parameters influencing light extinction in the water
column (ext_phytopl and ext_Ndet), since the results of the modeling, indicate that the
phytoplankton growth is limited mainly by light availability. Significant changes in phytoplankton
state variable correspond to the changes of the state variables representing dissolved nutrient forms: