Phytoplankton growth model parametrization
43
1.0,------------------------------------.~~------.
0.8
0.6
0.4
0.2
0.5
1
2
5
10
20
Phosphorus subsistence quota ([~g P] [mg C]-l)
Fig. 3.3. Cumulative frequency distribution of phosphorus subsistence quotas [(lig P) (mg Cr']
in different species of plankton algae (data from Table AIO.2; n = 40). ). Solid line Fitted
lognormal distribution; broken lines median and upper and lower quartiles
nor between marine and freshwater species (ANOVA: Fl,40 = 0.014, P = 0.908).
The resulting frequency distribution when all data in Table AI0.2 are pooled
(Fig. 3.3), indicate that phosphorus subsistence quotas are approximately lognormally distributed among species with median 3.8 (Jig P) (mg C).I and a
twofold interquartile range of 2.5-5.2 (Jig P) (mg C)'I.
Maximum Cell Quota (Q ". The minimum and maximum P quotas are not
independent parameters in the sense that we must always have Q ':s; Q ':
Given the variability in Q I as shown in Fig. 3.3, the distributions of Q I and
Q "when treated as independent parameters will most certainly be overlapping. In order to ensure that Q ':s; Q '~ it should be safer to estimate Q"
indirectly from the distribution of the phosphorus storage capacity, defined
as the ratio of maximal to minimal P requirements, or Q 7Q ': This
approach also allows the utilization of data sets where P quotas are given
on a per-cell basis (e.g., Gotham and Rhee 1981) without any conversion
factors to cell volume or carbon. On the other hand, several studies
describing P-limited growth through the Droop model have not included
the information necessary to calculate the ratio Q 'rQ ~ so that the data
set on phosphorus storage capacities (Table AI0.3) is less extensive (n = 20)
43
1.0,------------------------------------.~~------.
0.8
0.6
0.4
0.2
0.5
1
2
5
10
20
Phosphorus subsistence quota ([~g P] [mg C]-l)
Fig. 3.3. Cumulative frequency distribution of phosphorus subsistence quotas [(lig P) (mg Cr']
in different species of plankton algae (data from Table AIO.2; n = 40). ). Solid line Fitted
lognormal distribution; broken lines median and upper and lower quartiles
nor between marine and freshwater species (ANOVA: Fl,40 = 0.014, P = 0.908).
The resulting frequency distribution when all data in Table AI0.2 are pooled
(Fig. 3.3), indicate that phosphorus subsistence quotas are approximately lognormally distributed among species with median 3.8 (Jig P) (mg C).I and a
twofold interquartile range of 2.5-5.2 (Jig P) (mg C)'I.
Maximum Cell Quota (Q ". The minimum and maximum P quotas are not
independent parameters in the sense that we must always have Q ':s; Q ':
Given the variability in Q I as shown in Fig. 3.3, the distributions of Q I and
Q "when treated as independent parameters will most certainly be overlapping. In order to ensure that Q ':s; Q '~ it should be safer to estimate Q"
indirectly from the distribution of the phosphorus storage capacity, defined
as the ratio of maximal to minimal P requirements, or Q 7Q ': This
approach also allows the utilization of data sets where P quotas are given
on a per-cell basis (e.g., Gotham and Rhee 1981) without any conversion
factors to cell volume or carbon. On the other hand, several studies
describing P-limited growth through the Droop model have not included
the information necessary to calculate the ratio Q 'rQ ~ so that the data
set on phosphorus storage capacities (Table AI0.3) is less extensive (n = 20)