Figure 1.
Location of the sampling site (39° 30′.00 N, 13°30′.00 E) where the experimental data were collected.
(Courtesy of Ribera d’Alcalà et al., 2009 (Ref. [71])).
Figure 2.
Profiles of temperature (panels a, c, e, g) and density (panels b, d, f, h) acquired in the sampling site (39° 30′.00 N, 13° 30′.00 E).
Data were collected during four oceanographic cruises: VECTOR-TM1, 24 November 2006 (panels a, b); VECTOR-TM2, 3 February 2007 (panels c, d); VECTOR-TM3, 22 April 2007 (panels e, f); VECTOR-TM4, 9 June 2007 (panels g, h). The black lines have been obtained by connecting the experimental points corresponding to samples distanced of 1 meter along the water column. The total number of samples measured in the site is n = 196 for VECTOR-TM1, n = 198 for VECTOR-TM2, n = 199 for VECTOR-TM3, and n = 196 for VECTOR-TM4.
Figure 3.
Profiles of chl a concentration acquired in the sampling site (39° 30′.00 N, 13° 30′.00 E).
Data were collected during four oceanographic cruises: VECTOR-TM1, 24 November 2006 (panel a); VECTOR-TM2, 3 February 2007 (panel b); VECTOR-TM3, 22 April 2007 (panel c); VECTOR-TM4, 9 June 2007 (panel d). The black lines have been obtained by connecting the experimental points corresponding to samples distanced of 1 meter along the water column. The total number of samples measured in the site is n = 196 for VECTOR-TM1, n = 198 for VECTOR-TM2, n = 199 for VECTOR-TM3, and n = 196 for VECTOR-TM4.
Figure 4.
Scheme of the mechanism responsible for the phytoplankton distribution (modified from original figure by Alexey Ryabov).
Inset: (a) Prochlorococcus PCC 9511 (courtesy of Rippka et al., 2000 (Ref. [95])), (b) Micromonas NOUM17 (courtesy of Augustin Engman, Rory Welsh, and Alexandra Worden).
Table 1.
Parameters used in the model.
Table 2.
Monthly average values of vertical turbulent diffusivity in deeper layers (DD) and in upper mixed layer (DU), thickness of the upper mixing layer (ZU) and incident light intensity (Iin).
Figure 5.
Spatio-temporal behaviour of vertical turbulent diffusivity (left panel) and light intensity (right panel) simulated for the sampling site (39° 30′.00 N, 13°30′.00 E).
The values of the parameters are those of Table 2.
Figure 6.
Spatio-temporal behaviour of the five picophytoplankton groups and phosphorus concentrations simulated by the model.
The contour maps show the cell concentrations of (a) Synechococcus, (b) Haptophytes, (c) Prochlorococcus HL, (d) Pelagophytes, (e) Prochlorococcus LL and (f) nutrient. The values of the parameters used in the model are those shown in Tables 1 and 2.
Figure 7.
Spatio-temporal behaviour of chl a and Dvchl a concentrations.
Contour maps show the content of chlorophyll for (a) Synechococcus, (b) Haptophytes, (c) Prochlorococcus HL, (d) Pelagophytes, (e) Prochlorococcus LL and (f) all phytoplankton groups in the sampling site (39° 30′.00 N, 13°30′.00 E). The values of the parameters used in the model are those shown in Tables 1 and 2.
Figure 8.
Surface total chl a density as a function of time.
Red line shows, for a yearly cycle with a time resolution of one month, the surface total chl-a density obtained by integrating the theoretical profiles of the total chl a and Dvchl a concentration over the MAW (from the surface down to 200 m). The experimental data (green points) for the site analyzed (39° 30′.00 N, 13°30′.00 E) are those acquired in correspondence of the four sampling periods (VECTOR-TM1, 24 November 2006; VECTOR-TM2, 3 February 2007; VECTOR-TM3, 22 April 2007; VECTOR-TM4, 9 June 2007).
Figure 9.
Theoretical distributions (red line) and experimental profiles (green line) of the total chl a and Dvchl a concentration.
The numerical results, obtained by the five-population model and given as a function of the depth, are compared with the experimental data collected in the sampling site (39° 30′.00N, 13°30′.00E), during the oceanographic surveys: VECTOR-TM1, 24 November 2006 (panel a); VECTOR-TM2, 3 February 2007 (panel b); VECTOR-TM3, 22 April 2007 (panel c); VECTOR-TM4, 9 June 2007 (panel d).
Table 3.
Results of χ2 and reduced chi-square () goodness-of-fit test for the site investigated in correspondence of the four sampling periods.
Figure 10.
Magnitude, depth, and width of the DCM, as a function of time.
Red lines indicate theoretical results obtained for a yearly cycle with a time resolution of one month. Green points indicate experimental data acquired in the site analyzed (39° 30′.00 N, 13°30′.00 E) in correspondence of the four sampling periods (VECTOR-TM1, 24 November 2006; VECTOR-TM2, 3 February 2007; VECTOR-TM3, 22 April 2007; VECTOR-TM4, 9 June 2007).
Figure 11.
Phosphorus concentration at different depths as a function of time.
The figure shows, for a yearly cycle, the theoretical results of phosphorus concentration at 0 m (black line), 25 m (brown line), 50 m (green line), 75 m (pink line) and 100 m (blue line) of depth.