Figure 1.
SAZ-Sense voyage track and sampling locations.
Left panel (A) shows MODIS-Aqua 9-km resolution chlorophyll concentration (mg m
) and right panel (A) show Reynolds sea surface temperature (°C) daily composite images from 17 January to 20 February 2007. Voyage track direction is shown by black arrows and black circles are the process stations (P1, process station 1; P2, process station 2; P3, process station 3). Subtropical front (STF), Sub-Antarctic front north (SAF-N), Sub-Antarctic front south (SAF-S), and polar front (PF) are the approximate locations of major oceanic fronts observed during the cruise. Red arrow indicates the approximate direction of the East Australian Current (EAC).
Table 1.
Photosynthetic parameters and definitions used in this study.
Figure 2.
Profiles of mixed layer, euphotic depth, PAR, chl a, /
, and
.
Panel A shows profiles of mixed layer depth (, m), euphotic depth (
, m) for the whole cruise, and mean surface PAR (
, mol photons m
d
) and mean PAR in the mixed layer (
, mol photons m
d
) at P1, P2, and P3. Contour plots of (B) log (base-10) transformed in situ PAR (µmol photons m
s
), (C) chl
(mg m
), (D) effective photochemical efficiency of PSII (
/
, dimensionless), and (E) functional absorption cross section of PSII (
,
quanta
). White lines indicate the mixed layer depth.
Figure 3.
Night-time values of chlorophyll fluorescence parameters.
Maximum photochemical efficiency (/
, black circles) and dissolved iron (dFe, red triangles) at P1, P2 and P3 proxy (a station near P3) (A–C). Functional absorption cross section of PSII (
, black squares) and dFe at P1, P2 and P3 proxy (D–F). The data at P1 and P2 were from two independent casts and data at P3 proxy were from one cast. dFe data were obtained from [24].
Table 2.
Kendall's rank correlations between bio-optical properties and environmental variables.
Figure 4.
Kendall's rank correlations between dFe, /
, dd+dt
, and temperature.
Relationships between (A) dFe and /
, (B) dFe and dd+dt
, and between (C) temperature and
/
for data below 40 m. Relationship between (D) temperature and dd+dt
for surface (0–20 m) data. Kendall's rank correlation coefficients (
) at 95% significance levels are shown.
Figure 5.
Profiles of photosynthetic parameters.
Contour plots of (A) light saturated photosynthesis rate [, mg C (mg chl
)
h
], (B) initial slope of the P-E curve [
, mg C (mg chl
)
h
(µmol photons m
s
)
], (C) saturation irradiance (
, µmol photons m
s
), (D) maximum rate of photosynthetic electron transport from charge separation to carbon fixation (1/
, ms
).
Figure 6.
Profiles of photoprotective pigments and photochemical quenching.
Contour plots of (A) the sum of diadinoxanthin and diatoxanthin normalized to chl (dd+dt
), (B) the de-epoxidation state of the xanthophyll cycle [dt/(dd+dt)], and (C) photochemical quenching (
). White lines indicate the mixed layer depth.
Figure 7.
Depth profiles of mean chl -specific absorption coefficient of phytoplankton (
) at process stations.
at (A) 20 m, (B) 40 m, (C) 60 m, (D) 80 m. Dotted lines indicate the standard deviations.
Table 3.
Total chlorophyll concentrations (mg m
) and accessory pigment composition normalized to chl
(denoted with asterisks) with depth at each station.
Table 4.
Contribution (%) of each phytoplankton group to the total chlorophyll integrated to 120 m at each station.