Fig 1.
Map of sampling stations in four different cruises.
(a) March 2012; (b) July 2012; (c) March 2013; (d) July 2013. Four axial sections of the Yangtze Estuary are connected and marked by red lines. ETM regions are marked by dashed eclipses. Black dots indicate the sampling sites.
Fig 2.
Contour plots and spectral characteristics of five fluorescent components identified by PARAFAC.
The line plots present split-half validation data. Excitation (short-dashed lines) and emission (solid lines) loadings are presented for two independent halves of the dataset (red and blue lines).
Fig 3.
Fluorescence intensity (Fmax) of five fluorescent components (C1-C5) versus salinity.
Fig 4.
Variations of five fluorescent components in surface water samples along the axial section of the Yangtze Estuary.
ETM regions are indicated by green areas.
Fig 5.
Relative differences between surface and bottom FDOM concentrations along the axial section of the Yangtze Estuary in 2013.
The left is for section E in July 2013, and the right is for section F in March 2013. ΔC is calculated as the component concentration in bottom water subtracting the component concentration in surface water. Positive ΔC means a higher component concentration in bottom water than that in surface water.
Fig 6.
Relationship between salinity and ratios of Fmax of humic-like components to CDOM absorption coefficient for four cruises.