Table 1.
Changes in median iron and organic matter concentrations in the rivers since the beginning of monitoring until 2012.
Figure 1.
Yearly mean iron concentrations in the river mouths of three different rivers from 1976–2012.
Lines denote the linear regression equations, which were µmol Fe L−1 = 0.212× year – 413.2 (r2 = 0.56, p<0.001); µmol Fe L−1 = 0.477× year – 924.0 (r2 = 0.40, p<0.001); and 0.716× year – 1398.4 (r2 = 0.51, p<0.001) for Emån, Lyckebyån and Helgeån respectively.
Table 2.
Iron and organic matter concentrations and organic matter quality indicators of the experimental waters.
Figure 2.
Concentration of iron in suspension at different salinity after addition of artificial sea salt.
Table 3.
Iron in suspension at different salinities and iron transport capacity (α) for the different waters.
Figure 3.
Differences in iron and organic matter in suspension in river waters at 0 and 30 salinity.
A) ratio between iron and organic carbon, B) ratio of absorbance at 465 and 665 nm, C) specific UV absorbance at 254 nm and D) fluorescence index (ratio of emission at 470 and 520 nm and an excitation of 370 nm).
Figure 4.
Relationship between the fraction of initial iron remaining in solution (iron transport capacity) at a salinity of 30 and the molar iron:organic carbon ratio of the river water (r2 = 0.54, p<0.05).
Figure 5.
Concentration of iron in suspension at different salinity with and without iron amendments.