Table 2 Fe fluxes from Leverett Glacier and scaled up estimates for the Greenland Ice Sheet and Antarctic Ice Sheet.

From: Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans

Source

Mass flux

Fe flux a −1

  

Minimum

Mean

Maximum

Leverett catchment (Mg)

 DFe*

2.20 km3 a−1

0.0

0.9

4.5

 CNFe*

2.20 km3 a−1

28.5

85.8

578

 SSFe†

2.31 Tg a−1

2,540

3,470

4,160

 Total labile Fe

 

2,570

3,560

4,740

Greenland Ice Sheet (Gg)

 2000–2011 mean Q

DFe‡

418 km3 a−1

0.0

0.2

0.9

CNFe‡

418 km3 a−1

5.4

16.3

110

SSFe§

0.3–1.6 Pg a−1

403

695

2,430

Total labile Fe

 

409

712

2,540

2012 Q (Gg)

 DFe‡

665 km3 a−1

0.0

0.3

1.4

 CNFe‡

665 km3 a−1

8.6

26.0

175

 SSFe§

0.4–2.6 Pg a−1

642

1,110

3,870

 Total labile Fe

 

651

1,140

4,050

Antarctic Ice Sheet (Gg)

 DFe||

32.5–97.5 km3 a−1

0.1

0.1

0.2

 CNFe||

32.5–97.5 km3 a−1

8.5

17.1

25.6

 SSFe

0.03–0.10 Pg a−1

48.8

97.5

146

 Iceberg Fe#

1.25 Pg a−1

600

900

1,200

 Total labile Fe

 

657

1,010

1,370

  1. CNFe, colloidal/nanoparticulate Fe; DFe, dissolved Fe; SSFe, sediment-bound nanoparticulate Fe.
  2. Results presented to three significant figures.
  3. Q indicates meltwater discharge.
  4. *Calculated from minimum discharge-weighted mean and maximum Fe concentrations multiplied by the Leverett meltwater flux.
  5. †Calculated using minimum (0.11%) discharge-weighted mean (0.15%) and maximum (0.18%) FeA concentrations, multiplied by the suspended sediment flux.
  6. ‡Calculated from minimum discharge-weighted mean and maximum recorded concentrations from Leverett catchment, multiplied by the Greenland meltwater flux.
  7. §Calculated using minimum (0.643 g l−1), discharge-weighted mean (1.109 g l−1) and maximum (3.876 g l−1) suspended sediment concentrations recorded from Leverett catchment, and the discharge weight mean Leverett FeA of 0.15%. We decided to use this method of calculation owing to the uncertainty surrounding mean suspended sediment concentrations in Greenlandic meltwaters, compared with the low standard deviation of FeA in samples.
  8. ||Estimated using minimum (50% of mean), mean and maximum (150% of mean) meltwater fluxes from the study by Pattyn35 coupled with maximum DFe and CNFe concentrations recorded from Leverett catchment.
  9. Estimated using minimum (50% of mean), mean and maximum (150% of mean) meltwater fluxes from the study by Pattyn35, a suspended sediment load of 1 g l−1 and mean Leverett FeA of 0.15%.
  10. #From the study by Raiswell et al.10
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