Table 1 Data and calculations for all station occupations

From: Recycled iron fuels new production in the eastern equatorial Pacific Ocean

Date (YYYY/MM/DD)

Estimated source nitrate concentration (μmol kg−1)

Mixed layer nitrate (μmol kg−1)

Nitrate consumption (μmol kg−1)

Necessary dissolved iron concentration for nitrate consumption (nmol kg−1)

2005/04/16

16.0

4.0

12.0

0.98

2005/04/17

16.6

5.1

11.5

0.94

2005/04/18

14.4

5.3

9.1

0.74

2006/04/11

16.9

4.2

12.7

1.04

2007/04/11

17.8

7.1

10.7

0.87

2003/10/11

16.7

7.6

9.1

0.74

2003/10/11

15.0

8.3

6.8

0.55

2003/10/12

15.4

7.7

7.7

0.63

2005/11/15

15.5

9.3

6.1

0.50

2006/11/20

16.9

8.0

8.9

0.73

2004/12/12

15.3

5.2

10.1

0.82

  1. Source water nitrate concentration was estimated using nitrate isotope measurements for the first 10 stations in the list. Subsurface source water nitrate concentration for the last station was identified as a subsurface eastward velocity maximum, which is the Equatorial Under Current (based on refs. 14, 16 and see “Methods”). Nitrate consumption is calculated as the difference between the subsurface source water and surface mixed layer nitrate concentration. The dissolved iron concentration required to drive this nitrate consumption was calculated assuming an Fe:C requirement of 12.322 and a C:N requirement of 106:16.
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