Table 2 Fraction of primary production supported by nitrogen fixation

From: Nitrogen fixation under declining Arctic sea ice

   

Redfield C:N ratio

In situ C:N ratio

Station

Region

Regime

Fraction of in situ net primary production supported

C:N ratio (molar)

Fraction of in situ net primary production supported

18

CAO

Multiyear ice

1.8%

7.3

1.9%

26

CAO

Multiyear ice

2.2%

2.1

0.7%

38

CAO

Multiyear ice

4.2%

11.9

7.5%

50

CAO

Decaying multiyear ice

3.5%

2.8

1.5%

56_2021

CAO

Decaying multiyear ice

3.9%

14.9

8.6%

36

MIZ

Atlantic open water

0.4%

8.90

0.6%

37

MIZ

High-melt zone

-

-

-

42

MIZ

Pack ice (first year ice)

-

-

-

56_2022

MIZ

High-melt zone

-

-

-

57

MIZ

Atlantic open water

0.7%

11.12

1.1%

61

MIZ

High-melt zone

0.3%

8.65

0.4%

65

MIZ

Pack ice (first year ice)

0.3%

11.54

0.6%

108

LF

Land-fast ice

0.9%

30.84

4.0%

  1. Calculations of the fraction (%) of measured in situ net primary production supported by measured in situ nitrogen fixation rates. Calculations are performed with the Redfield (106:16; Redfield 193465) and station-specific in situ carbon to nitrogen (C:N, i.e., POC:PON) molar ratios, respectively. CAO Central Arctic Ocean, MIZ marginal ice zone, LF land-fast ice. The Stations 37, 42, and 56_2022 do not have values due to nitrogen fixation being below the limit of detection. All limit of detections for nitrogen fixation are found in Supplementary data sheet S1.
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