Table 2 Estimated contribution of UCYN-A1 and UCYN-A2 symbioses to community NFRs at select near- and offshore stations.

From: UCYN-A/haptophyte symbioses dominate N2 fixation in the Southern California Current System

Cruise

Stn

UCYN-A1/UCYN-A2

Number of cells

Measured

Estimated

Corrected estimate (maximum)

UCYN-A single-cell NFR (fmol N cell−1 d−1)

UCYN-A abundance (nifH copies l−1)

Community NFR (nmol N l−1 d−1)

UCYN-A volumetric NFR (nmol N l−1 d−1)

UCYN-A contribution to community NFR

Maximum UCYN-A single-cell NFR (fmol N cell−1 d−1)

Maximum UCYN-A volumetric NFR (nmol N l−1 d−1)

Maximum UCYN-A contribution to community NFR

SP1714

1

A1

10

3.6 (2.2)

4.1 × 104 (7.3 × 102)

2.3 (1.3)

0.15 (0.0)

6% (43%)

14.4

0.6

26%

SP1727

1

A2

6

125.8 (41.6)

9.3 × 104 (4.2 × 103)

2.2 (0.2)

1.7 (0.1)c

53% (16%)

503.2

4.7

213%

SP1727

5

A1

6

12.8 (13.5)

6.2 × 104 (1.5 × 103)

0.8 (0.1)a

0.8 (0.01)

99% (6%)

51.2

3.2

397%

SP1727

7

A2

6

279.9 (53.7)

1.2 × 105 (2.9 × 103)

6.7 (0.8)

3.6 (0.1)c

50% (28%)

1119.6

134

201%

SP1727

14

A1

10

5.7 (5.4)

8.8 × 105 (8.1 × 104)

3.4 (0.2)b

5.0 (2.7)

148% (270%)

22.8

20.1

590%

SP1727

14

A2

5

27.0 (15.4)

2.9 × 104 (1.1 × 102)

3.4 (0.2)b

0.8 (0.0)c

2% (7%)

108

0.3

9%

  1. Standard deviations for measured parameters and propagated errors for estimated parameters are in parenthesis. Maximum single-cell NFR using correction factors defined by [64], and the resulting maximum UCYN-A volumetric NFR and contribution to community are also reported.
  2. a NFR was BDL, value used is the detection limit.
  3. b NFR data from 10 m; N content at 3 m was below levels needed for accurate and/or precise isotopic measurement.
  4. c Potential contributions to volumetric NFR rates for the UCYN-A2 symbiosis assume that there are 10 nifH copies cell−1 [64].
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