Fig. 3
From: Marine nitrogen fixers mediate a low latitude pathway for atmospheric CO2 drawdown
How N2 fixation enables CO2 storage in the ocean. The response of the respired C inventory to aeolian Fe deposition experiments for five different representations of N2 fixers, with a demonstrating the relationship between respired C and Fe availability and b demonstrating the relationship between respired C and N2 fixation. The marker numbers refer to how N2 fixers are represented. Ones: no N2 fixers and no active N cycle. Twos: N2 fixers and N cycle (i.e., denitrification) reinstated but no N2 fixer carbon export (C:P = 0:1). Threes: N2 fixers C:P ratio increased to 165:1, half its default value. Fours: N2 fixers PO4 limitation enforced by increasing their half saturation coefficient \(\left( {K_{PO_4}^D} \right)\) from 10−10 to 0.1 mmol m−3. Fives: N2 fixers with default parameterisation. Colour shading of the markers indicates the mean surface PO4 concentration of the experiment. Background shading in b is a qualitative indicator of the transition from NO3 to PO4 limitation, where dark green to yellow indicates NO3 limitation and light blue indicates PO4 limitation. Source data are provided in the source data file
