Table 3.
Calculated permeability of the cell wall necessary to support anoxia in the interior of a Trichodesmium cell, based on measured rates of O2 uptake (that is, dark respiration), extracellular O2 concentrations in colonies and cell dimensions (average 5 μm length, 7 μm width)
| Respiration distribution | External O2 (μmol l−1) | Average O2 uptake (fmol cell−1 h−1) | Intensity of O2 consumption (mol s−1 m−3) | Permeability for O2 (m s−1) | Permeability for CO2 (m s−1) |
|---|---|---|---|---|---|
| Homogeneous | 329 | 608 | 1.49 | 4.6 × 10−6 | 3.7 × 10−6 |
| Heterogeneous | 329 | 3648 | 8.96 | 2.9 × 10−5 | 2.3 × 10−5 |
| Homogeneous | 187 | 194 | 0.48 | 2.6 × 10−6 | 2.1 × 10−6 |
| Heterogeneous | 187 | 1164 | 2.86 | 1.6 × 10−5 | 1.3 × 10−5 |
| Homogeneous | 101 | 198 | 0.49 | 4.9 × 10−6 | 3.9 × 10−6 |
| Heterogeneous | 101 | 1188 | 2.92 | 3.1 × 10−5 | 2.4 × 10−5 |
Scenarios with heterogeneous distribution of respiration assume a six‐fold higher respiration rate in diazocytes compared to vegetative cells. Permeability for CO2 was calculated from O2 permeability using a conversion factor of 0.7961 according to Ramsing & Gundersen (1994). For further details on the model, please refer to Supporting Information Notes S1.