Table 2.
Fermentation product concentration and equivalent electron balance in GN-I mat microcosms showing the amount of light captured electrons in fixed carbon analytes (during the day) and in fermentation by-products (produced at night).
| Daytime flux/storage | Nighttime flux/storage | Avg. diel flux/storage | e− equivalents | e− flux/storage | |
|---|---|---|---|---|---|
| mmol/m2 Avg. (SD) | mmol/m2 Avg. (SD) | mmol/m2 Avg. (SD) | mmol e−/m2 | ||
| Fixed inorganic-C (CH2O) | −121.4 (10.3) | 77.5 (6.9) | 99.5 (8.6) | 4 | 397.9 (34.4) |
| Glycogen | 21.2 (25.2) | −31.6 (30.4) | 26.4 (27.8) | 24 | 633.8 (667.2) |
| NET FERMENTATION | |||||
| Acetate | – | 14.9 (0.9) | 14.9 (0.9) | 8 | 119.2 (7.5) |
| Formate | – | 8.3 (1.2) | 8.3 (1.2) | 1 | 8.3 (1.2) |
| Propionate | – | 2.4 (0.5) | 2.4 (0.5) | 13 | 31.7 (6.1) |
| H2 | – | 0.83 (0.05) | 0.83 (0.05) | 2 | 1.66 (0.09) |
| TOTAL FERMENTATION | |||||
| Acetate | – | 28.0 (1.3) | 28.0 (1.3) | 8 | 224.2 (10.1) |
| Formate | – | 10.0 (1.0) | 10.0 (1.0) | 1 | 10.0 (1.0) |
| Propionate | – | 6.6 (1.2) | 6.6 (1.2) | 13 | 85.3 (15.1) |
| H2 | – | 1.77 (0.18) | 1.77 (0.18) | 2 | 3.55 (0.36) |
| % Fixed e− fermented | 81.2 (14.6) | ||||
| % Fixed e− taken up by accessory microbes | 40.8 (14.0) | ||||
Values were normalized to microcosm mat diel flux or storage rate and core cross-sectional area, mmol/m2. Net fermentation by-product measurements were from control microcosms, and total fermentation byproducts were from homogenized microcosms.