TABLE 2.
Fractions of DOC during incubations of microbial inocula from the two compartmentsa
| Inoculum | Day | Mean fraction (mg/liter of C) (SD)
|
||||
|---|---|---|---|---|---|---|
| cDOC | Humic acids | Polysaccharides | LMWA | Others | ||
| SW compartment | 0 | 13.1 (0.6) | 8.7 (0.1) | 0.5 (0.1) | ND (ND) | 3.9 (0.6) |
| 6 | 12.9 (0.5) | 9.0 (0.5) | 0.5 (0.1) | ND (ND) | 3.5 (0.0) | |
| 8 | 13.0 (0.2) | 9.0 (0.2) | 0.5 (0.0) | ND (ND) | 3.6 (0.1) | |
| 14 | 12.8 (0.1) | 8.9 (0.1) | 0.4 (0.1) | ND (ND) | 3.7 (0.0) | |
| Control | 1.5 (0.2) | 0.8 (0.1) | 0.1 (0.0) | ND (ND) | 0.5 (0.1) | |
| NE compartment | 0 | 12.5 (0.1) | 8.1 (0.1) | 0.6 (0.3) | 0.4 (0.4) | 3.3 (0.1) |
| 6 | 12.5 (0.4) | 8.4 (0.2) | 0.6 (0.3) | 0.1 (0.1) | 3.5 (0.2) | |
| 8 | 13.0 (0.7) | 8.8 (0.4) | 0.3 (0.1) | 0.1 (0.2) | 4.0 (0.7) | |
| 14 | 12.5 (0.1) | 8.6 (0.3) | 0.4 (0.2) | 0.1 (0.1) | 3.6 (0.1) | |
| Control | 1.3 (0.2) | 0.7 (0.1) | 0.1 (0.0) | ND (ND) | 0.5 (0.1) | |
a
Fractions are measured in prefiltered lake water from the SW compartment and in NaHCO3 solution (control) by size exclusion liquid chromatography and UV and organic carbon detection. LMWA, low-molecular-weight organic acids; ND, not detectable.