TABLE 1.
DOC concentration and optical properties of the DOM derived from Prochlorococcus
| DOM source | DOC (μM) | a254 (m−1) | S275–295b (10−2 nm−1) | Fluorescence intensity (RU)a |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Humic-like components |
Protein-like components |
|||||||||||
| Peak A (250/466)c | C2 (255/456) | Peak Mb (335/404) | C4b (325/396) | Peak C (355/450) | C3 (<250/368) | Peak T (270/342) | C1 (275/332) | C5 (275/300) | ||||
| Pro-medium | 160.9 | 0.19 | 0.12 | 0.09 | 0.08 | 0.06 | 0.13 | 0.15 | 0.13 | 0.04 | ||
| Pro-exudate | 234.0 | 3.37 | 2.88 | 0.36 | 0.36 | 0.22 | 0.22 | 0.20 | 0.19 | 0.25 | 0.24 | 0.08 |
| P-HS2 lysate | 259.5 | 3.65 | 3.29 | 0.37 | 0.34 | 0.27 | 0.26 | 0.21 | 0.14 | 0.19 | 0.18 | 0.08 |
| P-SSP7 lysate | 319.0 | 4.77 | 4.27 | 0.35 | 0.36 | 0.29 | 0.28 | 0.23 | 0.18 | 0.26 | 0.26 | 0.08 |
| P-HM2 lysate | 244.4 | 5.08 | 3.80 | 0.38 | 0.38 | 0.30 | 0.30 | 0.22 | 0.17 | 0.19 | 0.19 | 0.06 |
a
The FDOM components (C1 to C5), as identified by PARAFAC modeling, are shown with the corresponding FDOM components (peaks A, M, C, and T) identified by the peak-picking method. The data shown are the means of two replicates. RU, Raman units.
b
Significant difference between Pro-exudate and Pro-vDOM, t test (double tailed), P < 0.05.
c
Values in parentheses are excitation/emission wavelengths.