TABLE 3.
Distribution of Vibrio counts, nutrients and stable isotopes (mean value ± standard deviation) in the fractions: suspended particulate matter (SPM), nanoplankton (SPM < 20 μm), and SPM enriched with sediments (SPM-Sed).
| Variables | SPM (n = 22) | SPM < 20 μ m (n = 10) | SPM-Sed (n = 8) | K | p |
| Vibrio counts | |||||
| CVC (CFU × 103 mL–1) | 1.3 ± 2.9 | 1.7 ± 3.4 | 5.9 ± 11.5 | 1.7 | 0.426 |
| Vchomim1276 (cell × 103 mL–1) | 3.2 ± 3.4a | 1.6 ± 1.0a | 8.4 ± 5.5b | 11.0 | 0.004 |
| Vibrio-GV (cell × 103 mL–1) | 3.3 ± 2.8a | 3.3 ± 3.8a | 16.3 ± 12.0b | 15.0 | <0.001 |
| ompW (GU × 103 mL–1) | 1.7 ± 2.3a | 1.0 ± 0.9a | 26.1 ± 51.5b | 7.0 | 0.029 |
| ctxA (GU × 102 mL–1) | 3.9 ± 10.0 | 0.2 ± 0.6 | 8.4 ± 14.4 | 4.9 | 0.087 |
| Vibrio (OTUs x 102) | 6.0 ± 18.5 | 3.1 ± 7.6 | 2.7 ± 7.3 | 1.1 | 0.565 |
| Inorganic nutrients | |||||
| Phosphate (μM) | 4.5 ± 7.6 | 2.3 ± 1.5 | 4.2 ± 6.0 | 0.6 | 0.731 |
| Ammonium (μM) | 22.4 ± 40.9 | 11.4 ± 19.2 | 41.7 ± 64.6 | 2.0 | 0.362 |
| Nitrite (μM) | 2.7 ± 2.1 | 2.3 ± 2.3 | 2.4 ± 2.1 | 0.5 | 0.798 |
| Nitrate (μM) | 19.9 ± 10.7 | 20.6 ± 11.9 | 16.7 ± 11.8 | 0.5 | 0.785 |
| Silicate (μM) | 140 ± 63 | 117 ± 53 | 178 ± 118 | 1.4 | 0.505 |
| Organic nutrients | |||||
| DOC (μM) | 225 ± 100 | 216 ± 82 | 366 ± 179 | 5.3 | 0.071 |
| DON (μM) | 49.9 ± 172ab | 8.6 ± 4.1a | 124 ± 278b | 7.4 | 0.025 |
| POC (μM) | 240 ± 188a | 249 ± 165a | 1662 ± 1194b | 17.4 | <0.001 |
| PON (μM) | 39.2 ± 34.9a | 42.6 ± 36.3a | 220 ± 155b | 16.5 | <0.001 |
| C/N particulates | 6.3 ± 1.1 | 6.1 ± 0.7 | 7.3 ± 1.5 | 4.0 | 0.136 |
| Stable isotopes | |||||
| δ15N (‰) | 6.0 ± 2.8 | 6.0 ± 1.9 | 5.4 ± 2.8 | 0.4 | 0.825 |
| δ13C (‰) | −24.6 ± 2.2 | −24.4 ± 2.2 | −24.8 ± 0.9 | 2.5 | 0.288 |
Significant differences according to Kruskal-Wallis one-way analysis of variance are printed in bold, superscript letters indicate differences following Dunn pair-wise comparisons. CVC, culturable Vibrio counts; CFU, colony forming unit; Vchomim1276, Vibrio cholerae and V. mimicus identified with a CARD-FISH probe; Vibrio-GV, other Vibrio species identified with a CARD-FISH probe; ompW, outer membrane protein W gene for V. cholerae; GU, genomic units by qPCR; ctxA, cholera toxin A; OTUs, operational taxonomic units; DOC, dissolved organic carbon; DON, dissolved organic nitrogen; POC, particulate organic carbon; PON, particulate organic nitrogen.