TABLE 2.
Effects of UV-A alone or UV-A+UV-B on grazing mortality (GM) of Synechococcus spp. and nanoflagellate-specific grazing rates (GR) of P. bandaiensis
| Expt no. | Irradiance (W m−2)
|
Grazing measurementa
|
||||
|---|---|---|---|---|---|---|
| UV-A | UV-B | 0–6 hb
|
0–9 (10) hb
|
|||
| GM | GR | GM | GR | |||
| 1 | 0.00 | 0.00 | 0.08 (0.02) a | 6.7 (1.6) a | 0.13 (0.05) a | 10.8 (2.7) a |
| 5.47 | 0.00 | 0.05 (0.01) b | 5.5 (1.0) a | 0.06 (0.00) b | 6.8 (0.7) b | |
| 5.65 | 0.12 | 0.05 (0.01) b | 5.8 (0.8) a | 0.06 (0.01) b | 6.7 (0.4) b | |
| 2 | 0.00 | 0.00 | 0.06 (0.00) a | 2.9 (0.4) a | 0.08 (0.00) a | 5.1 (0.5) a |
| 9.48 | 0.00 | 0.04 (0.01) b | 2.5 (0.3) a | 0.05 (0.01) b | 3.3 (0.5) b | |
| 9.36 | 0.19 | 0.03 (0.01) c | 1.7 (0.1) b | 0.03 (0.00) c | 2.6 (0.1) b | |
a
Units: GM, 1/hours; GR, nanoliters cleared per nanoflagellate per hour. Numbers in parentheses are SD. All grazing measurements were calculated by determining changes in in vivo population fluorescence. In each experiment, values followed by the same letter are not significantly different from each other (P > 0.05, ANOVA).
b
The duration of UV-A exposure over which the grazing rates were calculated. In experiment 1, the longer period was 10 h.