Skip to main content
. 2005 Oct;71(10):6267–6275. doi: 10.1128/AEM.71.10.6267-6275.2005

TABLE 2.

Effect of irradiation on bacterial production, respiration, BGE, and carbon utilization (i.e., BCP plus bacterial respiration) in lake water with irradiated and nonirradiated humus incubated for 43 h

Humic isolate no. Treatment Avg ± SE value
Respiration (μg C liter−1 h−1) BCP (μg C liter−1 h−1) BGEa (%) C utilizationa (μg C liter−1 h−1)
3 Dark 7.3 ± 0.1b 2.0 ± 0.4 20.6 ± 2.3b 9.3 ± 0.3b
UV 9.7 ± 0.4 3.5 ± 0.7 26.2 ± 1.8 13.3 ± 0.4
10 Dark 8.8 ± 0.2b 4.1 ± 0.3b 31.8 ± 0.9 13.0 ± 0.2b
UV 9.8 ± 0.1 5.1 ± 0.4 33.8 ± 1.1 14.9 ± 0.2
11 Dark 8.0 ± 0.2b 1.7 ± 0.2b 17.6 ± 0.9b 9.7 ± 0.1b
UV 8.9 ± 0.3 3.3 ± 0.5 26.7 ± 1.0 12.2 ± 0.2
12 Dark 7.4 ± 0.1b 1.9 ± 0.2b 20.1 ± 0.8b 9.2 ± 0.1b
UV 8.6 ± 0.1 3.6 ± 0.7 28.4 ± 2.0 12.2 ± 0.5
Avg Dark 7.9 ± 0.4c 2.4 ± 0.6c 22.6 ± 3.2c 10.3 ± 0.9c
UV 9.3 ± 0.3 3.8 ± 0.4 28.8 ± 1.7 13.1 ± 0.7
Avg enhancement (% relative to dark) 18 ± 5c 71 ± 16c 32 ± 10c 29 ± 6c
a

BGE and carbon utilization are averages of all possible combinations between the independent measurements of respiration and production (i.e., n = 3 for bacterial production and respiration and n = 9 for BGE and carbon utilization). The average percent enhancement was calculated as [(irradiated−dark)/dark] × 100 ± standard error (n = 4). The numerical identification of the humic isolates is given in Table 1.

b

Indicates statistically significant differences between dark and UV treatments (t test for BCP and respiration and U test for BGE and carbon utilization, P < 0.05).

c

Indicates statically significant differences in average values and enhancement (paired t test, P < 0.05).