Comments |
P.466 right column bottom paragraph: "The density of virus-like particles (VLPs) was significantly higher than that of the microbes (t = −19.61, degrees of freedom (d.f.) = 236.96, P < 2.20 × 10^−16, Welch two sample t-test) and ranged from 9.03 × 10^5 to 3.86 × 10^7 (7.08 × 10^6 ± 3.01 × 10^5, mean ± standard error of the mean, s.e.m.) VLPs/ml versus 8.08 × 10^4 to 6.75 × 10^6 (1.09 × 10^6 ± 5.53 × 10^4, mean ± s.e.m.) microbes/ml. The log–log plot of these VLP and microbe abundances had a slope <1 (m = 0.59, t = 14.82, d.f. = 221, P (t-test, m ≠ 1) = 4.08 × 10^−21, R^2 = 0.50, slope significantly different from m = 1 by linear regression with t-test, Fig. 1a), indicating a downward concave relationship between these variables. As a result, the virus to microbe ratio (VMR) decreased significantly (analysed against host density, both log-transformed, m = −0.37, t = −9.52, d.f. = 221, P < 2.00 × 10^−16, R^2 = 0.29, linear regression) from a ratio of 25 to 2 VLPs per microbe (7.44 ± 0.24, mean ± s.e.m.) as microbial abundance increased from ~1 × 10^5 to greater than 6 × 10^6." |