Figure 2.

Box-whisker plots of enrichment factors in Arctic and Antarctic waters. Chemical variables (Sal: salinity; DOC: dissolved organic carbon; PO₄: phosphate; SiO₄: silicate; NO₃+NO₂: nitrite plus nitrate; and NH₄: ammonia concentrations) (A,B). Microbial parameters (VA: viral abundance; PA: prokaryote abundance; VPR: virus prokaryote ratio; VPL: viral lytic production; RLC: rate of lysed cells; %VMM: virus-mediated mortality; HNF: heterotrophic nanoflagellate abundances; and PNF: phototrophic nanoflagellate abundances) (C,D). Horizontal lines within boxes indicate the median of the distribution, and the box limits are 25% quartiles of the data. The whiskers cover the entire data range, except for outliers (°), some of which are off-scale. * Significant EF values different than 1. The horizontal line in each figure corresponds to EF = 1.