Extended Data Fig. 4: Boxplots of prokaryotic activities in the mesopelagic zone.
From: Distinct contributions of suspended and sinking prokaryotes to mesopelagic carbon budget
Rates of dark carbon fixation (yellow) and prokaryotic heterotrophic production (blue) were measured at the five PSSs (expressed in µmol C m⁻³ d⁻¹). Upper panels represent the “suspended” fraction (free-living prokaryotes and those attached to suspended particles), whereas lower panels represent the “sinking” fraction (prokaryotes attached to sinking particles). Each boxplot integrates measurements at 100, 200, 500, and 1000 m, with each depth analyzed in triplicate technical incubations (n = 12 data points per PSS). Technical replicates correspond to independent incubations of subsamples from the same Niskin or sediment trap collection. Boxplots (A), (B), (D), and (E) compare activities between PSSs, while (C) and (F) compare activities between fractions. Boxplots indicate the interquartile range (boxes), median (central line), and whiskers extending to 1.5×IQR. Statistical differences were assessed using Kruskal-Wallis multiple tests followed by Dunn post-hoc tests (* = p < 0.05) and the Wilcoxon-Mann-Whitney test (**** = p < 0.0001). Upper and lower panels cannot be compared directly, as the sampled volumes differ between Niskin bottles and sediment traps.
