Nutrient concentrations and ratios of the different expeditions. Box plots for the different expeditions showing water column concentrations of (A) nitrate (NO3–), (B) silicate (Si(OH)4), and (C) phosphate (PO43–), and the ratios (D) NO3–:Si(OH)4, (E) ΔNO3–:ΔSi(OH)4 and (F) NO3–:PO43–. The line in the middle of each box represents the median; the top and bottom limits are the 25th and 75th percentiles, respectively. The lines extending above and below each box (whiskers) represent the full range of non-outlier observations for each variable beyond the quartile range. The results of the Kruskal-Wallis H test depict regions with statistically significant differences at the 95% confidence level (p < 0.05). The codes of the significance test are *: p < 0.01, **: p < 0.001 and ***: p < 0.0001. The red stars show the maximum value in nutrient concentration (i.e., NO3–, Si(OH)4, PO43–) for the different expeditions. The dashed red lines indicate the Redfield ratios for (D) N:Si and (F) N:P. DOI: https://doi.org/10.1525/elementa.430.f6