Fig. 2
From: Reduced marine phytoplankton sulphur emissions in the Southern Ocean during the past seven glacials
Variability of nssSO42− flux at Dome Fuji (DF). a DF nssSO42− flux plotted against DF δ18O14,15. Data points represent 1000-year averages. Before averaging, the δ18O depths that differ from the ion data depths have been interpolated to match. Gray bar indicates the lower threshold of δ18O (−58‰), below which the nssSO42− flux decreases with δ18O, and the upper threshold (−57‰), above which the nssSO42− flux increases with δ18O. b DF nssSO42− flux plotted against DF nssCa2+ flux. Data points represent 1000-year averages. The slope of the solid red line (m = 2.4) represents the stoichiometric mass ratio of Ca/SO4 as CaSO4. The dashed red line shows the lower bound of the nssSO42− flux data with m = 2.4. Red and blue dots represent the data for warm and cold periods, respectively, corresponding to the δ18O values above and below the thresholds
