Fig. 1: Evaluation of the bioavailability of dissolved iron (dFe) in water from Baffin Bay in the Arctic.
From: Insights into the bioavailability of oceanic dissolved Fe from phytoplankton uptake kinetics
a, b Dissolved Fe uptake by Fe-limited phytoplankton species measured under stringent trace-metal clean protocols and internalized Fe plotted per cell (a) or as total internalized Fe (b). c, d Calculated Fe uptake rate constants for Baffin Bay water—kin-app—the measure of dFe bioavailability as probed by Fe-limited phytoplankton species. Plotting kin-app versus cellular surface area (S.A.) in a log-log plot yielded a single line (c), implying that all phytoplankton probe dFe bioavailability similarly when normalized to surface area (S.A.). Hence, a single kinetic term, kin-app/S.A., can describe the dFe bioavailability in these waters (d). The bioavailability of dFe in Baffin Bay is intermediate between that of inorganic Fe (Fe′) and that of Fe bound to the strong siderophore desferrioxamine B (FeDFB), determined previously. Each phytoplankton strain is labeled in a unique symbol and color that is consistent across all panels.
