Iron Size partitioning under Dec. 20, 2016 low flow (left) and Sep. 25, 2017 high flow conditions (right) as a function of distance downstream from S-79 for surface and bottom water column samples. Note the difference in the y-axis values. Soluble Fe (black) was determined by filtration of raw water through 0.02µm PES filters; colloidal Fe (red) was determined by the difference of soluble Fe and concentrations obtained after filtration of raw waters through PES filters (i.e. the traditionally operationally defined "dissolved" fraction). Particulate Fe (green) was obtained by difference of Fe concentrations in raw, unfiltered waters and the 0.2µm PES filtered concentration. All Fe concentrations were determined by first acidifying overnight with a solution of hydroxylamine hydrochloride (~pH 1), then analyzing with an acetate buffered Ferrozine solution. A long path length liquid waveguide capillary absorption cell (LWCC) was used when concentrations were below ~2µM.
This graph and data were contributed by Jordon Beckler, Geochemistry, FAU Harbor Branch.