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Regulation of phosphorus bioavailability by iron nanoparticles in a monomictic lake

Dissolved reactive phosphorous (DRP) in lake systems is conventionally considered to predominate over other dissolved P species, however, this view neglects an important set of interactions that occurs between P and reactive iron hydroxide surfaces. This study addresses the coupling of P with dispersed iron nanoparticles in lakes, an interaction that may fundamentally alter the bioavailability of P to phytoplankton. We used difusive gradients in thin flms (DGT) and ultrafltration to study Fe-P coupling in the water column of a monomictic lake over a hydrological year. Fe and P were predominantly colloidal (particle diameters>~5nm<~20nm) in both oxic epilimnetic and anaerobic hypolimnetic waters, but they were both DGT-labile under sub-oxic conditions, consistent with difusion and dissolution of Fe-and-P-bearing colloids within the DGT difusive gel. During peak stratifcation, increases in Fe and P bioavailability were spatially and temporally coincident with Fe nanoparticle dissolution and the formation of a deep chlorophyll maximum at 5–8m depth. These results provide a window into the coupling and decoupling of P with mobile iron colloids, with implications for our understanding of the behaviour of nutrients and their infuence on phytoplankton community dynamics.
Journal Article
Type of thesis
Saeed, H., Hartland, A., Lehto, N. J., Baalousha, M., Sikder, M., Sandwell, D. R., … Hamilton, D. P. (2018). Regulation of phosphorus bioavailability by iron nanoparticles in a monomictic lake. Scientific Reports, 8. https://doi.org/10.1038/s41598-018-36103-x
Nature Publishing Group
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