Photoreduction of iron in natural waters

Matt Metz

Document Type Dissertation/Thesis


The integration of flow injection analysis techniques with sensitive chemiluminescence detectors has resulted in a highly sensitive Fe(lll)/Fe(ll) analysis system, the FeLume(II). This new system is suitable for studying the redox cycling of Fe in natural waters--a process that is crucial for phytoplankton and for several other marine organisms, whose survival depends on a plentiful supply of bioavailable iron. The rate of Fe(lTI) reduction in seawater as a function of pH was determined using a solar simulator and the FeLume(ll). Results of this study demonstrate that a significant fraction of dissolved oceanic iron exists as Fe(ll) and that redox cycling of iron occurs readily in seawater. From the data obtained in the following experiments, Fe(II) oxidation rates were calculated, turnover rates of Fe(III)/Fe(II) were calculated, and a potential mechanism for Fe uptake by phytoplankton can be suggested.