Abstract – After twenty years of the International GEOTRACES program, marine sediments are now firmly established as important (local) sources of dissolved Fe (dFe) to the oceans. However, questions remain about the persistence and transport of such sediment-derived Fe in the water column. Marine sediments are thought to release dissolved Fe to porewaters by two main mechanisms: 1) reductive dissolution – production of Fe which occurs as a byproduct of microbial breakdown of organic matter in the anoxic ferruginous zone of sediments, and 2) non-reductive dissolution, or lithogenic weathering. Stable Fe isotope ratios (δ56Fe) have been instrumental in investigating these two sources, the speciation of dFe released, and the persistence of dFe in the water column. For example, Fe sourced from reductive (-1 to -3‰) or non-reductive (+0.1‰) dissolution have diagnostic δ56Fe signatures relative to the crust (+0.1‰) that may be used to trace and constrain sediment-derived dFe addition to the ocean. However, questions remain about the longevity of such source signatures due to potential fractionation associated with dFe complexation with organic matter/particle scavenging, and kinetic isotope effects as dFe is lost via oxidative precipitation. Attenuation of the sediment-derived signature may happen either at the local oxic-anoxic or sediment-water interface, or during transport. Here, using both open-ocean and marginal GEOTRACES studies, I will synthesize knowledge of the δ56Fe signatures of dFe attributed to sediments, the evidence for long-distance transport of sediment-derived Fe (that may maintain diagnostic Fe isotope signatures), and the constraints on the fractionation mechanisms that may attenuate these signals. I will especially focus on work from the Antarctic marginal seas, where both sediment dissolution mechanisms are important, and the North Pacific where synthesis of GEOTRACES sections (GP02 & GP15) demonstrates the long-distance transport eastward (~6000 km) of a conserved δ56Fe signature from reductive dissolution of sediments through the North Pacific Oxygen Minimum Zone, despite observed dFe loss by particle scavenging.