The oceanic release and measurement of iron from sediment dissolution processes
In recent decades, seafloor sediments were discovered to be a major contributor of the dissolved micronutrient iron (Fe) to global ocean, sustaining oceanic primary production and carbon export. Quantifying this input and understanding how it changes are urgently required for more accurate simulations of past and future oceanic conditions. In this talk, I will explain the need to discern the mechanisms responsible for the release of trace metals to the Ocean, in addition to measuring the rates of these processes, to effectively parameterise biogeochemical general circulation models (GCMs) of the ocean and climate. I will present the enduring observational evidence and our empirical basis for incorporating benthic Fe fluxes into biogeochemical GCMs, followed by recent isotopic evidence for additional ‘dissolution’ processes that govern the release of Fe from sediments: processes that are presently ill quantified and unaccounted for. Finally, I will illustrate how these recent discoveries are being used to propose new criteria influencing benthic flux in the worlds ocean’s, that may be used to highlight important but omitted areas of the global ocean which are desirable targets for future field programmes.