Tasty or Toxic? Biogeochemistry of marine sediments in a warming ocean

The importance of sediment processes in driving biogeochemical cycles, from blue carbon storage, to nutrients (silica, iron) and pollutants (lead, arsenic), are becoming increasingly recognized, from local to global scale [1]. However, accurately measuring fluxes from marine sediments presents a significant challenge as classical approaches (incubations, pore water gradients) focus on small scale diffusive processes, whereas sediment fluxes also depend on large scale and heterogeneous abiotic processes (e.g. temperature, tides, currents) and macrofaunal activities such as sediment reworking (bioturbation) and burrow ventilation (bioirrigation).
The aim of this study is to employ a cutting-edge radioisotopic disequilibrium approach [2] to quantify nutrient and pollutant fluxes from marine sediments across a range of future environmental settings such as climate warming and ocean acidification. This will be achieved by quantifying benthic fluxes around the UK across varying sediment types, associated macrofaunal communities, and differing levels of anthropogenic influence [3]. A key focus will be the comparison of the factors determining micronutrient flux between temperate UK waters and the western Antarctic Peninsula, where changing circulation is bringing increasing heat to the bottom waters of the shelf.