Marine Biogeochemical Extreme Events in European Shelf Seas

As the mean state of ocean oxygen and pH decreases through anthropogenic heating and carbon uptake, respectively, it is likely that ecologically damaging marine biogeochemical extreme events will occur with increasing frequency and intensity. Here, marine biogeochemical extreme event projections (RCP4.5, RCP8.5) will be analysed for the NW European shelf and Mediterranean Sea, since these regions have been identified as “hot spots’ for climate impacts and have experienced major marine heatwaves. Recent past (1960 - present) and projected future (present - 2099) changes in biogeochemistry will be analysed using high resolution (~ 12 km) model fields from a regional ocean biogeochemistry model to quantify changes in the frequency, persistence and spatial extent of marine biogeochemical extreme events. Specific focus will be given to the wider ecosystem impacts of marine biogeochemical events via, for example, ecologically relevant diagnostics like hypoxia (or ‘hypoxic events’ where [O₂]< 60 mmol l^-1) and carbonate saturation state.