Seasonal Variation in Sediment and Oxygen Fluxes in Shelf Seas

Sediments in shelf seas play an important role in cycling carbon and nutrients in the ocean. Physical processes in the benthic boundary layer set conditions experienced by these sediments (e.g. sediment resuspension or settling depends on wave or tide-driven flow). As part of the UK Shelf Seas Biogeochemistry programme, in situ measurements of velocity, suspended sediment, and oxygen were made in the Celtic Sea. An instrumented lander, including an eddy correlation oxygen flux system was deployed immediately before and after the spring phytoplankton bloom and again in late summer. These measurements were made in the presence of varying tidal, wave and storm conditions, and across the range of sediment found in shelf seas (sand to mud) with the goal of characterizing physical conditions and oxygen flux at the sediment-water interface. Early results presented here will compare benthic fluxes of oxygen and suspended sediment particle size distribution in May 2014 immediately after the spring phytoplankton bloom when benthic oxygen consumption should be high with measurements in August 2014 when biogeochemical activity at the sediment-water interface is expected to be reduced.