Oil particles and phytoplankton blooms settled onto northeastern Gulf of Mexico inner shelf and slope sediments after the 2010 Deepwater Horizon accident raising the question how the metabolism of these sediments responded to this fossil and modern organic matter input. Sands collected in 20 m water depth off the coast of Pensacola Beach Florida were incubated in flow-advection chambers with 3 treatments, weathered oil particles, oil particles + algal biomass, and algal biomass only. The microbial community composition was assessed with Illumina Miseq derived SSU rRNA gene amplicons initially and after 1 week at multiple depth intervals.