Explore how sediment depth changes oxygen supply to microbes, then explain why oxygen consumption varies with diffusion, compactness and respiration pathway.
Marine sediments form at the bottom of oceans. These sediments contain organic material from the surface waters. Scientists analysed samples drilled from the floor of the north Pacific Ocean, representing 86 million years of sedimentation. Graph A shows the data for oxygen concentrations in 28 metres of sediment and graph B shows the oxygen consumption per cell in 22 metres of sediment measured in femtomoles ( ).
Suggest reasons for the differences in oxygen consumption between the cells at 2 metres and at 22 metres.