“…Another well‐studied impact on the benthic community is a reduction in hyporheic exchange flow due to the deposition of excess fine sediment (Veličković, ; Wharton et al, ). Within the interstices, the breakdown of fine particulate organic matter (FPOM) increases sediment oxygen demand, exacerbating the hypoxia initiated by physical clogging (Chapman et al, ; Greig, Sear, & Carling, ; I. Jones, Growns, Arnold, McCall, & Bowes, ; Sear et al, ; Soulsby, Youngson, Moir, & Malcolm, ). Under such conditions, methanogenic microbial communities develop at the oxic–anoxic interface, resulting in the precipitation of ocherous masses of iron hydroxides (Emerson & Revsbech, ) and further saturating the bed matrix with fine particulate matter.…”