The effect of sediment-dwelling macrofauna on nitrifying bacteria was investigated by direct probing in their overlapping habitat, i.e., the upper few millimeters of freshwater sediments. Microsensors (O2, NH þ 4 , NO 2 3 , and diffusivity) were used at the sediment surface and inside animal burrows to record steady-state and dynamic distributions of reactants, respectively. Short-term changes ...
