The influence of bioturbation on physical, chemical and biological parameters in aquatic environments: A review

The role of benthic macroinvertebrates in sediment processing is of importance for investigators attempting to describe the dynamics of a wide range of materials in aquatic environments. Benthic macroinvertebrates have been shown to blur sediment stratigraphy, alter particle size and pore spaces, and influence shear strength of the sediment and turbidity of overlying waters. The macroinfauna can increase oxygen and Eh penetration into the sediment and shift pH levels in actively worked substrates. These changes have been correlated with trace element redistributions among physicochemical forms and the flux of N, P, PCBs, Cu, Fe, I, Hg, Mn, Si, Zn and radioisotopes to the water column. There is general agreement that bioturbation can stimulate microbial activity, although the data remain inconclusive. Realistic estimates of sediment particle mixing rates are required in order to estimate the impact of bioturbation on core dating techniques, material cycling studies and contaminant remobilisation from polluted spoils.