Changes in the sublittoral hard substrate communities in the Oosterschelde estuary (SW Netherlands), caused by changes in the environmental parameters

The sessile sublittoral communities on hard substrates in the Oosterschelde estuary and relevant environmental parameters were investigated from 1985 until 1990 to obtain a quantitative assessment of the effects of constructing a storm-surge barrier and secondary dams in the estuary. During the construction period 3 communities were sampled in the photic zone and 4 in the aphotic zone. The community structure changed rapidly 2 years after the completion of the construction works in response to lower tidal current velocities, greater sedimentation, especially fine sediments, and an increase in the transparency of the water. The changes were analysed statistically.