Historical analyses of coastal marine sediments reveal land-based impacts on the benthos

We document from a sediment core collected at 23 m water depth offshore of Separation Point on the northern coast of Aotearoa New Zealand’s South Island, 3000 years of natural and human-induced change to undisturbed offshore sediments that are protected from contact fishing methods. Multivariate analysis of sediment characteristics and sources of primary productivity successfully differentiated the pre-human (< 1500 AD), Māori, and European periods (> 1850).

Some field techniques used in a study of Tauranga Harbour.

A summary of the main field methods of research used in a sedimentological study of part of Tauranga Harbour is presented. The research concentrated on the tidal inlet which is the entrance to the Port of Tauranga. SCUBA divers have carried out direct observations of the sea bed and installed various monitoring devices. Sediment sampling programmes posed problems which were largely overcome by using a dredge-type sampler. Tidal currents in the boundary layer were measured one metre above the harbour floor at a number of monitoring stations.