Anthropogenic input of heavy metals to near-coastal sediment depocenters in the eastern North Sea and the Hauraki Gulf in historical times

Abstract

Since the beginning of the industrial revolution, and even earlier, near-coastal marine ecosystems are affected by various anthropogenic influences such as the enhanced input of heavy metals. In this thesis, the anthropogenically induced historical heavy metal input to near-coastal sediment depocenters in the eastern North Sea, the Helgoland mud area and the Skagerrak, and the Hauraki Gulf, NZ, is analysed and discussed. Enhanced heavy metal inputs to the Helgoland mud area and the Skagerrak commenced in medieval times and are attributed to early mining and smelting activities in medieval mining centres in Germany and Sweden. Due to the low present-day sediment input and the strong reworking of the sediments, the sediments of the Hauraki Gulf do not reveal any signal of heavy metal inputs, but provide new insights in the deposition and reworking of surficial sediments as a consequence of the interactions of wind-generated waves and the modern hydrodynamic regime.