Impact of deep-sea mining on redox environment, biogeochemical processes and element fluxes within and from sediments of the Clarion-Clipperton Zone, Pacific Ocean

Abstract

The economic interest in deep-sea mineral resources has grown in recent years. Minerals of interest include polymetallic nodules, which occur in extensive deposits at more than 4000 m water depth in the Clarion-Clipperton Zone (CCZ), NE Pacific Ocean. In light of recent technological advances in mining equipment, the CCZ represents a prospective area for commercial deep-sea mining. In the framework of this PhD thesis, sediments from four European contract areas for the exploration of polymetallic nodules in the CCZ and one of the protected Areas of Particular Environmental Interest (APEI) were investigated. Comprehensive pore-water and solid phase data were produced for undisturbed sediments and sediments from disturbance tracks of small-scale deep sea mining experiments. The presented studies provide new insights into the spatial and temporal variation of redox zonation, biogeochemical processes and element fluxes in the sediments and the impact of potential mining activities in the CCZ.