Cycling of phosphorus and manganese in the Arabian Sea during the Late Quaternary

Abstract

This thesis investigates phosphorus and manganese cycling in the Arabian Sea during the Late Quaternary, using sediment records recovered during the Netherlands Indian Ocean Programme (NIOP) in 1992. The first part is concerned with the reconstruction of Late Quaternary variability in paleoproductivity and oxygen minimum zone intensity. Special attention is given to manganese and sulphur accumulation patterns in order to trace back variations in bottom water oxygen content of the deep basin and continental slope. In the second part of this thesis P cycling in the Arabian Sea sediments is investigated. Pore water fluxes and solid-phase P speciation results are combined to assess the diagenetic processes controlling the benthic regeneration and burial of P. The contrasting environmental conditions that 'characterized the Arabian Sea in past and present provide an excellent opportunity to elucidate the mechanisms that govern P removal from the oceans, and to determine the potential role ofP cycling on changes in paleoproductivity over geological time scales.