2006/12/01 by Gerhard Schmiedl, Andreas Mackensen · 2 citations
Earth and Planetary Sciences · Environmental Science · #Geology and Paleoclimatology Research #Isotope Analysis in Ecology #Marine Biology and Ecology Research
paper · pdf · doi:10.1029/2006pa001284
The stable isotope composition of one epifaunal and three infaunal benthic foraminiferal species of a sediment core from 1800 m water depth of the western Arabian Sea was determined to evaluate deepwater oxygenation, organic matter remineralization, and early diagenetic processes during the past 190,000 years. The δ 18 O records reveal species‐specific metabolic effects, susceptibility to changes in carbonate ion concentration, and supralysoclinal calcite dissolution. The foraminiferal δ 13 C records reveal changes in the stable carbon isotope gradients of pore water dissolved inorganic carbon ( δ 13 C DIC ) and in the microhabitat depth of infaunal species. Maximum δ 13 C DIC offsets between bottom and pore waters ranged between mean values of 0.8 and 1.2‰ corresponding to estimates of deepwater oxygen concentration between approximately 1 and 2.7 mL L −1 . Intervals of improved deepwater oxygenation coincided with high benthic foraminiferal diversity and indicate the admixture of well‐oxygenated deepwater masses during interglacials. During interglacial maxima the δ 13 C difference between epifauna and shallow infauna indicates highest organic matter remineralization rates at times of maximum organic matter fluxes.