Program and Agenda

Abstract

BIOGEOCHEMICAL CYCLING DURING CRETACEOUS OCEANIC ANOXIC EVENTS

Cretaceous oceanic anoxic events (OAEs) may have been triggered by massive volcanic CO2 degassing as large igneous provinces (LIPs) were emplaced. Here, we present a comprehensive modeling study to decipher the marine biogochemical consequences of enhanced volcanic CO2 emissions. A coupled OAGCM was run to constrain general Late Cretaceous circulation fields. These were than used to develop and run a biogeochemical box model which is used for transient model runs with time-dependent volcanic CO2 forcing. The model considers continental weathering processes, marine export production, degradation processes in the water column, the rain of particles to the seafloor, benthic fluxes of dissolved species across the seabed, and burial of particulates in marine sediments. With an appropriate choice of parameter values the model produces ocean anoxia at low to mid latitudes and changes in marine δ 13C that are consistent with geological data. Major perturbations of the global carbon cycle, such as the formation of C-enriched marine organic matter may also explain the frequent occurrence of global anoxia during other geological periods characterized by high pCO2. Currently we are testing the influence of these major events on the O2 distribution in a climate model of intermediate complexity (UVic) incorporating important biogeochemical feedback loops from the sedimentary-water column interface, e.g. aspects of benthic phosphorous cycle.

Authors

Flögel, S., GEOMAR, Germany, sfloegel@geomar.de

Kuhnt, W., University of Kiel, Germany, wk@gpi.uni-kiel.de

Keller, D., GEOMAR, Germany, dkeller@geomar.de

Oschlies, A., GEOMAR, Germany, aoschlies@geomar.de

Wallmann, K., GEOMAR, Germany, kwallmann@geomar.de

Details

Oral presentation

Session #:063
Date: 2/27/2014
Time: 14:00
Location: 316 A

Presentation is given by student: No