Description du projet
Dévoiler les niveaux d’oxygène des océans grâce à la paléocéanographie
Recouvrant la majeure partie de la surface de la Terre, les océans ont une influence majeure sur le climat mondial. Ils déplacent la chaleur à travers le monde et stockent le carbone par le biais des cycles de vie marins. Le projet OxyQuant, financé par l’UE, étudie l’évolution de ces processus au fil du temps en examinant les concentrations d’oxygène dans les eaux de fond. Les chercheurs utiliseront des techniques d’échantillonnage des isotopes de l’iode et du cérium dans les sédiments et les débris de poissons fossilisés de différents environnements marins afin de créer une approximation des niveaux d’oxygène du passé. L’objectif est de fournir aux paléocéanographes une meilleure reconstitution quantitative de l’aspect des océans dans le passé, et éventuellement de’anticiper les changements climatiques futurs.
Objectif
Because of their sheer size and tight coupling to the atmosphere the oceans are a pivotal climate regulator. Their interaction with climate is associated with both physical processes such as ocean circulation, which redistribute heat, freshwater, and carbon around the globe, and biogeochemical processes, which ultimately control the strength of the biological carbon pump, and by inference the storage of remineralized carbon in the ocean interior. Seawater oxygen concentrations are intimately linked to both type of processes and are thus a crucial parameter for assessing the state of the oceans today but also in the past. Despite the crucial role these processes play on climate and climate variability, they remain surprisingly poorly understood. While paleoceanography offers a unique opportunity to observe the state and behaviour of the oceans under different boundary conditions, no reliable and widely applicable method for the quantitative reconstruction of past bottom water oxygen concentrations (BWO) has yet been established. Thus, the objective of OxyQuant is to develop and calibrate an innovative proxy toolkit to reliably reconstruct past BWO. To this end, three fundamentally independent approaches for which promising preliminary observations exist will be calibrated using a range of sediments retrieved from contrasted marine environments. While the first approach associated with the sedimentary concentrations of redox-sensitive trace metals, has already attracted much interest over the past decades, the other two methods, namely the organic matter – associated iodine and the stable isotope composition of authigenic cerium (δ142Ce) archived in fossilised fish debris, are novel and have yet to be comprehensively tested. Combined with their application in two case studies on glacial – interglacial time scales, OxyQuant will provide the paleoceanographic community with the means to finally fill the gap of quantitative reconstructions of past BWO.
Champ scientifique
Mots‑clés
Programme(s)
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme
Régime de financement
HORIZON-TMA-MSCA-PF-GF - HORIZON TMA MSCA Postdoctoral Fellowships - Global FellowshipsCoordinateur
24148 Kiel
Allemagne