Global biological productivity during abrupt climate change
Atmospheric oxygen (O2) is an essential component for life. The global biological O2 productivity has changed with Earth's climate change and, at the same time, has affected to global biosphere. Therefore, understanding how global biological O2 productivity responds to abrupt climate change is important to project future climate and environment change. However, former studies have been focused on global O2 productivity change over the glacial-interglacial transitions, mainly due to insufficient temporal resolution of existing data. This project aims to reconstruct the global primary productivity change over the Heinrich Stadial (HS). HS events are naturally occuring abrupt climate changes in the last glacial triggered by abrupt input of glacial meltwater into the North Atlantic Ocean. In this project, a new high-resolution record of triple oxygen isotopes of air O2 and COS concentrations will be produced throughout the HS events 1 to 5 using polar ice cores. Then the major controls and mechanisms will be explored by a series of sensitivity experiments using climate models with different complexities. This project will be carried out at the section of Physics of Ice, Climate and Earth at Niels Bohr Institute (PICE, University of Copenhagen). PICE equips the state of art analytical instruments and has developed the novel methods to study trace gas and isotopes in ice cores. The supervisor is a world expert of the triple oxygen isotopes of air O2 in ice cores. This project plans a secondment to Laboratory for Sciences of Climate and Environment (LSCE, University of Paris Saclay) for sensitivity experiments using climate models. LSCE is a leading institution of paleoclimate modelling, which allows a better understanding of major control mechanisms of the past productivity change.