PostDoctoral Research Fellowship

Koffman Bess G, Orono ME

Investigators

Abstract

This is a post-doctoral fellowship award that will support an early-career scientist to work on a project entitled: "Evaluating New Zealand as a source of dust to W. Antarctica during the Last Glacial Maximum (LGM)". Atmospheric dust aerosols are a source of iron (Fe) to the Southern Ocean, where micronutrient Fe limits biological production. It is hypothesized that during ice age climates, higher levels of aerosol Fe impacted marine primary production, and thus the global carbon and nitrogen cycles, substantially more than at present. Iron in relatively unweathered dust (such as that from New Zealand) is more soluble and biologically available than that from weathered sediments (such as from Australia). Therefore, a significant New Zealand dust input during glacial times implies a greater role for Fe fertilization of the Southern Ocean's Pacific sector. This project will test the hypothesis that young soils from New Zealand were a significant source of dust to the Southern Ocean and hence West Antarctica during the Last Glacial Maximum. The PI will characterize the New Zealand dust source by collecting samples from well-dated glaciogenic and other aeolian source sediments and analyze them for major and trace element chemistry and strontium, neodymium, lead, and helium isotopic ratios. She will make corollary measurements on samples of glacial-age ice from the Allan Hills (Victoria Land) and the Siple Dome A and Byrd 1968 deep ice cores (West Antarctica) to assess dust provenance in these previously unstudied regions of Antarctica. She also will use a fully coupled global climate model to evaluate the likelihood of dust transport from New Zealand to different regions of Antarctica through time, and the relative climatic importance of New Zealand vs. Australia in terms of iron-fertilization potential of dust deposited in the Pacific sector of the Southern Ocean. The PI will promote broader impacts for science and society by producing and disseminating an outreach video and by working directly in a socioeconomically and racially diverse New York City middle school classroom, where she will teach an earth sciences unit linking concepts from her research to students' own experiences.