Deciphering the Subantarctic South Pacific Ocean's Role in Pleistocene Climate Evolution with IODP Expedition 383 Sediments

Lead PI: Dr. Gisela Winckler , Dr. Jennifer L. Middleton , Farmer, Jesse R; Ravelo, Ana C; Basak, Chandranath

Unit Affiliation: Geochemistry, Lamont-Doherty Earth Observatory (LDEO)

May 2023 - April 2026
North America ; United States
Project Type: Research

DESCRIPTION: The Southern Ocean is a key element of the global climate system. It is home to the Antarctic Circumpolar Current, the fastest ocean current on Earth. As a strong carbon sink, it represents an important shield against some of the effects of human-caused greenhouse gas emissions. However, the processes driving the Southern Ocean?s variability are still poorly known. This project will investigate the role of the South Pacific in the climate system over the past 2 million years. It will do so using sediment cores recovered during a recent drilling expedition on the Joides Resolution. The project will generate records of surface ocean conditions that can inform our understanding of the capacity of the ocean to take up carbon dioxide and store it in the deep ocean. The geosciences are the STEM field with the least participation from underrepresented minorities. The project will use a cohort student program to actively promote diversity and broadened participation. Under the guidance of a psychology professor, the project will create an environment that enhances engagement, learning and innovation through diversity. A goal of this cohort approach is to shift geoscience education from a style based on gatekeeping to one that that is inviting and supportive of people from diverse backgrounds. The climate science community?s understanding of Earth?s long-term climate evolution predominantly comes from Northern Hemisphere climate records. Given the central role of the Southern Ocean in the global climate system and its proximity to the Antarctic Ice Sheet, the Southern Hemisphere data gap severely inhibits our ability to understand global changes in ocean-atmosphere-ice sheet dynamics and carbon cycling during major climatic transitions. Records from the South Pacific are especially valuable to improve our understanding of these processes, because the Pacific contains by far the largest surface area and volume fraction of the Southern Ocean and therefore holds the largest capacity for carbon storage in the deep ocean. This project proposes to generate high-resolution climate proxy time series over the past 2 million years with emphasis across the Mid-Pleistocene Transition (MPT) using new sediment cores recovered during Expedition 383. These long records will explore changes in climate/carbon dynamics at the ocean surface by reconstructing dust input, nutrient utilization, and export production and these records will be synthesized and interpreted with collaborators' records of sea surface temperature, water mass structure and circulation. Drawing from expertise across three US institutions, the project will produce an unprecedented suite of complementary biological and geochemical tracers at three drill sites (U1539, U1540, and U1541) in the Subantarctic Pacific.

BROADER IMPACTS: The proposed work will actively promote diversity and broadened participation in geoscience by supporting the professional development of multiple personnel at a variety of STEM career stages. The project centers around a cohort program, connecting three early career faculty, two senior women faculty, three geoscience PhD students, one Bridge-to-PhD student, and at least 8 undergraduate students, across two minority-serving institutions (UMB, UCSC), three public universities (UMB, UD, UCSC) and a private institution (Columbia/LDEO). The cohort will form a learning group that builds skills to promote diversity, equity and inclusion through ensuring equitable access, creating a holistic multi-model learning environment, and developing a culture of trust and accountability. The efficacy of the cohort activities will be assessed through collaboration with a Psychology Professor at UCSC and her graduate student with expertise in assessing mentoring and belonging programs. All materials and the outcomes of the cohort program will be published and may serve as a template for other collaborative groups in the geosciences.


National Science Foundation




University of Mass Boston, UC Santa Cruz, U of Delaware