A brGDGT-Based Reconstruction of Terrestrial Temperature From the Maritime Continent Spanning the Last Glacial Maximum

M. C. Parish, X. Du, S. Bijaksana, J. M. Russell

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The tropics exert enormous influence on global climate. Despite the importance of tropical regions, the terrestrial temperature history in the Indo-Pacific Warm Pool (IPWP) region during the last deglaciation is poorly constrained. Although numerous sea surface temperature (SST) reconstructions provide estimates of SST warming from the Last Glacial Maximum to the Holocene, the timing of the onset of deglacial warming varies between records and inhibits determining the forcings driving deglacial warming in the IPWP. We present a 60,000-year long temperature reconstruction based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) in a sediment core from Lake Towuti, located in Sulawesi, Indonesia. BrGDGTs are bacterial membrane-spanning lipids that, globally, become more methylated with decreasing temperature and more cyclized with decreasing pH. Although changes in temperature are the dominant control on brGDGTs in regional and global calibrations, we find that the cyclization of the brGDGTs is a major mode of variation at Lake Towuti that records important changes in the lacustrine biogeochemical environment. We separate the influence of lake chemistry changes from temperature changes on the brGDGT records, and develop a temperature record spanning the last 60,000 years. The timing of the deglacial warming in our record occurs after the onset of the deglacial increase in CO2 concentrations, which suggests rising greenhouse gas concentrations and the associated radiative forcing may have forced deglacial warming in the IPWP. Peaks in temperature around 55 and 34 ka indicate that Northern Hemisphere summer insolation may also influence land surface temperature in the IPWP region.

Original languageEnglish (US)
Article numbere2022PA004501
JournalPaleoceanography and Paleoclimatology
Volume38
Issue number3
DOIs
StatePublished - Mar 2023

Bibliographical note

Funding Information:
This material is based on work supported by National Science Foundation Grant EAR-2102856. The authors thank Gerald Tamuntuan, Satrio Wicaksono, Nigel Wattrus, and PT Vale Indonesia for field assistance. The authors acknowledge assistance and permission for this work from the Indonesian Ministry of Research and Technology (RISTEK). The authors also thank two anonymous reviewers for their thoughtful comments.

Funding Information:
This material is based on work supported by National Science Foundation Grant EAR‐2102856. The authors thank Gerald Tamuntuan, Satrio Wicaksono, Nigel Wattrus, and PT Vale Indonesia for field assistance. The authors acknowledge assistance and permission for this work from the Indonesian Ministry of Research and Technology (RISTEK). The authors also thank two anonymous reviewers for their thoughtful comments.

Publisher Copyright:
© 2023. American Geophysical Union. All Rights Reserved.

Keywords

  • brGDGT
  • Indo-Pacific Warm Pool
  • Last Glacial Maximum
  • Maritime Continent
  • temperature
  • Towuti

Continental Scientific Drilling Facility tags

  • IDLE

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