University of Oulu

Fraser, D., Kim, S. L., Welker, J. M., & Clementz, M. T. (2021). Pronghorn (Antilocapra americana) enamel phosphate δ18O values reflect climate seasonality: Implications for paleoclimate reconstruction. Ecology and Evolution, 11, 17005–17021.

Pronghorn (Antilocapra americana) enamel phosphate δ18O values reflect climate seasonality : Implications for paleoclimate reconstruction

Saved in:
Author: Fraser, Danielle1,2,3,4,5; Kim, Sora L.5,6; Welker, Jeffrey M.7,8,9;
Organizations: 1Palaeobiology, Canadian Museum of Nature, Ottawa, ON, Canada
2Department of Biology, Carleton University, Ottawa, ON, Canada
3Department of Earth Sciences, Carleton University, Ottawa, ON, Canada
4Department of Paleobiology, Smithsonian Institution, National Museum of Natural History, Washington, District of Columbia, USA
5Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming, USA
6Department of Life and Environmental Sciences, University of California, Merced, California, USA
7Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA
8Department of Ecology and Genetics, University of Oulu, Oulu, Finland
9UArctic, Oulu, Finland
10Program in Ecology, University of Wyoming, Laramie, Wyoming, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
Persistent link:
Language: English
Published: John Wiley & Sons, 2021
Publish Date: 2022-02-16


Stable oxygen isotope (δ18O) compositions from vertebrate tooth enamel are widely used as biogeochemical proxies for paleoclimate. However, the utility of enamel oxygen isotope values for environmental reconstruction varies among species. Herein, we evaluate the use of stable oxygen isotope compositions from pronghorn (Antilocapra americana Gray, 1866) enamel for reconstructing paleoclimate seasonality, an elusive but important parameter for understanding past ecosystems. We serially sampled the lower third molars of recent adult pronghorn from Wyoming for δ18O in phosphate (δ18OPO4) and compared patterns to interpolated and measured yearly variation in environmental waters as well as from sagebrush leaves, lakes, and rivers (δ18Ow). As expected, the oxygen isotope compositions of phosphate from pronghorn enamel are enriched in 18O relative to environmental waters. For a more direct comparison, we converted δ18Ow values into expected δ18OPO4* values (δ18OW-PO4*). Pronghorn δ18OPO4 values from tooth enamel record nearly the full amplitude of seasonal variation from Wyoming δ18OW-PO4* values. Furthermore, pronghorn enamel δ18OPO4 values are more similar to modeled δ18OW-PO4* values from plant leaf waters than meteoric waters, suggesting that they obtain much of their water from evaporated plant waters. Collectively, our findings establish that seasonality in source water is reliably reflected in pronghorn enamel, providing the basis for exploring changes in the amplitude of seasonality of ancient climates. As a preliminary test, we sampled historical pronghorn specimens (1720 ± 100 AD), which show a mean decrease (a shift to lower values) of 1–2‰ in δ18 OPO4 compared to the modern specimens. They also exhibit an increase in the δ18O amplitude, representing an increase in seasonality. We suggest that the cooler mean annual and summer temperatures typical of the 18th century, as well as enhanced periods of drought, drove differences among the modern and historical pronghorn, further establishing pronghorn enamel as excellent sources of paleoclimate proxy data.

see all

Series: Ecology and evolution
ISSN: 2045-7758
ISSN-E: 2045-7758
ISSN-L: 2045-7758
Volume: 11
Issue: 23
Pages: 17005 - 17021
DOI: 10.1002/ece3.8337
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: DF was supported by a Fulbright Fellowship, the Natural Science and Engineering Research Council of Canada (NSERC), a Peter Buck Postdoctoral Fellowship at the Smithsonian National Museum of Natural History, an NSERC Discovery Grant (RGPIN-2018-05305), and Canadian Museum of Nature Research Activity Grants. SLK was funded by NSF grant EAR- SGP 0847413 to MTC and T.C. Chamberlin Fellowship at the Univ. of Chicago. USNIP (US Network for Isotopes in Precipitation) was supported by a NSF Earth System History (0078433) and a NSF Major Research and Instrumentation award (0899776) to JMW. The precipitation collections and collaborations between USNIP and the National Atmospheric Deposition Network (NADP), its head-quarters and the individual site operators make USNIP possible. JMW has also been supported by his UArctic Research Chairship and the University of Oulu, Finland.
Dataset Reference: The data and R code for the Passey models are available via Dryad. The R code is also accessible via GitHub.
Copyright information: © 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.