| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | April 27, 2022 |
| Latest Amendment Date: | July 28, 2022 |
| Award Number: | 2200448 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Michael E. Jackson
OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | August 1, 2022 |
| End Date: | July 31, 2024 (Estimated) |
| Total Intended Award Amount: | $58,915.00 |
| Total Awarded Amount to Date: | $58,915.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
3227 CHEADLE HALL SANTA BARBARA CA US 93106-0001 (805)893-4188 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Office of Research Santa Barbara CA US 93106-2050 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ANT Earth Sciences |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
Much of our understanding of ice sheet behavior due to warming temperatures is based on how past ice sheets responded to warming associated with the end of the last ice age, 20,000 years ago. These studies rely on accurate dating of features left behind by the past ice sheets. The most commonly used method for determining the age of these features over the last ~40,000 years is radiocarbon dating. However, radiocarbon dating is not without its nuances, which are particularly pronounced around Antarctica. One of these nuances is determining the offset between the materials measured radiocarbon age and its true age. The purpose of this research is to use historically harvested whale bones from the Antarctic Peninsula, whose age is independently known, to determine that offset. A better understanding of that offset will allow more accurate estimates of past rates of ice sheet and sea-level changes across the Antarctic Peninsula over the last ~40,000 years.
Much of our understanding of how the Antarctic Ice Sheet will respond to future climate changes is based on studies of its past behavior. Those studies often rely on reconstructing its evolution since the Last Glacial Maximum, 20,000 years ago. Radiocarbon dating is the most commonly used method of dating Quaternary deposits for these reconstructions. However, the use of radiocarbon in Antarctica is hampered by some of the largest and least constrained radiocarbon reservoirs on the planet. The purpose of this research is to determine the radiocarbon reservoir for whale bones. This research will leverage an existing collection of 25 whale bones used for prior DNA research to determine the late Holocene radiocarbon reservoir for the Antarctic Peninsula. The whale bones are from specimens harvested at the turn of the 20th century prior to nuclear testing in the 1950s. Thus, their radiocarbon age will provide valuable new constraints on the radiocarbon reservoir for shallow waters around Antarctica. An added benefit of this approach is that given the DNA determination, we will also be able to determine if that radiocarbon reservoir varies across three species of whales, thus testing the common assumption that the radiocarbon reservoir does not vary significantly across different species.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Radiocarbon dating is arguably the most common method used to determine the age of old organic materials less than 50,000 years old. This method thus allows us to determine the age of past events in Earth history such as climate changes, sea-level changes, earthquakes, tsunami, etc. However, an accurate radiocarbon age requires several corrections to be made to the raw measurements. One of these corrections accounts for the "old carbon" in the environment. Within Antarctica, this correction can be on the order of thousands of years. In addition, in comparison to other regions of the globe, few constraints are available for this “old carbon” correction and little is known about how this correction varies geographically and by material/species dated. In this study we use whale bones salvaged from early 20th century whaling stations to determine the “old carbon” correction for coastal waters around the Antarctica Peninsula. Furthermore, the DNA from these previously collected whale bones has been sequenced and the species of the whale bones is known. We find that the “old carbon” correction for our samples is on the order of 1050+/-135 years. We also found that the correction varies by <100 years across whale species. When comparing our new results from the Antarctic Peninsula to previous results we find that the correction varies little across Antarctica and through time over the last approximately 14,000 years. Our new correction will allow the more accurate age determination of past events in Earth history across Antarctica.
In addition, we put up a booth advertising the Earth Sciences at the Higher Education Week of 12 local high schools that cater to groups underrepresented in Earth Sciences. Through that booth we were able to answer questions about what it is like to study Earth Sciences in college and what career opportunities are available to those with degrees in the Earth Sciences. In total, the fairs we attended were visited by over 6,000 high school seniors.
Last Modified: 08/30/2024
Modified by: Alexander R Simms
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