| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | August 7, 2015 |
| Latest Amendment Date: | August 7, 2015 |
| Award Number: | 1529133 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Enriqueta Barrera
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2015 |
| End Date: | August 31, 2019 (Estimated) |
| Total Intended Award Amount: | $68,156.00 |
| Total Awarded Amount to Date: | $68,156.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
2600 CLIFTON AVE CINCINNATI OH US 45220-2872 (513)556-4358 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Cincinnati OH OH US 45221-0222 |
| 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): | Geobiology & Low-Temp Geochem |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Land snails are one of the most common fossils in the terrestrial geologic record of North America. Their shells are composed of calcium carbonate and the oxygen isotopic composition of their shells record climatic conditions during growth. Therefore, the oxygen isotopic composition of land snails has the potential to reconstruct past climates on broad spatial and temporal scales. To date, however, there is a little understanding on the kinds of climatic information that can be inferred from the snails, and therefore, their current use as paleoclimatic archives is limited. This proposal will develop, test, and calibrate the oxygen isotope systematics of small land snails for use as a paleoclimatic proxy in terrestrial settings across North America. The modern calibration of this proxy will benefit society through the development of a terrestrial paleoclimatic proxy that is capable of reconstructing past climate over broad spatial and temporal scales and also will improve our understanding of the taxonomic diversity and spatial distribution of land snails, a fauna that is decreasing at an alarming rate globally. This project will teach and train future scientists, from high school to PhD candidates, integrate scientists from multiple fields (paleontology, biology, Quaternary geology), and broaden the participation of diverse and underrepresented groups. Dissemination of results will include a diverse audience (specialists and general public), in English and Spanish to reach the Hispanic community in USA and elsewhere. This project will establish linkages between underrepresented groups and STEM disciplines at research-intensive universities.
To calibrate the oxygen isotope systematics of modern land snails in North America, investigators will analyze the oxygen isotope composition of approximately 1,000 shell samples from modern snails collected along two selected transects that cross North America from southern Texas to Canada. They will identify the primary climatic controls on shell ä18O values by quantifying the relation between shell ä18O and relevant climatic variables (temperature, ä18O of precipitation, precipitation amount, relative humidity) using an evaporative steady-state flux balance-mixing model developed for land snails. Researchers hypothesize that: (1) the oxygen isotope composition of small land snails in temperate environments (latitudes of 26 to 48 degrees N) primarily will reflect the oxygen isotope composition of precipitation, and therefore can be used to infer past changes in precipitation oxygen isotope values; and (2) shell oxygen isotope values of snails living in arid to semi-arid environments will yield higher values than predicted because of low relative humidity values. After calibration of the oxygen isotope systematics for living specimens, investigators will conduct two case studies to determine how well the oxygen isotope values of small snails track the oxygen isotope records of speleothems or other proxy records. The proposed work will allow better quantification of past climate change over broad areas of North America, and from many different types of deposits.
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.
Climate change impacts the environment, global economies, and even geopolitical stability. In order to investigate the potential range of future climate variability and its long-term effects on the biosphere and civilization, a geo-historical perspective should be considered spanning centennial to multi-millennial timescales to understand the magnitude and scale of past climate events. To achieve this goal, scientists have tested, calibrated and validated an array of paleoclimate proxies, or natural archives that track climatic conditions far earlier in time than what can be studied using the instrumental record.
In the present proposal, the research team conducted intensive work over the course of four years with the goal of calibrating and validating an emerging and promising paleoclimate proxy, small land snail shells from North America. This goal was attained by exhaustive and unprecedented field sampling collection and geochemical analyses of the most common gastropod species across broad latitudinal transects ranging from the tropics to the high arctic tundra biome. The results demonstrate that small land snail shells from North America primarily track the oxygen isotopic signature of the precipitation and accordingly, ancient shells retrieved from sedimentary archives or archeological sites may be used as proxies for paleo-precipitation over broad spatial transects. However, not all species track this information in the same fashion, and controlling for taxonomy and body size is necessary in paleoclimate investigations. We also identified future directions of research to continue improving the validity and application of this proxy.
In this project, ten undergraduate and graduate students, many of them from underrepresented groups, have received substantial training and education on field and laboratory techniques. The research group was led by an early career Hispanic female who has enhanced her academic career and professional network through the execution of this project. The group has also completed a number of scientific papers that have been published in peer-reviewed journals, and have presented their findings to the scientific community and the general public to increase awareness and education about land snail ecology, conservation and climate change.
Last Modified: 10/29/2019
Modified by: Yurena Yanes
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