Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada
A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine...
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ftunivwestonta:oai:ir.lib.uwo.ca:earthpub-1028 2023-10-01T03:52:48+02:00 Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada Tahmasebi, Farnoush Longstaffe, Fred J Zazula, Grant 2018-01-01T08:00:00Z application/pdf https://ir.lib.uwo.ca/earthpub/25 https://doi.org/10.1371/journal https://ir.lib.uwo.ca/context/earthpub/article/1028/viewcontent/Tahmasebi__F._et_al.__2018_.pdf unknown Scholarship@Western https://ir.lib.uwo.ca/earthpub/25 doi:10.1371/journal. pone.0192713 https://ir.lib.uwo.ca/context/earthpub/article/1028/viewcontent/Tahmasebi__F._et_al.__2018_.pdf Earth Sciences Publications Yukon Territory eastern Beringia late Pleistocene carbon- and nitrogen-isotope vegetation baseline arctic ground squirrel bone collagen plant decomposition nitrogen cycling Earth Sciences Geochemistry Other Environmental Sciences Paleobiology Paleontology article 2018 ftunivwestonta https://doi.org/10.1371/journal 2023-09-03T07:00:59Z A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine paleodiet and reconstruct the paleoecosystem. This approach requires consideration of changes in C- and N-isotope dynamics over time and their effects on the terrestrial vegetation isotopic baseline. To test for such changes between the Late Pleistocene and modern time, we compared δ13C and δ15N for vegetation and bone collagen and structural carbonate of some modern, Yukon, arctic ground squirrels with vegetation and bones from Late Pleistocene fossil arctic ground squirrel nests preserved in Yukon loess deposits. The isotopic discrimination between arctic ground squirrel bone collagen and their diet was measured using modern samples, as were isotopic changes during plant decomposition; Over-wintering decomposition of typical vegetation following senescence resulted in a minor change (~0±1 ½) in δ13C of modern Yukon grasses. A major change (~2±10 ½) in δ15N was measured for decomposing Yukon grasses thinly covered by loess. As expected, the collagen-diet C-isotope discrimination measured for modern samples confirms that modern vegetation δ13C is a suitable proxy for the Late Pleistocene vegetation in Yukon Territory, after correction for the Suess effect. The N-isotope composition of vegetation from the fossil arctic ground squirrel nests, however, is determined to be ~2.8‰ higher than modern grasslands in the region, after correction for decomposition effects. This result suggests a change in N dynamics in this region between the Late Pleistocene and modern time. Article in Journal/Newspaper Arctic ground squirrel Arctic Alaska Beringia Yukon The University of Western Ontario: Scholarship@Western Arctic Canada Yukon |
institution |
Open Polar |
collection |
The University of Western Ontario: Scholarship@Western |
op_collection_id |
ftunivwestonta |
language |
unknown |
topic |
Yukon Territory eastern Beringia late Pleistocene carbon- and nitrogen-isotope vegetation baseline arctic ground squirrel bone collagen plant decomposition nitrogen cycling Earth Sciences Geochemistry Other Environmental Sciences Paleobiology Paleontology |
spellingShingle |
Yukon Territory eastern Beringia late Pleistocene carbon- and nitrogen-isotope vegetation baseline arctic ground squirrel bone collagen plant decomposition nitrogen cycling Earth Sciences Geochemistry Other Environmental Sciences Paleobiology Paleontology Tahmasebi, Farnoush Longstaffe, Fred J Zazula, Grant Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
topic_facet |
Yukon Territory eastern Beringia late Pleistocene carbon- and nitrogen-isotope vegetation baseline arctic ground squirrel bone collagen plant decomposition nitrogen cycling Earth Sciences Geochemistry Other Environmental Sciences Paleobiology Paleontology |
description |
A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine paleodiet and reconstruct the paleoecosystem. This approach requires consideration of changes in C- and N-isotope dynamics over time and their effects on the terrestrial vegetation isotopic baseline. To test for such changes between the Late Pleistocene and modern time, we compared δ13C and δ15N for vegetation and bone collagen and structural carbonate of some modern, Yukon, arctic ground squirrels with vegetation and bones from Late Pleistocene fossil arctic ground squirrel nests preserved in Yukon loess deposits. The isotopic discrimination between arctic ground squirrel bone collagen and their diet was measured using modern samples, as were isotopic changes during plant decomposition; Over-wintering decomposition of typical vegetation following senescence resulted in a minor change (~0±1 ½) in δ13C of modern Yukon grasses. A major change (~2±10 ½) in δ15N was measured for decomposing Yukon grasses thinly covered by loess. As expected, the collagen-diet C-isotope discrimination measured for modern samples confirms that modern vegetation δ13C is a suitable proxy for the Late Pleistocene vegetation in Yukon Territory, after correction for the Suess effect. The N-isotope composition of vegetation from the fossil arctic ground squirrel nests, however, is determined to be ~2.8‰ higher than modern grasslands in the region, after correction for decomposition effects. This result suggests a change in N dynamics in this region between the Late Pleistocene and modern time. |
format |
Article in Journal/Newspaper |
author |
Tahmasebi, Farnoush Longstaffe, Fred J Zazula, Grant |
author_facet |
Tahmasebi, Farnoush Longstaffe, Fred J Zazula, Grant |
author_sort |
Tahmasebi, Farnoush |
title |
Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
title_short |
Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
title_full |
Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
title_fullStr |
Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
title_full_unstemmed |
Nitrogen Isotopes Suggest a Change in Nitrogen Dynamics between the Late Pleistocene and Modern Time in Yukon, Canada |
title_sort |
nitrogen isotopes suggest a change in nitrogen dynamics between the late pleistocene and modern time in yukon, canada |
publisher |
Scholarship@Western |
publishDate |
2018 |
url |
https://ir.lib.uwo.ca/earthpub/25 https://doi.org/10.1371/journal https://ir.lib.uwo.ca/context/earthpub/article/1028/viewcontent/Tahmasebi__F._et_al.__2018_.pdf |
geographic |
Arctic Canada Yukon |
geographic_facet |
Arctic Canada Yukon |
genre |
Arctic ground squirrel Arctic Alaska Beringia Yukon |
genre_facet |
Arctic ground squirrel Arctic Alaska Beringia Yukon |
op_source |
Earth Sciences Publications |
op_relation |
https://ir.lib.uwo.ca/earthpub/25 doi:10.1371/journal. pone.0192713 https://ir.lib.uwo.ca/context/earthpub/article/1028/viewcontent/Tahmasebi__F._et_al.__2018_.pdf |
op_doi |
https://doi.org/10.1371/journal |
_version_ |
1778518934790602752 |