Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds

This study measured δ13C and δ15N of fresh and charred seeds from six different taxa of cereals and pulses. For each taxon, 12 different batches of seeds, all from the same growing context or field, were charred for 4, 8, or 24 hours at 215, 230, 245, or 260°C, with the thirteenth batch left uncharr...

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Main Authors: Nitsch, E, Charles, M, Bogaard, A
Format: Journal article
Published: Maney Publishing 2015
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author Nitsch, E
Charles, M
Bogaard, A
author_facet Nitsch, E
Charles, M
Bogaard, A
author_sort Nitsch, E
collection OXFORD
description This study measured δ13C and δ15N of fresh and charred seeds from six different taxa of cereals and pulses. For each taxon, 12 different batches of seeds, all from the same growing context or field, were charred for 4, 8, or 24 hours at 215, 230, 245, or 260°C, with the thirteenth batch left uncharred. The least charred samples showed no average offset compared to their uncharred counterparts, but among the charred seeds, every 15°C increase resulted in an increase in δ15N by 0.12‰, while increasing the duration of charring by 4 hours resulted in an average increase of 0.04‰. Differences in δ13C among the charred samples were only minimally dependent on time (+0.016‰/4 hours duration), but not temperature. The average offset for all batches and all taxa was minimal for δ13C, at +0.11‰ (95% confidence interval (CI) 0.003–0.22‰). The average offset for δ15N of 0.31‰ (95% CI 0.05–0.57‰) is smaller than the conservative estimate of 1‰ used in previous studies. We demonstrate that using this new, smaller charring offset for δ15N makes a significant difference in paleodietary models, one that further emphasizes the potentially high δ15N of manured crops relative to animal forage.
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spelling oxford-uuid:e3ba1fb3-fabe-4259-9b76-57bbe4facd1d2022-03-27T10:11:13ZCalculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seedsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:e3ba1fb3-fabe-4259-9b76-57bbe4facd1dSymplectic Elements at OxfordManey Publishing2015Nitsch, ECharles, MBogaard, AThis study measured δ13C and δ15N of fresh and charred seeds from six different taxa of cereals and pulses. For each taxon, 12 different batches of seeds, all from the same growing context or field, were charred for 4, 8, or 24 hours at 215, 230, 245, or 260°C, with the thirteenth batch left uncharred. The least charred samples showed no average offset compared to their uncharred counterparts, but among the charred seeds, every 15°C increase resulted in an increase in δ15N by 0.12‰, while increasing the duration of charring by 4 hours resulted in an average increase of 0.04‰. Differences in δ13C among the charred samples were only minimally dependent on time (+0.016‰/4 hours duration), but not temperature. The average offset for all batches and all taxa was minimal for δ13C, at +0.11‰ (95% confidence interval (CI) 0.003–0.22‰). The average offset for δ15N of 0.31‰ (95% CI 0.05–0.57‰) is smaller than the conservative estimate of 1‰ used in previous studies. We demonstrate that using this new, smaller charring offset for δ15N makes a significant difference in paleodietary models, one that further emphasizes the potentially high δ15N of manured crops relative to animal forage.
spellingShingle Nitsch, E
Charles, M
Bogaard, A
Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title_full Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title_fullStr Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title_full_unstemmed Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title_short Calculating a statistically robust δ13C and δ15N offset for charred cereal and pulse seeds
title_sort calculating a statistically robust δ13c and δ15n offset for charred cereal and pulse seeds
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AT charlesm calculatingastatisticallyrobustd13candd15noffsetforcharredcerealandpulseseeds
AT bogaarda calculatingastatisticallyrobustd13candd15noffsetforcharredcerealandpulseseeds