Publications by authors named "Rebekah A Stein"

2 Publications

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C plant carbon isotope discrimination does not respond to CO concentration on decadal to centennial timescales.

New Phytol 2021 03 22;229(5):2576-2585. Epub 2020 Nov 22.

Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 1100 N University Avenue, Ann Arbor, MI, 48109, USA.

Plant carbon isotope discrimination is complex, and could be driven by climate, evolution and/or edaphic factors. We tested the climate drivers of carbon isotope discrimination in modern and historical plant chemistry, and focus in particular on the relationship between rising [CO ] over Industrialization and carbon isotope discrimination. We generated temporal records of plant carbon isotopes from museum specimens collected over a climo-sequence to test plant responses to climate and atmospheric change over the past 200 yr (including Pinus strobus, Platycladus orientalis, Populus tremuloides, Thuja koraiensis, Thuja occidentalis, Thuja plicata, Thuja standishii and Thuja sutchuenensis). We aggregated our results with a meta-analysis of a wide range of C plants to make a comprehensive study of the distribution of carbon isotope discrimination and values among different plant types. We show that climate variables (e.g. mean annual precipitation, temperature and, key to this study, CO in the atmosphere) do not drive carbon isotope discrimination. Plant isotope discrimination is intrinsic to each taxon, and could link phylogenetic relationships and adaptation to climate quantitatively and over ecological to geological time scales.
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http://dx.doi.org/10.1111/nph.17030DOI Listing
March 2021

Rapid response to anthropogenic climate change by : implications for past climate reconstructions and future climate predictions.

PeerJ 2019 26;7:e7378. Epub 2019 Jul 26.

Department of Earth and Environmental Sciences, University of Michigan-Ann Arbor, Ann Arbor, MI, USA.

Carbon isotope values of leaves (δC) from meta-analyses and growth chamber studies of C plants have been used to propose generalized relationships between δC and climate variables such as mean annual precipitation (MAP), atmospheric concentration of carbon dioxide ([CO]), and other climate variables. These generalized relationships are frequently applied to the fossil record to create paleoclimate reconstructions. Although plant evolution influences biochemistry and response to environmental stress, few studies have assessed species-specific carbon assimilation as it relates to climate outside of a laboratory. We measured δC values and C:N ratios of a wide-ranging evergreen conifer with a long fossil record, (Cupressaceae) collected 1804-2017, in order to maximize potential paleo-applications of our focal species. This high-resolution record represents a natural experiment from pre-Industrial to Industrial times, which spans a range of geologically meaningful [CO] and δC values. Δ values (carbon isotope discrimination between δC and δC) remain constant across climate conditions, indicating limited response to environmental stress. Only δC and δC values showed a strong relationship (linear), thus, δC is an excellent record of carbon isotopic changes in the atmosphere during Industrialization. In contrast with previous free-air concentration enrichment experiments, no relationship was found between C:N ratios and increasing [CO]. Simultaneously static C:N ratios and Δ in light of increasing CO highlights plants' inability to match rapid climate change with increased carbon assimilation as previously expected; Δ values are not reliable tools to reconstruct MAP and [CO], and δC values only decrease with [CO] in line with atmospheric carbon isotope changes.
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http://dx.doi.org/10.7717/peerj.7378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6662565PMC
July 2019