A global Bayesian temperature calibration for lacustrine brGDGTs

Sosa, Pablo Martinez; Tierney, Jessica E.; Stefanescu, Ioana; Crampton-Flood, Emily Dearing; Shuman, Bryan N.; Routson, Cody

doi:10.31223/x5ps3p

Cited by 19 publications

(62 citation statements)

References 49 publications

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“…4). We also apply the global Bayesian calibration for lacustrine brGDGTs, known as BayMBT, using the baymbt_predict() MATLAB function (Martinez-Sosa et al, 2021). Following the approach of Martinez-Sosa et al (2021), we estimated the prior value for our dataset by calculating a mean temperature using the Russell et al (2018)…”

Section: Gdgt Analysismentioning

confidence: 99%

“…S2, S3). There are currently several lacustrine MBTʹ5ME calibrations that can be applied to reconstruct past temperature (Dang et al, 2018;Russell et al, 2018;Zhao et al, 2020;Martinez-Sosa et al, 2021). The calibration of Dang et al (2018) is based on alkaline lakes, and so is inappropriate to apply at Lake El'gygytgyn, which has a pH of ~6 (Cremer et al, 2005).…”

Section: Interpretation Of the Brgdgt Recordmentioning

confidence: 99%

See 1 more Smart Citation

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Lindberg

Daniels

Castañeda

et al. 2021

Preprint

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Abstract. The Mid-Pleistocene Transition (MPT) is a widely recognized global climate shift occurring between approximately 1,250 to 700 ka. At this time, Earth's climate underwent a major transition from dominant 40 kyr glacial-interglacial cycles to quasi-100 kyr cycles. The cause of the MPT remains a puzzling aspect of Pleistocene climate. Presently, there are few, if any, continuous MPT records from the Arctic yet understanding the role and response of the high latitudes to the MPT is required to better evaluate the causes of this climatic shift. Here, we present new continental biomarker records of temperature and vegetation spanning 1,142 to 752 ka from Lake El'gygytgyn (Far East Russia). We reconstruct warm-season temperature variations across the MPT based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) using the MBTʹ5ME proxy. The new Arctic temperature record does not display an overall cooling trend during the MPT but does exhibit strong glacial-interglacial cyclicity. Spectral analysis demonstrates persistent obliquity and precession pacing over the study interval and reveals substantial sub-orbital temperature variations at ~900 kyr during the first “skipped” interglacial. Interestingly, Marine Isotope Stage (MIS) 31, which is widely recognized as a particularly warm interglacial, does not exhibit exceptional warmth at Lake El'gygytgyn. Instead, we find that MIS 29, 27 and 21 were as warm or warmer than MIS 31. In particular, MIS 21 (~870 to 820 ka) stands out as an especially warm and long interglacial in the continental Arctic while MIS 25 is a notably cold interglacial. Throughout the MPT, Lake El'gygytgyn pollen data exhibits a long-term drying trend, with a shift to an increasingly open landscape noted after around 900 ka (Zhao et al., 2018), which is also reflected in our higher plant leaf wax (n-alkane) distributions. Although the mechanisms driving the MPT remain a matter of debate, our new climate records from the continental Arctic exhibit some similarities to changes noted around the North Pacific region. Overall, the new organic geochemical data from Lake El'gygytgyn contribute to expanding our knowledge of the high-latitude response to the MPT.

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Section: Gdgt Analysismentioning

confidence: 99%

Section: Interpretation Of the Brgdgt Recordmentioning

confidence: 99%

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Lindberg

Daniels

Castañeda

et al. 2021

Preprint

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“…Based on the branched GDGT concentrations, distributions, and isomerization, we conclude that the BayMBT calibration recently produced by Martinez-Sosa et al (2021) provides the most reliable paleotemperature reconstruction from the GDGTs.…”

Section: Brgdgtsmentioning

confidence: 84%

“…Figure S4 shows the raw MBT'5ME data, along with the three lakes-based calibrations discussed in the main text (Martinez-Sosa et al, 2021;Russell et al, 2018;Zhao et al, 2021). As can be seen, the temporal structure of the reconstructions is identical, as all three are based on the MBT'5ME index.…”

Section: Brgdgtsmentioning

confidence: 99%

Supplementary material to "Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)"

Lindberg¹,

Daniels²,

Castañeda³

et al. 2021

Preprint

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“…Since the methodological advances that allowed for the separation of 5-and 6-methyl isomers (De Jonge et al, 2014a) and the development of new calibrations, both modern (Hanna et al, 2016;Dang et al, 2018;Cao et al, 2020) and paleo (Super et al, 2018;Thomas et al, 2018;Crump et al, 2019;Harning et al, 2020) studies have continued to support a warm-season bias. Additionally, a recent Bayesian calibration found the mean temperature of Months Above Freezing (MAF) to be the only mode to significantly correlate with brGDGT distributions in a global lake sediment dataset (Martínez-Sosa et al, 2020). However, this warm-season bias has yet to be tested thoroughly in the regions in which it is most pronounced -namely, those with low MAT and high seasonality.…”

Section: Introductionmentioning

confidence: 99%

Comment on bg-2021-16

Naeher¹,

Raberg²,

Harning³

et al. 2021

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Distributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs) are frequently employed for reconstructing terrestrial paleotemperatures from lake sediment archives. Although brGDGTs are globally ubiquitous, the microbial producers of these membrane lipids remain unknown, precluding a full understanding of the ways in which environmental parameters control their production and distribution. Here, we advance this understanding in three ways. First, we present 43 new high-latitude lake sites characterized by low mean annual air temperatures (MATs) and high seasonality, filling an important gap in the global dataset. Second, we introduce a new approach for analyzing brGDGT data in which compound fractional abundances (FAs) are calculated within structural groups based on methylation number, methylation position, and cyclization number. Finally, we perform linear and nonlinear regressions of the resulting FAs against a suite of environmental parameters in a compiled global lake sediment dataset (n = 182). We find that our approach deconvolves temperature, conductivity, and pH trends in brGDGTs without increasing calibration errors from the standard approach. We also find that it reveals novel patterns in brGDGT distributions and provides a methodology for investigating the biological underpinnings of their structural diversity.Warm-season temperature indices outperformed MAT in our regressions, with Months Above Freezing yielding the highest-performing model (adjusted R 2 = 0.91, RMSE = 1.97°C, n = 182). The natural logarithm of conductivity had the second-strongest relationship to brGDGT distributions (adjusted R 2 = 0.83, RMSE = 0.66, n = 143), notably outperforming pH in our dataset (adjusted R 2 = 0.73, RMSE = 0.57, n = 154) and providing a potential new proxy for paleohydrology applications. We recommend these calibrations for use in lake sediments globally, including at high latitudes, and detail the advantages and disadvantages of each.

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A global Bayesian temperature calibration for lacustrine brGDGTs

Cited by 19 publications

References 49 publications

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Supplementary material to "Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)"

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A global Bayesian temperature calibration for lacustrine brGDGTs

Cited by 19 publications

References 49 publications

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Supplementary material to &quot;Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)&quot;

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Supplementary material to "Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)"