@article {cluett_lake_2023,
	title = {Lake Dynamics Modulate the Air Temperature Variability Recorded by Sedimentary Aquatic Biomarkers: A Holocene Case Study From Western Greenland},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {128},
	number = {7},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JG007106},
	month = {07/2023},
	pages = {e2022JG007106},
	abstract = {Quantitative temperature reconstructions from lacustrine organic geochemical proxies including branched glycerol dialkyl glycerol tetraethers (brGDGTs) and alkenones provide key constraints on past continental climates. However, estimation of air temperatures from proxies can be impacted by non-stationarity in the relationships between seasonal air and water temperatures, a factor not yet examined in strongly seasonal high-latitude settings. We pair downcore analyses of brGDGTs and alkenones measured on the same samples through the Holocene with forward-modeled proxy values based on thermodynamic lake model simulations for a western Greenland lake. The measured brGDGT distributions suggest that stable autochthonous (aquatic) production overpowers allochthonous inputs for most samples, justifying the use of the lake model to interpret temperature-driven changes. Conventional calibration of alkenones (detected only after 5.5 thousand years BP) suggests substantially larger temperature variations than conventional calibration of brGDGTs. Comparison of proxy measurements to forward-modeled values suggests variations in brGDGT distributions monotonically reflect multi-decadal summer air temperatures changes, although the length of the ice-free season dampens the influence of air temperatures on water temperatures. Drivers of alkenone variability remain less clear; potential influences include small changes in the seasonality of proxy production or biases toward specific years, both underlain by non-linearity in water-air temperature sensitivity during relevant seasonal windows. We demonstrate that implied temperature variability can differ substantially between proxies because of differences in air-water temperature sensitivity during windows of proxy synthesis without necessitating threshold behavior in the lake or local climate, and recommend that future studies incorporate lake modeling to constrain this uncertainty.},
	keywords = {Alkenone, Arctic, biogeochemical proxies, brGDGT, data-model comparison, proxy system modeling},
	issn = {2169-8961},
	doi = {10.1029/2022JG007106},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JG007106},
	author = {Cluett, A. A. and Thomas, E. K. and McKay, N. P. and Cowling, O. C. and Casta{\~n}eda, I. S. and Morrill, C.}
}
@article {2817,
	title = {Deglacial temperature controls on no-analog community establishment in the Great Lakes Region},
	journal = {Quaternary Science Reviews},
	volume = {234},
	year = {2020},
	month = {Jan-04-2020},
	pages = {106245},
	abstract = {Understanding the drivers of vegetation dynamics and no-analog communities in eastern North America is hampered by a scarcity of independent temperature indicators. We present a new branched glycerol dialkyl glycerol tetraether (brGDGT) temperature record from Bonnet Lake, Ohio (18{\textendash}8 ka) and report uncertainty estimates based on Bayesian linear regression and bootstrapping. We also reanalyze a previously published brGDGT record from Silver Lake, Ohio, using improved chromatographic methods. All pollen- and brGDGT-based temperature reconstructions showed qualitatively similar deglacial trends but varying magnitudes. Separating 5- and 6- methyl brGDGTs resulted in substantially lower estimates of deglacial temperature variations (6.4 {\textdegree}C) than inferred from earlier brGDGT methods and pollen (11.8 {\textdegree}C, 12.0 {\textdegree}C respectively). Similar trends among proxies suggest good fidelity of brGDGTs to temperature, despite calibration uncertainties. At both sites, the rise and decline of no-analog communities closely track brGDGT-inferred temperatures, with a lag of 0{\textendash}150 years. The timing of temperature and ecological events varies between Bonnet and Silver Lakes, likely due to age model uncertainties. Climate sensitivity analyses indicate a linear sensitivity of vegetation composition to temperature variations, albeit noisy and significant only with a 500-year bin. The formation of no-analog plant communities in the upper Midwest is closely linked to late-glacial warming, but other factors, such as temperature seasonality or end-Pleistocene megafaunal extinctions, remain viable.},
	keywords = {biomarkers, brGDGT, Climate sensitivity, Lagoons \& swamps, lakes, No-analog, North America, paleoclimatology, Pleistocene, pollen, sedimentology, Temperature, vegetation},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106245},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379119303713},
	author = {Fastovich, David and Russell, James M. and Jackson, Stephen T. and Williams, John W.}
}
