ORCID Profile
0000-0002-8251-6937
Current Organisation
University of Colorado at Boulder
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Publisher: Elsevier BV
Date: 03-2014
Publisher: American Geophysical Union (AGU)
Date: 07-2019
DOI: 10.1029/2018PA003442
Publisher: Wiley
Date: 11-10-2019
DOI: 10.1111/GCB.14836
Abstract: Arctic shrubification is an observable consequence of climate change, already resulting in ecological shifts and global-scale climate feedbacks including changes in land surface albedo and enhanced evapotranspiration. However, the rate at which shrubs can colonize previously glaciated terrain in a warming world is largely unknown. Reconstructions of past vegetation dynamics in conjunction with climate records can provide critical insights into shrubification rates and controls on plant migration, but paleoenvironmental reconstructions based on pollen may be biased by the influx of exotic pollen to tundra settings. Here, we reconstruct past plant communities using sedimentary ancient DNA (sedaDNA), which has a more local source area than pollen. We additionally reconstruct past temperature variability using bacterial cell membrane lipids (branched glycerol dialkyl glycerol tetraethers) and an aquatic productivity indicator (biogenic silica) to evaluate the relative timing of postglacial ecological and climate changes at a lake on southern Baffin Island, Arctic Canada. The sedaDNA record tightly constrains the colonization of dwarf birch (Betula, a thermophilous shrub) to 5.9 ± 0.1 ka, ~3 ka after local deglaciation as determined by cosmogenic
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-01-2020
Abstract: Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. The best model fits to the data required most outgassing to occur before the impact. When combined with other lines of evidence, these models support an impact-driven extinction. However, volcanic gases may have played a role in shaping the rise of different species after the extinction event. Science , this issue p. 266
Publisher: Elsevier BV
Date: 03-2019
No related grants have been discovered for Julio Sepúlveda.