Modelled dispersal patterns for wood and grass charcoal are different: implications for paleofire reconstruction

Sedimentary charcoal records provide useful perspectives on the long-term controls and behavior of fire in the Earth system. However, a comprehensive understanding of the nuances, biases, and limitations of charcoal as a fire proxy is necessary for reliable paleofire interpretations. Here, we use a charcoal dispersal model to answer the following questions: (1) How does the dispersal of wood and grass charcoal particles differ? (2) Do traditional conceptual models of charcoal dispersal reliably characterize grass charcoal dispersal? We find that small differences in shape (L:W) and density of grass and wood charcoal can cause substantial differences in particle dispersal and source area. Whereas the modelled dispersal of wood charcoal shows a localized deposition signal which decays with distance, grass charcoal shows more diffuse deposition lacking a localized center (for both >125 µm and >60 µm). Although paleofire research has typically not distinguished between fuel types, we show that the dispersal of charcoal derived from different fuels is unlikely to be uniform. Because differences in localization, production, and preservation could bias aggregate charcoal accumulation, caution should be taken when interpreting wood and grass-derived charcoal particles preserved in the same record. Additionally, we propose an alternative, dual background conceptual model of grass charcoal dispersal, as the traditional, two-component (peak and background) conceptual model does not accurately characterize the modelled dispersal of grass charcoal. Lastly, this mismatch of conceptualizations of dispersal mechanics implies that grass charcoal may not fit the criteria necessary for peak analysis techniques

Warehouse management system

Práca sa zaoberá návrhom a implementáciou na mieru šitého systému pre podporu správy skladového hospodárstva malého podniku s ohľadom na požiadavky konkrétneho zadávateľa. Systém zprehľadní správu skladových zásob a zjednoduší proces naskladnenia parsovaním dát z elektronickej podoby faktúr. Za cieľ si práca súčasne kľadie i overenie funkčnosti systému programovými testami i testami použiteľnosti.Aim of the thesis is to design and implement a web application as a warehouse management system according to the requirements of a company the system is built for. Besides providing greater clarity of used resources, system also simplifies the process of stocking by parsing contents of provided pdf invoices. Focus has also been placed on verification of the proper implementation of the system by means of unit and usability testing

Holocene Climatic Changes in the Alaskan Arctic as Inferred from Oxygen-Isotopic Analysis

Reconstructions of Holocene climate in the Alaskan Arctic allow for better understanding of how the region may respond to future climate changes. However, long-term records from the region are scarce. We conducted lithological and isotopic analyses at Wahoo Lake (69º 4.612, -146º 55.676) to infer Holocene climate variability in northern Alaska. Isotopic composition of modern water from this large, open-basin lake in the northern foothills of the Brooks Range suggests that winter precipitation dominates inputs to the lake. Isotopic composition of Pisidium exhibits large variations throughout the past 11,800 years, with δ18O values ranging between 11.6 and 14.2‰ (VSMOW) and δ13C between -2.3 and -7.1‰ (VPDB). Loss-on-ignition (LOI) shows high carbonate content (8.1-50.9%) in the subbasin sediments between 11.8-6.3 kcal BP, transitioning to lower carbonate (1.3-25.3%) and increased organic content (11.7-65.2%) between 6.3-1.4 kcal BP. High carbonate and elevated δ18O values (13.0-14.0‰) from 11.5-8.5 kcal BP likely reflect lower lake level and possibly evaporative enrichment of lake water, suggesting warm, dry summers during the early Holocene. The disappearance of Pisidium, paired with a decrease in calcite deposition at ~6.5 kcal BP, suggests increasing lake-level in the mid-Holocene, which is supported by a basal date of 5.3 kcal BP from a core of the shallow shelf of the lake. This increase coincided with lake-level increases in interior Alaska and likely resulted from enhanced regional effective moisture. The shelf sediments exhibit a marked increase in carbonate content at ~3.5 kcal BP and δ18O values generally rose from 12.4‰ at 3.5 kcal BP to 13.2‰ at 2.0 kcal BP (range = 11.6-14.2‰), suggesting increasing annual temperatures during this period. After 2.0 kcal BP, δ18O values fluctuate between 11.9-13.3‰, but generally decline until 1.0 kcal BP, suggesting dramatic temperature fluctuations in the late Holocene. These Holocene variations in δ18O values at Wahoo Lake generally correspond to fluctuations in total solar irradiance, suggesting that solar variability may have played an important role in Holocene climate change of the Alaskan Arctic. Understanding the role of solar irradiance on natural variability of climate in this region provides a framework for evaluating climatic response and sensitivity to anthropogenic forcing.Ope

Paleoenvironment and Archaeology Provide Cautionary Tales for Climate Policymakers

Federal climate policy in the United States is still in its infancy and is in large part characterized by efforts to reach a consensus on the very existence and causality of climate change. This has stemmed from a sociopolitical rift within the country, with the objectivity and usefulness of science attacked by detractors. Scientists who are most qualified to defend their methods and provide information to policymakers rarely have an institutional incentive to share this knowledge, but should be encouraged to communicate their findings to the public, especially those who receive public funding. By not doing so, they are effectively 1) keeping data and their interpretations within the academy alone, despite their importance to the public welfare, 2) losing public support through inactivity, and 3) potentially harming the future availability of research support in what has rapidly become a politically polarized funding atmosphere. Archaeologists and geoscientists in particular, as repositories of past ecological knowledge established through one method (Western academic) of empirical examination, are well positioned to broadcast to the public a variety of societal responses to long-term environmental change as well as the repercussions of political reorganization in the wake of resource shortage-induced societal collapse. This paper summarizes a few promising public outreach engagements on environment and climate change, and suggests further venues for institutional change at the university level. As an example of how multi-causal socio-ecological processes can be concisely packaged for consumption by the public and policymakers without oversimplifying data, we present a synthesis of regional case studies from the New and Old Worlds. Case studies are connected through anthropological processes of cooperation versus exclusion, subsistence shifts, sociopolitical (re)organization and hierarchy, violence, and disease in a preliminary attempt a) to identify the emotional and anecdotal psychology of our own society when it comes to the chang5Brett Kaufman, Christopher S. Kelly and Richard S. Vachula ing global environment, b) to discuss the issue of scalar differences between ancient and modern ecology, and c) to call on academics to introspectively alter our own attitudes and systems of incentives at the university level

Beringia and the peopling of the Western Hemisphere

Did Beringian environments represent an ecological barrier to humans until less than 15 000 years ago or was access to the Americas controlled by the spatial–temporal distribution of North American ice sheets? Beringian environments varied with respect to climate and biota, especially in the two major areas of exposed continental shelf. The East Siberian Arctic Shelf (‘Great Arctic Plain’ (GAP)) supported a dry steppe-tundra biome inhabited by a diverse large-mammal community, while the southern Bering-Chukchi Platform (‘Bering Land Bridge’ (BLB)) supported mesic tundra and probably a lower large-mammal biomass. A human population with west Eurasian roots occupied the GAP before the Last Glacial Maximum (LGM) and may have accessed mid-latitude North America via an interior ice-free corridor. Re-opening of the corridor less than 14 000 years ago indicates that the primary ancestors of living First Peoples, who already had spread widely in the Americas at this time, probably dispersed from the NW Pacific coast. A genetic ‘arctic signal’ in non-arctic First Peoples suggests that their parent population inhabited the GAP during the LGM, before their split from the former. We infer a shift from GAP terrestrial to a subarctic maritime economy on the southern BLB coast before dispersal in the Americas from the NW Pacific coast

A global database of Holocene paleotemperature records

A comprehensive database of paleoclimate records is needed to place recent warming into the longer-term context of natural climate variability. We present a global compilation of quality-controlled, published, temperature-sensitive proxy records extending back 12,000 years through the Holocene. Data were compiled from 679 sites where time series cover at least 4000 years, are resolved at sub-millennial scale (median spacing of 400 years or finer) and have at least one age control point every 3000 years, with cut-off values slackened in data-sparse regions. The data derive from lake sediment (51%), marine sediment (31%), peat (11%), glacier ice (3%), and other natural archives. The database contains 1319 records, including 157 from the Southern Hemisphere. The multi-proxy database comprises paleotemperature time series based on ecological assemblages, as well as biophysical and geochemical indicators that reflect mean annual or seasonal temperatures, as encoded in the database. This database can be used to reconstruct the spatiotemporal evolution of Holocene temperature at global to regional scales, and is publicly available in Linked Paleo Data (LiPD) format.Fil: Kaufman, Darrell. Northern Arizona University.; Estados UnidosFil: McKay, Nicholas. Northern Arizona University.; Estados UnidosFil: Routson, Cody. Northern Arizona University.; Estados UnidosFil: Erb, Michael. Northern Arizona University.; Estados UnidosFil: Davis, Basil. University Of Lausanne; SuizaFil: Heiri, Oliver. University Of Basel; SuizaFil: Jaccard, Samuel. University Of Bern; SuizaFil: Tierney, Jessica. University of Arizona; Estados UnidosFil: Dätwyler, Christoph. University Of Bern; SuizaFil: Axford, Yarrow. Northwestern University; Estados UnidosFil: Brussel, Thomas. University of Utah; Estados UnidosFil: Cartapanis, Olivier. University Of Bern; SuizaFil: Chase, Brian. Universite de Montpellier; FranciaFil: Dawson, Andria. Mount Royal University; CanadáFil: de Vernal, Anne. Université du Québec a Montreal; CanadáFil: Engels, Stefan. University of London; Reino UnidoFil: Jonkers, Lukas. University Of Bremen; AlemaniaFil: Marsicek, Jeremiah. University of Wisconsin-Madison; Estados UnidosFil: Moffa Sánchez, Paola. University of Durham; Reino UnidoFil: Morrill, Carrie. University of Colorado; Estados UnidosFil: Orsi, Anais. Université Paris-Saclay; FranciaFil: Rehfeld, Kira. Heidelberg University; AlemaniaFil: Saunders, Krystyna. Australian Nuclear Science And Technology Organisation; AustraliaFil: Sommer, Philipp. University Of Lausanne; SuizaFil: Thomas, Elizabeth. University At Buffalo; Estados UnidosFil: Tonello, Marcela Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Tóth, Mónika. Balaton Limnological Institute; HungríaFil: Vachula, Richard. Brown University; Estados UnidosFil: Andreev, Andrei. Alfred Wegener Institut Helmholtz Centre for Polar and Marine Research; AlemaniaFil: Bertrand, Sebastien. Ghent University; BélgicaFil: Massaferro, Julieta. Administración de Parques Nacionales. Parque Nacional "Nahuel Huapi"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Assessing changes in global fire regimes

PAGES, Past Global Changes, is funded by the Swiss Academy of Sciences and the Chinese Academy of Sciences and supported in kind by the University of Bern, Switzerland. Financial support was provided by the U.S. National Science Foundation award numbers 1916565, EAR-2011439, and EAR-2012123. Additional support was provided by the Utah Department of Natural Resources Watershed Restoration Initiative. SSS was supported by Brigham Young University Graduate Studies. MS was supported by National Science Centre, Poland (grant no. 2018/31/B/ST10/02498 and 2021/41/B/ST10/00060). JCA was supported by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 101026211. PF contributed within the framework of the FCT-funded project no. UIDB/04033/2020. SGAF acknowledges support from Trond Mohn Stiftelse (TMS) and University of Bergen for the startup grant ‘TMS2022STG03’. JMP participation in this research was supported by the Forest Research Centre, a research unit funded by Fundação para a Ciência e a Tecnologia I.P. (FCT), Portugal (UIDB/00239/2020). A.-LD acknowledge PAGES, PICS CNRS 06484 project, CNRS-INSU, Région Nouvelle-Aquitaine, University of Bordeaux DRI and INQUA for workshop support.Background The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Results Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios. Conclusion The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.Peer reviewe