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2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Chiara I. Paleari ◽  
Florian Mekhaldi ◽  
Florian Adolphi ◽  
Marcus Christl ◽  
Christof Vockenhuber ◽  
...  

AbstractDuring solar storms, the Sun expels large amounts of energetic particles (SEP) that can react with the Earth’s atmospheric constituents and produce cosmogenic radionuclides such as 14C, 10Be and 36Cl. Here we present 10Be and 36Cl data measured in ice cores from Greenland and Antarctica. The data consistently show one of the largest 10Be and 36Cl production peaks detected so far, most likely produced by an extreme SEP event that hit Earth 9125 years BP (before present, i.e., before 1950 CE), i.e., 7176 BCE. Using the 36Cl/10Be ratio, we demonstrate that this event was characterized by a very hard energy spectrum and was possibly up to two orders of magnitude larger than any SEP event during the instrumental period. Furthermore, we provide 10Be-based evidence that, contrary to expectations, the SEP event occurred near a solar minimum.


2022 ◽  
Vol 3 (1) ◽  
Author(s):  
Bernhard Aichner ◽  
Bernd Wünnemann ◽  
Alice Callegaro ◽  
Marcel T. J. van der Meer ◽  
Dada Yan ◽  
...  

AbstractHigh-altitude ecosystems react sensitively to hydroclimatic triggers. Here we evaluated the ecological and hydrological changes in a glacier-influenced lake (Hala Hu, China) since the last glacial. Rapid fluctuations of aquatic biomarker concentrations, ratios, and hydrogen isotope values, from 15 to 14,000 and 8 to 5000 years before present, provided evidence for aquatic regime shifts and changes in lake hydrology. In contrast, most negative hydrogen isotope values of terrestrial biomarkers were observed between 9 and 7,000 years before present. This shows that shifts of vapour sources and increased precipitation amounts were not relevant drivers behind ecosystem changes in the studied lake. Instead, receding glaciers and increased meltwater discharge, driven by higher temperatures, caused the pronounced ecological responses. The shifts within phytoplankton communities in the Late Glacial and mid Holocene illustrate the vulnerability of comparable ecosystems to climatic and hydrological changes. This is relevant to assess future ecological responses to global warming.


Author(s):  
Anna Grenaderova ◽  
◽  
Pavel Mandryka ◽  
Wang Xiaokun ◽  
Polina Senotrusova ◽  
...  

The article presents the results of a comprehensive interdisciplinary analysis of archaeological and palaeoecological data. The aim of the study was to identify climatic changes in the habitat and their impact on the formation of the palaeoeconomics of the ancient population, on the expansion or reduction of the area of archaeological cultures with foraging and producing economy. Based on the analysis of palaeosignals obtained by a complex of methods (pollen, botanical analysis of peat, charcoal analysis, determination of the ash content of sediments), the following intervals of changing conditions were identified: 7400—6800 calibrated years before present (cal. BP) — humidity reduction, 4850—4400 cal. BP — an increase in humidity, 3850—3150 cal. BP — decrease in humidity, 3150—2000 cal. BP — stable humid, with 1600 cal. BP — moisture reduction, 1250—700 cal. BP — minimal moisture. Changes in conditions are consistent with changes in the boundaries of the subzone of the southern taiga and forest-steppe, as well as with the range of cultures of Siberian hunters, fishers, gatherers and pastoralists. The results can be projected over the entire Siberian region.


2021 ◽  
Author(s):  
Lars Opgenoorth ◽  
Georg Miehe ◽  
Joachim Schmidt

Ding et al. (Science 2020) proposed that the extant lineages of the alpine flora of the Tibet Himalaya Hengduan region emerged by the early Oligocene. We argue that these results are based on misclassifying high montane taxa as alpine and that their data support alpine habitats only at about 7.5 mio years before present.


2021 ◽  
Vol 121 (2) ◽  
pp. 78-89
Author(s):  
Ryan Shell ◽  
Kristin Zimmerman ◽  
David Peterman ◽  
Charles Ciampaglio ◽  
Lauren Fuelling ◽  
...  

Karst features in the Silurian dolomites of Taylorsville MetroPark (Dayton Metropolitan Area, Ohio, United States) were explored from 2017 to 2018 to identify sites of paleontological interest. Initial landscape surveys recovered 124 skeletal elements (from 12 sites) that were attributed to 17 vertebrate species—including evidence of such extirpated animals as bobcats (Lynx rufus) and rattlesnakes (Crotalus sp.). Of the 12 sites, 9 sites contained remains from the historical era and 3 sites contained much older remains (n = 17) that were radiocarbon dated to approximately 1,400 years before present (YBP). Human remains at one site, butchered bones at another, and artifacts from a third suggest a long period of pre-colonial human use of the area. The presence of rare taxa expands pre-historical species lists and confirms the coexistence of many previously undocumented taxa from the area during the late, pre-colonial, Holocene Epoch.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ting-Yong Li ◽  
Jonathan L. Baker ◽  
Tao Wang ◽  
Jian Zhang ◽  
Yao Wu ◽  
...  

AbstractRapid permafrost degradation and peatland expansion occurred in Eurasia during the Early Holocene and may be analogous to the region’s response to anthropogenic warming. Here we present a 230Th-dated, multiproxy speleothem record with subdecadal sampling resolution from Kyok-Tash Cave, at the modern permafrost margin in the northern Altai Mountains, southwestern Siberia. Stalagmite K4, covering the period 11,400 to 8,900 years before present, indicates an absence of stable permafrost within three centuries of the Younger Dryas termination. Between 11,400 and 10,400 years ago, speleothem δ18O is antiphased between the Altai and Ural ranges, suggesting a reorganization of the westerly wind systems that led to warmer and wetter winters over West Siberia and Altai, relative to the zonally adjacent regions of Northern Eurasia. At the same time, there is evidence of peak permafrost degradation and peatland expansion in West Siberia, consistent with the interpreted climate anomaly. Based on these findings, we suggest that modern permafrost in Eurasia is sensitive to feedbacks in the ocean-cryosphere system, which are projected to alter circulation regimes over the continent.


Hereditas ◽  
2021 ◽  
Vol 158 (1) ◽  
Author(s):  
Úlfur Árnason

Abstract Background The Out of Africa hypothesis, OOAH, was challenged recently in an extended mtDNA analysis, PPA (Progressive Phylogenetic Analysis), that identified the African human populations as paraphyletic, a finding that contradicted the common OOAH understanding that Hss had originated in Africa and invaded Eurasia from there. The results were consistent with the molecular Out of Eurasia hypothesis, OOEH, and Eurasian palaeontology, a subject that has been largely disregarded in the discussion of OOAH. Results In the present study the mtDNA tree, a phylogeny based on maternal inheritance, was compared to the nuclear DNA tree of the paternally transmitted Y-chromosome haplotypes, Y-DNAs. The comparison showed full phylogenetic coherence between these two separate sets of data. The results were consistent with potentially four translocations of modern humans from Eurasia into Africa, the earliest taking place ≈ 250,000 years before present, YBP. The results were in accordance with the postulates behind OOEH at the same time as they lent no support to the OOAH. Conclusions The conformity between the mtDNA and Y-DNA phylogenies of Hss is consistent with the understanding that Eurasia was the donor and not the receiver in human evolution. The evolutionary problems related to OOAH became similarly exposed by the mtDNA introgression that took place from Hss into Neanderthals ≈ 500,000 YBP, a circumstance that demonstrated the early coexistence of the two lineages in Eurasia.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0253708
Author(s):  
Saman Heydari-Guran ◽  
Stefano Benazzi ◽  
Sahra Talamo ◽  
Elham Ghasidian ◽  
Nemat Hariri ◽  
...  

Neanderthal extinction has been a matter of debate for many years. New discoveries, better chronologies and genomic evidence have done much to clarify some of the issues. This evidence suggests that Neanderthals became extinct around 40,000–37,000 years before present (BP), after a period of coexistence with Homo sapiens of several millennia, involving biological and cultural interactions between the two groups. However, the bulk of this evidence relates to Western Eurasia, and recent work in Central Asia and Siberia has shown that there is considerable local variation. Southwestern Asia, despite having a number of significant Neanderthal remains, has not played a major part in the debate over extinction. Here we report a Neanderthal deciduous canine from the site of Bawa Yawan in the West-Central Zagros Mountains of Iran. The tooth is associated with Zagros Mousterian lithics, and its context is preliminary dated to between ~43,600 and ~41,500 years ago.


2021 ◽  
Author(s):  
Jakub Dan Zarsky ◽  
Vojtech Zarsky ◽  
Martin Hanacek ◽  
Viktor Zarsky

For tens of millions of years (Ma) the terrestrial habitats of Snowball Earth during the Cryogenian period (between 720 to 635 Ma before present - Neoproterozoic Era) were possibly dominated by global snow and ice cover up to the equatorial sublimative desert. The most recent time-calibrated phylogenies calibrated not only on plants, but on a comprehensive set of eukaryotes, indicate within the Streptophyta, multicellular Charophyceae evolved in Mesoproterozoic to early Neoproterozoic, while Cryogenian is the time of likely Anydrophyta origin (common ancestor of Zygnematophyceae and Embryophyta) and also of Zygnematophyceae – Embryophyta split. Based on the combination of published phylogenomic studies and estimated diversification time comparisons we found strong support for the possibility Anydrophyta likely evolved in response to Cryogenian cooling, and that later in Cryogenian secondary simplification of multicellular Anydrophytes resulted in Zygnematophyceae diversification. We propose Marinoan geochemically documented expansion of first terrestrial flora has been represented not only by Chlorophyta, but also by Streptophyta – including the Anydrophyta – and later by Zygnematophyceae, thriving on glacial surfaces until today. It is possible multicellular early Embryophytes survived in less abundant, possibly relatively warmer refugia, relying more on mineral substrates allowing retention of flagella-based sexuality. Loss of flagella and sexual reproduction by conjugation evolved in Zygnematophyceae during Cryogenian in a remarkable convergent way as in Cryogenian-appearing zygomycetous fungi. We thus support the concept of the important basal cellular exaptations to terrestrial environments evolved in streptophyte algae and propose this was stimulated by the adaptation to glacial habitats dominating the Cryogenian Snowball Earth. Including the glacial lifestyle in the picture of the rise of land plants increases the parsimony of connecting different ecological, phylogenetic and physiological puzzles of the journey from aquatic algae to the terrestrial floras.


2021 ◽  
Vol 117 (5/6) ◽  
Author(s):  
Yoel Rak ◽  
Eli Geffen ◽  
William Hylander ◽  
Avishag Ginzburg ◽  
Ella Ginzburg

A report on the skeletons of two individuals from the Malapa cave site in South Africa attributes them both to a new hominin species, Australopithecus sediba. However, our analysis of the specimens’ mandibles indicates that Australopithecus sediba is not a ‘Homo-like australopith’, a transitional species between Australopithecus africanus and Homo. According to our results, the specimens represent two separate genera: Australopithecus and Homo. These genera are known to have jointly occupied sites, as seen in several early South African caves, so one cannot rule out the possibility that Malapa also contains remains of the two taxa. Our results lead us to additionally conclude that all the Australopithecus species on which the relevant mandibular anatomy is preserved (not only the ‘robust’ australopiths but also the ‘gracile’ – more generalised – ones) are too specialised to constitute an evolutionary ancestor of Homo sapiens. Furthermore, given that the Malapa site contains representatives of two hominin branches, one of which appears to be Homo, we must seek evidence of our origins much earlier than the date assigned to Malapa, approximately 2 million years before present. Support for this claim can be found in Ethiopian fossils attributed to the genus Homo and dated at 2.4 and 2.8 million years before present.


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