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https://www.readbyqxmd.com/read/28704453/historical-%C3%AE-15n-records-of-saccharina-specimens-from-oligotrophic-waters-of-japan-sea-hokkaido
#1
Takanori Kuribayashi, Tsuyoshi Abe, Shigeru Montani
Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea)...
2017: PloS One
https://www.readbyqxmd.com/read/28698659/abrupt-emergence-of-a-large-pockmark-field-in-the-german-bight-southeastern-north-sea
#2
Knut Krämer, Peter Holler, Gabriel Herbst, Alexander Bratek, Soeren Ahmerkamp, Andreas Neumann, Alexander Bartholomä, Justus E E van Beusekom, Moritz Holtappels, Christian Winter
A series of multibeam bathymetry surveys revealed the emergence of a large pockmark field in the southeastern North Sea. Covering an area of around 915 km(2), up to 1,200 pockmarks per square kilometer have been identified. The time of emergence can be confined to 3 months in autumn 2015, suggesting a very dynamic genesis. The gas source and the trigger for the simultaneous outbreak remain speculative. Subseafloor structures and high methane concentrations of up to 30 μmol/l in sediment pore water samples suggest a source of shallow biogenic methane from the decomposition of postglacial deposits in a paleo river valley...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28696425/microbial-survival-strategies-in-ancient-permafrost-insights-from-metagenomics
#3
Rachel Mackelprang, Alexander Burkert, Monica Haw, Tara Mahendrarajah, Christopher H Conaway, Thomas A Douglas, Mark P Waldrop
In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in permafrost tens of thousands of years old but we know little about the metabolic and physiological adaptations to the challenges presented by life in frozen ground over geologic time. In this study we asked whether increasing age and the associated stressors drive adaptive changes in community composition and function. We conducted deep metagenomic and 16 S rRNA gene sequencing across a Pleistocene permafrost chronosequence from 19 000 to 33 000 years before present (kyr)...
July 11, 2017: ISME Journal
https://www.readbyqxmd.com/read/28696409/a-global-multiproxy-database-for-temperature-reconstructions-of-the-common-era
#4
(no author information available yet)
Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial...
July 11, 2017: Scientific Data
https://www.readbyqxmd.com/read/28681844/sea-level-fall-during-glaciation-stabilized-atmospheric-co2-by-enhanced-volcanic-degassing
#5
Jörg Hasenclever, Gregor Knorr, Lars H Rüpke, Peter Köhler, Jason Morgan, Kristin Garofalo, Stephen Barker, Gerrit Lohmann, Ian R Hall
Paleo-climate records and geodynamic modelling indicate the existence of complex interactions between glacial sea level changes, volcanic degassing and atmospheric CO2, which may have modulated the climate system's descent into the last ice age. Between ∼85 and 70 kyr ago, during an interval of decreasing axial tilt, the orbital component in global temperature records gradually declined, while atmospheric CO2, instead of continuing its long-term correlation with Antarctic temperature, remained relatively stable...
July 6, 2017: Nature Communications
https://www.readbyqxmd.com/read/28641809/re-emerging-infectious-diseases-from-the-past-hysteria-or-real-risk
#6
Charlier Philippe, Claverie Jean-Michel, Sansonetti Philippe, Coppens Yves, Augias Anaïs, Jacqueline Sophie, Rengot Fanny, Deo Saudamini
BACKGROUND: Work on human remains and old biological samples is a potential source of contamination by conventional or atypical infectious agents. Similarly, current and future environmental changes are a source of resurgence of ancient epidemic diseases. To what extent are anthropologists sorcerer apprentices (especially those working on ancient samples, i.e. paleo-anthropologists)? Are ancient skeletons, palaeosols and museum objects with a biological component at risk for current populations? Unless there are unfounded fears and undue risk… What can be learned from the recent scientific literature and the common sense of the researchers? METHODS: We have attempted to compile data from the literature and from our personal experience in the fields of anthropology, clinical medicine and epidemiology, in order to grasp the reality of the risk to the human population...
June 19, 2017: European Journal of Internal Medicine
https://www.readbyqxmd.com/read/28616163/a-genomic-assessment-of-species-boundaries-and-hybridization-in-a-group-of-highly-polymorphic-anoles-distichus-species-complex
#7
Daniel J MacGuigan, Anthony J Geneva, Richard E Glor
Delimiting young species is one of the great challenges of systematic biology, particularly when the species in question exhibit little morphological divergence. Anolis distichus, a trunk anole with more than a dozen subspecies that are defined primarily by dewlap color, may actually represent several independent evolutionary lineages. To test this, we utilized amplified fragment length polymorphisms (AFLP) genome scans and genetic clustering analyses in conjunction with a coalescent-based species delimitation method...
June 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28607415/molecular-phylogenies-indicate-a-paleo-tibetan-origin-of-himalayan-lazy-toads-scutiger
#8
Sylvia Hofmann, Matthias Stöck, Yuchi Zheng, Francesco G Ficetola, Jia-Tang Li, Ulrich Scheidt, Joachim Schmidt
The Himalaya presents an outstanding geologically active orogen and biodiversity hotspot. However, our understanding of the historical biogeography of its fauna is far from comprehensive. Many taxa are commonly assumed to have originated from China-Indochina and dispersed westward along the Himalayan chain. Alternatively, the "Tibetan-origin hypothesis" suggests primary diversification of lineages in Paleo-Tibet, and secondary diversification along the slopes of the later uplifted Greater Himalaya. We test these hypotheses in high-mountain megophryid anurans (Scutiger)...
June 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28607045/mio-pliocene-aridity-in-the-south-central-andes-associated-with-southern-hemisphere-cold-periods
#9
William H Amidon, G Burch Fisher, Douglas W Burbank, Patricia L Ciccioli, Ricardo N Alonso, Andrew L Gorin, Perri H Silverhart, Andrew R C Kylander-Clark, Michael S Christoffersen
Although Earth's climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2-5.5 Ma and with the Messinian Salinity Crisis from ∼6.0-5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear...
June 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28603673/a-methodology-of-theropod-print-replication-utilising-the-pedal-reconstruction-of-australovenator-and-a-simulated-paleo-sediment
#10
Matt A White, Alex G Cook, Steven J Rumbold
Distinguishing the difference between theropod and ornithopod footprints has proved a difficult task due to their similarities. Herein our aim was to produce a method where a skeleton could be more closely matched to actual fossilised footprints. The reconstructed pes of the Australian Megaraptoran Australovenator wintonensis was utilised for this footprint reconstruction. It was 3-D printed in life size, molded and cast to produce a flexible theropod foot for footprint creation. The Dinosaur Stampede National Monument, Lark Quarry, Queensland, Australia was used as our case study to compare fossilised dinosaur footprints with our reconstructed theropod prints...
2017: PeerJ
https://www.readbyqxmd.com/read/28598413/anthropogenic-climate-change-has-altered-primary-productivity-in-lake-superior
#11
M D O'Beirne, J P Werne, R E Hecky, T C Johnson, S Katsev, E D Reavie
Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production...
June 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28585926/a-monthly-global-paleo-reanalysis-of-the-atmosphere-from-1600-to-2005-for-studying-past-climatic-variations
#12
Jörg Franke, Stefan Brönnimann, Jonas Bhend, Yuri Brugnara
Climatic variations at decadal scales such as phases of accelerated warming or weak monsoons have profound effects on society and economy. Studying these variations requires insights from the past. However, most current reconstructions provide either time series or fields of regional surface climate, which limit our understanding of the underlying dynamics. Here, we present the first monthly paleo-reanalysis covering the period 1600 to 2005. Over land, instrumental temperature and surface pressure observations, temperature indices derived from historical documents and climate sensitive tree-ring measurements were assimilated into an atmospheric general circulation model ensemble using a Kalman filtering technique...
June 6, 2017: Scientific Data
https://www.readbyqxmd.com/read/28585365/tracking-a-century-of-changes-in-microbial-eukaryotic-diversity-in-lakes-driven-by-nutrient-enrichment-and-climate-warming
#13
Eric Capo, Didier Debroas, Fabien Arnaud, Marie-Elodie Perga, Cécile Chardon, Isabelle Domaizon
High-throughput sequencing of sedimentary DNA (sed-DNA) was utilized to reconstruct the temporal dynamics of microbial eukaryotic communities (MECs) at a centennial scale in two re-oligotrophicated lakes that were exposed to different levels of phosphorus enrichment. The temporal changes within the MECs were expressed in terms of richness, composition and community structure to investigate their relationships with two key forcing factors (i.e., nutrient enrichment and climate warming). Various groups, including Apicomplexa, Cercozoa, Chrysophyceae, Ciliophora, Chlorophyceae and Dinophyceae, responded to phosphorus enrichment levels with either positive or negative impacts on their richness and relative abundance...
June 5, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28582571/the-role-of-rubisco-kinetics-and-pyrenoid-morphology-in-shaping-the-ccm-of-haptophyte-microalgae
#14
Ana M C Heureux, Jodi N Young, Spencer M Whitney, Maeve R Eason-Hubbard, Renee B Y Lee, Robert E Sharwood, Rosalind E M Rickaby
The haptophyte algae are a cosmopolitan group of primary producers that contribute significantly to the marine carbon cycle and play a major role in paleo-climate studies. Despite their global importance, little is known about carbon assimilation in haptophytes, in particular the kinetics of their Form 1D CO2-fixing enzyme, Rubisco. Here we examine Rubisco properties of three haptophytes with a range of pyrenoid morphologies (Pleurochrysis carterae, Tisochrysis lutea, and Pavlova lutheri) and the diatom Phaeodactylum tricornutum that exhibit contrasting sensitivities to the trade-offs between substrate affinity (Km) and turnover rate (kcat) for both CO2 and O2...
June 3, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28582394/new-insight-into-hybridization-and-unidirectional-introgression-between-ammodytes-japonicus-and-ammodytes-heian-trachiniformes-ammodytidae
#15
Jin-Koo Kim, Seung Eun Bae, Soo Jeong Lee, Moon Geun Yoon
Based on northern (NOL) and southern (SOL) mitochondrial lineages, recently, it proposed the new species Ammodytes heian and revived the species name Ammodytes japonicus to describe sand lances from the northwestern Pacific Ocean. This study used molecular methods to investigate genetic relationships between the two sand lance species in Korea and Japan. In total, 154 specimens were collected from four locations in Korea (Baengnyeongdo in the Yellow Sea, Tongyeong in the Korean Strait, and Jumunjin and Gijang in the East Sea), and 50 specimens were collected from a single location in Japan (Wakkanai in the Okhotsk Sea)...
2017: PloS One
https://www.readbyqxmd.com/read/28566740/quaternary-fluvial-terraces-of-the-tiber-valley-geochronologic-and-geometric-constraints-on-the-back-arc-magmatism-related-uplift-in-central-italy
#16
Fabrizio Marra, Fabio Florindo, Carmelo Petronio
Through a geomorphological study relying on statistically assessed classes of hilltop elevations, we reconstruct a suite of paleo-surfaces along the Tiber River Valley north of Rome that we identify as fluvial terraces formed by interplay between global sea-level fluctuations and regional upift. Using biostratigraphic constraints provided by marine through continental deposits of Santernian age, we recognize the oldest terrace in this area, corresponding to an early coastal plain of late Santernian-Emilian age...
May 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28559352/tropical-cyclone-activity-enhanced-by-sahara-greening-and-reduced-dust-emissions-during-the-african-humid-period
#17
Francesco S R Pausata, Kerry A Emanuel, Marc Chiacchio, Gulilat T Diro, Qiong Zhang, Laxmi Sushama, J Curt Stager, Jeffrey P Donnelly
Tropical cyclones (TCs) can have devastating socioeconomic impacts. Understanding the nature and causes of their variability is of paramount importance for society. However, historical records of TCs are too short to fully characterize such changes and paleo-sediment archives of Holocene TC activity are temporally and geographically sparse. Thus, it is of interest to apply physical modeling to understanding TC variability under different climate conditions. Here we investigate global TC activity during a warm climate state (mid-Holocene, 6,000 yBP) characterized by increased boreal summer insolation, a vegetated Sahara, and reduced dust emissions...
June 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28555637/sea-level-records-from-the-u-s-mid-atlantic-constrain-laurentide-ice-sheet-extent-during-marine-isotope-stage-3
#18
T Pico, J R Creveling, J X Mitrovica
The U.S. mid-Atlantic sea-level record is sensitive to the history of the Laurentide Ice Sheet as the coastline lies along the ice sheet's peripheral bulge. However, paleo sea-level markers on the present-day shoreline of Virginia and North Carolina dated to Marine Isotope Stage (MIS) 3, from 50 to 35 ka, are surprisingly high for this glacial interval, and remain unexplained by previous models of ice age adjustment or other local (for example, tectonic) effects. Here, we reconcile this sea-level record using a revised model of glacial isostatic adjustment characterized by a peak global mean sea level during MIS 3 of approximately -40 m, and far less ice volume within the eastern sector of the Laurentide Ice Sheet than traditional reconstructions for this interval...
May 30, 2017: Nature Communications
https://www.readbyqxmd.com/read/28522869/ancient-river-inference-explains-exceptional-oriental-freshwater-mussel-radiations
#19
Ivan N Bolotov, Alexander V Kondakov, Ilya V Vikhrev, Olga V Aksenova, Yulia V Bespalaya, Mikhail Yu Gofarov, Yulia S Kolosova, Ekaterina S Konopleva, Vitaly M Spitsyn, Kitti Tanmuangpak, Sakboworn Tumpeesuwan
The concept of long-lived (ancient) lakes has had a great influence on the development of evolutionary biogeography. According to this insight, a number of lakes on Earth have existed for several million years (e.g., Baikal and Tanganyika) and represent unique evolutionary hotspots with multiple intra-basin radiations. In contrast, rivers are usually considered to be variable systems, and the possibility of their long-term existence during geological epochs has never been tested. In this study, we reconstruct the history of freshwater basin interactions across continents based on the multi-locus fossil-calibrated phylogeny of freshwater mussels (Unionidae)...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28516958/the-origin-and-degassing-history-of-the-earth-s-atmosphere-revealed-by-archean-xenon
#20
Guillaume Avice, Bernard Marty, Ray Burgess
Xenon (Xe) is an exceptional tracer for investigating the origin and fate of volatile elements on Earth. The initial isotopic composition of atmospheric Xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. Here we present high precision analyses of noble gases trapped in fluid inclusions of Archean quartz (Barberton, South Africa) that reveal the isotopic composition of the paleo-atmosphere at ≈3.3 Ga. The Archean atmospheric Xe is mass-dependently fractionated by 12...
May 18, 2017: Nature Communications
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