160 results match your criteria majority earth's

Novel Microbial Groups Drive Productivity in an Archean Iron Formation.

Front Microbiol 2021 30;12:627595. Epub 2021 Mar 30.

Department of Earth and Environmental Sciences, University of Minnesota Twin Cities, Minneapolis, MN, United States.

Deep subsurface environments are decoupled from Earth's surface processes yet diverse, active, and abundant microbial communities thrive in these isolated environments. Microbes inhabiting the deep biosphere face unique challenges such as electron donor/acceptor limitations, pore space/fracture network limitations, and isolation from other microbes within the formation. Of the few systems that have been characterized, it is apparent that nutrient limitations likely facilitate diverse microbe-microbe interactions (i. Read More

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Earth's carbon deficit caused by early loss through irreversible sublimation.

Sci Adv 2021 Apr 2;7(14). Epub 2021 Apr 2.

Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.

Carbon is an essential element for life, but its behavior during Earth's accretion is not well understood. Carbonaceous grains in meteoritic and cometary materials suggest that irreversible sublimation, and not condensation, governs carbon acquisition by terrestrial worlds. Through astronomical observations and modeling, we show that the sublimation front of carbon carriers in the solar nebula, or the soot line, moved inward quickly so that carbon-rich ingredients would be available for accretion at 1 astronomical unit after the first million years. Read More

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Dispersal syndromes drive the formation of biogeographical regions, illustrated by the case of Wallace's Line.

Glob Ecol Biogeogr 2021 Mar 6;30(3):685-696. Epub 2021 Jan 6.

Department of Ecology and Evolution University of Chicago Chicago IL USA.

Aim: Biogeographical regions (realms) reflect patterns of co-distributed species (biotas) across space. Their boundaries are set by dispersal barriers and difficulties of establishment in new locations. We extend new methods to assess these two contributions by quantifying the degree to which realms intergrade across geographical space and the contributions of individual species to the delineation of those realms. Read More

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Heterogeneous Hadean crust with ambient mantle affinity recorded in detrital zircons of the Green Sandstone Bed, South Africa.

Proc Natl Acad Sci U S A 2021 Feb;118(8)

Department of Geological Sciences, Stanford University, Stanford, CA 94305.

The nature of Earth's earliest crust and the processes by which it formed remain major issues in Precambrian geology. Due to the absence of a rock record older than ∼4.02 Ga, the only direct record of the Hadean is from rare detrital zircon and that largely from a single area: the Jack Hills and Mount Narryer region of Western Australia. Read More

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February 2021

In search of the RNA world on Mars.

Geobiology 2021 05 10;19(3):307-321. Epub 2021 Feb 10.

Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.

Advances in origins of life research and prebiotic chemistry suggest that life as we know it may have emerged from an earlier RNA World. However, it has been difficult to reconcile the conditions used in laboratory experiments with real-world geochemical environments that may have existed on the early Earth and hosted the origin(s) of life. This challenge is due to geologic resurfacing and recycling that have erased the overwhelming majority of the Earth's prebiotic history. Read More

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Physical Determinants of Vitamin D Photosynthesis: A Review.

JBMR Plus 2021 Jan 19;5(1):e10460. Epub 2021 Jan 19.

St John's Institute of Dermatology, School of Basic & Medical Biosciences King's College London London United Kingdom.

Vitamin D synthesis by exposure of skin to solar ultraviolet radiation (UVR) provides the majority of this hormone that is essential for bone development and maintenance but may be important for many other health outcomes. This process, which is the only well-established benefit of solar UVR exposure, depends on many factors including genetics, age, health, and behavior. However, the most important factor is the quantity and quality of UVR reaching the skin. Read More

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January 2021

Nickel isotopic evidence for late-stage accretion of Mercury-like differentiated planetary embryos.

Nat Commun 2021 01 12;12(1):294. Epub 2021 Jan 12.

State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China.

Earth's habitability is closely tied to its late-stage accretion, during which impactors delivered the majority of life-essential volatiles. However, the nature of these final building blocks remains poorly constrained. Nickel (Ni) can be a useful tracer in characterizing this accretion as most Ni in the bulk silicate Earth (BSE) comes from the late-stage impactors. Read More

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January 2021

Tropical peatlands and their contribution to the global carbon cycle and climate change.

Glob Chang Biol 2021 Feb 4;27(3):489-505. Epub 2020 Dec 4.

Earth System Science Center (CCST), National Institute for Space Research (INPE), São Paulo, Brazil.

Peatlands are carbon-rich ecosystems that cover 185-423 million hectares (Mha) of the earth's surface. The majority of the world's peatlands are in temperate and boreal zones, whereas tropical ones cover only a total area of 90-170 Mha. However, there are still considerable uncertainties in C stock estimates as well as a lack of information about depth, bulk density and carbon accumulation rates. Read More

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February 2021

Bows and arrows and complex symbolic displays 48,000 years ago in the South Asian tropics.

Sci Adv 2020 Jun 12;6(24):eaba3831. Epub 2020 Jun 12.

Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany.

Archaeologists contend that it was our aptitude for symbolic, technological, and social behaviors that was central to rapidly expanding across the majority of Earth's continents during the Late Pleistocene. This expansion included movement into extreme environments and appears to have resulted in the displacement of numerous archaic human populations across the Old World. Tropical rainforests are thought to have been particularly challenging and, until recently, impenetrable by early . Read More

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Three-dimensional solvation structure of ethanol on carbonate minerals.

Beilstein J Nanotechnol 2020 10;11:891-898. Epub 2020 Jun 10.

Physical Chemistry I, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.

Calcite and magnesite are important mineral constituents of the earth's crust. In aqueous environments, these carbonates typically expose their most stable cleavage plane, the (10.4) surface. Read More

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Identification of chondritic krypton and xenon in Yellowstone gases and the timing of terrestrial volatile accretion.

Proc Natl Acad Sci U S A 2020 06 8;117(25):13997-14004. Epub 2020 Jun 8.

Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS-Université de Lorraine, BP 20, F-54501 Vandoeuvre-lès-Nancy, France.

Identifying the origin of noble gases in Earth's mantle can provide crucial constraints on the source and timing of volatile (C, N, HO, noble gases, etc.) delivery to Earth. It remains unclear whether the early Earth was able to directly capture and retain volatiles throughout accretion or whether it accreted anhydrously and subsequently acquired volatiles through later additions of chondritic material. Read More

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Global human influence maps reveal clear opportunities in conserving Earth's remaining intact terrestrial ecosystems.

Glob Chang Biol 2020 08 5;26(8):4344-4356. Epub 2020 Jun 5.

National Geographic Society, Washington, DC, USA.

Leading up to the Convention on Biological Diversity Conference of the Parties 15, there is momentum around setting bold conservation targets. Yet, it remains unclear how much of Earth's land area remains without significant human influence and where this land is located. We compare four recent global maps of human influences across Earth's land, Anthromes, Global Human Modification, Human Footprint and Low Impact Areas, to answer these questions. Read More

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Strong hydrogen bonding in a dense hydrous magnesium silicate discovered by neutron Laue diffraction.

IUCrJ 2020 May 2;7(Pt 3):370-374. Epub 2020 Apr 2.

Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Tennesee, TN 37831, USA.

A large amount of hydrogen circulates inside the Earth, which affects the long-term evolution of the planet. The majority of this hydrogen is stored in deep Earth within the crystal structures of dense minerals that are thermodynamically stable at high pressures and temperatures. To understand the reason for their stability under such extreme conditions, the chemical bonding geometry and cation exchange mechanism for including hydrogen were analyzed in a representative structure of such minerals ( phase E of dense hydrous magnesium silicate) by using time-of-flight single-crystal neutron Laue diffraction. Read More

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NASA's first ground-based Galactic Cosmic Ray Simulator: Enabling a new era in space radiobiology research.

PLoS Biol 2020 05 19;18(5):e3000669. Epub 2020 May 19.

Brookhaven National Laboratory, Brookhaven, New York, United States of America.

With exciting new NASA plans for a sustainable return to the moon, astronauts will once again leave Earth's protective magnetosphere only to endure higher levels of radiation from galactic cosmic radiation (GCR) and the possibility of a large solar particle event (SPE). Gateway, lunar landers, and surface habitats will be designed to protect crew against SPEs with vehicle optimization, storm shelter concepts, and/or active dosimetry; however, the ever penetrating GCR will continue to pose the most significant health risks especially as lunar missions increase in duration and as NASA sets its aspirations on Mars. The primary risks of concern include carcinogenesis, central nervous system (CNS) effects resulting in potential in-mission cognitive or behavioral impairment and/or late neurological disorders, degenerative tissue effects including circulatory and heart disease, as well as potential immune system decrements impacting multiple aspects of crew health. Read More

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Quantitative High-Resolution Imaging of Live Microbial Cells at High Hydrostatic Pressure.

Biophys J 2020 06 23;118(11):2670-2679. Epub 2020 Apr 23.

Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York. Electronic address:

The majority of the Earth's microbial biomass exists in the deep biosphere, in the deep ocean, and within the Earth's crust. Although other physical parameters in these environments, such as temperature or pH, can differ substantially, they are all under high pressures. Beyond emerging genomic information, little is known about the molecular mechanisms underlying the ability of these organisms to survive and grow at pressures that can reach over 1000-fold the pressure on the Earth's surface. Read More

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Distinct assembly mechanisms underlie similar biogeographical patterns of rare and abundant bacteria in Tibetan Plateau grassland soils.

Environ Microbiol 2020 06 2;22(6):2261-2272. Epub 2020 Apr 2.

School of Biotechnology and Biomolecular Sciences, Australian Centre for Astrobiology, UNSW Sydney, Randwick, NSW, 2052, Australia.

Rare biosphere represents the majority of Earth's biodiversity and performs vital ecological functions, yet little is known about its biogeographical patterns and community assembly processes in terrestrial ecosystems. Herein, we investigated the community composition and phylogeny of rare (relative abundance <0.1%) and abundant (>1%) bacteria in dryland grassland soils on the Tibetan Plateau. Read More

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The Impact of Molecular Oxygen on Anion Composition in a Hazy Archean Earth Atmosphere.

Astrobiology 2020 05 10;20(5):658-669. Epub 2020 Mar 10.

Department of Chemistry, University of Colorado, Boulder, Colorado.

Atmospheric organic hazes are common in planetary bodies in our solar system and likely exoplanet atmospheres as well. In addition, geochemical data support the existence of an organic haze in the early Earth's atmosphere. Much of what is known about organic haze formation derives from studies of Saturn's moon Titan. Read More

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Renewable energy development threatens many globally important biodiversity areas.

Glob Chang Biol 2020 05 25;26(5):3040-3051. Epub 2020 Mar 25.

Centre for Biodiversity and Conservation Science (CBCS), The University of Queensland, St Lucia, Qld, Australia.

Transitioning from fossil fuels to renewable energy is fundamental for halting anthropogenic climate change. However, renewable energy facilities can be land-use intensive and impact conservation areas, and little attention has been given to whether the aggregated effect of energy transitions poses a substantial threat to global biodiversity. Here, we assess the extent of current and likely future renewable energy infrastructure associated with onshore wind, hydropower and solar photovoltaic generation, within three important conservation areas: protected areas (PAs), Key Biodiversity Areas (KBAs) and Earth's remaining wilderness. Read More

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Socialising over fruits and vegetables: the biocultural importance of an open-air market in Bandar Seri Begawan, Brunei Darussalam.

J Ethnobiol Ethnomed 2020 Jan 31;16(1). Epub 2020 Jan 31.

Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE1410, Brunei Darussalam.

Background: Earth's biocultural diversity comprising biological, cultural and linguistic diversities is being eroded quickly. Our ability to recognise and appreciate what is remaining is crucial for its survival. However, not all forms of diversity are appreciated equally and a growing trend in plant blindness indicates that humans ignore plants in the environment. Read More

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January 2020

The Clock Keeps Ticking: Circadian Rhythms of Free-Ranging Polar Bears.

J Biol Rhythms 2020 04 24;35(2):180-194. Epub 2020 Jan 24.

Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, USA.

Life in the Arctic presents organisms with multiple challenges, including extreme photic conditions, cold temperatures, and annual loss and daily movement of sea ice. Polar bears () evolved under these unique conditions, where they rely on ice to hunt their main prey, seals. However, very little is known about the dynamics of their daily and seasonal activity patterns. Read More

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Microbial Life in Impact Craters.

Curr Issues Mol Biol 2020 22;38:75-102. Epub 2020 Jan 22.

School of Geosciences, University of Aberdeen, King's College, Aberdeen, AB24 3FX, UK.

Asteroid and comet impacts are known to have caused profound disruption to multicellular life, yet their influence on habitats for microorganisms, which comprise the majority of Earth's biomass, is less well understood. Of particular interest are geological changes in the target lithology at and near the point of impact that can persist for billions of years. Deep subsurface and surface-dwelling microorganisms are shown to gain advantages from impact-induced fracturing of rocks. Read More

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October 2020

Altered levels of AOX1a expression result in changes in metabolic pathways in Arabidopsis thaliana plants acclimated to low dose rates of ultraviolet B radiation.

Plant Sci 2020 Feb 6;291:110332. Epub 2019 Nov 6.

Institute of Biology, Komi Scientific Centre, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.

UV-B is a damaging component of solar radiation that inevitably reaches the Earth's surface. Plants have developed response mechanisms to adapt to UVB exposure. The alternative oxidase (AOX) catalyzes the ATP-uncoupling cyanide-resistant alternative pathway (AP) in plant mitochondria and is thought to be an important part of the cellular defense network under stress conditions. Read More

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February 2020

Exploring cycad foliage as an archive of the isotopic composition of atmospheric nitrogen.

Geobiology 2020 03 26;18(2):152-166. Epub 2019 Nov 26.

Department of Earth & Space Sciences, University of Washington, Seattle, WA, USA.

Molecular nitrogen (N ) constitutes the majority of Earth's modern atmosphere, contributing ~0.79 bar of partial pressure (pN ). However, fluctuations in pN may have occurred on 10 -10  year timescales in Earth's past, perhaps altering the isotopic composition of atmospheric nitrogen. Read More

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Host-associated microbiomes drive structure and function of marine ecosystems.

PLoS Biol 2019 11 11;17(11):e3000533. Epub 2019 Nov 11.

Genome and Biomedical Sciences Facility, University of California, Davis, Davis, California, United States of America.

The significance of symbioses between eukaryotic hosts and microbes extends from the organismal to the ecosystem level and underpins the health of Earth's most threatened marine ecosystems. Despite rapid growth in research on host-associated microbes, from individual microbial symbionts to host-associated consortia of significantly relevant taxa, little is known about their interactions with the vast majority of marine host species. We outline research priorities to strengthen our current knowledge of host-microbiome interactions and how they shape marine ecosystems. Read More

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November 2019

Fine-Scale Biogeography and the Inference of Ecological Interactions Among Neutrophilic Iron-Oxidizing Zetaproteobacteria as Determined by a Rule-Based Microbial Network.

Front Microbiol 2019 25;10:2389. Epub 2019 Oct 25.

Department of Biology, College of Charleston, Charleston, SC, United States.

Hydrothermal vents, such as those at Lō'ihi Seamount and the Mariana Arc and back-arc, release iron required to support life from the Earth's crust. In these ecosystems, bacteria and archaea can oxidize the released iron and therefore play an important role in the biogeochemical cycles of essential nutrients. These organisms often form microbial mats, and the primary producers in these communities can support diverse higher trophic levels. Read More

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October 2019

A horizon scan of priorities for coastal marine microbiome research.

Nat Ecol Evol 2019 11 21;3(11):1509-1520. Epub 2019 Oct 21.

Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia.

Research into the microbiomes of natural environments is changing the way ecologists and evolutionary biologists view the importance of microorganisms in ecosystem function. This is particularly relevant in ocean environments, where microorganisms constitute the majority of biomass and control most of the major biogeochemical cycles, including those that regulate Earth's climate. Coastal marine environments provide goods and services that are imperative to human survival and well-being (for example, fisheries and water purification), and emerging evidence indicates that these ecosystem services often depend on complex relationships between communities of microorganisms (the 'microbiome') and the environment or their hosts - termed the 'holobiont'. Read More

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November 2019

Diamond-inclusion system recording old deep lithosphere conditions at Udachnaya (Siberia).

Sci Rep 2019 Aug 29;9(1):12586. Epub 2019 Aug 29.

School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.

Diamonds and their inclusions are unique fragments of deep Earth, which provide rare samples from inaccessible portions of our planet. Inclusion-free diamonds cannot provide information on depth of formation, which could be crucial to understand how the carbon cycle operated in the past. Inclusions in diamonds, which remain uncorrupted over geological times, may instead provide direct records of deep Earth's evolution. Read More

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A paleosol record of the evolution of Cr redox cycling and evidence for an increase in atmospheric oxygen during the Neoproterozoic.

Geobiology 2019 11 22;17(6):579-593. Epub 2019 Aug 22.

Department of Geology and Geophysics, Yale University, New Haven, CT, USA.

Atmospheric oxygen levels control the oxidative side of key biogeochemical cycles and place limits on the development of high-energy metabolisms. Understanding Earth's oxygenation is thus critical to developing a clearer picture of Earth's long-term evolution. However, there is currently vigorous debate about even basic aspects of the timing and pattern of the rise of oxygen. Read More

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November 2019

Evaluation of potential environmental benefits from seawater toilet flushing.

Water Res 2019 Oct 9;162:505-515. Epub 2019 Jul 9.

Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China; Water Technology Center, Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Water scarcity has become a global issue that has forced many communities to seek alternative water resources. The majority of water on the earth's surface comes from the sea. Seawater has the potential to mitigate water stress after proper treatment. Read More

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October 2019

Emerging investigator series: spatial distribution of dissolved organic matter in ice and at air-ice interfaces.

Environ Sci Process Impacts 2019 Jul;21(7):1076-1084

Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. and Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.

Dissolved organic matter (DOM) is a common solute in snow and ice at Earth's surface. Its effects on reaction kinetics in ice and at air-ice interfaces can be large, but are currently difficult to quantify. We used Raman microscopy to characterize the surface and bulk of frozen aqueous solutions containing humic acid, sodium dodecyl sulfate (SDS), and citric acid at a range of concentrations and temperatures. Read More

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