1,028 results match your criteria earth's history

Determination of Vanadium Isotope Compositions in Carbonates Using an Fe Coprecipitation Method and MC-ICP-MS.

Anal Chem 2021 May 7. Epub 2021 May 7.

CAS Key Laboratory of Mantel Materials and Environments, School of Earth and Space Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, People's Republic of China.

Vanadium isotope compositions (δ(V)) in marine carbonates are a potential proxy to trace global redox states of ancient oceans. Although high-precision δ(V) analyses are available for many geological materials, carbonate-hosted δ(V) data have not been reported yet due to extremely high matrix elements and low V contents (generally below 10 μg g). In this study, we developed an Fe coprecipitation method combined with an Fe column to preconcentrate V from the major matrix elements and subsequent four-step chromatographic procedures to further purify V in carbonates. Read More

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Threatened Neotropical seasonally dry tropical forest: evidence of biodiversity loss in sap-sucking herbivores over 75 years.

R Soc Open Sci 2021 Mar 10;8(3):201370. Epub 2021 Mar 10.

Departamento de Botánica y Zoología, CUCBA, Universidad de Guadalajara, Km 15.5 carretera Guadalajara-Nogales, Camino Ramón Padilla Sánchez No. 2100, C.P. 45200, Apdo. Postal 139, Las Agujas, Zapopan, Jalisco, Mexico.

Tropical forests cover 7% of the earth's surface and hold 50% of known terrestrial arthropod species. Alarming insect declines resulting from human activities have recently been documented in temperate and tropical ecosystems worldwide, but reliable data from tropical forests remain sparse. The sap-sucking tribe Athysanini is one herbivore group sensitive to anthropogenic perturbation and the largest within the diverse insect family Cicadellidae distributed in America's tropical forests. Read More

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Dubiofossils from a Mars-analogue subsurface palaeoenvironment: The limits of biogenicity criteria.

Geobiology 2021 May 5. Epub 2021 May 5.

Department of Earth & Planetary Science, University of California, Berkeley, CA, USA.

The search for a fossil record of Earth's deep biosphere, partly motivated by potential analogies with subsurface habitats on Mars, has uncovered numerous assemblages of inorganic microfilaments and tubules inside ancient pores and fractures. Although these enigmatic objects are morphologically similar to mineralized microorganisms (and some contain organic carbon), they also resemble some abiotic structures. Palaeobiologists have responded to this ambiguity by evaluating problematic filaments against checklists of "biogenicity criteria". Read More

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Centering microbes in the emerging role of integrative biology in understanding environmental change.

Integr Comp Biol 2021 May 3. Epub 2021 May 3.

Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 S Orange Ave., Newark, NJ.

We argue that the current environmental changes stressing the Earth's biological systems urgently require study from an integrated perspective to reveal unexpected, cross-scale interactions, particularly between microbes and macroscale phenomena. Such interactions are the basis of a mechanistic understanding of the important connections between deforestation and emerging infectious disease, feedback between ecosystem disturbance and the gut microbiome, and the cross-scale effects of environmental pollutants. These kinds of questions can be answered with existing techniques and data, but a concerted effort is necessary to better coordinate studies and data sets from different disciplines to fully leverage their potential. Read More

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Response of Key Metabolites during a UV-A Exposure Time-Series in the Cyanobacterium PCC 6912.

Microorganisms 2021 Apr 24;9(5). Epub 2021 Apr 24.

Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK.

Ultraviolet A (UV-A) is the major component of UV radiation reaching the Earth's surface, causing indirect damage to photosynthetic organisms via the production of reactive oxygen species (ROS). In comparison, UV-B causes both direct damage to biomolecules and indirect damage. UV-B is well studied in cyanobacterial research due to their long evolutionary history and adaptation to high levels of UV, with less work on the effects of UV-A. Read More

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Plume-driven recratonization of deep continental lithospheric mantle.

Nature 2021 Apr 28;592(7856):732-736. Epub 2021 Apr 28.

Lucara Diamond Corp, Vancouver, British Columbia, Canada.

Cratons are Earth's ancient continental land masses that remain stable for billions of years. The mantle roots of cratons are renowned as being long-lived, stable features of Earth's continents, but there is also evidence of their disruption in the recent and more distant past. Despite periods of lithospheric thinning during the Proterozoic and Phanerozoic eons, the lithosphere beneath many cratons seems to always 'heal', returning to a thickness of 150 to 200 kilometres; similar lithospheric thicknesses are thought to have existed since Archaean times. Read More

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Redox control on the tungsten isotope composition of seawater.

Proc Natl Acad Sci U S A 2021 May;118(18)

Department of Marine Geology, Leibniz Institute for Baltic Sea Research, 18119 Rostock, Germany.

Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth's history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Read More

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Warm early Mars surface enabled by high-altitude water ice clouds.

Proc Natl Acad Sci U S A 2021 May;118(18)

Aeolis Research, Chandler, AZ 85224.

Despite receiving just 30% of the Earth's present-day insolation, Mars had water lakes and rivers early in the planet's history, due to an unknown warming mechanism. A possible explanation for the >10-y-long lake-forming climates is warming by water ice clouds. However, this suggested cloud greenhouse explanation has proved difficult to replicate and has been argued to require unrealistically optically thick clouds at high altitudes. Read More

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Subseafloor sulphide deposit formed by pumice replacement mineralisation.

Sci Rep 2021 Apr 23;11(1):8809. Epub 2021 Apr 23.

Institute for Marine-Earth Exploration and Engineering, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan.

Seafloor massive sulphide (SMS) deposits, modern analogues of volcanogenic massive sulphide (VMS) deposits on land, represent future resources of base and precious metals. Studies of VMS deposits have proposed two emplacement mechanisms for SMS deposits: exhalative deposition on the seafloor and mineral and void space replacement beneath the seafloor. The details of the latter mechanism are poorly characterised in detail, despite its potentially significant role in global metal cycling throughout Earth's history, because in-situ studies require costly drilling campaigns to sample SMS deposits. Read More

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Transforming fire management in northern Australia through successful implementation of savanna burning emissions reductions projects.

J Environ Manage 2021 Apr 19;290:112568. Epub 2021 Apr 19.

Darwin Centre for Bushfire Research, Charles Darwin University, Darwin NT, 0909, Australia; Bushfire & Natural Hazards Cooperative Research Centre, East Melbourne Vic, 3002, Australia; North Australian Land and Sea Management Alliance, PO Box 486 CDU NT 0815, Australia.

Savannas are the most fire-prone of Earth's biomes and currently account for most global burned area and associated carbon emissions. In Australia, over recent decades substantial development of savanna burning emissions accounting methods has been undertaken to incentivise more conservative savanna fire management and reduce the extent and severity of late dry season wildfires. Since inception of Australia's formal regulated savanna burning market in 2012, today 25% of the 1. Read More

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People have shaped most of terrestrial nature for at least 12,000 years.

Proc Natl Acad Sci U S A 2021 Apr;118(17)

School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Australia 4072.

Archaeological and paleoecological evidence shows that by 10,000 BCE, all human societies employed varying degrees of ecologically transformative land use practices, including burning, hunting, species propagation, domestication, cultivation, and others that have left long-term legacies across the terrestrial biosphere. Yet, a lingering paradigm among natural scientists, conservationists, and policymakers is that human transformation of terrestrial nature is mostly recent and inherently destructive. Here, we use the most up-to-date, spatially explicit global reconstruction of historical human populations and land use to show that this paradigm is likely wrong. Read More

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Evidence from South Africa for a protracted end-Permian extinction on land.

Proc Natl Acad Sci U S A 2021 Apr;118(17)

Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL 60605.

Earth's largest biotic crisis occurred during the Permo-Triassic Transition (PTT). On land, this event witnessed a turnover from synapsid- to archosauromorph-dominated assemblages and a restructuring of terrestrial ecosystems. However, understanding extinction patterns has been limited by a lack of high-precision fossil occurrence data to resolve events on submillion-year timescales. Read More

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An evolutionary system of mineralogy. Part I: Stellar mineralogy (>13 to 4.6 Ga).

Am Mineral 2020 Apr;105(5):627-651

Earth and Planets Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road NW, Washington, DC 20015, U.S.A.

Minerals preserve records of the physical, chemical, and biological histories of their origins and subsequent alteration, and thus provide a vivid narrative of the evolution of Earth and other worlds through billions of years of cosmic history. Mineral properties, including trace and minor elements, ratios of isotopes, solid and fluid inclusions, external morphologies, and other idiosyncratic attributes, represent information that points to specific modes of formation and subsequent environmental histories-information essential to understanding the co-evolving geosphere and biosphere. This perspective suggests an opportunity to amplify the existing system of mineral classification, by which minerals are defined solely on idealized end-member chemical compositions and crystal structures. Read More

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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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Melatonin synthesis genes N-acetylserotonin methyltransferases evolved into caffeic acid O-methyltransferases and both assisted in plant terrestrialization.

J Pineal Res 2021 Apr 12:e12737. Epub 2021 Apr 12.

Department of Cell Systems and Anatomy, UT Health, Long School of Medicine, San Antonio, TX, USA.

Terrestrialization is one of the most momentous events in the history of plant life, which led to the subsequent evolution of plant diversity. The transition species, in this process, had to acquire a range of adaptive mechanisms to cope with the harsh features of terrestrial environments compared to that of an aquatic habitat. As an ancient antioxidant, a leading regulator of ROS signaling or homeostasis, and a presumed plant master regulator, melatonin likely assisted plants transition to land and their adaption to terrestrial ecosystems. Read More

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A brief history of carbon monoxide and its therapeutic origins.

Nitric Oxide 2021 Apr 7;111-112:45-63. Epub 2021 Apr 7.

Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Anesthesiology and Critical Care, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany. Electronic address:

It is estimated that 10% of carbon throughout the cosmos is in the form of carbon monoxide (CO). Earth's earliest prebiotic atmosphere included the trinity of gasotransmitters CO, nitric oxide (NO), and hydrogen sulfide (HS), for which all of life has co-evolved with. The history of CO can be loosely traced to mythological and prehistoric origins with rudimentary understanding emerging in the middle ages. Read More

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Oxygen isotopes trace the origins of Earth's earliest continental crust.

Nature 2021 Apr 31;592(7852):70-75. Epub 2021 Mar 31.

Geological Survey of Western Australia, Department of Mines, Industry Regulation and Safety, East Perth, Western Australia, Australia.

Much of the current volume of Earth's continental crust had formed by the end of the Archaean eon (2.5 billion years ago), through melting of hydrated basaltic rocks at depths of approximately 25-50 kilometres, forming sodic granites of the tonalite-trondhjemite-granodiorite (TTG) suite. However, the geodynamic setting and processes involved are debated, with fundamental questions arising, such as how and from where the required water was added to deep-crustal TTG source regions. Read More

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A trampoline effect occurring in the stages of planetary reseeding.

Ian von Hegner

Biosystems 2021 Mar 27;205:104412. Epub 2021 Mar 27.

Aarhus University, Ny Munkegade 116, DK-8000, Denmark. Electronic address:

Impactors have hit the Earth since its formation and have continued to be infrequent guests throughout the Earth's history. Although the early part of the Earth's history was marked by these violent events, life was present early, possibly existing already in the Hadean Eon. It is possible that life has been, and still is, transported between the worlds of the solar system, owing to impacts leading material away from the impact region. Read More

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The Lived Experience of Victims of Catastrophic Coastal Erosion: A cycle of impact, consequence and recovery.

Sultan Qaboos Univ Med J 2021 Feb 15;21(1):e94-e102. Epub 2021 Mar 15.

Department of Maternal & Child Health, Sultan Qaboos University, Muscat, Oman.

Objectives: Environmental hazards are part of the Earth's natural cycle and are ongoing within human history. When vulnerable situations meet environmental hazards, disasters occur where human and natural costs could be enormous. This study aimed to explore the experiences of the victims of coastal erosion during the monsoon season. Read More

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February 2021

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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The phylogeographic history of Krascheninnikovia reflects the development of dry steppes and semi-deserts in Eurasia.

Sci Rep 2021 Mar 23;11(1):6645. Epub 2021 Mar 23.

Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna (BOKU), Gregor-Mendel-Straße 33, 1180, Vienna, Austria.

Constituting one of Earth's major biomes, steppes are characterised by naturally treeless extra-tropical vegetation. The formation of the Eurasian steppe belt, the largest steppe region in the world, began in Central Asia during the Neogene. In the glacial stages of the Pleistocene, steppe displaced forest vegetation, which in turn recolonised the area during the warmer interglacial periods, thus affecting the distribution of plants adapted to these habitats. Read More

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Aerodynamics and the role of the earth's electric field in the spiders' ballooning flight.

Moonsung Cho

J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021 Mar 13;207(2):219-236. Epub 2021 Mar 13.

Animal Physiology, University of Rostock, Albert-Einstein-Str. 3, 18059, Rostock, Germany.

Some spiders aerially disperse relying on their fine fibres. This behaviour has been known as 'ballooning'. Observations on the ballooning behaviour of spiders have a long history and have more recently received special attention, yet its underlying physics is still poorly understood. Read More

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A multiscale view of the Phanerozoic fossil record reveals the three major biotic transitions.

Commun Biol 2021 Mar 8;4(1):309. Epub 2021 Mar 8.

Integrated Science Lab, Department of Physics, Umeå University, Umeå, 90736, Sweden.

The hypothesis of the Great Evolutionary Faunas is a foundational concept of macroevolutionary research postulating that three global mega-assemblages have dominated Phanerozoic oceans following abrupt biotic transitions. Empirical estimates of this large-scale pattern depend on several methodological decisions and are based on approaches unable to capture multiscale dynamics of the underlying Earth-Life System. Combining a multilayer network representation of fossil data with a multilevel clustering that eliminates the subjectivity inherent to distance-based approaches, we demonstrate that Phanerozoic oceans sequentially harbored four global benthic mega-assemblages. Read More

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Organic matter and water from asteroid Itokawa.

Sci Rep 2021 Mar 4;11(1):5125. Epub 2021 Mar 4.

The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.

Understanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth's astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and N/N ratios (δD =  + 4868 ± 2288‰; δN =  + 344 ± 20‰) signifying an explicit extra-terrestrial origin. Read More

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Causes of global extinctions in the history of life: facts and hypotheses.

Vavilovskii Zhurnal Genet Selektsii 2020 Jul;24(4):407-419

Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.

Paleontologists define global extinctions on Earth as a loss of about three-quarters of plant and animal species over a relatively short period of time. At least five global extinctions are documented in the Phanerozoic fossil record (~500-million-year period): ~65, 200, 260, 380, and 440 million years ago. In addition, there is evidence of global extinctions in earlier periods of life on Earth - during the Late Cambrian (~500 million years ago) and Ediacaran periods (more than 540 million years ago). Read More

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The evolution of oxygen-utilizing enzymes suggests early biosphere oxygenation.

Nat Ecol Evol 2021 04 25;5(4):442-448. Epub 2021 Feb 25.

Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.

Production of molecular oxygen was a turning point in the Earth's history. The geological record indicates the Great Oxidation Event, which marked a permanent transition to an oxidizing atmosphere around 2.4 Ga. Read More

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From Empedocles to Symbiogenetics: Lynn Margulis's revolutionary influence on evolutionary biology.

Dorion Sagan

Biosystems 2021 Jun 20;204:104386. Epub 2021 Feb 20.

As a primary expositor of the work of Lynn Margulis collaborating with her over thirty years on over thirty books and forty articles, scientific and popular, I attempt here to summarize her unique and lasting influence on evolutionary biology. Describing life on Earth as the multi-billion-year evolution of microbial communities, from prokaryotes maintaining Earth's atmosphere away from thermodynamic equilibrium to all eukaryotes as polygenomic beings, Margulis's interdisciplinary work has deeply influenced multiple fields including systematics, theories of the evolution of metabolism, paleobiology, and biogeochemistry. Overturning the neo-Darwinist narrative that speciation almost always occurs by the gradual accumulation of random mutations, Margulis's work revives a discarded philosophical speculation of the pre-Socratic Empedocles, who suggested that Earth's early beings both merged and differentially reproduced (were naturally selected); a speculation that was rejected by Aristotle probably because it smacked of mythological chimeras that had no place in observational biology, and later by Charles Darwin, who mentioned Aristotle's rejection of Empedocles to show that he knew of but did not accept natural selection, thus helping lay his own claim to its own proper scientific presentation in a Victorian culture whose thinking of origins was dominated not by Greek mythology but Christian special creation. Read More

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Modern dolomite formation caused by seasonal cycling of oxygenic phototrophs and anoxygenic phototrophs in a hypersaline sabkha.

Sci Rep 2021 Feb 18;11(1):4170. Epub 2021 Feb 18.

Department of Physical and Environmental Sciences, Biogeochemistry Group, University of Toronto Scarborough, Toronto, Canada.

The "Dolomite Problem" has been a controversy for over a century, owing to massive assemblages of low-temperature dolomite in ancient rocks with little dolomite forming today despite favorable geochemical conditions. Experiments show that microbes and their exopolymeric substances (EPS) nucleate dolomite. However, factors controlling ancient abundances of dolomite can still not be explained. Read More

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February 2021

A global environmental crisis 42,000 years ago.

Science 2021 02;371(6531):811-818

Archaeology and Natural History, School of Culture History and Language, ANU College of Asia and the Pacific, Canberra, ACT 2601, Australia.

Geological archives record multiple reversals of Earth's magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees () to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. Read More

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February 2021

Breakup of a long-period comet as the origin of the dinosaur extinction.

Sci Rep 2021 Feb 15;11(1):3803. Epub 2021 Feb 15.

Department of Astronomy, Harvard University, 60 Garden Street, Cambridge, MA, 02138, USA.

The origin of the Chicxulub impactor, which is attributed as the cause of the K/T mass extinction event, is an unsolved puzzle. The background impact rates of main-belt asteroids and long-period comets have been previously dismissed as being too low to explain the Chicxulub impact event. Here, we show that a fraction of long-period comets are tidally disrupted after passing close to the Sun, each producing a collection of smaller fragments that cross the orbit of Earth. Read More

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February 2021