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Categories: Geoscience: Geology, Paleontology: Climate

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Scientists have made a surprising discovery that sheds new light on the role that oceanic deoxygenation (anoxia) played in one of the most devastating extinction events in Earth's history. Their finding has implications for current day ecosystems -- and serves as a warning that marine environments are likely more fragile than apparent. New research, published today in leading international journal Nature Geosciences, suggests that oceanic anoxia played an important role in ecosystem disruption and extinctions in marine environments during the Triassic--Jurassic mass extinction, a major extinction event that occurred around 200 million years ago.  Surprisingly however, the study shows that the global extent of euxinia (an extreme form of de-oxygenated conditions) was similar to the present day.

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Research shows that variations in pyrite sulfur isotopes may not represent the global processes that have made them such popular targets of analysis and interpretation. A new microanalysis approach helps to separate out signals that reveal the relative influence of microbes and that of local climate.

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The Hunga Tonga-Hunga Ha'apai volcano changed the chemistry and dynamics of the stratosphere in the year following the eruption, leading to unprecedented losses in the ozone layer of up to 7% over large areas of the Southern Hemisphere.  

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Using historical records from around Australia, an international team of researchers have put forward the most accurate prediction to date of past Antarctic ice sheet melt, providing a more realistic forecast of future sea level rise.   The Antarctic ice sheet is the largest block of ice on earth, containing over 30 million cubic kilometers of water.   Hence, its melting could have a devasting impact on future sea levels. To find out just how big that impact might be, the research team turned to the past.  

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Ancient cycad lineages that survived the extinction of the dinosaurs may have done so by relying on symbiotic bacteria in their roots to fix atmospheric nitrogen. The finding came from an effort to understand ancient atmospheres, but became an insight into plant evolution instead.

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Researches used rhenium as a proxy for fossil carbon in order to quantify the rate at which Earth naturally releases carbon dioxide into the atmosphere and found that high rates of carbon breakdown persist across the different geographical profiles of a river basin.

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A new study has revealed that water from the Earth's surface can penetrate deep into the planet, altering the composition of the outermost region of the metallic liquid core and creating a distinct, thin layer. Illustration of silica crystals coming out from the liquid metal of the Earth's outer core due to a water-induced chemical reaction.

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With help from an experienced underwater cave-diving team, researchers have constructed the most complete map to date of the microbial communities living in the submerged labyrinths beneath Mexico's Yucatán Peninsula. Researchers found the cave system's microbiome is distinct from the nearby sea, and microbial communities vary between cave systems forming distinct 'neighborhoods.'  

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Past cold periods such as the Little Ice Age were associated with reduced strength of North Atlantic currents and increased surface salinity in the Caribbean. This was accompanied by disturbances in the distribution of salt to the north leading to longer, stronger cooling phases in the northern hemisphere.

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During the last ice age, the last glacial maximum about 20,000 years ago, the climate in the North Atlantic underwent much greater multi-centennial variability than it does in the present warm period. This is supported by evidence found in ice and seafloor cores. Researchers have now shown, based on a climate model, that internal mechanisms such as temperature and salinity distribution in the ocean are driving this multi-centennial variability.

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A new study takes an important step toward reconstructing a global history of water over the past 2,000 years. Using geologic and biologic evidence preserved in natural archives -- including 759 different paleoclimate records from globally distributed corals, trees, ice, cave formations and sediments -- the researchers showed that the global water cycle has changed during periods of higher and lower temperatures in the recent past.

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The remnants of an ancient planet that collided with Earth to form the Moon lie deep within the earth, according to a new model.

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Researchers have mapped how land use changed across Britain throughout the last century. The new map reveals how and where some 50 per cent of semi-natural grassland was lost, including 90 per cent of the country's lowland meadows and pasture, as the nation intensified its agriculture.

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Large geomagnetic storms disrupt radio signals and GPS. Now, researchers have identified the previous underestimated role of the ionosphere, a region of Earth's upper atmosphere that contains a high concentration of ions and free electrons, in determining how such storms develop. Understanding the interactions that cause large geomagnetic storms is important because they can disrupt radio signals and GPS. Their findings may help predict storms with the greatest potential consequences.

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A new Antarctic ice sheet modeling study suggests that meltwater flowing out to sea from beneath Antarctic glaciers is making them lose ice faster.   

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Examining how plates move in Earth's mantle and how mountains form is no easy feat. Certain rocks that have sunk deep into Earth's interior and then returned from there can deliver answers.

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The explosion of the underwater volcano Kolumbo in the Aegean Sea in 1650 triggered a destructive tsunami that was described by historical eye witnesses. A group of researchers has now surveyed Kolumbo's underwater crater with modern imaging technology and reconstructed the historical events. They found that the eyewitness accounts of the natural disaster can only be described by a combination of a landslide followed by an explosive eruption.

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Venus, may have once had tectonic plate movements similar to those believed to have occurred on early Earth, a new study found. The finding sets up tantalizing scenarios regarding the possibility of early life on Venus, its evolutionary past and the history of the solar system.

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Human populations in Neolithic Europe fluctuated with changing climates, according to a new study.

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Scientists analyzed open-source data to track vegetation changes across North America since the end of the Pleistocene Epoch, and conclude that humans have had as much of an impact on the landscape as the retreat of the glaciers at the end of the Ice Age.