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All Articles Tagged As: oxygen
 | A turning point in the history of life occurred two to three billion years ago with the unprecedented appearance and dramatic rise of molecular oxygen. Now researchers report they have identified an enzyme that was the first ? or among the first ? to generate molecular oxygen on Earth. ...> Full Article |
 | The appearance of oxygen in the Earth's atmosphere probably did not occur as a single event, but as a long series of starts and stops, according to geoscientists who investigated rock cores from the FAR DEEP project. ...> Full Article |
 | The appearance of oxygen in the Earth's atmosphere probably did not occur as a single event, but as a long series of starts and stops, according to an international team of researchers who investigated rock cores from the FAR DEEP project. ...> Full Article |
New University of Alberta research shows the first evidence that oxygen-breathing bacteria occupied and thrived on land 100 million years earlier than previously thought.
The researchers show the most primitive form of aerobic respiring life on land came into existence 2.48 billion years ago.
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Research from MIT suggests O2 may have been made on Earth hundreds of millions of years before its debut in the atmosphere, keeping a low profile in "oxygen oases" in the oceans. The MIT researchers found evidence that tiny aerobic organisms may have evolved to survive on extremely low levels of the gas in these undersea oases.
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 | After the biggest mass extinction in Earth's history -- 250 million years ago -- algae and bacteria in the ocean rebounded so fast that they consumed virtually all the oxygen in the sea, slowing the recovery of the rest of marine animals for several million years. ...> Full Article |
 | Researchers at the University of California, Riverside report that the transition from a generally oxygen-rich ocean during the Cambrian to the fully oxygenated ocean we have today was not a simple turn of the switch, as has been widely accepted. Their work shows the ocean fluctuated between oxygenation states 499 million years ago; such fluctuations, they say, played a major, perhaps dominant, role in shaping the early evolution of animals on the planet. ...> Full Article |
Researchers funded by the Biotechnology and Biological Sciences Research Council at the University of Oxford have uncovered a clue that may help to explain why the earliest evidence of complex multicellular animal life appears around 550 million years ago, when atmospheric oxygen levels on the planet rose sharply from 3 percent to their modern day level of 21 percent.
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While there continues to be considerable debate among geologists about the availability of oxygen in the Earth's mantle, recent discoveries by a University of Rhode Island scientist are bringing resolution to the question.
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A University of Alberta geomicrobiologist and his PhD student are part of a research team that has identified phosphorus as the mystery ingredient that pushed oxygen levels in the oceans high enough to establish the first animals on Earth 750 million years ago.
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 | Billions of years ago, Earth differed greatly from our modern environment -- the ancient atmosphere contained almost no oxygen. The life-supporting atmosphere we currently enjoy did not develop overnight. On the most basic level, biological activity in the ocean shaped the oxygen concentrations in the atmosphere. A paper published by Nature Geoscience shows that "oxygen oases" in the surface ocean were sites of significant oxygen production long before the breathing gas began to accumulate in the atmosphere. ...> Full Article |
 | Recent work with geochemical proxies for oxygen levels suggests that oxygen levels continued to fluctuate long after the Great Oxygenation Event 2.7 billion years ago, and that the oceans were many different flavors of anoxic right up until the Edicaran period, 600 million years ago. What happened in the intervening 2 billion years will be contested until scientists have more data, says a geochemist at Washington University in St. Louis. ...> Full Article |
Scientists from the Field Museum in Chicago and Royal Holloway University of London publishing their results this week in the journal Nature Geoscience have shown that the amount of charcoal preserved in ancient peat bogs, now coal, gives a measure of how much oxygen there was in the past.
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 | A new study of Pacific Ocean sediments off the coast of Chile has found that offshore waters experienced systematic oxygen depletion during the rapid warming of the Antarctic following the last "glacial maximum" period 20,000 years ago. ...> Full Article |
Much of our planet's mineral wealth was deposited billions of years ago when Earth's chemical cycles were different from today's. Using geochemical clues from rocks nearly 3 billion years old, a group of scientists including Andrey Bekker and Doug Rumble from the Carnegie Institution have made the surprising discovery that the creation of economically important nickel ore deposits was linked to sulfur in the ancient oxygen-poor atmosphere.
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 | A research team led by University of California, Riverside geoscientists has corroborated evidence that oxygen production began in Earth's oceans at least 100 million years before the Great Oxidation Event (GOE). The researchers analyzed 2.5 billion-year-old black shales, which revealed that episodes of hydrogen sulfide accumulation in the oxygen-free deep ocean occurred nearly 100 million years before the GOE. Scientists have long believed that the early ocean was characterized by high amounts of dissolved iron. ...> Full Article |
 | Oxygen deficiency in the Baltic Sea has never been greater than it is now. But it is not an effect of climate change but rather of increased inputs of nutrients and fertilizers. This is the finding of researchers at the University of Gothenburg, Sweden, who have analyzed the ocean climate of the Baltic Sea since the 16th century. ...> Full Article |
Using a completely new method, researchers have shown that high atmospheric and oceanic oxygen content makes the climate colder. In prehistoric times, the earth experienced two periods of large increases and fluctuations in the oxygen level of the atmosphere and oceans. These fluctuations also lead to an explosion of multicellular organisms in the oceans, which are the predecessors for life as we know it today. The results are now being published in Nature.
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Earth's earliest ice ages may have been due to the rise of oxygen in Earth's atmosphere, which consumed atmospheric greenhouse gases and chilled the earth. Alan J. Kaufman, professor of geology at the University of Maryland, Maryland colleague James Farquhar, and a team of scientists from Germany, South Africa, Canada, and the US, uncovered evidence that the oxygenation of Earth's atmosphere coincided with the first widespread ice age on the planet.
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Sedimentary rocks created more than 2.4 billion years ago sometimes have an unusual sulfur isotope composition thought to be caused by the action of ultra violet light on volcanically produced sulfur dioxide in an oxygen poor atmosphere. Now a team of geochemists can show an alternative origin for this isotopic composition that may point to an early, oxygen-rich atmosphere.
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The Earth's original atmosphere held very little oxygen. This began to change around 2.4 billion years ago when oxygen levels increased dramatically during what scientists call the "Great Oxidation Event." The cause of this event has puzzled scientists, but researchers writing in Nature have found indications in ancient sedimentary rocks that it may have been linked to a drop in the level of dissolved nickel in seawater.
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 | Red jasper cored from layers 3.46 billion years old suggests that not only did the oceans contain abundant oxygen then, but that the atmosphere was as oxygen rich as it is today, according to geologists. ...> Full Article |
 | Researchers have moved another step closer to explaining changes in the chemistry of the deep oceans – and the sudden appearance of large animal fossils – more than 500 million years ago. ...> Full Article |
 | The rise of oxygen and the oxidation of deep oceans between 635 and 551 million years ago may have had an impact on the increase and spread of the earliest complex life, including animals, according to a new study. ...> Full Article |
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