All Articles Tagged As: oxygen

Hypoxia increases as climate warms (12/25/2009)

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

Rich ore deposits linked to ancient atmosphere (11/21/2009)

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. ...> Full Article

A new wrinkle in ancient ocean chemistry (10/30/2009)

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

Warmer climate not the cause of oxygen deficiency in the Baltic Sea (10/18/2009)

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

More oxygen - colder climate (9/11/2009)

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. ...> Full Article

The rise of oxygen caused Earth's earliest ice age (5/11/2009)

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. ...> Full Article

Origins of sulfur in rocks tells early oxygen story (4/18/2009)

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. ...> Full Article

Did a nickel famine trigger the 'Great Oxidation Event'? (4/10/2009)

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. ...> Full Article

Deep-sea rocks point to early oxygen on Earth (3/25/2009)

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

Geologist finds clues to ancient chemistry of deep oceans (7/24/2008)

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

Two Oxygenation Events In Ancient Oceans Sparked Spread Of Complex Life (3/7/2008)

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