* Astronomy

New Study Finds Oceans Arrived Early to Earth

Earth is known as the Blue Planet because of its oceans, which cover more than 70 percent of the planet's surface and are home to the world's greatest diversity of life. While water is essential for life on the planet, the answers to two key questions have eluded us: where did Earth's water come from and when?
While some hypothesize that water came late to Earth, well after the planet had formed, findings from a new study led by scientists at the Woods Hole Oceanographic Institution (WHOI) significantly move back the clock for the first evidence of water on Earth and in the inner solar system.
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Volcanoes Deliver Two Flavours of Water

Seawater circulation pumps hydrogen and boron into the oceanic plates that make up the seafloor, and some of this seawater remains trapped as the plates descend into the mantle at areas called subduction zones. By analysing samples of submarine volcanic glass near one of these areas, scientists found unexpected changes in isotopes of hydrogen and boron from the deep mantle. They expected to see the isotope "fingerprint" of seawater. But in volcanoes from the Manus Basin they also discovered evidence of seawater distilled long ago from a more ancient plate descent event, preserved for as long as 1 billion years. The data indicate that these ancient oceanic "slabs" can return to the upper mantle in some areas, and that rates of hydrogen exchange in the deep Earth may not conform to experiments. The research is published in the February 26, 2012, advanced on line publication of Nature Geoscience.
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Space Observatory Provides Clues to Creation of Earth's Oceans

Astronomers have found a new cosmic source for the same kind of water that appeared on Earth billions of years ago and created the oceans. The findings may help explain how Earth's surface ended up covered in water.
New measurements from the Herschel Space Observatory show that comet Hartley 2, which comes from the distant Kuiper Belt, contains water with the same chemical signature as Earth's oceans. This remote region of the solar system, some 30 to 50 times as far away as the distance between Earth and the sun, is home to icy, rocky bodies including Pluto, other dwarf planets and innumerable comets.
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Evidence for Iron-Rich Ancient Ocean Changes View of Earth's Early History

Over the last half-billion years, the ocean mostly has been full of oxygen and teeming with animal life. But earlier, before animals evolved, oxygen was harder to come by.
Now a new study, led by researchers at the University of California, Riverside (UCR), reveals that the ancient deep ocean was not only devoid of oxygen but also rich in iron, a key biological nutrient for nearly a billion years longer than previously thought--right through a key evolutionary interval that culminated in the first rise of animals.
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