Earth ChangesS


Better Earth

Antarctic iceberg found floating near Macquarie Island

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© Murray Potter/APA large iceberg spotted off Macquarie Island.
Dean Miller, an Australian fur seal biologist, was the first person to spot the large white object floating past Macquarie island in the far south-west corner of the Pacific Ocean.

"I've never seen anything like it. We looked out to the horizon and just saw this huge floating island of ice," Miller told the Australian Antarctic division. "It was a monumental moment for me as it was the first iceberg I have seen."

Estimated to be about 50m high - from the waterline - and 500m long, the iceberg is now about five miles (8km) off the north-west of Macquarie island, halfway between New Zealand and Antarctica south-west corner of the Pacific Ocean.

Scientists have said it is rare for icebergs to be seen so far north. Neil Young, an Australian Antarctic division glaciologist, said: "The iceberg is likely to be part of one of the big ones that calved from the Ross ice shelf nearly a decade ago.

"Throughout the year several icebergs have been drifting slowly northwards with the ocean current towards Macquarie Island. We know there are also a few more icebergs 100km-200km to the west of the island."

Clock

Greenland ice loss 'accelerating'

Ilulissat glacier
© BBCThe Ilulissat glacier has retreated by approximately 15km over the past decade
The Greenland ice sheet is losing its mass faster than in previous years and making an increasing contribution to sea level rise, a study has confirmed.

Published in the journal Science, it has also given scientists a clearer view of why the sheet is shrinking.

The team used weather data, satellite readings and models of ice sheet behaviour to analyse the annual loss of 273 thousand million tonnes of ice.

Melting of the entire sheet would raise sea levels globally by about 7m (20ft).

Bizarro Earth

Chile: Earthquake Magnitude 6.5 - Tarapaca

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© USGS
Date-Time:
Friday, November 13, 2009 at 03:05:55 UTC

Friday, November 13, 2009 at 12:05:55 AM at epicenter

Location:
19.348°S, 70.246°W

Depth:
10 km (6.2 miles) set by location program

Region:
TARAPACA, CHILE

Distances:
95 km (60 miles) S of Arica, Chile

95 km (60 miles) N of Iquique, Chile

150 km (95 miles) S of Tacna, Peru

1560 km (970 miles) N of SANTIAGO, Chile

Bizarro Earth

Oil industry sinkhole threatens to swallow city

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© National Cave And Karst Research Institute/APUnlike the Carlsbad Caverns, collapsed brine wells like this one in nearby Artesia, N.M., aren't natural.
Parts of the New Mexico town near Carlsbad Caverns National Park could collapse because of irresponsible extraction practices by the oil industry.

"U.S. 285 south subject to sinkhole 1,000 feet ahead," reads a bright yellow sign along the stretch of highway heading through Carlsbad, N.M.

Normally a motorist driving through the area might not find a sign like that unusual. The city is, after all, home to Carlsbad Caverns National Park, a network of some of the largest natural caverns in North America. But on this occasion, the sign's sharp colors make the message clear: what's happening in Carlsbad is not natural.

In fact, the massive sinkhole currently running through the center of town was created by the oil industry. As MSNBC reports, it was formed over three decades as oil field service companies pumped fresh water into a salt layer more than 400 feet below the surface and extracted several million barrels of brine to help with drilling.

If it collapses, the unnatural cavern is likely to take with it a church, a highway, several businesses and a trailer park. Massive fissures currently cleave through town, and one business owner has said that structural cracks have even formed in his store.

Bizarro Earth

Earth's Early Ocean Cooled More than a Billion Years Earlier than Thought

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© Michael Tice, Texas A&M UniversityGreen and orange photosynthetic microbial mats line an outflow channel from a hot spring in Yellowstone National Park.
The scalding-hot sea that supposedly covered the early Earth may in fact never have existed, according to a new study by Stanford University researchers who analyzed isotope ratios in 3.4 billion-year-old ocean floor rocks. Their findings suggest that the early ocean was much more temperate and that, as a result, life likely diversified and spread across the globe much sooner in Earth's history than has been generally theorized.

It also means that the chemical composition of the ancient ocean was significantly different from today's ocean, which in turn may change interpretations of how the early atmosphere evolved, said Page Chamberlain, professor of environmental earth system science.

When rocks form on the ocean floor, they form in chemical equilibrium with the ocean water, incorporating similar proportions of different isotopes into the rock as are in the water. Isotopes are atoms of the same element that have different numbers of neutrons in the nucleus, giving them different masses. However, because the exact proportion of different isotopes that go into the rock is partly temperature dependent, the ratios in the rock provide critical clues into how warm the ocean was when the rock formed.

Bizarro Earth

Mini Ice Age Took Hold Of Europe In Just Months

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© Tancrediphoto.com/Stone/GettyBig freezes can happen fast
Just months - that's how long it took for Europe to be engulfed by an ice age. The scenario, which comes straight out of Hollywood blockbuster The Day After Tomorrow, was revealed by the most precise record of the climate from palaeohistory ever generated.

Around 12,800 years ago the northern hemisphere was hit by the Younger Dryas mini ice age, or "Big Freeze". It was triggered by the slowdown of the Gulf Stream, led to the decline of the Clovis culture in North America, and lasted around 1300 years.

Until now, it was thought that the mini ice age took a decade or so to take hold, on the evidence provided by Greenland ice cores. Not so, say William Patterson of the University of Saskatchewan in Saskatoon, Canada, and his colleagues.

The group studied a mud core from an ancient lake, Lough Monreagh, in western Ireland. Using a scalpel they sliced off layers 0.5 to 1 millimetre thick, each representing up to three months of time. No other measurements from the period have approached this level of detail.

Carbon isotopes in each slice revealed how productive the lake was and oxygen isotopes gave a picture of temperature and rainfall. They show that at the start of the Big Freeze, temperatures plummeted and lake productivity stopped within months, or a year at most. "It would be like taking Ireland today and moving it up to Svalbard" in the Arctic, says Patterson, who presented the findings at the BOREAS conference in Rovaniemi, Finland, on 31 October.

Fish

Last chance for Tuna - Tagging the tigers of the sea

Pablo Cermeño balances at the back of the small boat, legs braced, harpoon at the ready. Beneath him in the crystal waters his target is clearly visible: a shimmer of metallic turquoise that tacks left, right, left again as it is hauled inexorably towards the surface. The fisherman grunts and sweats as he does battle with the giant fish, reeling, pulling and reeling again.


Better Earth

Are Our Oceans Made of Extraterrestrial Material?

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© Michele HoganPacific ocean.
Contrary to preconceived notions, the atmosphere and the oceans were perhaps not formed from vapors emitted during intense volcanism at the dawning of our planet. Francis Albarède of the Laboratoire des Sciences de la Terre (CNRS / ENS Lyon / Université Claude Bernard) suggests that water was not part of the Earth's initial inventory but stems from the turbulence caused in the outer Solar System by giant planets. Ice-covered asteroids thus reached the Earth around one hundred million years after the birth of the planets.

The Earth's water could therefore be extraterrestrial, have arrived late in its accretion history, and its presence could have facilitated plate tectonics even before life appeared. The conclusions of the study carried out by Albarède feature in an article published on the 29 October 2009 in the journal Nature.

Space agencies have got the message: wherever there is life there has to be water. Around 4.5 billion years ago, the Earth was bequeathed with sufficient water for oceans to form and for life to find favorable niches in the seas and on the continents resulting from plate tectonics. In comparison, the Moon and Mercury are dry, mortally cold deserts, Mars dried up very quickly and the surface of Venus is a burning inferno.

Bizarro Earth

5.6 Earthquake Hits Mindanao, Philippines

A moderate earthquake measuring 5.6 on the Richter scale occurred in Mindanao, the Philippines at 9.48pm on Wednesday night.

The Malaysian Meteorological Department said in a statement that the quake's epicentre was located 231km southeast of Cebu, the Philippines and 934km northeast of Sandakan, Sabah.

However, the earthquake did not pose any tsunami threat.

Binoculars

Elephant Seals Sleep While Diving, Study Suggests

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© Karen SeagleA pair of elephant seals takes an afternoon snooze on the beach near San Simon, California
Migrating northern elephant seals slowly drift downward to rest in the ocean depths, according to a new study of the animals' dive patterns.

Moving from their breeding colonies in California to their wintering areas in the mid-Pacific and around Alaska, the seals spend two to eight months at sea without a single pit stop.

There's no land to climb on along the roughly 2,000- to 3,000-mile (3,200- to 4,800-kilometer) voyage, and the seabed is often miles below the surface.

The marine mammals' grueling trek had many researchers wondering: When and how do elephant seals sleep?

It's long been known that, during the seals' epic migrations, the animals engage in repetitive dives down to depths of 984 feet (300 meters) or more.

Now a study of young elephant seals has revealed that during some of these dives, elephant seals roll on their backs and allow themselves to sink.