Poll: Obama makes big gains among black voters

(CNN) -- Sen. Hillary Clinton has lost a large amount of support among African-Americans, with a majority of black Democrats now supporting Sen. Barack Obama, according to a new poll out Friday.

Sen. Barack Obama has the support of a majority of black Democrats, a poll found.

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In a national survey by CNN/Opinion Research Corp., 59 percent of black Democrats backed Obama, an Illinois Democrat, for their party's presidential nomination, with 31 percent supporting Clinton, the senator from New York.

The 28 point lead for Obama is a major reversal from October, when Clinton held a 24 point lead among black Democrats.

"There's been a huge shift among African-American Democrats from Clinton to Obama. African-American Democrats used to be reluctant to support Obama because they didn't think a black man could be elected. Then Obama won Iowa and nearly won New Hampshire. Now they believe," said Bill Schneider, CNN senior political analyst.

"Obama's lead over Clinton among black men is more than 50 points, and among black women, once a Clinton stronghold, Obama has an 11 point advantage," said CNN polling director Keating Holland.

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It also appears the recent bickering between Clinton and Obama and their campaigns over race has hurt both candidates. Clinton has the support of 42 percent of all registered Democrats in the new survey, down seven points from last week's CNN/Opinion Research Corp. poll. Obama has the backing of 33 percent of those questioned, down three percentage points in a week.

The beneficiary appears to be former Sen. John Edwards of North Carolina, who jumped 5 points, to 17 percent.

"Why have Clinton and Obama both lost support over the past week? One word: squabbling. If two candidates get into a fight, the third candidate usually gains. Sure enough, John Edwards gained," Schneider said.

Rep. Dennis Kucinich of Ohio is at 3 percent in the new poll, with former Sen. Mike Gravel of Alaska with support of less than 0.5 percent.

In the battle for the Republican presidential nomination, the survey suggests Sen. John McCain remains the front-runner, but his support among registered Republicans has dropped 5 points since last week's survey, which was taken immediately after the senator from Arizona won the New Hampshire primary.

McCain is at 29 percent, with former Arkansas Gov. Mike Huckabee at 20 percent and former Massachusetts Gov. Mitt Romney at 19 percent, up five points from last week. Romney won Tuesday's Michigan primary.

"There was a Michigan bounce," Schneider said. "But McCain still leads. Conservatives, however, are divided between McCain at 26 percent, Huckabee at 24 percent and Romney at 20 percent. Saturday's South Carolina GOP primary should tell us if there's going to be a conservative favorite in this race."

About half the interviews for the new poll were taken before the Michigan primary results were known.

The poll indicates Huckabee may be hurt by perceptions about his leadership abilities.

"Nearly half of registered Republicans say he does not have the leadership skills and vision a president should have. Romney and McCain score much better on this measure," Holland said.

Rudy Giuliani is at 14 percent in the new survey. That's a drop of four points from last week's poll for the former New York mayor.

"Giuliani's support is half of what it was in November, when he last led in the national polls. Giuliani has a problem on issues. Forty-five percent of registered Republicans say they disagree with him on issues that matter to them. McCain ranks highest among registered Republicans on both measures," Holland said.

Former Sen. Fred Thompson of Tennessee has the backing of 9 percent of registered Republicans in the survey, with Rep. Ron Paul of Texas at 6 percent and Rep. Duncan Hunter of California at 1 percent.

Looking ahead to the general election, the GOP has several matters to address. The poll indicates Democrats are much more enthusiastic than Republicans about voting so far this year.

"If that pattern persists, turnout may be a concern for the GOP in November," Holland said.

When all voters nationwide are asked to evaluate the major candidates in both parties, only one Republican candidate, McCain, fares well on issues and personal qualities. Most registered voters say Clinton and Obama -- as well as McCain -- have the necessary leadership skills and vision to be president. But most voters don't feel that way about Romney, Giuliani and Huckabee.

The same is true on issues. A majority of registered voters nationwide say McCain, Obama and Clinton agree with them on issues that matter, but a majority of voters disagree with Romney, Giuliani and Huckabee on important issues.

The economy continues to top the list of the public's biggest concerns, with Iraq, terrorism and health care not far behind. Four in 10 Americans now say the economy is in good shape, down 6 points since December and 14 points since the fall. Nearly six in 10, 59 percent, say the economy is in poor shape.

Regarding Iraq, the number of Americans who say things are going well for the U.S. has jumped 12 points since November, to 46 percent. Support for the war has grown 3 points in the same time.

The poll involved interviews with 1,393 adult Americans, including 448 registered voters who describe themselves as Democrats and 377 registered voters who describe themselves as Republicans. They were interviewed from January 14-17.

The poll's sampling error is plus-or-minus 5 percentage points for the Republican respondents, 4.5 percentage points for the Democratic respondents, and 8 percentage points for the African-American Democrat respondents. E-mail to a friend

All About Barack Obama • Hillary Clinton • John McCain

Bush calls for quick, temporary tax relief to spur economy

WASHINGTON (CNN) -- President Bush on Friday proposed a temporary, broad-based tax relief package aimed at spurring the nation's slowing economy.

"We can provide a shot in the arm" to the economy, President Bush said Friday at the White House.

During remarks at the White House, Bush, flanked by economic advisers, said the nation's economy is at risk for a downturn and Congress must act to head off trouble.

"This growth package must be big enough to make a difference in an economy as large and dynamic as ours," Bush said.

"By passing a growth package quickly, we can provide a shot in the arm to keep a fundamentally strong economy healthy, and it will help keep economic sectors that are going through adjustments, such as the housing market, from adversely affecting other parts of our economy." Watch more of Bush's tax outline »

It should equal about 1 percent of the nation's gross domestic product, or roughly $140 billion, he added. Bush said the economy will continue to grow but at a slower rate.

The president offered no specific details of the proposed package, but he did insist that it include tax incentives for business, "including small businesses, to make major investments in their enterprises this year." Bush also said the economic package must include "rapid income tax relief" for consumers to "lift our economy at a time when people otherwise might spend less."

Although Democratic leaders in Congress expressed general support for Bush's remarks, other Democrats on Capitol Hill met the president's proposal with suspicion.

Two Democratic leadership aides made it clear Friday that the growth package would not win support from Democratic leaders unless it includes relief for low and middle income earners.

"We want to include people who pay taxes, not necessarily income taxes -- a lot of lower income people pay payroll taxes," said one aide. Another source stated flatly, "We're not going to pass a bill in the House that doesn't include low-income people."

Sen. Charles Schumer, D-New York, said he was disappointed that Bush did not include stimulus-spending measures aimed at helping the disadvantaged such as extending unemployment benefits. Schumer said such spending initiatives would jump-start the economy faster than tax cuts alone.

"I think if we avoid any of the ideological fights, we could actually pass something so that it would take effect on March 1," Schumer said.

House Speaker Nancy Pelosi, D-California, expressed agreement with Bush on "the need to provide assistance immediately," saying in a statement that "we must invest our resources in such a way that injects confidence and consumer demand, promotes economic growth and creates jobs."

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Senate Majority Leader Harry Reid, D-Nevada, said, "I also agree that our focus must be on finding temporary measures that will do the job effectively."

Sen. Edward Kennedy, D-Massachusetts, agreed that "we must act swiftly to boost the economy" but stressed the need to help families who "are struggling every day to pay their bills, heat their homes and pay their mortgages."

Bush's remarks came a day after talks on the subject with Democratic and Republican lawmakers, and following Federal Reserve Chairman Ben Bernanke's call for a fiscal stimulus package to help an economy beset by plummeting stock prices and a credit and mortgage crunch.

Bush said Friday he was encouraged by his discussions with lawmakers. "I believe there is enough broad consensus that we can come up with a package that can be approved with bipartisan support."

Existing income tax cuts supported by the Bush administration are due to expire in 2010, and the president called on Congress to make them permanent.

"Unless Congress acts, the American people will face massive tax increases in less than three years," Bush said. "This tax increase would put jobs and economic growth at risk." Watch experts explain how to goose the economy »

The proposed stimulus package comes as a leading gauge of future economic activity was released Friday by the Conference Board. The December report showed a decline for a third straight month for the U.S. leading index -- down two-tenths of a percent. The report cited housing permits for the largest negative contribution to the index. See chart showing Americans' recession fears »

On Thursday, the Dow Jones industrial average of stock prices dropped more than 300 points after reports of slowing growth and massive debt write-offs by Merrill Lynch. The brokerage giant reported a nearly $10 billion loss for the fourth quarter of 2007 and wrote off more than $11 billion in bad mortgage debts.

Former Treasury Secretary Lawrence Summers stressed the importance of whom any relief package would target. "It needs to go to people who are going to spend it," Summers said Friday on CNN's "American Morning." "That means particularly those who rely on tax refunds -- those receiving benefits, those whose incomes have been hurt by the downturn."

Bernanke told the House Budget Committee on Thursday that he does not believe the economy will enter a recession, but he said he expects growth to proceed at a slow pace this year and possibly into early 2009. He said Congress needs to take decisive action to boost the economy.

"To be useful, a fiscal stimulus package should be implemented quickly and structured so that its effects on aggregate spending are felt as much as possible within the next 12 months or so," Bernanke said. But he said any package should be "explicitly temporary" to avoid running up the government's long-term debt.

Bernanke stopped short of suggesting that the Bush tax cuts should be made permanent, telling lawmakers he supports "the law of arithmetic."

"What comes in at least has to equal what goes out at some point," he said.

In 2001, Americans received checks from the government designed to stimulate the economy. Individuals received $300 and families $600.

Twenty to 40 percent of the checks were spent within days. Consumers saved one-third of the money, and two-thirds went back into the economy within two quarters, officials said. E-mail to a friend

CNN's Deirdre Walsh contributed to this report.

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Humans Blamed in Coral Reef Disappearance

Jan. 9, 2008 -- The world's coral reefs are in alarming decline, but what -- or who -- is most to blame?

A groundbreaking study published Wednesday singles out human settlement, especially coastal development and agriculture, as the main culprit, even more so than warming sea waters and acidification linked to global warming.

The study focuses on the Caribbean, where declining reefs are endangering species of wildlife as well as tourism and fishing that are vital for the local economy, says lead author, Camilo Mora, of Dalhousie University in Halifax, Canada.

"The continuing degradation of coral reefs may be soon beyond repair if threats are not identified and rapidly controlled," he said.

Teasing apart the complicated web of factors driving reef destruction -- overfishing, runoff of pesticides and pollution, hurricanes, climate change -- is crucial for devising the best conservation strategies.

There might not be enough time for second or third chances, Mora said.

But a welter of contradictory evidence, most of it gathered from single sites, has made it nearly impossible to figure out what causes what.

Which is why Mora and University of Miami marine biologist Robert Ginsburg decided to compare several large-scale databases that had never been systematically cross-referenced.

Focusing on corals, fishes and macroalgae, or seaweed, in 322 sites across 13 countries in the Caribbean, the study matched environmental and ecological data against patterns of human population density, coastal development and agricultural land use.

Also included were data on hurricanes, biodiversity, fish populations and coral disease.

Sifting through all these statistics showed clearly that the number of people is the main driver of the mortality of corals, along with declining fish biomass and increases in algae.

But different kinds of human activity resulted in different impacts, the study revealed.

Higher population density in coastal areas produces more sewage and depletes fish stocks, both of which are directly responsible for coral mortality.

But chemical discharges from agricultural land drives an increase in macroalgae, which is indirectly linked to coral loss.

Warmer sea surfaces are also contributing to coral decline, but not hurricanes, said the study, published in the journal Nature.

"The human expansion in coastal areas inevitably poses severe risks to the maintenance of complex ecosystems such as coral reefs," Mora said.

Within a reef, predators prey on plant-eating fish, herbivores graze on seaweed, which in turn interacts with living coral. "A threat in any one group may escalate to the entire ecosystem," Mora explained.

"The array of human stressors ... are significantly affecting all major groups of coral reef organisms."

The study also concluded that while Marine Protected Areas help restore fish populations, they do nothing to protect coral.

A fifth of the world's marine reefs have already been destroyed and half are threatened because of human impact, whether directly or as a consequence of rising temperatures driven by climate change, according to the World Conservation Union (IUCN).

Coral reefs support some of the richest areas of biodiversity in the world, including many species that depend on reefs for shelter, reproduction and foraging.

Coral reefs also provide livelihoods for 100 million people and form the basis for industries such as tourism and fishing, worth $30 billion a year, says the IUCN.

Deep Sea Vents: Hot, Wet, Weird

Jan. 9, 2008 -- Thirty years ago, scientists exploring the depths of the ocean came across jets of hot water, spewing from the sea floor, which hauled up flecks of gold and other minerals from Earth's interior and nurtured weird, resilient microbial life forms.

In a paper issued on Wednesday, marine seismologists looking at a site in the East Pacific say they have gained insights into how this unique plumbing system of hydrothermal vents works.

The jets are found thousands of feet below the surface on the mid-ocean ridges -- geologically active "mountain ranges" -- formed from mighty tectonic plates that push into each other and form spines along the ocean floor.

Until now, the main hypothesis about hydrothermal vents has been that gigantic pressure forces seawater through large faults along the flanks of the ridge.

The water, the theory goes, is then heated by coming into proximity with volcanic rock before re-emerging at the middle of the ridges, where the vents are usually clustered.

But in the first detailed investigation into vent circulation, a team led by Maya Tolstoy of Columbia University's Earth Observatory in New York has come up with a different picture.

They placed seismometers over a 1.54-square-mile area of the East Pacific Rise, about 500 miles southwest of Acapulco, that has been under study for the past 15 years.

The sensors monitored tiny earthquakes that happen 8,125 feet below the surface. Around 7,000 of these brief, shallow quakes were recorded in 2003 and 2004 alone.

The tremors also built up an image of how the water circulates, because the quakes were intriguingly clustered around where the cold water entered the rock.

The map drawn by Tolstoy's team shows a down-flow pipe that descends about 2,275 feet into the ridge, then fans out for about 650 feet.

The water then plunges down another 1,950 feet until it arrives just above a bulge of magma. There, the water is heated and disgorged along the ridge through a dozen vents about 1.2 miles north of the entrance pipe.

Tolstoy's team contends that what appear to be tiny quakes are caused by the physical stress of cold water passing through hot rocks.

And, contrary to the prevailing hypothesis, they believe the water travels not through large faults but through systems of tiny cracks, and at a much higher rate of turnover than previously thought.

The paper, published by the British journal Nature, adds critical knowledge about seafloor currents and the nutrient flows that feed them. It also furthers understanding about the mechanics of heat transfer from Earth's crust to the seafloor.

Hydrothermal vents are sometimes called "black smokers" for the bilious clouds of material that emits from their chimneys.

Plate Tectonics: Earth's Lucky Geology

an. 11, 2008 -- Four decades after the rise of the great, unifying theory of plate tectonics, geologists are still scratching their heads over a lot of the details.

Unanswered, for instance, are basic questions like how the shifting and colliding of plates got started, what keeps plates moving, why other planets in our solar system lack plate tectonics, and how important all the geological turmoil might be to the evolution of life.

"We didn't get it all right the first time, so let's ask the questions," said geologist Vicki Hansen of the University of Minnesota at Duluth, referring to the fact that despite decades of work, many mysteries remain.

Hansen recently stirred the pot with a controversial hypothesis published in last month's issue of the journal Geology. Meteorite impacts early in Earth's history, she suggested, created the first rifts in the crust, jump-starting plate tectonics.

Prior to the 1960s, geologists were hard pressed to explain such basic things as how most mountain ranges formed and why volcanic regions and earthquakes were clustered in certain parts of the planet. Plate tectonics put these phenomena, and many others, into a single, unified framework.

That framework is an Earth with a rocky crust divided into plates that are moving, rifting, colliding and overrunning each other. It finally made sense of a previously nonsensical geography and is now recognized as one of the greatest scientific breakthroughs of the 20th century.

Energizer Bunny Tectonics?

Another iconoclastic hypothesis just out last week goes after the question of whether plate tectonics ever stops. Has it ever done so? Geologist Paul Silver of the Carnegie Institution of Washington thinks it's possible.

"It's an implicit assumption that plate tectonics never shuts down," Silver told Discovery News. "But it's nowhere stated in plate tectonics theory."

Silver and his colleague Mark Behn proposed in the Jan. 4 issue of Science that all it takes to stop plate tectonics is the devouring of the crustal plate under the Pacific Ocean. And that's not as far-fetched as it sounds.

The Pacific Plate is surrounded by most of Earth's overriding (subducting) crust collision zones, so it's getting smaller all the time. Eventually, roughly 350 million years from now, the surrounding adjacent continents will collide.

Meanwhile, the lost crust is being made up on the other side of the planet by the Mid-Atlantic Ridge, which has been efficiently churning out magma and expanding the Atlantic for millions of years.

The end result would be a supercontinent, no remaining subduction zones, and virtually no plate tectonics, at least for a while.

Accidental Earth

In recent years, plate tectonics has also become a matter of importance in the search for life on other planets. Is it, for instance, just a coincidence that Earth is the only planet in our solar system known to have both life and plate tectonics?

Probably not.

"Plate tectonics helps make a planet habitable," said astrobiology researcher Diane Valencia of Harvard University. It does so by regulating a planet's climate, she said.

Valencia and her colleagues recently published an article in the Astrophysical Journal outlining how very large, rocky planets in other solar systems -- which they call super-earths -- can have plate tectonics, and therefore be great candidates for life.

On Earth plate tectonics help regulate the planet's long-term temperature by recycling climate-warming carbon from the atmosphere, Valencia explains.

Plate tectonics allows captured carbon that is buried in the seas to find its way back into the atmosphere via subduction zones. Where one plate is pushed under another, carbon-rich, wet ocean sediments are pressed into the Earth's mantle, where they are heated. The water there helps melt the sediments, which then buoy upwards to create chains of volcanoes -- which release the carbon back into the atmosphere.

"If you don't have plate tectonics, you don't have this way of transporting materials out of (and back into) the atmosphere," said Valencia.

This sort of recycling -- which takes place over a over a million-year timescale -- doesn't eliminate some millennial-scale climate swings, she said. But it's a thermostat which keeps Earth's long-term climate within the range that allows water to remain liquid -- the habitable range for life.

What this means for other planets in other solar systems is that plate tectonics can expand the Goldilocks zone of habitability around a star -- where it's neither too hot nor too cold -- by allowing a planet to better regulate its own temperature and keep water wet.

Very large, rocky planets -- those super-earths -- would be the most likely places for life because their greater internal heat causes them to experience larger forces on thinner plates, Valencia asserts. As a result, they would be particularly good at regulating their climates and allowing life to evolve.

It's likely that the lack of plate tectonics is the reason that both Mars or Venus -- Earth's closest local sibling planets -- are dead, Valencia explained.

"If Mars were to have plate tectonics, it would have to be bigger early on," said Valencia. This is because plate tectonics require a planet to have a lot of interior heat to keep things moving. Smaller planets dissipate their heat faster, and so have a very short window of time for plate tectonics.

Venus, on the other hand, is about the same size as Earth, but it lacks water, said Hansen. Without water in the mantle to help melt rocks and trigger volcanic recycling of material, Venus' crust appears to have remained stiff and locked up forever. Had Venus held more water, or if it had been a super-sized rocky planet, it too would have had plate tectonics and perhaps life.

The implication of all this, of course, is that little old Earth lucked out. A little less water and the planet may not have had plate tectonics. Climate swings would have been harsher, and life might have foundered early on.

Earth, just barely large enough to have the internal heat; just wet enough to melt and recycle its crust -- may have barely made the cut for life.