News briefs from the frontiers of science

Tree discovery yields clues on ancient forests; why ethanol may not be a pollution solution.

from the April 19, 2007 edition

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In Los Angeles and regions like the Northeast, smog increased when ethanol replaced gasoline. In the Southeast, smog concentrations fell. The difference in smog levels was the result of differences in weather patterns, the background level of other smog ingredients, and the levels of hydrocarbons and oxides of nitrogen in the two fuels.

The study projects that by 2020, cases of ozone-related health problems would be 4 percent higher nationally, while in some areas, such as Los Angeles, cases would be 9 percent higher than if drivers fueled up with gasoline. The results suggest that to get the best balance of air quality and reduced levels of greenhouse gases, plug-in hybrid cars or those powered by fuel cells might be better options. The study appeared in the April 18 issue of the journal Environmental Science and Technology.

Ocean ridges need to vent

Undersea ridges, where Earth's crust spreads and renews itself, are hot spots for marine biologists and geologists alike. Now, Chinese and US researchers exploring the bottom of the southwest Indian Ocean say they have discovered a large field of hydrothermal vents along an ultra-slow spreading ridge, a type of ridge long thought to be too cool to host them.

Hints that this type of ridge could be a geological and biological hothouse first came from the Gakkel Ridge in the Arctic Ocean, the slowest-spreading ridge on the planet. During a 2001 expedition aboard the US Coast Guard icebreaker Healy, researchers found nine vents, twice as many as theories predicted.

The Indian Ocean team, which included scientists from the Woods Hole (Mass.) Oceanographic Institution, gathered the data in February and March during a Chinese-led expedition aboard the country's research vessel Dayang 1. Sensors aboard robotic undersea vehicles detected plumes of the hot, mineral-laden water the vents spew, and the team used sonar to map the extent of the vent field, which covers an area somewhat larger than a football field. The vent site is one of the largest yet discovered, the scientists say.

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