Science Digest

Global Gases

We knew that cow burps were a major source of the greenhouse gas methane in the atmosphere. Now add belches of methane gas from vents on the bottom of the ocean to the list of significant methane sources.

Substantial amounts of methane gas can reach the ocean surface and the atmosphere from seafloor vents as deep as 600 meters, according to a study out Sunday in Nature Geoscience. Scientists had previously thought that deep-sea seeps do not reach the surface because the bubbles would dissolve. This research, from Evan Solomon at the University of California at San Diego and his colleagues, suggests that current estimates of the contribution of oceanic methane to the atmosphere may be too low.

-- Rachel Saslow

On Good Behavior

To test the idea that a sense of moral inferiority might encourage future moral behavior, Northwestern University psychologists told 46 undergraduates that they were taking a handwriting test. One-third of the participants copied positive-trait words such as "caring, generous and fair"; one-third wrote negative words including "selfish, disloyal and greedy"; and the control group wrote the neutral words "book, keys and house." The participants then wrote short stories about themselves, including all of the words they had just copied.

When they were finished, researchers asked the participants if they would like to make a donation of up to $10 to charity. The control group donated an average of $2.71. The average increased to $5.30 for the negative-traits group -- "those whose moral identity was threatened," the authors wrote -- and fell to $1.07 in the positive-traits group.

The study shows that people who engage in immoral behavior "cleanse" themselves with good work, according to Northwestern's Rumen Iliev, who wrote the Psychological Science journal article with Douglas Medin and Sonya Sachdeva.

-- Rachel Saslow