Earth/Environment

Tar balls in the sky
The burning of trees, crop residues and other types of biomass can spew huge quantities of soot and other carbonaceous pollutants, including nanosized tar balls. Researchers at Arizona State University in Tempe now find that these tar balls have almost the same light-absorbing and air-warming capacity as soot — and the quantity of tar balls present in biomass smoke plumes can be roughly double that of soot. Owing to tar balls’ potency and the huge quantities of biomass burned globally, climate-warming computer programs should start taking these pollutants into account, the authors recommend online March 8 in the Journal of Geophysical Research. —Janet Raloff

Listen to a faraway volcano
Iceland’s infamous Eyjafjallajökull volcano didn’t just shut down European airspace last spring — it also sent low-frequency vibrations ringing through the atmosphere as far away as Tunisia. Fourteen stations set up to detect “infrasound” vibrations for the purposes of monitoring atmospheric nuclear tests also picked up signals from the April–May 2010 eruption of Eyjafjallajökull, an international team of scientists will report in Geophysical Research Letters. Even modest-sized volcanic eruptions can thus be detected from far away, and infrasound detectors could complement traditional volcanic monitoring. —Alexandra Witze

Nonstick hemoglobin
A new study finds signs of potential toxicity in a common pollutant: perfluorodecanoic acid, a breakdown product of stainproof and greaseproof coatings on consumer goods and food packaging. In test tube studies, PFDA disrupted the structure of hemoglobin and myoglobin, the oxygen-carrying proteins in blood and muscle, researchers at China’s Shandong University found. The PFDA-induced structural changes should render the proteins less able to bind oxygen, the scientists observe. In contrast, smaller related perfluorinated compounds (such as PFOA) had little effect on the proteins, the scientists report online March 10 in the Journal of Agricultural and Food Chemistry.  —Janet Raloff

Superfund improves infant health
University scientists claim they have the first evidence that cleanups of Superfund sites protect babies in the womb. In a March working paper issued by the National Bureau of Economic Research, researchers compare the health of more than 620,000 infants born to families near these hazardous sites. Birth defects — which typically occur early in pregnancy — fell 20 to 25 percent in the five years after cleanups compared with the five years before cleanups started, especially among families living within 2,000 meters of Superfund sites. Infant mortality data suggest cleanups of the 51 most toxic sites allowed more than 323 additional babies to survive. —Janet Raloff

Bottoms up in the Arctic
One-quarter of the places containing frozen methane on the Arctic Ocean’s seafloor may warm substantially in the coming century, a new study suggests. Using computer simulations of the Arctic’s future, German and French researchers found that the greatest warming will occur in shallow regions where warm water enters from the Atlantic. If these areas start to warm up, heat-trapping methane could bubble to the surface and add to the effects of global warming, the scientists report in an upcoming Geophysical Research Letters. —Alexandra Witze