Earth/Environment

Early plate tectonics

Slivers of ancient rock may show that plate tectonics, the movement of large chunks of crust that is a defining feature of Earth’s surface today, has been happening for at least 3.7 billion years. Researchers in England, Australia and China say they’ve identified intact pieces of the Earth’s mantle in the ancient, highly squished rocks of southern Greenland. If so, the slivers must have come from one early crustal plate diving beneath another, scraping up pieces of the deeper Earth, the team writes in a paper appearing May 24 in Geology. —Alexandra Witze

Tomatoes: CO2 is galling

As concentrations of carbon dioxide rise, certain plants may lose more battles with pests, Chinese scientists report in the May 24 PLoS One. Researchers grew tomatoes at concentrations of carbon dioxide representing current levels (390 parts per million) and at those predicted to exist near the end of the century (780 ppm). When exposed to tiny nematodes, which are common soil parasites, tomatoes breathing the elevated carbon dioxide suffered most. They developed more tumorlike galls in their roots than did plants at current carbon dioxide levels and produced fewer flavonoids and other antioxidant compounds. The researchers linked this greater parasite damage to the reduced activity of genes managing certain plant defense compounds. —Janet Raloff

Babies face high flame-retardant exposures

Eighty percent of baby products containing polyurethane foam are treated with flame retardant chemicals, a U.S. team of chemists finds. After testing 101 common products, they calculate that babies’ exposure to TDCPP, the flame retardant that turned up most, would be higher than adults encounter — and “higher than acceptable daily intake levels of TDCPP set by the Consumer Product Safety Commission.” The testing found five products still in use that had been treated with a flame retardant that has since been banned: decabrominated diphenyl ether, the scientists reported May 18 in Environmental Science & Technology. And two products contained organophosphate flame retardants never before reported in the environment or commercial products. —Janet Raloff

China’s pollution cuts downstream rains

Industrial growth in China since the early 1980s has darkened its skies with plenty of pollutant particles. A team of U.S. researchers now reports that satellite data show the concentrations of tiny aerosol particles climbed some 40 percent throughout that period over the Shanghai-Nanjing and Jinan industrial regions. Downwind rains over the East China Sea, meanwhile, diminished by one-third over the same period, they report May 10 in Geophysical Research Letters. The scientists say that learning why pollution had this effect might suggest weather impacts of possible geoengineering tactics, like seeding skies with particles to slow global warming. —Janet Raloff