Making the ocean hostile to life
Higher levels of greenhouse gases from burning fossil fuels aren’t just warming the atmosphere. They’re also making the oceans more acidic at an unprecedented pace—and threatening sea life. A new review of geologic records shows that seas are acidifying faster than at any time in the past 300 million years, a period that encompasses four mass extinctions, LiveScience.com reports. “What we’re doing today really stands out,’’ says Columbia University paleoceanographer Bärbel Hönisch. Over the past 100 years, as the oceans have absorbed higher levels of CO2, their acidity has risen by 30 percent. Acidification is happening 10 times faster now than it did 56 million years ago, when a mysterious spike in CO2 caused a massive extinction, as acidic water ate away the shells of plankton. The current pace of change could lead to acid levels that would likely destroy “organisms we care about,” Hönisch says, including coral reefs, oysters, mussels, and salmon. It may already be too late to prevent major die-offs. In terms of predicting what will happen to marine ecosystems, Hönisch says, “we are entering an unknown territory.”

The Iceman had heart disease
Living the simple outdoor life didn’t protect prehistoric man from some very familiar medical problems. The newly sequenced genome of a 5,300-year-old mummified body found frozen in the Italian Alps has revealed lactose intolerance and heart disease. Since hikers discovered the Tyrolean Iceman in 1991, researchers have determined that he had bad knees, sore joints, and cavities when he was killed by an arrow at the age of about 46. Now, an analysis of the Iceman’s nuclear DNA shows that he had brown eyes, brown hair, and type O blood, and that he carried Lyme disease—the first known case. His inability to digest milk products was probably the genetic norm then, since people during his time were only beginning to farm. The genetic evidence of hardening of the arteries suggests that if he hadn’t been shot, he “might have had a heart attack soon after,” anthropologist Albert Zink of the European Academy of Research tells The New York Times. Scientists often blame modern heart disease on rich food and little exercise, but the Iceman “wasn’t obese” and “was very active,” Zink says, suggesting that the genetic roots of heart disease are deeper than previously thought.

Antarctica’s alien invaders
Scientists and tourists visiting Antarctica are unwittingly bringing with them thousands of invasive plant seeds that could threaten the continent’s unique ecosystem, a new study shows. After vacuuming the luggage and outerwear of a sample of the more than 40,000 people who set foot in Antarctica annually, researchers estimated that 71,000 seeds are likely arriving every year. Many of the hitchhiking seeds come from the Arctic and other cold climates—where visitors last wore their warm gear—and are able to establish themselves in Antarctica. And climate change is warming the Antarctic Peninsula faster than almost any place else on the planet, making it more vulnerable to foreign pests that previously couldn’t thrive there. Plants such as Iceland poppies and annual bluegrass, a common weed in the U.S., have recently taken root there, and if visitors fail to improve their “biosecurity measures,” then “rats, sparrows,” and other aggressive species could soon follow, study author Steven L. Chown of Stellenbosch University in South Africa tells BBCNews.com. “In the long term,” says New Zealand ecologist Philip Hulme, “it’s going to be a big problem.”

Why women seek conflict
Men who say that their wives or girlfriends deliberately pick fights may be on to something. A new study shows that in romantic relationships, men feel best when they can tell that their significant others are happy; women, on the other hand, are most content when their partners are upset or agitated, because the intensity of their emotions shows they’re invested in the relationship. Researchers videotaped 156 married and unmarried couples discussing recent episodes that had upset them; then they had the couples watch the tape and answer questions about how they felt at different points. They discovered that “women tend to want to engage around conflict,” Massachusetts General Hospital psychologist Shiri Cohen tells NPR.org. That’s because women feel most connected when they can tell that their partners are distressed—or when the men understand that the women are suffering. Men, on the other hand, find conflict threatening, and feel best about their relationships when their partners are in a good mood. How can both styles hope to peacefully coexist? “The more men and women try to be empathetic to their partner’s feelings,” Cohen says, “the happier they are.” That means that women have to accept men when they’re blithely content, while men must be willing to deal with women’s occasional need to be unhappy.