Health & Science

The Great Barrier Reef is dying

The world’s largest coral reef ecosystem is spiraling toward collapse. New research shows that Australia’s Great Barrier Reef, which spans some 133,000 square miles and is home to tens of thousands of species, has lost more than half of its coral over the past 30 years. The extent of the loss is “just mind blowing,” University of North Carolina biologist John Bruno tells NBCNews.com. Worldwide, coral reefs have declined by 20 percent in recent decades, mostly because of climate change and the acidification of the seas. Bruno says scientists have long assumed that the Great Barrier Reef‘s “isolation, size, and huge biodiversity” would help it resist that decay. In recent years, though, warming waters there have killed coral and spawned more powerful cyclones that damage the delicate reefs. Meanwhile, fertilizer runoff from Australia has fueled a population boom among plankton, which feed the larvae of voracious, coral-eating starfish. Marine scientists say only a drastic curbing of fertilizer use can slow the starfish advance, allowing the coral, which now covers only 14 percent of the reef, to begin growing back. Otherwise, coral cover could fall to just 5 percent in the next decade.

An ancient stream on Mars

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NASA’s Curiosity rover has uncovered proof that water once flowed swiftly across the surface of Mars. In its first major discovery since its spectacular landing in August, Curiosity beamed back close-up photos showing what appears to be a dry stream bed, filled with small, rounded pebbles, Space.com reports. Analysis of the size and smooth shape of the pebbles suggests that they once tumbled down a fast-moving stream “with a depth somewhere between ankle and hip deep,’’ says the mission’s lead scientist, William Dietrich of the University of California, Berkeley. Researchers have long believed that channels visible on the surface of Mars are evidence that the planet was once covered in water, but Curiosity’s photos mark “a transition from speculation to direct observation,” Dietrich says. The streams apparently flowed for thousands of years before Mars dried up a couple of billion years ago and became the arid land it is today. What intrigues NASA is that “a long-flowing stream can be a habitable environment,” says mission scientist John Grotzinger. Curiosity will now search for carbon, which would indicate that microorganisms may have once existed on Mars.

Remnants of childbirth

Carrying a baby boy in her womb can change a woman’s brain permanently—and may protect her against Alzheimer’s disease later in life. Researchers analyzed the brains of 59 women who died between the ages of 32 and 101 and found that two thirds of them had bits of male DNA, which scientists believe migrated from male fetuses the women carried. Fetal cells from daughters might be there, too, but would be harder to detect. Though the sample was small, the study found that women with the largest amount of male DNA were also the least likely to have developed Alzheimer’s, suggesting “that the presence of fetal cells in the female brain prevents disease,’’ cardiologist Hina Chaudhry of Mount Sinai School of Medicine tells ScienceNow.org. Previous research has shown that fetal cells migrate through the placenta into a woman’s blood and organs—causing a condition called “microchimerism”—but until now researchers weren’t sure the cells could enter the brain. Scientists believe that microchimerism from male fetuses may help protect against certain diseases, such as breast cancer. But there’s also evidence that it may increase the risk of colon cancer and some autoimmune disorders.

The cuteness factor

Adorable photos of baby animals may seem distracting, but they can actually aid concentration in the workplace, Time.com reports. Japanese researchers had volunteers complete several tasks designed to test their focus, including playing a board game like Operation, in which they had to remove small pieces from a cramped hole with tweezers without brushing the sides of the hole. In the middle of the task, the volunteers took a break to look at pictures of cute baby animals, adult animals, or tasty-looking foods. After the break, researchers found, the volunteers who had viewed the baby animals performed markedly better than the other groups—improving their motor performance by 44 percent and their number-spotting ability by about 16 percent. The finding suggests that cute things “not only make us happier,” but also compel us to act “more deliberately and perform tasks with greater time and care,” the researchers say. That’s because we evolved to be attentive and patient in the presence of babies—qualities that also make us better workers.