Due friday 9AM:When howling winds whip up in Earth’s largest deserts, it’s time to head for cover. Billowing gusts kick up sand, forming walls of fast-moving dust that can block the sun. “You can’t see anything that’s more than a few meters away,” says Joseph Prospero, an atmospheric chemist at Florida’s University of Miami, who studies dust storms. Grains of sand pelt against your skin like thousands of piercing needles, and musty-smelling grit coats your mouth and nostrils. “The amount of dust that gets in the air feels suffocating,” says Prospero. For people who live in and around the deserts along Earth’s midsection—such as Central Asia’s Gobi Desert and Africa’s Sahara Desert—dust storms frequently disrupt daily routines. “When a storm kicks up, you just have to go inside and wait it out,” says Prospero. But scientists have discovered that the effects of dust storms extend much farther than the deserts’ sandy borders. Global winds lift dust from Asia and Africa and carry it to other continents thousands of miles away, including North America. Now, many scientists are concerned that the grimy visitor may be putting people and other organisms in danger. Hoping to learn more about the storms’ potential health risks, researchers are following the dust trails. WORLD TOUR During the Asian dust storm season—from March through May—winds frequently blow dust clouds eastward across the Pacific Ocean. In just a week, the dust can complete a journey from Asia, over the Pacific, and across the entire United States. As Asia’s storms settle, windstorms begin kicking up dust in Africa’s deserts. Between May and October, African dust drifts westward across the Atlantic Ocean, making its way toward the southeastern coast of the U.S. and islands in the Caribbean Sea. FOUL CLOUDS The billows of traveling dust disrupt air quality—creating hazy skies along their routes. Eventually, the winds slow and can no longer keep the sandy particles airborne. The dust drops from the sky, depositing a gritty film on every exposed surface. Studies have shown that this falling desert dust is actually an important nutrient for plants. “Researchers think that rain forests in the northern Hawaiian Islands are nurtured by Asian dust events,” says Dale Griffin, a microbiologist with the U.S. Geological Survey. 5 10 15
What is the author’s central claim about the windblown dust moving from continent to continent? Use two details from the passage to support your response.According to the author of “A Soft Spot for Crows,” the fact that crows live in cities or towns is an example of their intelligence. Explain the author’s reasoning and tell whether or not it is sound.