Corals have annual growth bands similar to tree rings. Each band marks a year of the coral’s life. And a coral’s porous structure acts like a natural sieve, collecting dust every year, Bhattacharya explains. In this way, corals are similar to instruments that can be used to estimate dust from desert regions over the past few centuries. As dust from a desert storm blows over the ocean, some falls down into the water column and becomes trapped in a coral’s skeleton.
Bhattacharya’s research now indicates that long-running drought sends clouds of dust into the atmosphere. The dust changes cloud properties in ways that can largely prevent them from raining out moisture. So the warming temperatures associated with climate change can create dry conditions that lead to drought. Such findings might provide useful planning information to help people in arid parts of the world who depend on sufficient rain for drinking water and crops.
Bhattacharya enjoys investigating the lessons about how storms’ movement of dust can affect climate. She says it “has given me a pretty exciting life.”
Finding fuel in rocks
John Zumberge always loved being outdoors. So decades ago, he started his career by scouting hillsides, looking for natural oil dribbling out of rocks or in small pools in soil. He’d hammer away at various sites, collecting rocky rubble to take back to a lab for analysis. Today, he works in a lab, analyzing the quality of fossil fuels such as oil and natural gas. These fuels form over long periods of time from the remains of living organisms and are used to power vehicles and to produce electricity.
As a petroleum geochemist, Zumberge studies the oily, flammable liquid that is the source of gasoline, kerosene and other products. He tries to understand how oil and gas at certain underground pockets moving around. This helps oil producers identify the best places to drill down and extract energy-rich fuels.
He is also a businessman: Together with a friend, Zumberge co-owns GeoMark Research, Ltd., in Houston. This company examines the quality and source of oil and gas deposits deep in the earth.
Zumberge uses high-tech tools to analyze petroleum, also known as crude oil, for chemical fossils, sometimes called biomarkers. These chemicals offer clues to the type of rock, buried far underground, in which the oil formed. The chemicals can also provide information about the oil’s quality. For example, rocky shale produces oil with low concentrations of sulfur impurities. Limestone tends to produce oil with lots of sulfur. To keep air pollution levels low, companies that produce gasoline will pay more for low-sulfur oil, Zumberge explains.