DNA

Coral reefs are some of the oldest, most diverse ecosystems on Earth, and among the most valuable. They nurture 25% of all ocean life, protect coasts from storms and add billions of dollars yearly to the global economy through their influences on fisheries, new pharmaceuticals, tourism and recreation. Today, the world’s coral reefs are degrading at unprecedented rates due to pollution, overfishing and destructive forestry and mining practices on land. Climate change driven by human activities is warming and acidifying the ocean, triggering what could be the largest coral bleaching event on record. Under these combined pressures, scientists project that most corals could go extinct within a few generations. I am a marine biologist at the Smithsonian’s National Zoo and Conservation Biology Institute. For 17 years, I have worked with colleagues to create a global science program called the Reef Recovery Initiative that aims to help save coral reefs by using the scienc...

Human fear of sharks has deep roots. Written works and art from the ancient world contain references to sharks preying on sailors as early as the eighth century B.C.E. Relayed back to land, stories about shark encounters have been embellished and amplified. Together with the fact that from time to time – very rarely – sharks bite humans, people have been primed for centuries to imagine terrifying situations at sea. In 1974, Peter Benchley’s bestselling novel “Jaws” fanned this fear into a wildfire that spread around the world. The book sold more than 5 million copies in the U.S. within a year and was quickly followed by Steven Spielberg’s 1975 movie, which became the highest-grossing film in history at that time. Virtually all audiences embraced the idea, depicted vividly in the movie and its sequels, that sharks were malevolent, vindictive creatures that prowled coastal waters seeking to feed on unsuspecting bathers. But “Jaws”...

Henry David Thoreau, the environmental philosopher and author of “Walden”, was a keen observer of seasonal change. In 1862, for example, he wrote in the Atlantic Monthly: “October is the month of painted leaves. Their rich glow now flashes round the world. As fruits and leaves and the day itself acquire a bright tint just before they fall, so the year near its setting. October is its sunset sky; November the later twilight.” Over the past 20 years, researchers have used Thoreau’s observations of plant flowering, leaf emergence on trees and shrubs, bird migration and spring ice melt on Walden Pond to study how these events have changed since the 1850s, largely in response to climate change. Ecologists have also pulled data for modern-day research from museum specimens, journals of hunting guides and bird and butterfly club reports. Comparisons with historical records have provided insights into shifts in the natural world caused by climate chang...