The journey around Cape Horn, at the southern tip of South America, is one of the most treacherous in the world. The cape has claimed hundreds of ships and thousands of sailors. Not many commercial vessels make the journey today. But for sail-powered yachts, rounding the cape is a big attraction—like climbing Mount Everest. Cape Horn is named for t…

The coconut crab is the 800-pound gorilla of many tropical beaches. Not only is it the biggest and strongest crab on land, it’ll eat just about anything—animal, vegetable, or even mineral. Coconut crabs are found in tropical environments in the Indian and southwestern Pacific oceans. They hatch in the sea, where they float around for a few weeks. T…

It looks like something a six-year-old dreamed up in art class—the body of a fish, the “wings” of a bird, the legs of a crab, and even the taste buds of a human tongue. Throw in some loud croaks and grunts, and you’ve got one of the ocean’s many oddities: the sea robin. The fish is found in warm waters around the globe—usually in shallow water with…

A steep change in the slope of a riverbed can create rapids—regions where the water is especially fast and choppy—and dangerous. The same thing applies to rivers in the sky. Steep changes in altitude, temperature, or pressure can concentrate the water, creating rapids. They can cause downpours that are especially fast and heavy—and dangerous. That …

The great white shark has the most fearsome reputation of all sharks. But it might not be the biggest of the predator sharks. That honor might go to the Pacific sleeper shark. The biggest one ever seen appeared to be about 23 feet long—longer than the biggest great white. The Pacific sleeper is found mainly in cold waters around the rim of the nort…

Currents at the bottom of the ocean can be just as fickle as wind currents at the surface. They can turn, speed up or slow down, and even reverse course. And they can change in just days or even hours. That’s the conclusion of the most detailed study of sea-floor currents to date. Researchers anchored 34 instrument packages across a thousand-square…

In the spring of 1956, a doctor in the Japanese village of Minamata reported an outbreak of a troubling new disease. It was seen mainly among children, and it affected the central nervous system. The disease quickly spread, with hundreds of cases reported, then thousands. It took years for scientists to work out the cause: poisoning from industrial…

The parrotfish is like a house cleaner who does a great job of keeping things tidy, but sometimes breaks a glass. You want to keep them around, but you just wish they’d be a little less destructive. For the parrotfish, the “houses” are coral reefs. They clean tiny organisms off the coral, keeping the coral healthy. But they also chip off pieces of …

The exhaust produced by ocean-going ships can contribute to our warming climate. Most ships burn fossil fuels, so they spew out atmosphere-warming compounds. But some of their contribution to global warming may be a result of lower emissions—not of carbon, but of sulfur. One of the compounds produced by burning fossil fuels is sulfur dioxide. Sunli…

The many creatures that dig into the sediments at the bottom of the ocean are ecosystem engineers. Their burrowing, foraging, and even pooping change the ocean landscape—not just close by, but miles away. Sediments have been described as the oceans’ compost heaps. They contain bits of rock and dirt washed out to sea by rivers. They also contain bit…