For the seagrass beds of southern Texas, rising sea level may be a case of give and take—or make that take and give. Higher waters are killing off some seagrass. But as the water rises even higher, newly submerged land has the potential to increase the total seagrass area. Seagrass is important for many coastal ecosystems. It can protect the coast …

The “beards” of marine mussels aren’t just a fashion statement. They anchor the mussels to the sea floor, attach to each other to form large “beds,” and hold out potential invaders. They’re also playing a role in materials research—scientists study the beards to learn how to make water-proof glue for many applications. The beards consist of a bundl…

Early in World War II, the Navy began using sonar to probe for enemy U-boats. Ships would send out pulses of sound, then measure their reflection to figure out what was below. But early observations revealed something a little disconcerting: The ocean floor wasn’t where it was supposed to be—it was a lot closer to the surface. Sonar operators thoug…

Pufferfish in Japan are known for one thing. They’re a delicacy that can be deadly. Their organs contain a highly toxic compound that can kill in minutes. But one species of pufferfish has a different distinction: Its males might be the most creative artists in the oceans. In 1995, divers off the coast of Japan saw an unusual pattern in the sand on…

As Earth gets warmer, scientists expect to see some changes in hurricanes. There might not be more of them, but the strongest ones might be much more intense. To better understand what might happen, scientists are digging deep into the past. They’re looking at how often especially powerful hurricanes made landfall when climate conditions were simil…

Until 2011, no one knew that a couple of groups of dolphins found along the coast of southeastern Australia were a separate species from all other dolphins. Burrunan dolphins are related to the two other known species of bottlenose dolphins. There are two groups of Burrunans—about 250 dolphins in all. But today, no one knows how much longer the spe…

“Million Mounds” may be overstating the case a bit, but there’s no doubt it’s one of the most extensive deep-water coral reefs on the planet. Or make that part of one. Scientists recently discovered that the system extends far beyond Million Mounds—the biggest deep-water coral reef yet seen. The entire complex stretches along the southeastern Atlan…

For a tiny marine worm found in the Bay of Naples and elsewhere, life ends in a frenzy. The worms lose a lot of their internal organs, their eyes get bigger, and they rise to the surface. There, as they paddle furiously, they release sperm and eggs, creating the next generation. And it’s all triggered by moonlight. The worms are one of more than 10…

Conditions in the Arctic Ocean may be about to switch gears. That could mean that Arctic waters would become more like those in the North Atlantic—a process known as “atlantification.” As a result, sea ice would disappear a lot faster than it has in recent years. The rate of sea-ice loss peaked in 2007. The total amount of ice is still going down, …

Some tiny sea snails may look like angels, but they act more like little devils. They rip their favorite prey from their shells. And the prey just happens to be a relative. Sea angels are found around the world, from the arctic to the tropical waters near the equator. Most range from the surface to depths of a couple of thousand feet, although some…