When beluga whales want to communicate with each other, they just use the ol’ melon—a blubber-filled structure on their forehead. Researchers have found that the whales intentionally change the shape of the melon. That may convey different emotions or intentions—whether they want to play, mate, or just hang out.

Belugas live in and around the Arctic Ocean. They have a thick layer of blubber to protect them from the cold. And they don’t have a fin on their back, which allows them to easily glide below the ice.

They use their melon to send out pulses of sound, which helps them locate prey and predators and keep tabs on their fellow whales. They produce such a variety of sounds that they’re called “the canaries of the sea.”

Belugas are the only whales known to change the shape of the melon. Researchers studied what the shapes might mean. They spent a year observing two males and two females in an aquarium. And they followed up with shorter looks at more than 50 whales in a second location.

The scientists recorded more than 2500 melon shapes, which fit into five major categories. Almost all of the changes in shape took place when a beluga was around another whale. Many of the changes were associated with courtship, with males about three times more likely to make a change than females. But other changes were related to other social interactions, such as playing. So when a beluga has something to say, it just uses the ol’ melon.

The most powerful undersea volcano ever recorded had an impact on our entire planet—from pole to pole, and all the way to outer space. And it may continue to impact parts of the world for years.

The Hunga Tonga volcano is in the southern Pacific Ocean, well east of Australia. It staged a massive eruption in January of 2022. It blasted more than two cubic miles of rock and ash into the sky, and created tsunamis all across the Pacific. Shock waves in the atmosphere raced around the planet for days.

Satellites and balloons recorded effects at altitudes of up to about 180 miles. The eruption rattled the ionosphere—an electrically charged region that extends well into space. That disrupted some GPS signals and radio communications.

Hunga Tonga also blasted about 150 million tons of water vapor into the atmosphere. By late 2023, most of the water was still there. In fact, a layer of atmosphere a few dozen miles high contained more water vapor than had ever been seen there before.

In the southern hemisphere, the combination of water vapor and sulfur from the eruption damaged the ozone layer during the winter and spring of 2023.

And one study found that the aftermath of the eruption could affect the climate in parts of the world through 2029. North America could see warmer winters, while the winters in Scandinavia and parts of Australia could be colder and wetter—lingering effects of a monster volcano.

One of the changes that goes along with aging is hair color. Red, blonde, black—regardless of the original color, our hair almost always turns gray or silver.

Fish don’t have hair, but many of them do change color as they age. They can take on different color schemes as they move through different stages of life.

Fish change color for many reasons. Some of the changes happen in a flash—a fish might blend into the background to protect itself from predators. Other changes are more gradual. A fish might change color when it switches gender, for example.

Many fish keep the same basic scheme throughout life—especially those that spend their lives in the open ocean. The ones that are more likely to change color as they age are those that move around—they’re born in one place, but they shift habitats as they grow and mature.

Salmon, for example, have stripes when they hatch, in rivers and streams. When they move out to sea, though, they take on a smoother, silvery tone. American eels, on the other hand, are colorless when they hatch, in the open ocean. But as they mature, and move into rivers and streams, they turn dark on top and light-colored on the bottom. And when they return to the ocean to spawn, they turn silvery bronze.

And in some species, only some members change color as they age. Only males of the bluehead wrasse adopt the namesake color, and only when they mark out a territory—a colorful signal that they’re ready to take a mate.

Some of the largest cities in Southeast Asia could be hit by bigger, badder tropical cyclones in the decades ahead. A recent study found that warmer seas and air could change where storms in the region form, how quickly they ramp up, and how long they hang around. The changes could be especially deadly for major cities along the coast.

Researchers used computer models to simulate more than 64,000 cyclones in the region during three eras: 1881 to 1900, 1981 to 2000, and 2081 to 2100. For the future decades, they looked at what conditions would be like under both moderate and extreme warming for the rest of this century. They compared the results for past decades to real storm systems.

The models showed that tropical cyclones—both typhoons and smaller systems—are likely to be born farther north in the western Pacific Ocean, the South China Sea, and the Bay of Bengal, near India. That puts the storms closer to land. The systems are likely to strengthen much more quickly. And they’re likely to last longer after they move ashore. That means higher storm surges, heavier rains, and stronger winds—a deadly combination.

The study said the cities likely to be hardest hit are Bangkok, Thailand; Haiphong, in Vietnam; and Yangon, in Myanmar. Today, their combined population is about 17 million. But they’re expected to grow quite a bit by the end of the century—putting more people at risk from powerful tropical cyclones.

Storms on the Sun can have both beautiful and annoying results. They create widespread displays of auroras—the northern and southern lights. But they can damage satellites, disrupt radio communications, and knock out power grids on the ground. They might even cause some whales to strand themselves.

Solar storms produce huge outbursts of energy and charged particles. Among other things, those outbursts can change the strength and direction of the lines of magnetic force around Earth. Many animals rely on the magnetic field for navigation, including some birds and fish, sea turtles, and lobsters. The list also includes at least two species of whale: gray and sperm whales.

Studies in recent decades have found correlations between the strandings of these whales and solar storms. One study, for example, looked at 400 years of sperm whale strandings in the North Sea. It found much higher stranding rates in years when the Sun was especially “stormy.” A study of 30 years of gray whale strandings found similar peaks—especially when the Sun produced a lot of radio static.

Researchers speculate that the storms could essentially “blind” the whales to the magnetic field. The disoriented whales then could find themselves in shallow waters, and unable to escape.

There’s no confirmation that the storms are causing these strandings. So scientists are studying the subject in greater detail—trying to understand how storms on the Sun can affect life in the oceans.

The female blanket octopus glides through the ocean like a winged phantom. When she’s threatened, she extends some of her arms. That spreads the webbing between the arms, like a flowing cape. The shiny cape makes the octopus look bigger—perhaps scaring away predators.

The octopus is impressive even without the cape. An adult female can be six and a half feet long—the size of a basketball player. Her mate, on the other hand, is about as big as a walnut—perhaps an inch across. And a female may weigh up to 40,000 times as much as a male. That’s the biggest difference in the size of adult males and females in the animal kingdom.

Blanket octopuses are found around the world. They’re in the open ocean and around coral reefs. They’re immune to the sting of a Portuguese man-o’-war, so males and young females sometimes tear off the tentacles and use them to defend themselves against predators.

These octopuses are rarely seen. In fact, the first live male wasn’t discovered until 2001. In part, that’s because of its size—it’s tough to spot something that small in the open ocean. In addition, the male is almost colorless.

A male grows a long arm that it fills with sperm. When he finds a mate, he rips off the arm and hands it to her—then dies. She then stores it in a pouch until she’s ready to fertilize her eggs. She may accept the arms of several suitors. After the eggs hatch, she may die as well—the final act for this phantom of the oceans.

The mangrove tunicate is a mild-looking little creature. It’s a type of sea squirt. It’s only about an inch long, and it feeds by pumping seawater through its body and filtering out the goodies. It’s found in colonies in the roots of mangrove forests around the Gulf of Mexico, the Caribbean, and the Atlantic coast of the United States.

Yet this little critter is a powerful cancer fighter. Researchers have used a compound it produces to create a cancer treatment known as trabectedin. It’s used against several types of cancer—especially those in soft body tissue, such as muscles and fat.

Cancer cells find ways to defeat many types of medication. The cells repair themselves, then continue growing and dividing, forming bigger tumors.

A recent study looked at how trabectedin fights cancer. Researchers discovered that the medication “breaks” the DNA inside cancer cells. Although the cells can fix some types of breaks, these appear to be unfixable—the cancer can’t overcome the disruption. That kills the cancer cells and slows or halts their spread.

Sea squirts are surprisingly close genetic relatives to people. And they’re easy to handle and study, so they’re popular lab subjects. So scientists have used sea squirts to create other medications, including cancer treatments. One produced from a different species is used to fight skin cancer, for example. So these quiet little creatures may yield even more treatment options in the decades ahead.

Marine scientists can’t be everywhere at once. To really understand what’s happening below the waves, though, they need a lot of observations—from many places at many times. So they’re getting help from recreational divers. The divers can carry instruments, or just log what they see.

One project is set to begin in December. Known as BlueDot, it’ll provide insights into how the Mediterranean Sea is warming up—not only at the surface, but down to more than a hundred feet.

Many divers wear small computers on their wrists. The computer records location, depth, temperature, and more. Divers who undergo special training can upload those observations to a central database. Scientists then analyze the results, producing a much better picture of the changing sea.

Another project has been around since 2010—the Great Goliath Grouper Count. Divers at artificial reefs off the coast of Florida log details about the goliath grouper.

It’s one of the largest species of bony fish—up to eight feet long and 800 pounds. But the grouper was overfished, so its population plunged. It’s been protected since 1990, so the numbers have gone up. But the extent of the recovery is still unclear.

Volunteer divers keep an eye out for the grouper during the first half of June. They report where they see the fish, the depth, the size of the fish, and more. That helps biologists determine the goliath grouper population—even if they can’t be everywhere at once.