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.

Hotter oceans are bad for just about everyone. They can destroy coral reefs, cause fish to move to new ranges, and rev up monster hurricanes.

There are problems for octopuses as well. Adults of some species aren’t getting as big as they used to, for example. And a recent study found that the still warmer waters we’ll see in the future could cloud their vision. That would make it harder to catch a meal or get away from predators.

Researchers studied the southern keeled octopus, which is found in shallow waters around Australia. It’s a small octopus that burrows into the sand during the day, then comes out at night to hunt.

The scientists placed females in tanks at three different temperatures: a control temperature of 66 degrees Fahrenheit; the modern summer temperature of 72 degrees; and 77 degrees, which is the projected summer temperature for the end of the century.

Almost all the eggs laid in the two cooler tanks hatched. But two of the three mothers in the warmest tank died while tending their broods, so none of the eggs hatched. The mother of the third brood survived, but less than half of her eggs hatched.

Scientists also studied proteins in the octopus embryos that are important for vision. They keep the lenses clear, and they produce pigments that capture light. The study showed that the warmer the water, the less effective the proteins were. So octopuses that hatch in a hotter ocean might need glasses to find their way.

The ocean floor is turning into a dumping ground. A recent study found that millions of tons of plastic litter the bottom of the world’s oceans and seas. About half of that debris sits in shallow waters near coastlines. And a lot more is expected to settle in the oceans over the coming decades.

The world generates millions of tons of plastic every year—enough to fill a garbage truck every minute. And a lot of it finds its way into the ocean—through runoff, offshore dumping, lost fishing gear, and other sources.

Much of this debris floats on the surface. Some of it forms giant patches, such as the well-known Great Pacific Garbage Patch. Over time, though, a lot of plastic drops into the ocean depths, and much of it settles on the bottom.

To understand how much plastic litters the ocean floor, researchers in Australia poked through the results of many studies. They then developed computer models to analyze those results. Their best model used observations by remotely operated vehicles in the deep ocean.

Their study focused on bits of plastic at least five millimeters across. That accounts for plastic bags, bottles, fishing gear, and other bigger chunks. The model showed that there should be a lot of this debris—somewhere between three million and 12 million tons as of 2020. Almost half of that should be close to shore.

Plastic use is projected to double over the next couple of decades—adding a lot more litter to the ocean floor.

Some strange holes pockmark the bottom of the North Sea. They can be anywhere from a few feet to hundreds of feet wide. But all of them are about four inches deep. That doesn’t match the kinds of pits produced by geological processes or ocean currents. Instead, a recent study says they were created on porpoise.

Scientists have known about the pits for years. The most common explanation said they were produced by blobs of methane bubbling up through the sediments. But such pits are cone shaped. And wider methane pits are also deeper.

To learn more about these odd depressions, researchers studied the floor of the North Sea off the coast of Germany. Using sophisticated sonar, they mapped the sea floor in great detail. They saw more than 40,000 of the pits. And they found that, over a six-month-period, the pits changed. Some of them got bigger, others merged, and new ones took shape.

The scientists also studied ocean currents and marine life in the region. And they found that it’s part of the habitat of the harbor porpoise.

The team suggested that the porpoises scour the shallow pits while they’re hunting for sand eels, which can burrow a few inches into the sediments. The porpoises are known to use their snouts to dig into the soft sand and mud. That poking around may scare the critters out of their hiding places, making them easy prey. And stirring up one sand eel might make others try to get away as well—escaping from pits dug by hungry porpoises.

If you live near the coast, few words are scarier than these: Category Five. That’s the classification for the most powerful hurricanes. The storms have maximum sustained winds of at least 157 miles per hour. And their potential damage is catastrophic. They can flatten houses, bring massive storm surges, and cause heavy rainfall well inland.

In recent years, the most powerful tropical storms have been getting even stronger. And as our planet continues to warm up, they’re expected to get stronger still. So some scientists think it’s time to add even scarier words to the tropical-storm lexicon: Category Six. To qualify for this category, a storm would have wind speeds of at least 192 miles per hour.

A recent study found that five storms would have reached that threshold in the past nine years—four typhoons in the western Pacific Ocean, and one hurricane in the eastern Pacific—Hurricane Patricia. It hit the Pacific coast of Mexico with peak sustained winds of 215 miles per hour—the strongest storm yet recorded.

The study also projected that such monster storms will become more common in the years ahead. Climate change is making the oceans warmer, providing extra “fuel” to power typhoons and hurricanes. That may not increase the number of tropical storms, but it is expected to make the strongest of them even more intense. Some would even qualify for Category Six—a scarier name for the most powerful storms.

Scientists in Australia are trying to paint the sea floor red. They’re giving a helping hand to the red handfish—one of the most endangered fish on the planet.

The fish is only three or four inches long. It’s named for the fins on its sides, which are shaped like small hands. In fact, the fish uses those fins to walk along the ocean floor—it seldom swims. The hands can be pinkish brown, but they can also be bright red, along with the mouth and other body parts.

Red handfish used to be common around Tasmania, a large island off the southeastern coast of Australia. Today, the population is down to about 100 adults. They’re found in two small patches that are no bigger than football fields.

In part, the population has dwindled because of an explosion in the number of sea urchins. Fishers have caught a lot of rock lobsters, which eat the urchins. Without the lobsters, the urchins have gobbled the kelp that forms an important part of the handfish habitat.

Scientists are trying to rebuild the handfish population. In 2021 and ’23, they hatched eggs in the lab, then released the youngsters into the wild. And in late 2023, they gathered 25 adults from the ocean and housed them in tanks. That was to protect them from a “marine heatwave” that could have killed off some of the fish. They, too, were scheduled to be returned to their ocean homes.

These efforts could help the red handfish survive—adding some splashes of color off the coast of Tasmania.

A massive hailstorm blasted northeastern Spain a couple of years ago. It lasted only 10 minutes or so. But it produced the largest hailstones ever recorded in the country—the size of softballs. It might have been kicked up a couple of notches by another type of “weather” event—a marine heatwave.

The storm roared to life on August 30th, 2022. It caused major damage to roofs, cars, and crops. It injured 67 people, and killed a toddler, who was hit in the head by one of the giant hailstones.

A recent study blamed the intensity of the storm on global climate change. Scientists simulated climate conditions under different levels of air and ocean warming.

The storm took place during a marine heatwave in the western Mediterranean Sea. The surface water temperature topped 85 degrees Fahrenheit—five degrees higher than normal. That produced more evaporation, which fed extra moisture into the air. It also heated the air, providing the energy to build storm clouds. As hailstones developed, strong updrafts pushed them back up, so they just kept getting bigger and bigger. Finally, they became heavy enough to plunge to the ground—causing chaos.

The study said the hailstorm itself could have happened without today’s higher temperatures. But it would not have been as intense or as destructive.

Major hailstorms have been getting more common across Spain and the rest of Europe. And the study says that trend should continue—powered by our warming climate.