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.

Many gardeners use clam shells as decorations. But not many garden the clams themselves. Yet clam gardens can yield more clams than untended shorelines, provide more species diversity, and even protect the clams from the acidity in today’s oceans.

Clams were gardened as early as 4,000 years ago by the people of the Pacific Northwest, from Alaska to Washington. In some regions, the gardens lined the entire coastline.

The gardens consisted of short walls built along the shore, forming enclosures, with terraces behind the walls. Water flowed in, and some of it was trapped as the tide rolled out. That provided habitat for littleneck and butter clams.

The gardens were abandoned after European settlers moved in. But research over the past decade shows that the gardens were highly effective. They could produce up to twice as many littleneck clams as uncultivated areas, and four times as many butter clams. The gardens also attracted other life, including seaweed and sea cucumbers, providing a more diverse diet for the gardeners.

Gardens also contained a lot of clam shells, which provide the minerals clams need to make new shells. That’s especially important today, because higher levels of ocean acidity make it harder for clams to produce shells.

The Swinomish people of Washington have recently built new clam gardens. They produce food, provide a training ground, and give scientists a place to study the gardens and their “crops”—butter and littleneck clams.

Life along the American coastline has been getting more perilous. Earth’s warming climate is causing a rise in sea level, an increase in major hurricanes, more marine heatwaves, and many other problems. That costs time, money, and lives. And things are expected to get even worse in the decades ahead.

A new national climate assessment, issued in late 2023, forecasted that sea level will rise an average of almost a foot from 2020 to 2050. That equals the total rise over the past century. As a result, the report says that coastal flooding at high tide should happen 5 to 10 times more often. Erosion will wash away beaches and bring cliffs tumbling down. And some hurricanes will become far more destructive.

The assessment says the combination of the changing climate and human adaptations, such as more seawalls and levees, will make it more difficult for coastal ecosystems to adapt. Such ecosystems function as buffers against tropical storms, help control erosion, and provide habitat for fish and other organisms.

The report says that some actions now may help minimize the impacts of climate change and human adaptations in the future. Restoring coastal habitat is one of the most important. Cities and towns can also beef up their infrastructure—moving roadways and improving stormwater systems, for example. And they can start planning to relocate people and buildings to less-hazardous areas—to meet the growing threat of climate change.

Thresher sharks are some of the “snappiest” fish in the oceans. They have an oversized tail fin that looks like a scythe—and is almost as deadly. A shark “snaps” the fin like someone snapping a towel in a locker room, stunning its prey. And a recent study worked out some of the details on how the shark does it.

Threshers are found around the world. Most stay fairly close to shore, and not very deep. Adults can grow to about 20 feet long.

What really sets them apart is that snapping motion. A shark first winds up a bit like a baseball pitcher. It twists its body in one direction, its tail in the opposite direction. The tail, which is almost as long as the body, is held high. The shark then uncoils, snapping the tail around in a fast, powerful motion. It then takes a minute to relax before grabbing its prey.

Researchers recently studied the spines of 10 thresher sharks that had stranded on shore or been caught by anglers. The sharks ranged from an embryo to an adult 13 feet long.

The scientists did CAT scans on the sharks, revealing the structure of the shark spines and vertebrae. The work showed that the vertebrae in the body are longer and thicker than those close to the tail—a trait that developed as the sharks got older. The interiors of the two types of vertebrae were different as well.

The researchers said the differences may make a thresher more flexible while adding strength to its tail—allowing the sharks to “snap up” their dinner.

It may sound surprising, but many mountains are hiding from us—some of which may be more than a mile high. Scientists are finding more of them all the time, though—at the bottom of the sea. A research cruise in 2023, for example, found four of them in the Southern Ocean.

The scientists were studying the Antarctic Circumpolar Current, which circles around Antarctica. It’s the strongest ocean current in the world. It prevents most of the warm water from the other oceans from reaching Antarctica. But some warm water sneaks through. That makes the Antarctic ice melt faster, speeding up the rise in global sea level.

Researchers were looking for these “leaks,” and studying how the warm water was flowing around Antarctica. As part of their work, they used sonar to scan a 7700-square-mile patch of the ocean floor. They also used an orbiting satellite to look for small “bumps” on the surface that indicate the presence of mountains.

They found a chain of eight mountains, called seamounts. They’re extinct volcanoes that formed within the past 20 million years. Some of them were already known, but four had never been seen before. The tallest is almost a mile high.

The mountain range is in the middle of the Antarctic Circumpolar Current. As the current flows over and between the mountains, it forms turbulent patches that break off as eddies. Those whorls can disrupt the current, allowing warmer water to punch through—helping thaw out the frozen south.