Seaweed farms offer many benefits. They provide food for people, habitat for fish and other organisms, and protection against erosion during storms. They can help prevent “red tides,” and could become a source of biofuel.

Seaweed stores carbon in the sediments on the ocean floor. That helps reduce the amount of carbon dioxide in the atmosphere, which is the major cause of our warming climate.

Wild seaweed forests already stash away huge amounts of carbon. Farms cover a much smaller area, so their benefit is smaller. But seaweed farming is a “growing” business—the yield has been increasing by more than seven percent per year. Almost all of the farming takes place in Asia. The United States is a minor player, but farms have been developed in New England, the Pacific Northwest, and Alaska.

Researchers studied the sediments below 20 seaweed farms in various parts of the world. The oldest, in Tokyo Bay, has been around for 320 years. The largest, in China, covers 58 square miles.

The scientists found that the amount of carbon in the sediments below the farms was twice that found in the surrounding sediments. And they found that as a farm ages, it becomes more efficient at “planting” the carbon.

Estimates say that seaweed farms could cover many times their present area by 2050. And the researchers said that if the farms are efficiently managed, they could become important weapons in the fight against our warming climate.

Alexandria, Egypt, has stood for almost 2400 years. Today, though, parts of it are crumbling—one building at a time. As Earth’s climate changes, the Mediterranean Sea is rising, the coast is eroding, and saltwater is seeping into groundwater supplies. That weakens buildings, causing them to collapse. And according to a recent study, without action to protect the coastline, the problem will get worse in the years ahead.

Alexandria is the largest city on the Mediterranean, and one of the busiest ports. But its maritime location is causing trouble. Researchers looked at records of building collapses over the past quarter century. They also compared the coastline to that of previous decades, studied the soil, and made other observations.

They found that 280 buildings have collapsed in the past 20 years. Over that span, the rate of collapse jumped from fewer than one per year to almost 40. Almost all of the destroyed buildings were within a mile of the coast.

The jump was largely the result of climate change. Higher sea level and stronger storms have eroded the coastline by an average of 12 feet per year, with one district averaging 120 feet. And seawater is filtering into aquifers below the city. That corrodes foundations, causing buildings to crumble.

The scientists recommended creating dunes and greenbelts along the coast to keep the Mediterranean at bay—and keep Alexandria from crumbling into the sea.

Most corals are homebodies. They settle in one spot, link with hundreds or thousands of their friends, and never move. They build the structures we recognize as corals: rock-like spires, branches, domes, and others.

But a few corals “walk” along the sea floor. They don’t go very far. And they certainly don’t get there in a hurry. But their mobility helps them find more stable waters, avoid being buried in the sediments, and have a safe space to reproduce.

A recent study showed how one species gets around. Biologists in Australia placed mushroom corals—which are only an inch or two long—in aquariums. They put white lights on one side of the tanks—like the light in shallower waters. And they put blue lights—like deeper waters—on the other side. And they recorded the “action” on video.

When they turned on one set of lights or the other, 87 percent of the corals went toward the blue light. And when they turned on both sets, all of the corals moved toward the blue light—showing a preference for greater depths.

The corals didn’t sprint toward the deep end, though—they averaged less than two inches per day, with a maximum of about nine inches.

The video showed that the corals moved in a way similar to jellyfish. The corals inflated tissues at the edges of their bodies, then squeezed and twisted muscles on their sides, causing them to “hop” forward.

Each tiny hop took an hour or two—a slow but steady pace for a walking coral.

Earth’s warming climate has really heated up Atlantic hurricanes in recent years. Two recent studies, in fact, found that hurricane wind speeds were boosted by an average of 18 miles per hour. That was enough to kick most of the hurricanes to a higher category—including some that were juiced up to category five, the most powerful of all.

As the atmosphere heats up, it warms the oceans. And heat is what powers hurricanes. So warmer oceans make hurricanes more intense.

Scientists studied the impact of warmer oceans on the intensity of hurricanes in the North Atlantic Ocean from 2019 through ’23. In a separate study, they looked at the 2024 season.

The researchers used records of sea-surface temperatures, models of Earth’s climate, and statistical analyses. They used those details to simulate what hurricanes might have been like without human-caused global warming. And they compared those results to the actual hurricanes.

The results were astounding. The winds of 80 percent of hurricanes from 2019 through ’23 were boosted by roughly one category. And all 11 hurricanes in 2024 were kicked up, by anywhere from nine to 28 miles per hour. That includes boosts to the top level for both category five hurricanes.

Heavier winds cause more damage. They blow more stuff over, and they create a bigger storm surge. So as long as the oceans keep getting hotter, hurricanes might keep getting stronger.

A couple of years ago, marine biologists bought some giant “seabugs” from fishers in Vietnam. The creatures had been pulled from the mud at the bottom of the South China Sea. They were up to a foot long, weighed a couple of pounds, and had armor plating. The creature had never been cataloged before—it was a new species. Its face resembled the mask of Darth Vader, so the scientists named the seabug after him.

Bathynomus vaderi is one of thousands of marine species discovered in recent years. The list includes fish, corals, crabs, worms, jellies, and others. Unlike the giant seabug, most have been gathered during scientific expeditions.

In early 2024, for example, researchers announced the discovery of more than a hundred new species off the west coast of South America. The scientists had sampled life along an underwater mountain chain, at depths of up to three miles. Each mountain had its own ecosystem, including deep-sea coral reefs and sponge gardens.

Another group found more than five thousand new species across a wide span of the Pacific Ocean, between Hawaii and Mexico. It’s a prime site for possible mining operations, which biologists say could destroy entire species.

Some new species have been found in closets; in 2023, researchers classified some fish that had been captured and preserved 30 years earlier.

An international group hopes to catalog tens of thousands of new species over the coming decade—no matter where they find them.

There’s a big hole in the Indian Ocean. It’s nothing you can actually see. And the ocean itself isn’t especially deep. Instead, it’s a hole in Earth’s gravitational field—the weakest pull across the entire planet.

The “hole” was discovered in 1948. It’s centered about 750 miles off the southwestern coast of India. It covers more than a million square miles—more than a third the area of the Lower 48 states. Gravity there is so weak that surrounding regions of the ocean pull water away from it. As a result, sea level above the hole is about 350 feet lower than the global average.

In 2023, using computer models of the motions of the plates that make up Earth’s crust, scientists suggested the hole may be the remnant of another ocean—the Tethys Ocean. It vanished tens of millions of years ago.

The ocean was wedged between two “super”-continents—slabs that held most of the world’s total land area. But the motions of the plates pulled apart one of the continents. That pushed the plate that held the Tethys Ocean deep into the mantle—the layer below the crust.

The ocean floor reached its deepest point below the surface about 20 million years ago. It pushed away dense blobs of rock, allowing lighter rock to bubble up from below. The lighter rock exerts a weaker pull than the rocks around it.

Scientists still need to confirm that scenario—a possible explanation for a giant “hole” at the bottom of the Indian Ocean.

For an oyster, gender is more than a matter of genetics—it’s also about the environment. Water temperature, salinity, pollution, and other factors determine whether an oyster will be male or female. And a recent study added something new to the list: acidity.

The oceans are becoming more acidic as they absorb carbon dioxide from the air. Over the past couple of centuries, they’ve taken up about a third of all the CO2 added to the atmosphere through the burning of fossil fuels. Today, the concentration of CO2 in the oceans is at its highest in 800,000 years. By the end of the century, it could be at its highest in 20 million years.

The more-acidic waters make it harder for oysters and other creatures to make their shells. And researchers looked at the impact on the sex of oysters. They gathered oysters from the wild and from hatcheries—both in China—and put them in tanks with different levels of acidity. The oysters in the more-acidic water spawned about three times more females than males.

The scientists then placed the new generation in two locations in the wild, with different levels of acidity. Both groups spawned more females than males, but the ratio was higher in the more-acidic waters.

Researchers conducted lab studies to understand how this happens. They found that the higher acidity turned on female-producing genes, and turned off the male-producing genes.

So oysters face one more threat from the world’s changing oceans.

The great white shark probably is the most feared of all ocean animals. It gained that scary reputation 50 years ago thanks to a blockbuster movie: Jaws. The movie premiered on June 20th, 1975, and quickly became the all-time box office champion. It scared a lot of people out of the water—and set off a frenzy of shark killings. People killed thousands of them, and even competed in shark-hunting tournaments.

Great whites can be fearsome. They’re responsible for more human deaths than any other species of shark. In fact, a series of attacks along the New Jersey coast in 1916 was one of the inspirations for the novel upon which the movie was based.

But the sharks aren’t nearly as nasty as portrayed on screen. The movie version was much bigger than any real great white ever seen. And it was stronger and more tenacious.

Biologists say that great whites don’t pursue humans. Instead, a shark may attack because it confuses a person or surfboard with a seal, one of its favorite meals.

Great whites don’t have especially good eyesight, and they probably are color blind. So they look for dark silhouettes on the surface contrasted with the bright sky above. And scientists recently suggested a way to use that trait to keep the sharks from attacking. Researchers towed seal decoys behind a boat in shark-infested waters. And they found that adding stripes of bright lights to the underside of a decoy kept the sharks at bay—making it safer to get back in the water.