Science and the Sea podcast The University of Texas Marine Science Institute

It snows in the oceans. Bacteria, the skin cells of fish, fish poop, and bits of sand and dirt all clump together. These “snowflakes” can be up to an inch or two across. Many of them are eaten as they sink toward the ocean floor. But others float all the way to the bottom—a trip that can take weeks.
The snow falls all the way down even in the deepest waters, where the pressure can be a thousand times the surface pressure or greater. In fact, a recent study suggests the pressure might actually help the snowflakes survive in the deep ocean.
Scientists in Denmark made their own version of marine snow. They then put some in several different tanks. They rotated the tanks so that the snow was always “falling.” And they increased the pressure in the tanks every day. They then opened some of the tanks when the snow had reached different “depths” to see how much had remained intact.
Down to the equivalent of about four miles, the snowflakes gradually fell apart, and the living bacteria basically shut down. Below that depth, however, the process stopped—the flakes held together. By the time they hit about six miles—deeper than more than 99 percent of the world’s oceans—about half of the original flakes had survived.
Marine snow is the main food source for much of the life on the floor of the deep oceans. It also socks away carbon from the atmosphere, helping reduce global warming. So about all we can add is this: Let it snow, let it snow, let it snow!

Killer whales near the Atlantic coast of Spain and Portugal have been living up to their name. From May 2020 through the end of 2023, they “killed” four boats and attacked hundreds of others. Marine biologists are still trying to explain why.
They’re not the first reported whale attacks in that part of the world. In fact, the earliest known attacks anywhere took place in the northeastern Mediterranean, near Constantinople. Those attacks were blamed on a single whale: Porphyrios.
The attacks took place about 1500 years ago. They lasted for 50 years. The attacker might have been a sperm whale, although orcas—killer whales—are more common in that region. Porphyrios attacked all types of boats. Sailors traveled around its home waters to avoid the danger.
Most of the recent attacks have involved sailing vessels. Orcas approach from behind a boat and ram into the rudder, disabling the craft. They sometimes hit the hull as well, poking holes that sink the boats.
All of the attacks have been near the coast or in the Strait of Gibraltar. They may have been started by a single female, named White Gladis. The groups often are led by a larger orca, with smaller, younger ones learning from their elder.
Scientists have speculated that White Gladis was injured in a collision with a boat, or entangled with a fishing net, and was after revenge. Others say it’s just a fad—a type of play that’s passed from whale to whale—a scary fad for sailors.

According to an old saying, a rising tide floats all boats. And in the decades ahead, rising waters will threaten all coastal cities.
As our planet gets warmer as the result of human activities, sea level is rising. So cities along the coast will see more flooding—more often, with higher water levels. But a recent study says the risk isn’t the same for everyone.
Researchers calculated the possible effects of climate change combined with natural fluctuations in sea level. That included El Niño, tropical cyclones, and other events. They used a temperature increase at the high end of current predictions, then compared their numbers to conditions in 2006.
They found that, by the end of the century, the combination could boost the risk of coastal flooding around the world by 20 to 30 percent compared to global warming alone.
The study said the risk will go up for most coastal cities, including those in the United States and Australia. New York, for example, could see 18 times more flooding events with climate change alone, but 25 times more when natural events are factored in.
The numbers are even higher in Bangkok, Manila, and other major cities in Asia. Manila, for example, could see 18 times more floods with climate change alone, but 96 times more with the combo. And those same Asian cities would have to build much more extensive defenses to protect themselves—from the combined impact of Mother Nature and human-produced climate change.

In 1983, roadworkers cut a notch in a hillside in Lorraine, a region in northeastern France. Paleontology students examined the exposed layers of rock. They found fossils of an ancient sea creature.
Scientists just recently studied the fossils in detail. They found that the fossils were the remains of a type of giant marine reptile that hadn’t been seen before. It was about 16 feet long, with jaws four feet long. It plied the Tethys Sea, which covered parts of present-day Europe. Because it was discovered in Lorraine, scientists named it Lorrainosaurus.
The creature was a member of a group known as pliosaurs. Earlier research had found that pliosaurs were around at least 165 million years ago. This discovery, along with fossils from another specimen, found in Switzerland, pushed that to about six million years earlier. So pliosaurs appeared near the end of the age of the dinosaurs.
Larger relatives of the pliosaurs began to take over as the top predators in the seas about 175 million years ago. They displaced some giant fish, giant crocodiles, and other big guys. That might have happened because oceans around the world began to cool off about then. The change might have killed the food sources of the previous kings of the sea.
The pliosaurs began to dominate on their own soon after. They remained the top ocean predators for about 80 million years—a long reign for the Lorrainosaurs and their giant cousins as the kings of the sea.

The Gulf Stream plays a big role in the weather and climate on both sides of the Atlantic Ocean. A recent study concluded that the Gulf Stream is slowing down. That could have an impact on everything from hurricanes to heatwaves.
The Gulf Stream is a strong current of warm water. It starts in the Gulf of Mexico, then flows up the East Coast of the United States. It then veers eastward into the North Atlantic, and finally around western Europe, where it warms part of the continent. The Gulf Stream is one of a network of currents that encircles the Atlantic Ocean.
Studies have suggested that the Gulf Stream is changing. And a study released in 2023 said it found the best proof of that to date.
Scientists analyzed observations collected since 1982. They looked at data from instruments in the water, undersea communication cables, and orbiting satellites. The scientists used computer models to combine the observations. Their work showed that the Gulf Stream had slowed down by about four percent over the past four decades.
The study says that the change could have an effect on Atlantic hurricanes, sea level along the American coastline, the frequency of droughts and floods in the U.S. and Europe, and more.
Researchers said they couldn’t conclude whether the slowdown was caused by climate change, natural ocean cycles, or a combination of the two. Regardless of the cause, a critical ocean current appears to be slowing down—with possibly dire consequences in the decades ahead.

Many people like to have some “white noise” in the background while they work or sleep. And some fish seem to like it as well. A recent study found that young Atlantic cod were attracted to a background “hum” like that produced by offshore wind turbines.
Researchers in Norway studied the impact of a low-frequency hum on 89 larval cod. They put the fish in mesh containers, then placed them in a fjord in Norway. They played the humming sound to half of the fish, but not the other half. And they recorded how the fish responded on video.
The cod that didn’t hear the sound all aimed toward the northwest. But most of those that did hear it aimed toward the sound—suggesting the fish could be attracted to wind turbines.
And there are plenty of them. As of 2022, the North Sea had more than 40 wind farms with more than 2600 turbines. And Europe has agreed to ramp up offshore wind power almost 10-fold by 2050. That means thousands more turbines, all of which will transmit a low hum into the water.
Scientists aren’t sure what that will mean for cod and other organisms. But the study suggests that young cod could decide to settle around the turbines. Fishing fleets don’t operate near the turbines, so that could offer some protection. On the other hand, the hum might drown out the sounds produced by the fish themselves, which they use for mating and other activities. So we don’t know whether that “white noise” will be good or bad for ocean life.