Science and the Sea Podcast

For anyone who’s ever had a cold, the flu, or any other illness caused by a virus, getting rid of viruses might sound like a good idea. But many viruses play important roles in the environment. That includes marine viruses. They recycle nutrients, and can help control other microscopic organisms. So it’s good to keep them around. But in the northwestern Mediterranean Sea, viruses are disappearing in a hurry. The drop corresponds to changes in the sea caused by Earth’s warming climate. Marine scientists have been keeping tabs on Blanes Bay since the early two-thousands. It’s on the coast of Spain, about 40 miles from Barcelona. An observatory there monitors the temperature, salinity, and clarity of the water. And it samples the water once a month. Lab work reveals the amounts of nutrients and other compounds in the water, along with the populations of bacteria and viruses. Scientists recently used several techniques to analyze the observations from 2005 to 2022. The work showed that the virus population remained steady until about 2011. But since then the population has gone down dramatically. At the same time, the water has gotten warmer. That suggests the viruses are being thinned out by climate change. Reducing the virus population could impact the amount of nutrients in the water, making the region less productive. That could hurt the fishing industry. So the lack of viruses could actually harm the people along the Mediterranean coast. The post Vanishing Viruses appeared first on Marine Science Institute. The University of Texas at Austin..

The oceans near the poles are cold—really cold. Because of the salt content, water temperatures can remain below freezing for most or all of the year. And that can be bad for life. Ice crystals can develop in the blood and other fluids, destroying cells. Yet many species of fish thrive in these frigid environments. In part, that’s because they produce proteins that work like antifreeze. Inspired by those fish, researchers have developed a synthetic version of the proteins. The “mimics,” as they’re called, could prevent medications that have to be kept cold from freezing. They also could be used to prevent the formation of ice crystals in many other products. Earlier studies nailed down the details of the fish proteins. Whenever a crystal begins to form, the proteins wrap it up. They change the structure of the crystal, keep it from getting any bigger, and lower the freezing temperature. That combo prevents the cold from damaging cells. Researchers isolated the key features of the proteins, then found a way to replicate them in the lab. They tested their brew in living cells. It protected the cells from freezing, and it wasn’t toxic. It also wasn’t a problem for the bacteria in the human digestive system. The researchers say their antifreeze can be manufactured easily and inexpensively. So it could make it easier to store and ship some medications, and extend the shelf-life of ice cream and other frozen foods—a gift from some cold, cold fish. The post Fish Antifreeze appeared first on Marine Science Institute. The University of Texas at Austin..

Cats sometimes drop food at their owner’s front door—lizards, mice, or other small prey. A recent study found that killer whales sometimes offer food to people as well. But the reason for that sharing is unclear. Orcas are social animals. They hunt together, they play, and they share their food. And they’re often found around people. They swim along with boats and divers, and they’ve even hunted with human fishers. In a recent study, scientists compiled reports of orcas sharing food with people on boats, in the water, or on shore. They found 34 examples, including some from their own experience. Many of the events were photographed or caught on video. To qualify for the study, a whale had to approach the people, not the other way around. It had to get close before releasing the food. And it couldn’t take the food back right away—it had to wait for a response from the people. The sharing orcas included males and females, of all ages. Sometimes a single whale made the offer, but sometimes it was two or more. They offered fish, birds, mammals, and other treats. They sometimes waited minutes for a response. And if the human didn’t snatch the food, or gave it back, the whale sometimes offered it again. The researchers said there could be several reasons for the sharing. It could be a way to communicate or to learn more about the people. It could simply be a way of playing. Or it could be a way to lure the people in—a not-so-friendly way of sharing. The post Sharing Orcas appeared first on Marine Science Institute. The University of Texas at Austin..

Most of the tropical storms that roar across the Atlantic basin are born over Africa—especially the really big ones. They begin as low-pressure systems over the Sahara Desert, and are pushed into the Atlantic Ocean by a powerful jet stream. La Niña may boost that process. A recent study found that it may help create stronger systems over Africa, potentially leading to stronger tropical storms. La Niña is part of a back-and-forth cycle in the eastern Pacific Ocean, from warmer to cooler waters. La Niña is the cooler phase. And it can impact climate across the globe. The study found a link between La Niña and African easterly waves—the systems that form over Africa and head out to sea. During La Niña years, the waves are stronger, wetter, and more turbulent, so they produce more thunderstorms. That brings heavier rains to parts of Africa, the Caribbean, and the Americas, even if the systems don’t become tropical storms. La Niña changes the way air circulates across the entire planet. Over Africa, it appears to strengthen two jet streams, and it pushes one of them northward. It also has an effect on the African monsoon season. Those changes rev up the easterly waves—and the intensity of hurricanes. African easterly waves give birth to about 60 percent of all tropical cyclones in the Atlantic, Caribbean, and Gulf—and more than 80 percent of the major ones. So understanding the link between La Niña and the waves could improve hurricane-season forecasts. The post Stronger Waves appeared first on Marine Science Institute. The University of Texas at Austin..

The frigid waters of the Arctic and Antarctic hide some giants: sea spiders the size of serving trays, sharks as long as minibuses, half-ton squid twice that length—almost all of them the largest examples of their type anywhere on the planet. This phenomenon is known as polar gigantism. Biologists are still trying to explain it. In fact, they’re even trying to confirm that it’s a real thing; giants have been found in the deep ocean, and they may also inhabit other parts of the ocean, but we just haven’t seen them yet. There’s no doubt that giants inhabit the Arctic and Southern Oceans—the coldest waters of all. The list includes sponges, sea spiders, shellfish, tube worms, and others. Some of these creatures are many times the size and weight of most of their counterparts elsewhere. The colossal squid, for example, is not only the largest squid, but the largest invertebrate of any kind. Several explanations have been proposed for polar gigantism. The leading idea is the oxygen-temperature hypothesis. It says there’s more oxygen in colder waters, so there’s plenty to support larger organisms. And in the cold, the animals grow more slowly but they may live longer, allowing them to reach giant proportions. As an example, the Greenland shark, which can reach lengths of 24 feet, can live for centuries. Not every type of polar marine animal is a giant—some are especially small. So scientists are still pondering what makes some of them the giants of the deep. The post Polar Giants appeared first on Marine Science Institute. The University of Texas at Austin..

If you happen to have a spare fiber in your undersea fiber-optic cable, marine scientists might like to have a chat. They’re using the cables to listen to the sounds of the oceans—from the rumble of underwater earthquakes to the low moans of blue whales. Scientists typically listen in with special undersea microphones. But they’re expensive, and their range is limited. Fiber-optic cables stretch across hundreds of thousands of miles of ocean floor, so they offer greater coverage at lower cost. The technique is known as D-A-S—distributed acoustic sensing. A laser fires regular pulses through the cable. Any disturbance introduces a “strain” on the cable. That causes some of the light to reflect back to the source. Analysis of this reflection tells scientists when and where it happened. It can also tell them the cause of the change. Early experiments tested the technique as a way to listen for earthquakes and landslides. More recently, biologists have been checking out D-A-S as well. They’ve done tests with dedicated cables, and with existing cables that are used for telecommunications. Scientists can piggyback on those cables—using fibers that aren’t otherwise in service. The cables have detected the vocalizations of blue whales and other large whale species. The technique could help biologists count the number of whales, monitor their movements, and look at how they’re impacted by shipping—a new type of communication for undersea fibers. The post Piggybacking appeared first on Marine Science Institute. The University of Texas at Austin..

1933 was a bad year for the Eastern Shore of Virginia. Slime mold wiped out the eelgrass beds in the shallow coastal waters. A big hurricane made things even worse. Without the seagrass habitat, fish and crab populations were decimated, and bay scallops vanished. And neither seagrass nor scallops were seen again for almost seven decades. Today, though, both are recovering. Healthy eelgrass covers 10,000 acres. And there are enough scallops that people are talking about opening a recreational harvesting season. The comeback began when a scientist at the College of William & Mary discovered a small patch of eelgrass, in 1997. He then began a program to restore the grass along the Eastern Shore, which is separated from the mainland by Chesapeake Bay. As the beds expanded, researchers began looking at restoring bay scallops. The scallops are about three inches across. They use small tentacles on the edges of their shells to sense their surroundings, and gills to filter food from the water. Scientists harvested scallops from North Carolina and elsewhere. They cultivated new generations in the lab, then slowly released them into the wild. And the population has taken off. A 2025 survey found by far the highest number of scallops since the project began. And researchers estimated the population could double over the following year and a half. That could make it possible for people to harvest a few of the tasty morsels in the coming years. The post Restoring Scallops appeared first on Marine Science Institute. The University of Texas at Austin..

After the 1944 D-Day invasion of Europe, Germany launched a months-long attack on London and Belgium. Its V-1 “buzz bombs” killed thousands. Today, though, the remnants of some of these terror weapons are providing homes for marine life. An estimated 1.6 million tons of unexploded munitions litter German waters. The weapons were dumped at the end of the two world wars. As their metal casings rust away, their toxic explosives wash into the water. And that should be bad for marine life. But a recent study found abundant life at a previously unknown dump site: fish, tube worms, anemones, crabs, and sea stars. The site is at the edge of the Baltic Sea. It’s about 60 to 70 feet deep, and it’s between two well-known dump sites. Researchers mapped the area with underwater cameras. They found a dozen unexploded weapons, which they identified as V-1 warheads. They also found life—a lot more than expected. Some organisms were living on the metal casings. Others were in the nearby sediments, although few were on the actual explosives. The scientists saw a low diversity of life—there were fewer species than found on natural surfaces in the region. But the density of life was greater than on the surrounding seabed. Most of the rock was dredged from the bottom of the region for construction projects in the 19th and 20th centuries. So the warheads provide some of the few hard surfaces around—dangerous homes off the German coast. The post Dangerous Living appeared first on Marine Science Institute. The University of Texas at Austin..

Some of the clouds that waft across the Southern Ocean may have an icky source: penguin poop. Ammonia in the poo mixes with other chemicals in the air. That creates the “seeds” that form water droplets, which clump together to make clouds. Water doesn’t form droplets on its own. It has to have something to glom on to—a grain of dust, a bit of pollen, or some other solid particle. Some of the particles are known as aerosols. They form when different chemicals link up in the air. And the clouds they create are brighter than other clouds, so they reflect more sunlight—helping control Earth’s temperature. And that’s what appears to be happening with the poop. Researchers discovered the connection during the summer of 2023. They were studying the atmosphere from an island off the northernmost tip of Antarctica. That part of the continent has two large colonies of Adelie penguins—about 45,000 breeding pairs in all. When the winds blew across the island from the open ocean, the air contained almost no ammonia. But when the wind blew in from the continent, the amount of ammonia in the air increased by a factor of a thousand—picked up from the penguin poo. When the penguins moved to their winter grounds, the amount of ammonia dropped, but still remained high—carried from the leftover poo. The ammonia mixed with sulfur produced by microscopic organisms in the ocean to produce aerosols—the “seeds” for clouds over the Southern Ocean. The post Poopy Clouds appeared first on Marine Science Institute. The University of Texas at Austin..

A symphony is playing in the estuaries of South Carolina—the sounds of shrimp, fish, dolphins, and other creatures. To marine biologists, each sound is like a musical note. Individual notes reveal details about the species that produce them. The symphony reveals the rhythms and health of the complete estuary. Estuaries are shallow regions where rivers meet the sea. They host a wide variety of life. But the waters tend to be murky, so it’s hard to see what’s going on. So instead, researchers in South Carolina have been listening to estuaries since 2013. They’ve placed a network of underwater microphones on special platforms. They record the soundscape around the clock, along with water and weather conditions. And there’s plenty to hear: the clicks of snapping shrimp…the purring of weakfish…the grunts of black drum…the calls of bottlenose dolphins…the rat-a-tat of silver perch… Scientists use the recordings to learn about the habits of all these species—whether they’re more active during the day or at night, for example, or how their activity changes with the seasons. They also learn how each species reacts to hurricanes and other major weather events, as well as human activities, such as boating and underwater construction. The sounds also help scientists understand whether Earth’s changing climate is jumbling the notes—perhaps throwing the underwater symphony off-key. The post Underwater Symphony appeared first on Marine Science Institute. The University of Texas at Austin..

You don’t have to be anywhere near an ocean storm to feel its power. Big waves can travel far across the ocean, causing damage thousands of miles from the storm itself. These waves are called swells. They’re much longer from one peak to the next than typical waves. They can reach monstrous heights close to a storm, but they calm down as they move away from it. The waves are created by winds inside a storm. They push the water, building peaks. Individual waves overlap, creating even bigger waves. The waves can organize themselves into smooth, evenly-spaced groups. Scientists recently analyzed the swells produced by storms in 2023 and ’24. They used measurements made by a satellite that studies the surfaces of both the oceans and bodies of fresh water. It takes images of the surface, and uses a laser altimeter to measure its height. The scientists compared the results to those from other satellites dating back to 1991. They found that a storm in the Pacific Ocean in 2024 produced the biggest swells ever seen from space. The average height of the waves was 65 feet. Individual waves could have been much higher. And the waves were up to three-quarters of a mile long. The swell still packed a wallop when it hit the Americas, causing damage and deaths from Canada to Peru. Scientists tracked it as it rippled outward for more than two weeks. It ranged from the northern Pacific to the tropical Atlantic—a span of 15,000 miles for some really “swell” ocean waves. The post Swell Waves appeared first on Marine Science Institute. The University of Texas at Austin..

It’s easy to gain weight on a road trip—restaurant meals and junk food add up. But that’s not the case for some humpback whales. According to a recent study, a group of humpbacks lost an average of 24,000 pounds per adult during its annual migration—the equivalent of a city bus. The whales feed around Antarctica. They filter the tiny organisms known as krill from the water. So by autumn, the whales are nice and fat. The 103 adults in the study averaged about 33 tons apiece. When autumn arrives, the humpbacks head into warmer waters. They cruise along the Pacific coast of South America, and settle in their summer breeding grounds, near Colombia—a trip of several thousand miles. But they don’t feed along the way, so they lose weight. Researchers used drones to shoot pictures and video of the whales at both ends of their journey. They measured the sizes of the whales, and found them to be a lot thinner from late winter through spring. From that, they calculated the change in body mass. The whales lost most of their blubber—more than a third of their total body weight. The scientists also calculated what it would take to pack on that much weight: 125,000 pounds of krill for every whale. And that’s a problem. Our changing climate has reduced the supply of krill. It’s also changed where the krill are found. So, in the years ahead, it might be harder for the whales to fuel up before they hit the road. The post Feast or Fast appeared first on Marine Science Institute. The University of Texas at Austin..

Second place doesn’t get a lot of attention: the second-tallest mountain, the second expedition to reach the North Pole, silver medalists in the Olympics. The second-deepest spot in the oceans isn’t exactly a household name either: the Tonga Trench. The deepest spot is in the Mariana Trench, in the western Pacific Ocean. It’s about 36,000 feet deep—almost seven miles. That’s a few hundred feet deeper than the lowest spot in the Tonga Trench. The Tonga is in the southern hemisphere, northeast of New Zealand. It’s more than 800 miles long, and runs parallel to the islands of Tonga. Its deepest spot is the Horizon Deep. It’s named for the ship that discovered it back in 1952. The trench is created by the motions of two of the plates that make up Earth’s crust. One plate is plunging below the other. The Tonga Trench is a groove where the descending plate disappears below the other. And the crust along one section of the trench is disappearing faster than at any other spot on Earth—about nine inches per year. A couple of expeditions have taken a close look at the trench. They found an abundance of life along its steep walls and all the way to the bottom. One thing they didn’t find was evidence of humans. Explorations of the world’s other major trenches have all found trash—even in the deepest parts. But the Tonga Trench is pristine—a top ranking for the second-deepest spot in the oceans. The post Tonga Trench appeared first on Marine Science Institute. The University of Texas at Austin..

Kelp forests are some of the most important habitats in coastal waters around the world. They provide breeding grounds for fish and shellfish, and protect juveniles from predators. They absorb carbon dioxide, which helps control climate change. But the forests are vanishing—they’re being devoured by sea urchins. In part, that’s because the forests are losing their protectors. In New Zealand, one of those protectors is rock lobsters—known locally as kōura. But they’re vanishing, too, as the result of overfishing. Kōura are different from the lobsters in the United States—they don’t have the big claws, and their bodies are spikier. Sea urchins are among their favorite prey. So a healthy population keeps the urchins in check—and the kelp beds lush. Much of New Zealand is bordered by big beds of kelp. They’re populated by two main species. One of them is the fastest-growing organism on Earth—it can grow by more than two feet in a single day. But warming oceans have damaged some of those beds. Sea urchins like the warmer waters, so they move in and feast on the weakened kelp. Commercial fishing operations began harvesting huge numbers of kōura in the early 1900s. Today, there are some restrictions—including complete bans in marine reserves. Even so, the population continues to drop. With fewer kōura, urchins not only devour the kelp, they can block any recovery—unmolested by the one-time protectors of the forests. The post Missing Protectors appeared first on Marine Science Institute. The University of Texas at Austin..

Sharks and rays are in trouble. A study a few years ago found that the global population had dropped by more than 70 percent since 1970. And three-quarters of all shark and ray species could face extinction in the next few decades. The main threat is overfishing. Sharks and rays are valued for their meat, fins, and liver oil. Some countries provide strong protections. Others—especially those where the fish are big business—have weak protections or none at all. And even where sharks and rays are protected, it can be hard to keep track of them. A recent study found that some fairly new techniques could help: rapid DNA testing and environmental DNA—finding out which species are present in a region just by analyzing the water. That could help scientists monitor populations and movements. And it could help management and enforcement agencies know if protected species are being caught and sold illegally. The study looked at 25 years of research into rapid DNA and environmental DNA testing. These techniques are much faster than traditional DNA testing. They’re also much less expensive. So it might be possible to deploy them in the field—identifying shark and ray species on the spot. The study said there’s a lot of work to be done to make that happen. The technology has to get easier to use. And scientists have to compile a more thorough database of shark and ray DNA. Still, the technique offers a possible way to ease the stress on these troubled fish. The post Rapid ID appeared first on Marine Science Institute. The University of Texas at Austin..

The Japanese spider crab is harmless to people. But it might not look that way if you happened across it at the bottom of the Pacific Ocean. It can span 12 feet—the largest known crab on the planet. The crab’s hard body is typically about a foot long, and the crab weighs 35 or 40 pounds. It has 10 legs. Eight of them are for walking along rocky ocean bottoms. The other two hold powerful claws. The claw legs are longer than the walking legs on males, but shorter on females. Japanese spider crabs spawn in fairly warm, shallow waters, primarily off the Pacific coast of Japan. Juveniles are pretty small. As they reach adulthood, though, they grow to giant proportions. And they move to deeper waters—generally a few hundred feet to a thousand feet or deeper. The crabs can’t swim. Instead, they scuttle along the bottom looking for food. They nab small fish and crack open clams. They also scavenge for dead animals, and scrape algae off the rocks. Because of their size and hard shells, the crabs face few threats—mainly from fishers, because they’re considered a delicacy in parts of Japan. And they’re well disguised—their mottled, spiny appearance blends into the background. Just to be safe, though, juveniles sometimes disguise themselves. They pluck bits of kelp, sponges, or other organisms. They chew on them for a little while, then stick them on their shells. That helps keep these imposing but harmless creatures safe at the bottom of the Pacific Ocean. The post Giant Crabs appeared first on Marine Science Institute. The University of Texas at Austin..

For many native Hawaiians, the centerpiece of just about any New Year’s celebration is onaga, a fish that’s also known as ruby snapper or longtail red snapper. It’s served at everything from weddings to birthdays, but it’s especially popular at year-end celebrations—in part because it’s a symbol of good fortune. It’s prized for its light pink flesh, mild flavor, and its texture—all of which are considered just right for sashimi. Onaga is one of the “deep seven” bottomfish—a culturally important group that includes six species of snapper and one species of grouper. All seven species are found throughout the Hawaiian Islands. A snapper known as ‘ōpakapaka is the most common, accounting for about half of the annual catch. Onaga ranks second. Adult onaga generally are about two to two-and-a-half feet long and weigh up to about 18 pounds, although they can grow to twice that weight. The top half of the body is red or pink, while the underside is white. The fish are found above rocky sea floors throughout the tropical Pacific Ocean, usually at depths of no more than a thousand feet. Commercial fishing decimated many of the bottomfish stocks during the middle of the 20th century. Today, the bottomfish are protected by both state and federal regulations. Commercial fishers are limited to hook-and-sinker operations—no nets allowed. That’s helped the population rebound—ensuring happy New Year celebrations for years to come. The post Holiday Greetings appeared first on Marine Science Institute. The University of Texas at Austin..

The Franciscana dolphin has quite the schnozz. Its beak is longer in relation to the size of its body than that of any other dolphin or whale—up to 15 percent of the animal’s total length. The Franciscana has another distinction: It’s the only “river dolphin” that doesn’t actually live in freshwater rivers. Instead, it lives in saltwater. It’s found along the coast of South America, from southern Brazil to central Argentina. It’s in bays and estuaries, and up to a few miles out to sea in the Atlantic Ocean. Franciscana dolphins have several other names. The most common is La Plata, for a region of Brazil where it’s abundant. The dolphins are among the smallest of all dolphin species—no more than six feet long, and weighing up to a hundred pounds or so. They’re grayish brown on top, and lighter underneath. As they age, though, they turn gray-white, so fishermen have given them yet another name: “white ghosts.” That’s not just because of their color. Franciscanas move through the water slowly and quietly, perhaps to avoid attracting the attention of killer whales and other predators. But those aren’t their greatest threats. Hundreds of the dolphins are caught in fishing nets every year. Coastal pollution, habitat destruction, and other human activities are also problems. So while no one knows the exact population, Franciscanas are listed as “vulnerable”—threatened by people who can’t keep their own schnozzes out of the dolphins’ business. The post Big-Beaked Dolphins appeared first on Marine Science Institute. The University of Texas at Austin..

A type of damsel fish from the other side of the world has invaded the Gulf of Mexico. But it doesn’t appear to be doing much harm to the fish that were already there—at least not so far. The Regal Damselfish comes from the Indian and western Pacific oceans. It’s only about four inches long, and it lives on coral reefs, in shallow coastal waters. The invader was first seen in the Gulf in 2013. It probably hitchhiked on an oil platform that was moved from the eastern hemisphere. A recent study looked at how the fish spread across the Gulf through 2021. It also looked at how other types of fish fared—especially those that compete with the invaders for resources. Researchers from the University of Texas Marine Science Institute and elsewhere counted the fish found in sections of five reef systems along the coast of Mexico. They then used mathematical models to estimate the total populations of the entire system. The invading damsel fish spread across all the reefs in the study area. At the same time, the populations of its competitors dropped. But so did the populations of some of the other species of fish that don’t compete with the invaders. That suggests that the dip in the number of competing fish had some other cause. One possibility is loss of habitat caused by human activities. One of the reefs in the study is near a busy port that’s growing bigger. So that might be damaging the reefs more than the invasion of the damsel fish. The post Harmless Invasion appeared first on Marine Science Institute. The University of Texas at Austin..

The wolves on a small island in Alaska have a diet problem. They’ve wolfed down dangerously high levels of mercury—a result of eating sea otters. Pleasant Island is a mile off the coast of Glacier Bay National Park, in Alaska’s panhandle. Wolves have decimated the island’s population of deer, which used to be their main prey. So the wolves started eating sea otters. In fact, otters now make up about two-thirds of their diet. Biologists have been studying the wolves for years. When a pack member died in 2020, they found that its tissues held extremely high levels of mercury—a nasty toxin. So they compared mercury levels of the island’s wolves to the wolves along the adjacent coastline and in the middle of Alaska. The mainland wolves eat mainly moose and deer. The island wolves have much higher levels of mercury. Some of the levels were the highest ever seen in any wolves anywhere in the world. Mercury builds up in marine organisms. Larger organisms eat lots of smaller ones, allowing the mercury concentration to grow as it moves up the food web. Sea otters are near the top of the web, so they build up a lot of mercury. And when the wolves eat the otters, they get high doses of mercury as well. The population of sea otters on the coast of Alaska and British Columbia has been increasing. And wolves along the coast appear to be incorporating more otters into their diets. So wolf populations could face greater mercury-contamination problems in the years ahead. The post Dietary Problems appeared first on Marine Science Institute. The University of Texas at Austin..