Science and the Sea Podcast

The dwarf seahorse doesn’t sound like a great hunter. It’s only about an inch long, and its swimming speed is barely perceptible. But it’s as deadly as an Old West gunslinger-it catches more than 90 percent of the prey it targets. The dwarf seahorse is found in shallow coastal waters in the Bahamas, southern Florida, and the Gulf of Mexico. It lives mainly in seagrass beds or similar habitats, where it can hide from predators. Males and females mate for life, with the males carrying the offspring. The most amazing thing about the seahorse, though, is its hunting. It feeds on tiny organisms. And its digestive system isn’t very efficient, so it has to eat a lot of them. But its main food-a crustacean known as a copepod-is really fast. It can cover 500 times its own body length every second-the equivalent of a six-foot person swimming at 2,000 miles per hour. The dwarf seahorse can’t keep up with that. Its top speed is about five feet per hour. Instead, researchers at the University of Texas Marine Science Institute found that it uses some streamlining and a lighting-quick “draw.” The angle and contours of its head are such that it doesn’t produce a “wake” in front of it, so a copepod can’t feel its approach. At a distance of just one millimeter, the seahorse tilts its head and sucks in the prey. The whole thing takes just a thousandth of a second. That makes the seahorse an efficient hunter-the dead-eye of the seas. The post Dead-Eye Hunters appeared first on Marine Science Institute. The University of Texas at Austin..

In the winter of 2022 and ’23, a dozen “atmospheric rivers” flowed ashore in California-dense bands of clouds that can carry more water than the Mississippi River. They spawned heavy rains, which helped relieve a nasty drought. But they also caused flooding, mudslides, and other problems. A recent study says that atmospheric rivers could produce more soggy winters in California by the end of the century. The change would be triggered by changes in a deep current in the North Atlantic Ocean that’s part of the “global ocean conveyor belt,” which distributes heat around the planet. The North Atlantic current carries warm water from the tropics along the coast of North America and eastward to Europe. That helps keep the climate in Europe fairly mild. After that, the water sinks into the deep ocean, then flows southward again. But a warming planet has caused the current to weaken. And what happens in the oceans has a big effect on what happens in the atmosphere. Researchers used computer models to simulate that link, and look at the climate impact around the globe. They found that a weaker current would change the amount of water vapor in the air and create stronger winds at high altitudes. Those winds would spawn more atmospheric rivers over western North America. Antarctica could see more precipitation as well. But parts of the Arctic would see less-big changes in the atmosphere caused by big changes in the Atlantic Ocean. The post More Rivers appeared first on Marine Science Institute. The University of Texas at Austin..

Some gray whales have been making dangerous detours in recent years. During their annual migrations along the Pacific coast of the United States, they’ve been ducking into bays to eat and rest. But that increases the risk of collisions with ships. To reduce the risk, researchers have developed some systems for tracking the whales and passing the details to mariners. Eastern North Pacific gray whales spend the summer in the Arctic, where they feed. They head south in the fall, for the bays and lagoons of Baja California, where they give birth-a round trip of about 12,000 miles. But rising ocean temperatures have cut their Arctic food supply. Many of them have starved to death. From 2016 to 2025, the population dropped by almost half. Migrating whales used to pass by the bays. But now, weakened by the lack of food, they’re entering the bays to forage. So the number of ship strikes has gone way up. A team has developed tracking tools for use in San Francisco Bay. One tool combines visual sightings with detections by underwater microphones. Another, which debuted in 2026, uses infrared cameras linked to an AI system. They detect the whales’ body heat and the puffs of air from their blowholes. The whales’ locations are posted online. The Coast Guard also sends out the details via radio. That allows vessels to change course or speed to avoid an impact-making the detour a little less risky for the migrating whales. The post Traffic Control appeared first on Marine Science Institute. The University of Texas at Austin..

Biting into a bunch of sea grapes is a bit like having a mouthful of Pop Rocks-lots of little “pops,” followed by bursts of flavor. But in the case of the sea grapes, it’s the briny flavor of the ocean. Sea grapes aren’t really grapes at all. They’re a form of seaweed-a type of green algae that’s especially common in parts of Asia and the western Pacific Ocean. It grows in shallow waters near the coast-usually at depths of no more than 10 feet or so-and usually on rocky bottoms. It can form large beds or meadows. A sea grape organism anchors itself to the bottom. Horizontal stems branch outward, growing “fronds” that are spaced a few inches apart. Each frond can be a foot long, and is packed with grapes-delicate bulbs of liquid about a millimeter across. The size of the bulbs has earned them another name: sea caviar. Sea grapes have been cultivated in the Philippines since the 1950s, and in Japan since the ’60s-especially the island of Okinawa. They’re known by several names in Japan, including lato and umibudo. And they’re a popular delicacy. The grapes are eaten in salads and sushi, as a garnish, or on their own as a treat. Sea grapes are good sources of vitamins, minerals, fiber, and antioxidants. They have antifungal and antibiotic properties, and they appear to lower blood pressure. They also have potential uses in skin-care products. Perhaps best of all, they continue to provide little bursts of flavor for their many fans. The post Sea Grapes appeared first on Marine Science Institute. The University of Texas at Austin..

If you put a lid on a pot of boiling water, most of the heat stays inside the pot. But when you take the lid off, a lot of heat escapes, warming the air around the pot. The same thing has been happening in the Pacific Ocean. For several years, La Niña acted as a lid, trapping a lot of heat in the ocean. Then El Niño came along and took the lid off. That released huge amounts of heat into the atmosphere, helping to produce the hottest year ever recorded. From 2020 to 2023, there was a sequence of La Niñas-periods of especially cool surface waters in the eastern Pacific. They trapped the heat in the deeper ocean. The La Niñas were followed by a moderately strong El Niño-especially warm surface waters. That took the lid off the trapped heat. Research has shown that, from July 2023 through June 2024, the average global temperature was about two-thirds of a degree Fahrenheit higher than during the previous 12 months. That’s the largest single-year jump seen so far. Almost all of that rise was driven by the higher ocean surface temperatures produced by the transition from three years of La Niña to El Niño.             Not all oceans contributed equally to the increase. Most of the heat came from tropical regions. The tropical Pacific Ocean, the Indian Ocean, and the tropical North Atlantic Ocean accounted for 80 percent of the bump. In all, they contributed about half a degree Fahrenheit to the average temperature around the entire planet. The post Taking the Lid Off appeared first on Marine Science Institute. The University of Texas at Austin..

When you clean out the attic, you never know what treasures you might find. For scientists at Woods Hole Oceanographic Institution in Massachusetts, it was a “golden oldie”-the earliest known audio recording of a whale. Scientists can study the recording to learn how whale songs might have changed, and how the ocean soundscape has changed-especially the sounds produced by people. The sounds of a humpback whale were recorded near Bermuda in March of 1949. Researchers from Woods Hole and the Navy were testing sonar gear and studying ocean sounds. They used a type of dictation machine to record underwater sounds on plastic disks. At the time, the researchers weren’t sure what they were hearing-they didn’t know about whale sounds. But today, we know that whales make a lot of sound-especially humpbacks. They produce clicks, whistles, and calls. The sounds help them navigate, find prey, and locate other whales. Most of the elaborate sounds come from males. They can “sing” for up to 20 minutes at a time. In 1949, the oceans were pretty quiet. Today, they’re suffused with the sounds of ships, oil exploration, wind turbines, and other human activities. This “noise pollution” is one of the greatest threats facing the whales. It could injure them, or interfere with their ability to feed or mate. So knowing how ocean sounds have changed over the decades could help us better understand these “talkative” giants and their noisy home. The post Golden Oldie appeared first on Marine Science Institute. The University of Texas at Austin..

The ocean floor and the wind-swept prairies of the west have something in common: tumblin’ tumbleweeds. On the prairie, they’re nasty bushes teeming with sharp thorns. In the ocean, they’re growing clumps of red algae known as rhodoliths. They can tumble along with the currents until they get too heavy, when they settle down for good. Rhodoliths are found in all the world’s oceans, from the tropics to the arctic. They often congregate in large, dense beds. They need sunlight to produce energy, so they’re most common in shallow coastal waters. Many species of rhodolith begin with a small clump of algae around a hard nucleus, like a grain of sand or a bit of shell. They attract more algae, so they grow. Over time, they form hard skeletons, like corals-a process that takes carbon dioxide from the atmosphere, helping store carbon in the ocean. They come in several shapes. But they all consist of solid knots or branches with open spaces between. That makes them important members of the marine ecosystem. When they get big enough to settle down, they fill the same role as coral reefs. They offer protected spaces for fish, crabs, worms, and other species. That attracts other life, forming a busy ecosystem-and often creating productive fishing grounds. Rhodolith beds help in other ways as well. They can stabilize the sediments close to shore and filter impurities from the water, for example non-thorny benefits from some tumblin’ tumbleweeds. The post Marine Tumbleweeds appeared first on Marine Science Institute. The University of Texas at Austin..

Young manta rays off the coast of Florida have something in common with pop stars and athletes: They have groupies. A recent study found that several species of fish like to hang out with the rays. That can provide advantages for the groupies. Scientists have been watching a manta-ray nursery in South Florida for a decade. Most of the rays inhabit shallow waters less than a mile from shore. And most of them are juveniles. The study looked at 465 videos of the rays. Researchers identified 59 individual rays in the images, some of which were present for several years.  In the videos, the manta rays had an average of a half-dozen groupies. Every ray had at least one, and one especially popular manta ray had more than 200. Most of the followers were cobia, remora, or jack-fish. Some of the remoras were attached to the rays. Most of the other fish congregated on the ray’s right side, below or behind one of its wide “wings.” The groupies might receive several benefits from the relationship. They might be able to grab food scraps, or save energy by swimming in the ray’s wake. They might also use the rays as shelter. Groupies like those found around manta rays also are common around other giant fish, such as the whale shark—the largest of all living species of fish. These followers also may be able to feast on the big guy’s table scraps, or to coast along in its wake—better perks than T-shirts for marine groupies. The post Manta-Ray Groupies appeared first on Marine Science Institute. The University of Texas at Austin..

 Big swaths of the Southern Ocean have been going green. Summertime “blooms” of the tiny plant-like organisms known as phytoplankton are covering a much larger area. That makes the ocean look greener. And that could be kicking off big changes in the life around Antarctica. The trend started in 2016 and ’17. Before then, the sea ice around Antarctica had been pretty stable for years. But it decreased dramatically—disappearing across an area as big as Texas and New Mexico combined. And the ice has been dwindling ever since—a loss seen year ’round. To understand how that’s affected life in the Southern Ocean, researchers looked at satellite photos. They studied the color of the ocean surface. Regions with more phytoplankton looked greener. On average, almost 70 percent of the study region showed a significant increase in summer phytoplankton over the past decade. The researchers compared those findings to the numbers of tiny animals found in the water—krill and salps. Krill look like shrimp, and they’re a major food source for whales, fish, and other organisms. Salps have jelly-like bodies, and they’re not a major food source for any big ocean predators.  The change in phytoplankton appears to be favoring the salps—they seem to like the regions with less ice and extra phytoplankton more than the krill do. But any long-term change in the balance between salps and krill could impact the entire ecosystem—a “green” conundrum in the Antarctic. The post Going Green appeared first on Marine Science Institute. The University of Texas at Austin..

If you dig into the sand below the tide line along many of the world’s beaches, there’s a chance you’ll dig up some potatoes. They’re small, fuzzy, and fragile. But they’re not the kind of spuds you serve with butter and sour cream. Instead, they’re sea potatoes—a type of sea urchin—smaller cousins of the ones with long, painful spines. A typical sea potato is maybe two or three inches long. It’s encased in a thin shell, known as a test. The shell is shaped a bit like a heart—hence the potato’s other name, heart urchin. A pattern on one side of the shell forms the outline of a sea star—another of the sea potato’s relatives. Soon after it hatches, a sea potato burrows a few inches into the sand at the bottom of shallow coastal waters. It then spends the rest of its life there. It excavates a small “den,” with side pockets for air and wastes. The den is lined with a layer of mucus. Small, yellow hair-like spines lie flat against the sea potato’s back. They trap air so the animal doesn’t drown. “Tube feet” push it through the sediments at about an inch per day. As it moves, the critter funnels the sand into its mouth. Its digestive system then filters out the goodies—algae, the remains of dead animals, and nutrients from the sand itself. The shells of thousands of dead sea potatoes sometimes wash up on the beach—the result of extreme weather or some other big shock. Otherwise, they’re seldom seen—hidden in the sand just off-shore. The post Sea Potatoes appeared first on Marine Science Institute. The University of Texas at Austin..