Science and the Sea podcast

The University of Texas Marine Science Institute

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NATURAL SCIENCES
EVERY TWO WEEKS

The goal of Science and the Sea is to convey this understanding of the sea and its myriad life forms to everyone, so that they, too, can fully appreciate this amazing resource.

1 DAY AGO

Getting Worse

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.

2 min
15 SEPT

Thresher Sharks

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.

2 min
8 SEPT

New Mountains

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.

2 min
1 SEPT

Crab Burrows

When you build a house, it affects the surrounding ecosystem. The same thing applies to houses built by fiddler crabs in salt marshes. Their burrows can help or hinder the surrounding plants, affect the flow of water, and perhaps cause the marsh to send more greenhouse gases into the air. Thanks to all of that, fiddlers are sometimes described as “ecoengineers.” Fiddler crabs are only about an inch across. They’re found in salt marshes all along the coast. They dig burrows that can be long and deep. The burrows protect the crabs from predators and the environment. They also give the crabs a place to mate. In fact, the quality of a burrow plays a role in a female’s pick of a partner. The burrows pass below the marsh grasses. They can form networks that allow water and nutrients to flow through the marsh. They can “aerate” the soil, increasing the growth of the grass—something that can boost the discharge of greenhouse gases from microbes in the soil. But if the burrows are too extensive, they can damage root systems, slowing growth. A recent study simulated these effects with computers. The work showed that a lot of their impact may depend on the details of the burrows themselves—their depth and shape, the number of entrances, and more. Burrows that are deeper and have more “doors” may increase the exchange of water between aquifers and the surface, for example—changing the ecosystems around these small but abundant houses.

2 min
25 AUG

Sounding Off

In 1875, Navy lieutenant commander Charles Dwight Sigsbee and his ship, the George S. Blake, began a journey into the history books. They started measuring the depth of the Gulf of Mexico with a mechanism that Sigsbee created. When the job was finished three years later, the ship had measured the entire Gulf—the first ocean basin to have an accurate map of all its contours. Sailors had been measuring depths for centuries. They threw a rope with a heavy weight on the end into the water. Distances were marked on the rope every few feet. Counting the marks revealed the ocean depth. The technique became known as depth sounding. Crew members would “sound off” the depth as the rope played out. But it wasn’t especially accurate—especially for deep water. But it improved in the mid-19th century. Sir William Thomson of England developed a machine to do the job, using piano wire on a motorized spool. Sigsbee refined that design. He made the machine larger and more stable, and replaced the piano wire with steel. That improved accuracy. His device became known as the Sigsbee sounding machine. And it was the standard for measuring depths for 50 years. Scientists named many of the features mapped by the Blake after its commander. So maps of the Gulf of Mexico show the Sigsbee Escarpment, Sigsbee Abyssal Plain, and Sigsbee Deep—the deepest spot in the Gulf—first recorded by Sigsbee’s machine a century and a half ago.

2 min
18 AUG

Olive Growers

Olive trees are sprouting all across the Balearic Islands—a chain off the Mediterranean coast of Spain. The largest island, Mallorca, has more than 800,000 cultivated trees. They yield a good portion of the world’s supply of extra virgin olive oil. More trees—of both wild and cultivated varieties—have been showing up on the surrounding islands. They’ve been planted not by farmers, but by sea gulls. The gulls eat olives—especially those from Mallorca—then fly miles over the Mediterranean to their home islands. Once there, they spit up the olive pits, which can sprout and grow trees. Biologists recently studied yellow-legged gulls, which are common across the Balearic Islands. The scientists brought some of the birds into the lab, and attached GPS trackers to others. They also examined the populations of olive trees in the islands. The researchers found that the birds ate both wild and cultivated olives. But they preferred the ones raised on farms. On average, they flew about three miles farther to get them—about eight miles per trip, although some gulls flew more than 60 miles. The gulls upchucked most of the olive pits on the rocky outcrops where they nest. But many of the pits were dropped where they could produce trees. On one island, an area that had been mostly grass and shrubs was being transformed into an olive grove, with both wild and domestic varieties—thanks to the wings and appetites of yellow-legged gulls.

2 min
11 AUG

Climate Ripples

The classic example of chaos theory is called the butterfly effect: If a butterfly flaps its wings over China, it creates ripples in the air that might eventually trigger storms over the Americas. Something similar may be playing out over the South China Sea and the surrounding land: Changes in climate conditions there may influence the rest of the world. The South China Sea covers almost one and a half million square miles. It’s bounded by Southeast Asia and the islands of the Philippines and Indonesia. Influenced by climate change in Asia, its waters are warming faster than most of the world’s oceans. Scientists say that’s influencing conditions not only across the region, but worldwide. There’s more evaporation from the warmer waters, which is changing circulation patterns in the atmosphere above it, for example. These patterns interact with others. That creates a ripple effect that can travel around the globe—like the ripples caused by that pesky butterfly. Climate models suggest possible impacts on specific regions as the South China Sea and the surrounding area get even warmer. The timing and strength of El Niño and La Niña might change, for example. Ditto for the monsoons in Asia. The Americas might see greater extremes in temperature and precipitation, parts of Asia might have more spring and summer droughts, and sea ice could change in both the Arctic and the Antarctic—some possibly chaotic results of our changing climate.

2 min
4 AUG

Phantom Giant

If you’re afraid of the dark, you should avoid the “midnight zone” in the oceans. It’s so far down that no sunlight ever reaches it. The zone’s inhabitants include creatures with bulging eyes and big, sharp teeth, and some with bright, wiggling “lures” to attract prey. One inhabitant also looks like the stuff of nightmares, but it’s a threat only to small fish and other tiny creatures: Stygiomedusa gigantea—the giant phantom jelly. Its “body”—known as a bell—is about three feet across. It can expand to several times that size, though, perhaps to wrap up its prey. Four “arms” trail away from the bell. They can be more than 30 feet long, and they wave through the currents like a ripped-up bedsheet in a summer breeze. The arms are classified as “mouth” arms—they sense prey in the dark ocean, then grab it and pull it up to the stomach. But unlike many jellies, the arms don’t have stingers. The giant phantom jelly has been spotted in all the world’s oceans except the Arctic. But it’s not easy to see because it usually stays deep—anywhere from a few thousand feet to about four miles. In fact, since the first one was reported, in 1899, scientists have logged only a few more than a hundred confirmed sightings. Despite the lack of sightings, biologists say the giants may be common—but hidden in the dark waters of the midnight zone.

2 min
28 JUL

Marine Lingo

In a classic Jules Verne novel, the submarine Nautilus travels “20,000 leagues under the sea.” You might think that “20,000 leagues” indicated the sub’s depth. But you’d need a really deep ocean for that: a league is three miles, so 20,000 leagues is 60,000 miles. The title tells us how far the Nautilus traveled through the oceans. Over the centuries, sailors and mapmakers created new units of measure, with new words to describe them, for plying the world’s oceans. Some of the words have been heaved overboard, but some are still in use. One of the lesser-used units is the fathom, which does indicate depth. It comes from a word in Old English that means “outstretched arms.” That’s because a fathom originally was based on the span of a man’s fully spread arms. Eventually, its length was set at six feet. So the deepest point in the ocean is 6,000 fathoms down. One unit that’s still in common use is the nautical mile—1.15 land-based miles. It marks the size of one minute of latitude—the location north or south of the equator. And it’s the basis for the word knot: one knot is one nautical mile per hour. It originated in the 17th century. Sailors estimated their speed by throwing out a piece of wood attached to a rope. Knots were tied in the rope at specific lengths. Sailors counted the number of knots that spooled out over a given time—a knotty way to measure speed.

2 min
21 JUL

Telescopefish

The telescopefish has a cast-iron stomach. Not only can the stomach digest prey that’s bigger than the telescopefish itself, but it’s as dark as cast iron. That prevents the fish’s prey from getting revenge by attracting critters that might eat the telescopefish. There are two known species of telescopefish. Members of both species are small—no more than about six to eight inches long. They’re found in fairly warm waters around the world, at depths of a third of a mile to a mile and a half or so. Little or no sunlight reaches that far down. So the fish has developed sensitive eyes that poke outward from the head like a pair of binoculars or long telescopes—hence the name “telescopefish.” It may use those peepers to see the faint silhouettes of prey above it. It may glide through the water vertically so it can keep its eyes aimed upward. In addition, it can see fish and other prey that produce their own light, shining through the darkness. When it spies a meal, the telescopefish grabs hold with a mouthful of sharp teeth. It can extend its jaw so wide that it can swallow prey up to twice its own size. Such big prey are folded in half inside the stomach. But the telescopefish is translucent, so its glow-in-the-dark meals might attract the attention of predators. To prevent that, its stomach is black and opaque—like a blackout curtain or a cast-iron skillet. So its prey remains hidden—protecting the telescopefish in the dark ocean depths.

2 min

10 Episodes

The goal of Science and the Sea is to convey this understanding of the sea and its myriad life forms to everyone, so that they, too, can fully appreciate this amazing resource.

Creator

The University of Texas Marine Science Institute
Years Active

2015 - 2024
Episodes

10
Rating

Clean
Show Website

Science and the Sea podcast

Science and the Sea podcast

Episodes

Getting Worse

Thresher Sharks

New Mountains

Crab Burrows

Sounding Off

Olive Growers

Climate Ripples

Phantom Giant

Marine Lingo

Telescopefish

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