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Science and the Sea podcast

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

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

Endangered!

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Only one species of penguin lives north of the equator -- and it’s nowhere near the North Pole. Instead, it inhabits the warm, sunny Galapagos Islands, off the coast of South America. But it’s endangered -- its population has dwindled to just a couple of thousand. Without help, it could vanish.

The Galapagos penguin is one of more than 5600 species of birds, fish, turtles, and other marine critters that need help. They’re listed as threatened, endangered, or critically endangered by an international organization. The United States maintains its own endangered species list.

To be listed, a species has to be in danger of becoming extinct, or disappearing from a particular region. There’s no specific number to guide the process -- no minimum population, for example. But before a species is declared “threatened” or worse, scientists evaluate its numbers, its habitat, how quickly it reproduces, the threats it faces, and other factors.

Being on the “endangered” list provides various levels of protection. In the United States, protection is provided by the Endangered Species Act. It bans hunting the species, guards its habitat, and takes other steps to keep it from vanishing.

And there are many cases where conservation efforts have helped species rebound. In 1941, there were only about 16 known whooping cranes in the U.S. With decades of work, though, today the population is more than 800. The crane is still endangered -- but at least it’s still around.

Jan 16 2022

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Arctic Layers

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To borrow an old phrase, everything old is new again. Consider life in the Arctic Ocean. As the ocean warmed up after the last Ice Age, it was divided into several layers. The layering made life hard for the smallest members of the marine food chain. And with the Arctic growing warmer now, the same thing could happen again. That could limit not only microscopic life, but larger organisms as well.

Researchers probed the history of the Arctic by studying fossils found in the sediments. In particular, they looked at the single-celled organisms known as foraminifera. Their fossilized shells preserve a record of the nutrients they consumed.

The researchers found a big change about 11,000 years ago, at the end of the Ice Age. As global sea level rose, water from the Pacific Ocean began pouring into the Arctic. Pacific water is warmer and less salty than water from the Atlantic, making it less dense. So when the waters came together, they created layers of different temperature and salinity.

In those conditions, nitrogen -- a key nutrient -- stayed in deeper Atlantic waters. The small organisms at the surface couldn’t go that deep, so their numbers stayed low. And without those organisms, the populations of fish and other large creatures were low as well.

About 6,000 years ago, the layering became less prominent. But today, the Arctic is getting warmer. That may once again create the layered structure seen in the past -- and limit life near the top of the Arctic Ocean.

Jan 09 2022

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Volcanic Nap

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A volcano responsible for one of the most powerful eruptions of the last 10,000 years may be settling in for a nap -- the result of higher sea levels.

Santorini Volcano is in the Aegean Sea, southeast of mainland Greece. About 3600 years ago, it staged a spectacular eruption. It may have blown 15 cubic miles of rock and gas into the air. The eruption has been blamed for the demise of the nearby Minoan culture. And that could have triggered the legend of the lost city of Atlantis.

Researchers combed through records of 360,000 years of eruptions. They used marine sediments mixed with the volcanic rock and ash to gauge sea level. They found that when it was at least 125 feet below the current level, the volcano started acting up. And as the sea level dropped even lower, Santorini got even more active.

Water atop the volcano may act like the lid on a pressure cooker, keeping Santorini from boiling over. As the water level drops, though, the pressure inside the volcano takes over. The walls start to crack, and molten rock from a chamber deep below the surface forces its way upward. When the water pressure is low enough, the volcano erupts, pumping out ash and gas, then lava.

As sea level rises, though, the process is reversed. The cracks begin to seal, and the eruptions come to a halt.

The researchers found that of 211 big eruptions, all but three took place when sea level was much lower. And with sea level on the rise, that suggests Santorini could be ready for a nap.

Jan 02 2022

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Migraine Relief

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Salmon, tuna, herring, and other fish aren’t just tasty. They’re packed with omega-3 fatty acids -- healthy fats that may help improve everything from Alzheimer’s to heart disease to arthritis. And a recent study found that you might be able to add migraines to the list as well.

Migraines affect millions of Americans. They generate sharp pain, nausea, and other nasty symptoms. A migraine can last for hours, and it can make it impossible to work or do much of anything else. And many people have chronic migraines, with many attacks per month.

Some small studies had provided evidence that omega-3 from fatty fish could ease some of the migraine symptoms. Researchers extended that work to a larger sample -- 182 migraine sufferers.

They were divided into three groups. The control group ate a diet that roughly matched the amount of omega-3 found in a typical American diet. A second group got a lot of omega-3 from fatty fish, while a third got the fish plus high levels of similar compounds from other sources.

Participants recorded their migraine symptoms. The groups with higher levels of fatty acids from fish reported that migraines were less frequent, didn’t last as long, and didn’t impair their ability to function as much. And scientists found less of a pain-related chemical in their blood.

The researchers say the omega-3 compounds may reduce inflammation in a key nerve bundle in the brain -- bringing at least a little relief from the agony of migraines.

Dec 26 2021

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Snowflake Eels

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The snowflake moray eel has been known to slither onto the beach to catch a tasty crab. That’s not all that unusual -- several species of fish sometimes leave the water to eat. But the snowflake really leaves the water behind. Unlike other fish, it can swallow its prey without swallowing water to wash it down.

The snowflake is found in tropical waters across the Indian and Pacific oceans, from Africa to Mexico and Central America. It lives on reefs or rocky sea floors, where it can hide from predators. It’s typically about a foot and a half long, although it’s been known to top three feet. And it’s covered with white splotches that resemble snowflakes.

Like all moray eels, the snowflake has two sets of jaws. It uses the first to grab its prey. And it uses the second set to pull the prey in.

Researchers who’d heard stories about snowflakes coming ashore to eat decided to see how it might work. They studied eels in captivity over a period of six years -- seven individuals, for up to eight months at a time. In particular, they trained the snowflakes to come out of the water to eat. They then watched what happened.

They found that the eels not only grabbed the food that was left for them, but they swallowed it on land as well. They didn’t have reserves of water in their jaws to help swallow -- the prey was pulled in by the second set of jaws. The experiment showed that the eels can eat just fine without any water at all -- either for catching a meal or for washing it down.

Dec 19 2021

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Flexible Arms

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If your arms and legs are a little stiff when you get out of bed in the morning, you might be envious of the octopus. It has some of the most flexible appendages yet studied. Its eight arms can move in several ways, in any direction, and at any point on the arm.

The arms make up more than half of the octopus’s body weight. That’s because an octopus relies on them for just about everything it does: moving through the ocean, finding and catching prey, fighting, mating, and camouflaging itself from predators. Special receptors on the arms act like noses and tongues -- they “sniff” odors in the water and “taste” the objects they touch to see if they’re yummy treats or something to avoid.

All of that activity requires the octopus to stick its arms in some small, twisting spaces -- holes in the ocean floor or small openings in rocks or reefs. That’s one reason the arms need to be so flexible.

To find out how flexible, researchers spent months recording 10 octopuses in the lab. When they analyzed the video, they noted more than 16,000 specific motions. From that, they determined that all the arms could bend, twist, or get longer or shorter. They could bend up or down or side to side, and twist all the way around. And all of those motions could take place at any spot on any arm.

The researchers noted that scientists have long talked about the flexibility of octopus arms. But this was the first study to confirm that octopuses don’t have to worry about stiff joints in the morning.

Dec 12 2021

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Setting a Baseline

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Doctors sometimes run tests even when they know you’re just fine. The tests tell them how your body works when it is fine, making it easier to figure out what’s wrong when you’re sick.

Marine biologists sometimes do the same thing with fish. They run tests to see how the fish operate under current environmental conditions. That can help them figure out how the fish are faring in the future under different conditions.

An example is some work done by scientists at the University of Texas Marine Science Institute. They studied the role of an enzyme in the blood that affects how a fish “breathes in the good air and breathes out the bad.”

The enzyme is carbonic anhydrase. It was already known to help fish get rid of carbon dioxide in the blood. But some fish have a lot more of the enzyme than they need to take care of CO2.

So the researchers checked whether carbonic anhydrase also effects how oxygen is transported in the blood. In the lab, they tested the blood of red drum, a popular sportfish in the Gulf of Mexico. When they cut the amount of the enzyme by half, the amount of oxygen passed from the blood to the tissues also was cut in half. And when they doubled the amount, the rate of oxygen delivery doubled as well.

The researchers say that keeping an eye on the enzyme in fish in the wild could be one way to monitor their health -- and how they’re adapting to the changing oceans.

Dec 05 2021

2mins

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Deep Life

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Life can find a niche just about anywhere, from tall mountaintops to the bottom of the deepest parts of the ocean. And it doesn’t stop there. Microscopic organisms live in the sediments below the ocean floor. A recent study found such organisms at depths of three-quarters of a mile, where temperatures were far above the boiling point of water.

The study was part of the International Ocean Discovery Program, which studies all the world’s oceans. Researchers drilled into the sediments at the bottom of the Nankai Trough, off the coast of Japan. It’s a groove in the ocean floor where one slab of Earth’s crust is plunging below another. The bottom is filled with deep layers of sediments deposited in the last few million years.

During a two-month cruise in the autumn of 2016, researchers picked a spot where the water was three miles deep. They then drilled far into the sediments -- almost all the way to the crust. At that depth, the temperature reached about 250 degrees Fahrenheit -- far above the boiling point. Yet even in those conditions, a detailed look at the chemistry of the sediments revealed abundant evidence of microscopic life.

Another study, released in 2020, reported the discovery of 40,000 species of microbes from 40 drill sites around the world. None of the sites probed sediments with such high temperatures, though. But the combination of studies shows that you can find life just about anywhere on Earth -- even far below the bottom of the sea.

Nov 28 2021

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Listening In

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You can learn a lot about people by eavesdropping on their conversations: where they’ve been, where they’re going, what they’re thinking. And the same thing applies to fish. Listening to their conversations can reveal when they’re busiest, how they move around during the day and the year, when it’s mating season, and much more.

A recent study, for example, listened to a type of rockfish off the coast of California. Researchers studied bocaccio rockfish in the Channel Islands National Marine Sanctuary, near Los Angeles. Bocaccio are a popular commercial and sport fish. They weigh up to 20 pounds and are up to three feet long. They can live for 50 years. But they grow slowly, so if the population is reduced, it takes a long time to recover.

Microphones at depths of 65 to 500 feet “listen” to the soundscape in the islands all the time. Scientists study the audio to learn about many species, and to understand how marine life is affected by sounds created by people.

For the bocaccio study, researchers analyzed sounds during the fall of 2018 and spring of 2019. They found that the fish were louder at night, with peaks around dusk and dawn. There wasn’t much difference in sound between the seasons, though, indicating that the rockfish don’t “talk” more or less during mating season.

The researchers plan to expand their study to cover other times of year, and to plot hour-by-hour changes in the conversation -- learning more about an important species by eavesdropping.

Nov 21 2021

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Dirty Water

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The world’s oceans just keep getting more polluted. That’s not good for anything living in them or near them -- including people. In fact, ocean pollution may cause millions of premature deaths every year.

A recent study looked at hundreds of smaller studies done over the last few years. It put them together to provide a look at conditions around the globe. It found that pollution is widely spread, and it’s getting worse.

It’s made worse by increased manufacturing, bigger farming operations, and bigger coastal populations, among other causes. All of them generate wastes that find their way into the oceans.

Mercury is more common in the oceans than ever, for example. It comes mainly from coal-fired power plants. Mercury accumulates in fish and shellfish, which people eat. It can harm the brains of unborn children, and increase the risk of cancer and heart problems in adults.

Fertilizers, raw sewage, and other runoff lead to more and longer harmful algal blooms. Some of the algae produce toxins that can be deadly. So when they show up, fishing areas and beaches have to shut down.

Plastics are a growing problem as well. About 10 million tons wash into the oceans every year. As they break down, their chemicals can enter the food chain. Many of the chemicals are toxic, so they can cause health problems for marine organisms and the people who eat them.

The report says it’ll take a lot of work to clean up the oceans -- making them safer for life everywhere.

Nov 14 2021

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