Posts Tagged 'public radio'



A Blue View: Rainforests of the Sea

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 p.m. as John brings to the surface important issues and fascinating discoveries making waves in the world today.

July 24, 2013: Coral Reefs: Rainforests of the Sea

A Blue View podcast

Click here to listen to John discuss the importance of 
protection coral reefs.

Sometimes called the rainforests of the sea, coral reefs are colorful, intricate ecosystems—among the most incredible natural wonders in the world. Their brilliant hues and diverse inhabitants make them a favorite of scuba divers and ocean enthusiasts around the world. But, coral reefs are also in grave danger—and saving these ancient splendors is both a necessary and feasible goal.

blacktip reef

Our newest exhibit, Blacktip Reef, is the re-creation of a vibrant Indo-Pacific reef!

According to a report by the World Resources Institute, 75 percent of the world’s reefs are considered threatened due to a combination of risks. Climate change has made bleaching, which is a massive die-off of coral polyps, and disease outbreaks more common. Increased carbon in our oceans results in ocean acidification, which, in turn, destroys the very structure of the reef. Overfishing and destructive fishing practices are disturbing the balance of these complex ecosystems. Coastal development, pollution, coral mining, and unsustainable tourism activities are adding additional stresses to an already challenged habitat. Some scientists fear that at this rate, living coral reefs could vanish from earth within a generation unless drastic action is taken.

Surprisingly, while coral reefs make up just two-tenths of a percent of the ocean floor, they support about 25 percent of all marine animals. They are critical spawning, nursery, breeding, and feeding grounds for thousands of species.

Many people don’t realize that corals are in fact animals, closely related to jellyfish and anemones. There are both hard and soft corals, and all live together in colonies, creating a foundation for all the other inhabitants of the reef, from tiny darting fishes to large apex predators like sharks and everything in between.

There’s no question that these ecosystems are environmentally critical, but they are also important economic drivers, creating millions of jobs and providing a sustainable tourism resource when properly managed. Coral reefs also serve as natural barriers for islands and other communities, helping to prevent erosion and minimizing the impact of waves and storms. In fact, according to the National Oceanic and Atmospheric Administration, up to 90 percent of the energy from wind-generated waves is absorbed by reefs.

NOAA also estimates that ocean temperature will rise nearly two degrees within this century from the greenhouse gases already released, which will undoubtedly threaten these critical ecosystems even more. As marine scientists explore just how coral reefs will cope with increasing acidity in the world’s oceans, it is abundantly clear that we must act to save these oceanic treasures.

Scientists are now studying coral reefs along Mexico’s Yucatan Peninsula, where underwater springs naturally lower the pH of the surrounding seawater. There, researchers are learning how corals respond to higher acidity in a natural setting. On the other side of the world, a U.S. climate scientist is conducting an experiment on Australia’s Great Barrier Reef to see whether antacid could boost coral growth by slowing seawater acidification.

These researchers are taking threats to our coral reefs seriously, and we need to do the same. The single biggest thing you can do to slow the deterioration of reefs is to reduce your own carbon footprint by driving less and conserving energy at home. We can also to make sustainable seafood a priority and vigorously support steps to enforce proper management of these resources. We do well to remember that our actions on land—our stormwater, trash, and yard runoff—all eventually work their way to the sea and impact coral reefs. We can all keep coral reefs in mind as we go about our daily lives—and remember that water connects us all.

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A Blue View: The Unfair Attack on Sharks

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 p.m. as John brings to the surface important issues and fascinating discoveries making waves in the world today.

July 10, 2013: Sharks Unfairly Attacked

A Blue View podcast

Click here to listen to John discuss the bad
reputation sharks have gotten over the years. 

Sharks have long captured the imagination of the public. These days, even shark sightings make national news. Just this past June, great white shark sightings in Massachusetts and New Jersey cleared beaches and were widely reported across the country.

Often thought of as mindless, aggressive killers, sharks—and their toothy jaws—are featured prominently in movies and TV shows, always adding drama with a hint of fin visible above the water’s surface. Despite the fascination that we all feel for sharks, these important apex predators remain seriously misunderstood.

Most people think of great whites when they think of sharks, but there are actually more than 375 shark species, ranging in size from the 8-inch dwarf lantern shark to the 65-foot whale shark.

Here are just a few shark species that can be found at the Aquarium:

The vast majority of sharks are carnivores, but exactly what they eat depends on what they can catch. Larger shark species may prefer seals or large fish. Other species may opt for mollusks, clams, squid, and other small marine animals. One thing is certain—humans are not the preferred menu choice—far from it.

Of the hundreds of shark species, only 12 are considered even potentially dangerous to people, with great whites, bull sharks, and tiger sharks responsible for most attacks on humans. In 2012, approximately 80 shark attacks occurred worldwide, with seven fatalities. When one considers how fearful the general public is of sharks, it’s remarkable to learn that as many as 100 million sharks are killed by people each year. The fact is, sharks have far more to fear from humans.

While sharks may be at the top of the food chain, they are susceptible to threats such as shark finning, overfishing and bycatch. As top predators, most shark species produce relatively few offspring and take years to reach reproductive maturity. The whale shark, for example, doesn’t reproduce until the age 30. When killed in great numbers, sharks don’t have the opportunity to reproduce, and the long-term viability of the population is threatened.

So why should we worry about sharks? Let’s start with the fact that they’re absolutely critical to healthy ocean ecosystems. Scientists refer to sharks as a keystone species, meaning that the whole complex food web relies on them. From their perch at its top, sharks keep populations of other fish in check, naturally select out old and sick fish, and control populations so that other prey fish can’t cause an imbalance in the ecosystem. By doing the essential job of population control, sharks actually ensure adequate biodiversity in marine habitats.

Besides regulating the food web, sharks are believed to keep coral reefs, sea grass beds, and other vital habitats healthy. Essentially, sharks regulate the behavior of other species by intimidating them, preventing any one species from over-consuming critical habitat.

Because of the severe population decline of many shark species, several states, Maryland included, have taken steps to protect sharks by prohibiting the sale, trade, and transfer of shark fins, and many conservation organizations are advocating for even greater protection of these ocean-dwellers.

This summer, if you’re fortunate enough to spent time at the ocean, don’t let fear of sharks prevent you from enjoying the water. Be sensible, but not afraid. As you’ve no doubt heard, you face much greater risk driving to the shore than you do from the sharks that live there!

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A Blue View: Rising Seas

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 26, 2013: Rising Seas

A Blue View podcast

Click here to listen to John discuss the impact
climate change is having on rising sea levels. 

On these hot summer days, our thoughts tend toward ice cream cones and tall glasses of ice water on a sweltering afternoon rather than the melting of ice sheets around the world. But just as the ice melting in your glass causes the water level to rise, so too does the melting of the world’s ice shelves.

Perhaps you’ve seen the incredible videos of massive chunks of ice breaking away from a glacier, causing crashing impressively into the sea. Until recently, it was thought that this was the primary cause of ice loss in Antarctica. But in fact, a study by NASA and university researchers indicates that warming oceans are also dissolving the ice from underneath the ice shelf at unprecedented rates, causing the greatest loss of Antarctic ice shelf mass. Scientists plan to use these data to help determine how ice shelves melt, improving projections of how the ice sheet might respond to a warming ocean and contribute to sea level rise.

Ice loss is not just occurring at the poles: NASA researchers have discovered that glaciers outside of the ice sheets of Greenland and Antarctica lost an average of 571 trillion pounds of mass each year during the six-year study period, causing sea levels to rise almost two-tenths of an inch during that time. This actually matches the sea level rise attributed to the combined ice loss of the Greenland and Antarctica ice sheets.

Ice melting isn’t the only contributor to sea level rise. Warming temperatures cause waters to warm and expand. In turn, warming waters take up more volume. This phenomenon is called thermal expansion. The combination of ice melting and thermal expansion means that sea level rise is not just a possibility…it is happening now, and the only question is how fast it’s going to rise.

Many scientists now believe that sea levels will rise by no less than one to two feet by 2100. And without dramatic reductions of greenhouse gas emissions, the threat could be much more substantial.

The East Coast in particular is at greater risk from sea level than other areas of the world, mainly due to ocean currents and differences in seawater temperature and ocean salinity, according to climate scientists. The U.S. Geological Survey found that sea levels from North Carolina to Boston climbed by about 2 to 4 millimeters a year between 1950 and 2009 as compared to a global average of one-half to 1 millimeter.

These amounts may seem small and unimportant, but the repercussions from these rising levels are anything but. Imagine increased coastal flooding, shoreline erosion, loss of wetlands, and destroyed homes and businesses on the order of superstorm Sandy. Sea level rise does affect us all.

We need to take steps to control warming, as sea surface temperature and sea level rise are inextricably linked. According to the EPA, sea surface temperatures have risen at an average rate of 13 one-hundredths of a degree per decade since 1901. As small as that may sound, over 112 years, that’s an increase of one and a half degrees, which is already impacting not only sea level, but also coral reefs and other essential ocean habitats, migration and breeding patterns, the intensity of storms, and the spread of invasive species and marine diseases.

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A Blue View: Dolphin Earthquake Study

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 19, 2013: Dolphin Earthquake Study

A Blue View podcast

Click here to listen to Dr. Mark Turner discuss how
our dolphins reacted to last year’s earthquake.

On August 23, 2011, a magnitude 5.8 earthquake occurred with its epicenter approximately 118 miles from the National Aquarium, Baltimore. A short time before the dolphin pavilion started shaking from the earthquake, an Aquarium volunteer logging the activities of four dolphins noticed that they all started to swim very quickly in close formation, something she could not recall ever having seen before. She had enough time to note this behavior in her handwritten log before the building suddenly started shaking. At the same time all this was happening, the underwater sounds in the dolphin pools were being recorded using a pair of hydrophones (i.e., underwater microphones). The combination of the in-person observation and the hydrophone recordings provides valuable insight into dolphin behavior.

When an earthquake occurs, seismic waves radiate out from the focus of the earthquake at different velocities. The fastest of these, called the primary wave or P-wave, can travel at speeds of 15,000 miles per hour. However, although very fast, P-waves often are unnoticed by humans. The S-wave and surface waves, the ones that shake everything and cause the worst destruction, travel at much slower speeds.

Although no humans at the Aquarium that day reported feeling the P-wave, its trace did show up in our hydrophone recordings almost 22 seconds before the arrival of the S and surface waves. In view of the P-wave’s appearance in the recordings and the dolphins’ behavior, marine mammal researcher Mark Turner believes the dolphins felt the P-wave, and the volunteer observed their reaction to it. Listen to the hydrophone’s recording: 

This is a clip of the underwater sounds in the dolphin pools when the August 23, 2011, Virginia earthquake occurred. Two hydrophones were recording at the time. The left stereo channel is the recording from the hydrophone in the front pool where a dolphin presentation was in progress. The right channel is from the back holding pool where fast swimming in an unusual configuration was observed. In the video that accompanies the sound clip, the top two panels show the raw signal picked up by each hydrophone. The top panel is from the front pool and the bottom one is from the holding pool.

The bottom two panels are spectrograms. A spectrogram is a visual representation of sounds in which the x-axis is time and the y-axis is frequency. In a spectrogram a dolphin whistle will appear as a dark, wavy line, and a squawk can sometimes appear as a stack of parallel wavy lines.

The sound clip begins at almost exactly the time the earthquake started in VA. The various seismic waves traveled from the earthquake’s focus to Baltimore at different velocities, with the P-wave arriving first, 27 seconds into the clip. Although the very low frequency vibrations induced by the P-wave are visible in the upper panels, they are inaudible, although you might hear some water splashing. The S and surface waves (the ones that are very loud and shook everything) did not arrive until almost 22 seconds later, 49 seconds after the beginning of the clip.

You may hear some of the presentation music, a bit louder in the left channel. If you listen carefully you will also hear (and see in the spectrograms) dolphin clicks, squawks and whistles. And, of course, you will hear the loud noises made by the earthquake surface waves as they sounded underwater.

An excellent overview of the different seismic waves with animations can be found by clicking here.

All signal displays were generated using Raven Pro, Interactive Sound Analysis Software, Bioacoustic Research Program at the Cornell Lab of Ornithology.

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A Blue View: Explore A Shore Responsibly

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 12, 2013: Explore the Shore

A Blue View podcast

Click here to listen to John discuss the importance
of responsibly enjoying the shore!

Whether boating, fishing, or just walking along the sandy shore, spending time on the water is a classic summer pastime. For many of us, these visits are an opportunity to explore. From birds, crabs, and fish, to the occasional dolphin and seal sighting, an amazing diversity of life lives in harmony along the shore. It is critical, though, as many of us make our way to the water, that we take responsibility for the ways that our actions impact the environment.

When we get too close to certain wildlife, for example, we can unintentionally cause a nest failure or force an animal to flee, putting its survival at risk. Never feed wildlife, not even the bread scraps from your beach picnic, and avoid sensitive sand dunes by sticking to walkways. And when boating, obey posted speed limits and slow down while motoring through shallow waterways. Respect these natural habitats by observing wildlife from a distance—close enough to appreciate the beauty of these incredible ecosystems but far enough away to leave wildlife and plants undisturbed.

It’s also essential to dispose of trash properly. Every summer, people leave their footprints—and a whole lot of trash—along our coasts. From fishing line to plastic bags, our throwaways can throw our oceans into turmoil if we don’t dispose of these materials responsibly.

Fishing line is particularly dangerous to animals. Wildlife often eat or become entangled in monofilament line, which is practically invisible. One unfortunate sea turtle was found with an astounding 590 feet of fishing line in his gut. One study showed that more than 50 percent of sea turtles stranded on a beach contained traces of debris in their digestive tracts. Sixty-five percent of those animals had ingested plastic bags, and it’s no wonder: the U.S. International Trade Commission reported that 102 billion plastic bags were used in the United States in 2008 alone—that’s a bag a day for every woman, man and child.

Though there are many statistics citing the numbers of animals that die as a result of marine debris each year—one estimate in fact is 100,000 marine mammals and millions of birds and fishes—this area of study is evolving. The National Oceanic and Atmospheric Administration’s Marine Debris Program is taking essential strides in supporting efforts to research, prevent, and reduce the impacts of marine debris, but it’s clear that we can’t afford to wait to take action. The bottom line is that even one piece of garbage on the beach is one too many.

This year, think about your impacts as you pack for your day at the beach. A great place to start is reusable goods. It’s often windy by the shore, so keep your trash and belongings from blowing into the ocean. Some popular fishing areas provide safe recycling containers for monofilament line. You can also ship monofilament to the Berkley Recycling Center in Iowa. This company will use your line to create Fish-Habs, which are four-foot underwater habitat structures made from recycled fishing line, milk cartons, and soft drink bottles. These cubes attract fish and encourage plant growth, providing natural cover necessary to maintain healthy habitats.

Whatever you do, follow this one essential rule when you’re at the shore this summer: When it’s time to go home, leave nothing but your footprints!


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