Science and the Sea podcast

The University of Texas Marine Science Institute

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. read less

Ocean Gyres
May 21 2023
Ocean Gyres
Much of the water in the world’s oceans is herded like cattle being driven to market—not by cowboys on horseback, but by strong currents. Known as gyres, they help control global temperatures and the nutrients available in different parts of the oceans. They also round up floating debris, forming giant garbage patches.Gyres are formed by the winds, Earth’s rotation, and the land. Winds drag the ocean water, forming currents. The currents are deflected by Earth’s rotation. They’re pushed clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere.The surface currents drag the water below them, so the effects of the wind run deep. That sets up a “ring” of currents that circulate around the oceans. Finally, the land acts as a barrier, holding the currents in place.There are five major gyres—two in the Pacific Ocean, two in the Atlantic, and one in the Indian. The water inside the gyres tends to be fairly calm. That prevents deep water from rising to the surface. Since the deeper water contains more nutrients, surface waters inside the gyres have less life than in the currents.The gyres carry debris that was washed into the oceans from land. The debris forms large plastic “garbage dumps.” Bigger bits of plastic wear down into smaller bits that are gobbled up by fish, birds, and some of the ocean’s tiniest creatures. That’s a health hazard for the creatures, and for the people who eat them—rounded up by the “cowboys” of the open ocean.
Green Doughnuts
May 14 2023
Green Doughnuts
Green doughnuts are typically something you want to avoid. But some giant green doughnuts on Australia’s Great Barrier Reef may actually be good for us. They may store carbon on the ocean floor. That keeps it out of the atmosphere, where it would add to climate change.The “doughnuts” are created by a type of green algae, known as Halimeda. Each one forms a flat or crinkled disk that can range from less than an inch to several feet across. Combined, they form circular beds that can cover many acres—beds that look like green doughnuts.The largest beds are found on the Great Barrier Reef. They’re on the outside of the reef, where a lot of nutrient-rich water flows up from the ocean. In fact, they may cover as much area as the reef’s famous corals.The beds are important for a couple of reasons. For one thing, like the coral reefs, they provide habitat for a lot of other life. And for another, they lock up carbon that might otherwise be in the atmosphere.That’s because Halimeda has a hard skeleton. The skeletons contain calcium carbonate, a carbon-rich compound. When the algae die, the skeletons form fossil beds that hold the carbon. Over thousands of years, that builds up huge beds—keeping a lot of carbon out of the air.A recent research cruise drilled as deep as 20 feet into the beds on the Great Barrier Reef. Those results will tell us more about these “green doughnuts”—and their possible contribution to the health of Earth’s environment.
Sibling Play
Apr 23 2023
Sibling Play
Young killer whales off the coast of Washington and British Columbia like to nip at each other. That leaves white scars on their backs and sides—but they’re not permanent. That allows biologists to use the scars to learn about the life histories of these endangered animals.They’re looking at southern resident killer whales—the smallest of the four types of resident killer whales. There are only 73 known members. They live in family groups, with the offspring staying with their mothers all their lives.A recent study analyzed 38 years of photographs of the southern residents. Scientists identified individual whales from the patterns of scratches, known as rakes. Over the years, early rakes fade away, while new ones appear. That allowed the scientists to track changes, revealing patterns in interactions between the whales.Perhaps not surprisingly, rakes are more common on younger whales, and on males rather than females.The researchers suggest that most of the scars are the result of play between siblings. But there could be a more serious purpose, as the whales try to move up in the family pecking order.Researchers also found that the number of rakes went up when the whales’ main food supply, Chinook salmon, was most abundant. That could be because more whales congregate then. Or it could be because the extra food gives the whales more pep for horseplay—make that whale play—so the youngsters have plenty of energy to nip at their friends and family.
Relocation Plans
Apr 9 2023
Relocation Plans
Sea birds face all kinds of threats these days: a warmer climate, decreasing food supplies, attacks by invasive species, and others. One of the most basic is rising sea level, which threatens to cover some of their nesting grounds. To help species survive, conservationists are relocating sea bird chicks to higher ground.An example is the Tristram’s storm petrel. It breeds in the Northwestern Hawaiian Islands. But it was wiped out on the island of Midway by rats, and it’s threatened by plastic pollution on other islands in the chain.And on the island of Tern, it’s threatened by the rising waters. Tern covers just 26 acres. And much of that was built up by the Navy during World War II for use as an airstrip. The runway is rarely used today, but it’s still there. Even so, there’s plenty of room for petrels and other species of birds, sea turtles, and seals.But the island extends only six feet above sea level. And with the ocean rising, petrel nesting grounds could be flooded out in the years ahead. So a conservation group recently moved about 40 chicks to new digs on the island of Oahu, 500 miles away.The group had already moved some chicks to another island a few years ago. And it’s done the same thing with other species, including albatross and another species of petrel. Most of the chicks have survived and returned to their new homes to breed.So relocating a few chicks today could help Tristram’s storm petrel survive for decades to come.
Attack!
Mar 26 2023
Attack!
Blue crabs live their entire lives in the water. That’s where they eat, breed, and even breathe. So, some marine scientists were a bit astonished when they saw blue crabs popping out of muddy pits on shore to grab fiddler crabs. Blue crabs are found all along the East Coast and the Gulf of Mexico, on the bottoms of shallow bays and estuaries. They have been seen to dart out of the water to grab prey, but only by a few feet. But in September of 2021, researchers in Virginia saw them emerging from small pits in the sand. It was low tide, so some of the pits were up to a couple of hundred feet from the water. In some cases, the crabs “exploded” from the pits to snatch fiddler crabs that were close by. In other cases, they crept out of the pits and snuck up on their prey. They then dragged the fiddler crabs back to the pits for a leisurely meal. And it was clear the blue crabs had been hanging out for a while. The scientists said some of the pits were littered with fiddler crab claws “like the discarded bones of villagers outside a dragon’s lair.” The researchers returned a couple of weeks later with cameras to confirm the goings-on. They recorded the crabs digging their pits, switching to new ones, and even kicking other crabs out of their pits. The scientists found one other report of such behavior, but nothing had been formally recorded. So, this is the first confirmed instance of blue crabs living—and attacking—from outside their usual watery environment.