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.
Back From the Edge
Back From the Edge
The Steller sea lion used to be a common sight along the Pacific coast, from Alaska to California. But for some reason, the sea lion’s population plunged. So in 1990, the sea lion was placed on the endangered species list, which gave it legal protections. Thanks to conservation efforts, the species in the eastern half of its range recovered. And in 2013, the eastern Steller sea lion was removed from the endangered list.Over the decades, more than 700 species of plants and animals have been added to the endangered species list. Only about 30 have been taken off the list because they recovered.To be removed, there has to be an increase in the population of the threatened or endangered species. In the case of the sea lion, the population of the eastern group had climbed by more than four percent per year for 30 years. And the population has to be sustainable -- potential threats must be under control.The marine species that have been removed from the list include the brown pelican in Florida and Alabama, several groups of humpback whales, and one group of gray whales.Other species have been removed from the list because they shouldn’t have been put there in the first place. A seagrass in Florida was dropped because it turned out to belong to a species that was healthy and widely spread.But some species aren’t so lucky. The Caribbean monk seal was removed from the list in 2008 -- after it became extinct.
Nature doesn’t always work in ways that seem to make sense -- at least at first glance. You might expect, for example, that as giant whales disappeared from the Southern Ocean during the 20th century, their prey -- tiny organisms known as krill -- would flourish. But that didn’t happen. Instead, the krill began disappearing as well.Baleen whales use a comb-like structure known as baleen to filter krill and other small organisms from the water. And each whale can gulp tons of food every day. A recent study, in fact, found that the average whale consumes three times as much food as previously estimated.Based on that number, the study calculated that baleen whales consumed about 200 million tons of krill from the Southern Ocean in 1900 alone. But industrial-scale whaling killed most of the giants -- especially blue whales. So in 2000, the whales took only one million tons of krill.Despite the disappearance of the big predators, though, the number of krill in the Southern Ocean is only a fraction of what it once was. In fact, the total amount of krill in the ocean today is less than the giant predators ate every year before big-time whaling.One possible reason for the decline: a lack of whales. Researchers noted that big whales recycle a lot of nutrients into the ocean. The amount of recycled iron alone has dropped by 99.9 percent -- making the Southern Ocean a lot less productive for both krill and the giant whales they sustain.
May 15 2022
The tusk of a narwhal has a lot of uses. It may help the whale attract a mate, sense prey, and stun its prey. It inspired folktales of unicorns. And today, it’s helping scientists examine changes in the environment.A narwhal tusk can reach up to 9 or 10 feet in length. It’s actually a tooth that grows from the upper jaw of a male. It forms a new layer every year. And like the rings of a tree, each layer records a little about the year, including the narwhal’s diet and its exposure to pollution.Narwhal spend most of their time in the Arctic, including months under the ice. But as the ice has thinned out, things have changed.Researchers logged those changes in a recent study of 10 tusks. They were collected by native populations in Greenland during their traditional hunts. The layers in the tusks recorded the years 1962 through 2010.During the early decades of that period, the narwhal fed mainly on fish that live under the ice. After about 1990, though, they consumed more species found away from the ice -- an indication that the whales were spending less time under the ice.The study also showed that the levels of mercury in the narwhals had jumped in recent years. Mercury causes problems with the nervous system and reproduction. The narwhal doesn’t have a way to get rid of it, so it builds up.The mercury may come from coal-fired power plants. Whatever its source, though, it could make life tougher for the whales with the versatile tusks.
May 8 2022
The groups that rescue and treat sick or injured sea turtles take advantage of a lot of modern science: the latest medications, CAT scans, laser surgery, and much more. But some of those groups also use one of the most ancient treatments of all: honey. Some even keep their own beehives to maintain a fresh supply.Honey has been used as a treatment for people for thousands of years. It’s been applied to cuts and scrapes, burns, and other wounds. And both ancient accounts and modern research tell us that it can help heal a variety of injuries.It does so in several ways. For starters, it can kill bacteria. In fact, jars of honey found in ancient Egyptian tombs were still edible -- they hadn’t spoiled at all. In part, that’s because honey is acidic, so not much can live inside it. And when it comes in contact with a wound, it creates a mild form of hydrogen peroxide, which helps clean the wound.Research has shown that honey also helps reduce inflammation, speeds up the removal of dead skin, and forms an air-tight barrier that protects a wound. And honeycomb can be molded to fit oddly shaped wounds, adding more protection.There are some caveats. The honey has to be fresh and unprocessed -- heat can destroy some of its healing properties. And it’s most effective when combined with other therapies. But it’s proven so successful that it’s routinely used at sea turtle rescue centers in Texas, Florida, Georgia, and elsewhere -- a sweet treatment for injured creatures.
May 1 2022
Fish make a lot of noise. They grunt, click, pop, squeak, groan, buzz, and make many other sounds. And they’ve probably been talking for a long time.Scientists have long known that some fish make sounds. In fact, some fish are named for their sounds: drums ... grunts ... and croakers ... among others. Like land animals, they use sound to attract mates, avoid predators, find prey, and defend their territory.As scientists have studied the ocean soundscape in more detail, they’ve discovered that fish sounds are quite common. A recent study by researchers at Cornell, for example, concluded that most fish use some sort of sound.The researchers looked at recordings of fish, along with previous studies of fish sounds. They also looked at how fish are put together -- many fish have structures that produce sounds. Muscles around the swim bladder, for example, squeeze the bladder, producing grunts and croaks. And certain bones rub against each other, making clicks and other sounds.The researchers concluded that fish first began producing sounds at least 155 million years ago. And different families of fish independently evolved the ability to make sound at least 33 different times. Additional research could reveal sound capabilities going even farther back in time, involving even more fish -- showing that fish have been talking to each other for a long, long time.
Apr 24 2022
Covid-19 has impacted just about every aspect of life. One of those impacts is ocean pollution. Millions of masks, gloves, and other pieces of debris have washed up on beaches or into the open ocean. That’s a problem not just for human life, but for all life in or around the oceans.Masks and other protective gear can be whisked into the oceans by rivers, winds, drainage systems, and other avenues. Winds and tides drive some of the trash onto the beaches. Scientists have recorded old masks and other equipment on beaches around the world. Trash has been seen on the sea floor and even floating in the open ocean as well.One study estimated that one-and-a-half billion masks entered the oceans in 2020 alone. And another said that 25,000 tons of plastic debris from Covid had entered the oceans by the end of 2021.For people, used protective gear is an eyesore and a health hazard. For other life, it can be deadly. Many shorebirds have become entangled in masks and gloves, and some have died after trying to eat them. Seals, crabs, and other animals have gotten tangled up as well.And over the coming years and even centuries, much of the plastic debris could break down into smaller pieces. Birds, fish, sea turtles, and other critters could die after eating these toxic leftovers. So the effects of Covid-19 could extend far into the future -- and far out to sea.
Apr 17 2022
Long-finned pilot whales like to talk. They produce a wide variety of clicks, buzzes, whistles, and calls. That allows them to identify friends and family, even over long distances. And it may also help keep them safe from killer whales.Long-finned pilot whales are fairly small as whales go. They can reach lengths of 20 to 25 feet, and weigh two or three tons. They have a stout body, with long, curving flippers. They live in pods of a dozen or so, headed by the mother of the clan. And the pods can cluster in groups of hundreds of animals.There are two species of long-finned pilot whales. One inhabits the North Atlantic Ocean, from the Americas to Europe. The other lives in the Southern Ocean, which surrounds Antarctica. The populations might not have mixed with each other in more than 10,000 years.But a recent study that listened to the sounds of southern whales for the first time found that many of their calls are almost identical to those of the northern population. It also found that many of the southerners perform “duets” -- two whales singing together, with one starting and the other following along.And like their northern cousins, the southern whales emit calls that are quite close to those of killer whales. The copy-cat calls may help the pilot whales evade detection by the killer whales. They could also help the pilot whales grab a few scraps left by the killer whales -- sly calls that make life a little easier for these talkative whales.
Apr 10 2022
Pearl and Hermes
In April of 1822, the ships Pearl and Hermes were hunting whales far from the main islands of Hawaii when they found something bigger. They ran aground on an atoll -- a ring of coral reefs atop a dead undersea volcano. The sailors made it to one of the atoll’s tiny islands, where they lived for months before rescue. And today, the atoll is named for their ships.Pearl and Hermes is near the northwestern tip of the Hawaiian Island chain, about 1300 miles from Honolulu. It’s part of the oldest section of the chain, which formed more than 20 million years ago.The atoll covers about 450 square miles. The islands -- roughly a half-dozen of them -- cover just 80 acres. There are no trees on any of them -- just grasses and a few other scrubby plants. But the islands are nesting grounds for many birds, including several rare species, as well as monk seals and sea turtles.And the waters of the atoll teem with life -- fish, shellfish, and many others. In fact, Pearl and Hermes has a higher concentration of marine life than any other part of the Northwestern Hawaiian Islands.Today, the atoll is part of America’s biggest national monument. That protects its isolated life from human contact -- but not human problems. Plastic and other debris collects in the reefs. A few years ago, conservationists cleared out about 90 tons of junk.Archaeologists have found several shipwrecks on the reef -- including those of Pearl and Hermes -- whaling ships that caught a big one.
Apr 3 2022
Seagrass beds face many threats these days: pollution, reduced habitat, and stronger tropical storms, to name a few. Another is disease. As the oceans get warmer, organisms that cause diseases multiply quickly. They attack the grass, killing or weakening not just individual plants, but entire meadows.Seagrass is an important part of the marine ecosystem. It purifies the water, and it provides habitat for fish and shellfish. They attract birds, mammals, and other creatures. So losing the seagrass beds is bad not only for life in the water, it’s bad for a lot of life on land as well.Beds have been especially hard hit by seagrass wasting disease. In the 1930s, it killed 90 percent of the seagrass along the North Atlantic coast. And today, it’s having a big impact in the Pacific as well.Scientists recently studied the disease in seagrass beds in the San Juan Islands, off the northern corner of Washington. They looked at how many plants were infected, what impact the disease had on their leaves and roots, and more.They found that most of the plants in their survey had the disease. As they got it, their leaves lost their green color, then developed big dead spots. Perhaps more important, infected roots held smaller stashes of carbohydrates -- food to sustain the grass through the winter.So as the oceans continue to warm, these and other seagrass beds could face more severe disease outbreaks -- and be less able to bounce back from one year to the next.
Mar 27 2022
A recent study says that seaweed grown in farms could be a twofer: It could reduce the pollution in estuaries while producing nutritious food.Seaweed is grown commercially in some parts of the world, but it’s been slow to catch on in the United States. It’s picking up in some parts of the country, though -- especially Maine and Alaska.The study was conducted by researchers in the United States and Israel. They developed a model of how large-scale seaweed farms located in estuaries might impact the environment.The model also looked at what economic benefits the farms might yield.The model simulated different lighting conditions, temperatures, and nutrients to evaluate how the farms would perform in different seasons. The model was checked against a small experiment in which a type of seaweed was grown in an estuary.The scientists were especially concerned about nitrogen. It’s a key ingredient in fertilizers. When it washes into the oceans, though, it can cause environmental damage, such as red tides and “dead zones” where there’s little or no oxygen in the water.The model showed that the seaweed was efficient at removing nitrogen from water in an estuary. It could even remove nitrogen from already polluted estuaries, helping to clean them up.At the same time, the seaweed contains healthy proteins and starches, so it could be sold as food for people or animals. So cleaning up coastal waters also could be an economic engine -- a “twofer” for seaweed farming.
Mar 20 2022