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.
No place is safe. Trash and pollution make their way into just about every nook and cranny on Earth -- including the deep oceans. A few years ago, for example, explorers found a plastic bag in the Mariana Trench, the lowest spot on the entire planet. And in 2020, scientists reported that organisms in two ocean trenches contained high levels of mercury -- most of which was produced by human activities.
Mercury is pumped into the atmosphere by coal-fired power plants, silver mines, and other facilities. It can waft high into the air, where it can travel thousands of miles before settling to the land or oceans. It’s ingested by microscopic organisms. They convert it to an especially nasty form, known as methyl-mercury, which can cause birth defects and other health problems.
In the oceans, larger organisms eat the microscopic ones. So the mercury works its way through the food chain. When the larger organisms die, their remains drop to the bottom.
Researchers sampled life from depths of more than six miles in two trenches in the Pacific Ocean -- the Mariana and the Kermadec. And they found that levels of mercury in the sampled animals were similar to those found in fish from closer to the surface, where there should be more mercury. They also found that the mercury came mainly from human activities. That suggests that dead fish carry mercury from near the surface all the way to the bottom. So even the deepest parts of the oceans can’t escape this nasty element.
The giant squid is one of the biggest animals in the oceans. A typical adult is 35 or 40 feet long, and some are even bigger. Yet it’s almost never seen. Much of what we know about the creature comes from dead ones that washed up on shore. Only a few have been photographed alive and well in the oceans.
In 2018, though, a research team easily detected the giant squid’s presence in the Sea of Japan -- through molecules of its DNA in the water. The technique could help scientists keep tabs on the squid population throughout the world.
In fact, eDNA -- “e” for “environmental” -- could help keep tabs on just about all marine life. Every organism sheds bits of DNA -- through its wastes or dead skin cells, for example. Marine scientists could scoop up a bucket of water from anywhere, then test it against a library of genetic “barcodes” for the DNA of just about any creature they could think of -- like a cashier checking out an order of groceries.
E-DNA could be used to monitor the populations of fisheries, track endangered species, determine the impacts of oil spills and other environmental problems, and much more. A recent test in the waters off New Jersey found there was a good match between the species caught in nets and those identified through their DNA in the water. And as technology matures, the match is expected to get even better. That will allow scientists to keep their “eyes” on animals throughout the world’s oceans -- even the elusive giant squid.
Melting glaciers are a big problem. As their water pours into the oceans, it raises the global sea level -- a problem that will get worse in the years ahead. But they could trigger more immediate problems for people who live near them: tsunamis.
As our planet warms up, glaciers are getting thinner. And they’re backing away from the coastline, exposing land that might have been covered up for millennia. Such land might be unstable, so it could create a massive landslide. As the rocks and dirt slam into the ocean, they could generate a tsunami that would ripple along the coastline and beyond.
Researchers studied that possibility in Prince William Sound in southeastern Alaska. It’s best known as the site of the Exxon Valdez oil spill, in 1989. Today, it’s ringed by several small towns. In non-COVID times, it’s a popular spot for cruise ships and other visitors.
A glacier on an inlet known as Barry Arm Fjord has been trickling away for decades. Researchers used satellites to track its retreat, and computer models to simulate what might happen in the years ahead.
They found that the exposed slope at the edge of the glacier has slipped by about 400 feet in the last few years. And an earthquake or other big event could cause it to plunge into the sound in seconds -- generating a tsunami. It could overwhelm the settlements on the sound. And it could churn up oil at the bottom of the sound left over from the Exxon Valdez -- just one more possible problem from melting glaciers.
Anyone whose quiet afternoon at the beach has been disturbed by loud boats will feel sympathy for the male oyster toadfish. Boats can overwhelm its call to females. And it can get the fish all mixed up as well, causing it to change its call or even clam up for hours.
The oyster toadfish isn’t the most sympathetic looking creature in the sea. It’s about a foot long, with a big head, a body covered in mucus and warts, a powerful bite, and spines on its back that are venomous. It lives in shallow bays and estuaries, mainly around oyster reefs. It’s found along the East Coast, mainly from Cape Cod to Florida.
When it’s time to mate, the male toadfish builds a nest on the sea bed. When the nest is ready, the fish emits a loud call. It’s called a boatwhistle, although it sounds more like a foghorn.
The female swims over the nest of her selected mate and lays her eggs. The male watches over them until they hatch, then keeps an eye on the youngsters for a few weeks more.
A recent study, though, found that boats and other human-created sounds may disrupt that cycle. Researchers listened in to the calls of oyster toadfish in a saltwater pond on the coast of Massachusetts. They found that when boats were zipping through the pond, their engines overpowered the toadfish calls. The fish then changed their calls, or stayed quiet. The changes lasted for hours. So loud boats could keep toadfish apart -- perhaps cutting the populations of these ugly little fish.
Blue dragons are among nature’s most efficient recyclers. But what they’re recycling, you don’t want. They absorb the stinging cells of the Portuguese man o’ war and similar creatures, then use them to deliver a nasty sting of their own.
Blue dragons are a type of sea slug. They’re small and elegant -- about an inch long, with wing-like structures that make them look like angels. And they have a shimmering blue color scheme that gives them their formal name: Glaucus atlanticus -- the blue one of the Atlantic.
The little critters inhale a bubble of air that allows them to float at the top of the ocean. In fact, they “hang” upside down from the ocean surface. One side of the dragon’s body is blue-white, while the other is darker blue and silver. That allows it to blend into the sky or the ocean, depending on the viewing angle.
That’s one way the blue dragon stays safe from predators. Another is its powerful sting. Blue dragons eat the man o’ war -- a jellyfish-looking organism with tentacles that extend deep into the water. The tentacles are lined with cells that contain venom. The venom doesn’t affect the blue dragon. Instead, the dragon digests the edible parts of the tentacles, and absorbs the stinging cells. It stores them in small sacs in the “fingers” at the end of its wing-like appendages. When it’s threatened, it stings. And since it stores many cells in each sac, its sting can be more potent than that of the man o’ war -- an efficient but nasty bit of recycling.
The 2020 hurricane season was a mean one. It produced 30 named storms, which was a new record. Thirteen of the storms became hurricanes, which was tied for the second most on record. A dozen storms hit the United States -- another record. And combined, the storms produced an estimated 37 billion dollars in damages.
Some of the damage occurred far inland, as heavy rains produced massive floods. And according to a recent study, the inland damage could get even worse in the years ahead. That’s because a warmer climate is causing storms to weaken more slowly after they hit land. They come ashore absolutely “soaking” wet, so they produce heavy rains for a lot longer.
Researchers looked at records of tropical storms in the North Atlantic over the last 50 years. They found that in the early 1960s, the storms lost three-quarters of their “punch” in the first 24 hours after coming ashore. Storms in recent years, though, lost only half of their intensity during that first day.
Computer simulations of storms produced a likely reason for the difference: warmer oceans. Warmer water produces more evaporation, which is what powers big tropical storm systems. So when a storm that was born over a warmer ocean hits the shore, it holds a lot more water than the storms of a half-century ago. That provides the “juice” to keep a tropical system going long after it hits land -- putting regions far from the ocean at greater risk of dangerous flooding.