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.
Killer whales are a bit provincial. They’re split into small regional populations that stay on their own -- they almost never interact with others. The smallest of these groups is the Southern Resident population. It’s found in the Pacific Northwest. There are so few of the whales that they’re listed as an endangered species.
The population is split into three smaller groups, known as pods. Each pod consists of several families, which are headed by older females. Each pod has its own range, and even its own dialect.
All three pods spend most of the year around Washington’s Puget Sound, where they gorge on Chinook salmon. During the winter, though, they range far afield. Whales have been tracked as far north as Alaska and as far south as central California -- up to thousands of miles in a single season.
The total population of Southern Residents has never been big. Estimates say there probably were a couple of hundred of them in the 19th century. But whaling, plus capture for marine parks, drastically reduced the numbers. New protection policies produced a rebound, but it didn’t last. In recent years, the number of whales has remained in the mid-70s. There have been few new births, and there are more newborn males than females, which makes it harder to rebuild the population.
To add to their woes, the number of salmon has gone down, while pollution and boat noise have gone up -- increasing the pressure on this isolated group of killer whales.
Even if you live a thousand miles from the ocean, it still has an impact on your life. It provides food, fuel, and other resources. It’s a “superhighway” for transporting goods between countries. It provides jobs and attracts tourists. And it offers some of the most beautiful views on the planet. In short, it’s a critical resource -- and a common heritage -- for everyone on Earth.
A United Nations program is designed to preserve some of that heritage. It’s designated 50 World Heritage marine sites in 37 countries. They’re scattered across the whole planet.
To receive that designation, a site has to offer a unique ecosystem, a wide variety of life, special geological processes, or what the U.N. calls “incomparable” beauty. The list includes some sites that would be on just about anyone’s roster of outstanding ocean resources -- the Great Barrier Reef in Australia, for example, or the Galapagos Islands off the coast of South America. But it also includes lesser-known sites in such far-flung locales as Belize, Vietnam, Iceland, and Yemen. There are three sites in the United States: the Everglades in Florida, plus giant sites in Alaska and Hawaii.
In 2005, the U.N. added a management program to help keep the sites going. It keeps an eye on how countries protect the sites, studies how climate change is affecting them, and helps managers at different locations trade tips and ideas -- preserving some pieces of a shared heritage.
Jellybeans on a Reef
The smallest fish on coral reefs appear to have two main jobs. One is to make more fish. And the other is to get eaten.
These little guys are known as cryptobenthic reef fishes. “Crypto” indicates that they’re mostly hidden, and “benthic” means they stay close to the ocean floor. Most are no more than half an inch long. They include thousands of species across many families. And because they’re so tiny and colorful, they’re sometimes called the Skittles or jellybeans of the reef.
Marine biologists have been paying attention to these fish in recent decades. They’ve found that there are lots of them. They may account for half of the total number of fish on a reef. And they don’t go far. Adults seldom range more than a couple of feet. And even the larvae, which in most species can travel hundreds of miles through the ocean, appear to stay within a few miles of their home reef.
Cryptobenthic fish live in tiny nooks and crannies in the reefs. Some of them avoid getting eaten by mimicking other organisms, or by producing chemicals that keep the predators away. Even so, the fish are a major food source: They may account for more than 50 percent of the total mass of all fish eaten on a reef. That makes them a vital link in the food chain.
Like most other reef organisms, they face some big problems: loss of habitat, climate change, pollution, and invasive species, among others. Their loss could leave the bigger organisms on a reef feeling a lot hungrier.
You can’t hide from satellites -- especially if you stain the ground with large patches of poo. Of course, it helps if the ground is the pure white snow and ice of Antarctica.
Scientists have used these brown stains to locate more than half of the colonies of emperor penguins. Because a colony can contain thousands of penguins, the patches of poo can be quite large.
Emperor penguins are the largest of all penguins. They stand about four feet tall, and can weigh 85 pounds. They live in colonies on sea ice around the coastline of Antarctica. Each colony spends about nine months of the year on the same patch of ice -- one reason they leave easy-to-see stains.
Before 2009, scientists had found only about 30 colonies. But that year, they started using satellites and airplanes to find patches of poo, known as guano. That almost doubled the number of known colonies.
And in 2020, they reported the discovery of eight more colonies. The scientists used images from a satellite that has higher-resolution cameras than earlier satellites. That allowed them to spot smaller patches of guano, which are produced by smaller colonies.
With those discoveries, scientists have cataloged 61 colonies of emperor penguins, with a total population of more than half a million. But if Earth’s climate keeps changing at its current pace, much of the ice they live on could vanish. That could slash the population by 80 percent by the end of the century -- a number that could scare the guano out of any penguin.
Polycyclic aromatic hydrocarbons -- PAHs -- are compounds that can be both good and bad. On the good side, they form the “bark” on a slice of brisket, which adds flavor. On the bad side, they can cause cancer, so it’s best to avoid them.
PAHs are also bad for young fiddler crabs. In combination with direct sunlight, in fact, they’re killers.
PAHs are among the compounds found in crude oil. When oil spills into the ocean, some of it settles to the bottom. Many of the compounds in the oil can remain in the sediments for years. None of those compounds is good for marine life. And PAHs are especially bad.
A recent study found that juvenile fiddler crabs are among the organisms at risk from them. Researchers placed adult crabs that were ready to reproduce in tanks. The sediments at the bottom of the tanks contained PAHs, at levels that might be seen a few years after an oil spill.
Female crabs carry their eggs outside their bodies. So as the crabs burrow, their eggs are exposed to whatever chemicals are mixed with the sediments.
When the eggs hatch, the juveniles spend most of their time near the surface, where they’re exposed to sunlight. And the ultraviolet rays in the sunlight can cause a toxic reaction.
The study found that adult crabs didn’t seem to be harmed by the combination of PAHs and sunlight. And neither did juveniles that weren’t exposed to the light. But most of the juveniles that did see strong daylight died -- victims of a toxic combination.
Dozens of mermaids MERMAIDS drift with the currents of the South Pacific. They listen for the rumble of earthquakes on the ocean floor. Then they pop to the surface to tell seismologists what they’ve heard.
These MERMAIDS don’t have flippers, though. They’re scientific devices: Mobile Earthquake Recorder in Marine Areas by Independent Divers -- MERMAIDS.
Seismologists record earthquakes to learn what’s happening below Earth’s surface. Sound waves bounce around inside the planet. Recording those waves from many locations allows the scientists to map what’s below the surface.
There aren’t many recording stations on the ocean floor, though. But there’s a lot of activity below the oceans. The plates that make up Earth’s crust move apart there, and new crust forms as molten rock bubbles up from below.
MERMAIDS were designed to provide a fairly cheap way to monitor ocean earthquakes. Each probe drifts a mile or more below the surface. A microphone listens for quakes. When it hears a possible quake, it rises to the surface and beams its readings to scientists via satellite. MERMAIDS also record water temperatures, and using GPS to track their position allows scientists to trace the currents.
In one early experiment, MERMAIDS monitored the waters around the Galapagos Islands for two years. Their observations revealed a giant mass of hot rock pushing upward from deep in the mantle.
Today, about 60 MERMAIDS are operating in the southern Pacific Ocean -- listening for rumbles below the sea.